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VW 910/ 921 - Dr. Westerboer

1. 68 6 Statistics and data storage suuuessss 69 6 1 The VW921 Storage Memory Organization 70 6 1 1 The record storage siensnernernennoin in n nenne 70 6 1 2 The st tistics St ra iss oeiee epiteni eapon es 72 6 1 3 The flight log book storage eeen 74 6 1 3 1 The flight number eee 74 6 1 3 2 The flight date eese 75 6 1 3 3 The takeoff time essen 75 6 1 3 5 The flight time essent 76 6 1 3 6 Managing the statistics storage sess 76 6 2 The serial interface linen i a t i Gri eai 78 6 2 1 Printing of the statistics data eee 79 6 2 2 Printing the Flight Log book eeeeee 83 6 2 3 Data output format during the flight 83 7 Miscellaneous esses enema 86 7 1 Installation none enero ete 86 7 2 Compensati m z outre ie eet 89 7 3 Compass Compensation csecesseccesreeesseeceseeceseeceseeeesaeeesaeers 92 7 4 Selecting the Glider Model and its Polar 92 1 System Overview The core of the Variometer is wholly and newly developed absolute and differential pressure sensor It consists of two metal membranes adjacent to each other which produce travel proportional to pressure The travel is measured using semiconductors which react
2. Fig of 5 1 1 2 Grouping of the flights in the record storage since even long flights hold only 40 to 50 event records All flights are stored with complete event records in the record memory marked with the same flight number as in the flight log book For example in the record storage the flights are marked in the following way 71 11 01 97 The last flight is flight 143 flight 142 reached the end of the record storage memory and continued to write to the beginning of the memory The oldest recorded flight was flight 132 The next flight 144 will begin at record 44 The sixth event of the flight is the take off time when the events of the oldest flight 132 are overwritten Then the whole flight record is deleted and this part of the memory is freed The process can be repeated several times during a long flight where the short old flights will be overwritten Because of this dynamic memory management it is not possible to define the number of flights which are readable from the statistics analysis The largest number of flights is the same as stored in the flight log book storage max 15 flights With very long flights this number will be reduced accordingly The record storage is not accessible by the user you can access the data only through the statistics display mode thru a printout or downloading it to another computer You have to load each single flight into the Statistics storage memory 6 1 2 The stat
3. active leg bearing of momentary position to the active turn point n a En NODUM pn activebearingn 1 0 UR The active bearing value displayed again in menu position 1 0 with lower case characters ee aN ee ee a a e T Temperature C 0 5UR 13 0 C optional Displays the temperature at the Temperature sensor location E gy ee Sn Leg n 3 n DL S6 0 0 or 2 n DL The already covered distance of leg n If the valid start and end point were over flown Sn will be set to the programmed value When the active route is displayed with GPS reception only the course line route is recognized as completed It is displayed as one of these 3 signs inactive leg active leg no flight signal active leg in flight PNCURGOGU Mc Ly active leg n d DL s3 23 8 2 0 DL The already covered distance on the active leg 1 eu 23 11 01 97 S Nu The sum of all the already covered legs Sto Flight speed sensor 0 Sto distance 283 Here the total nautical mile performance is summed from the flight speed sensor and the circle glide switch which received signals and analyzed them since takeoff t Flight time 0 4UR t 3 41 0 0 DL 0 0 UR TRK Track 0 SUR TRK 2199 TRK The Track is the current movement direction over the ground Wind shifting and the alike in opposition to compass direction are not considered Time hh mm 0 4 DL programmable The programmable re
4. 25 11 01 97 with GPS From the real flight route above the ground and the flight route in the air the wind component is calculated over the last 10 20 independent of AV without GPS The wind component is calculated from the exact correction of the distances on the route section In both cases the value is only received if the flight route is in the direction of the target point 3 4 The statistics mode Thanks to the development of inexpensive memory chips it is now possible to record all the data which the computer handles during a long cross country flight process it and make it accessible to the pilot either during or more usually after the flight In this way the computer becomes a flight data recorder which is far superior to the conventional time height barograph trace in terms of both resolution and the sheer wealth of numeric information contained The statistics mode is a display mode in which the display alone changes all other processes run in the background unaffected and continuously This special display mode is activated by switching the Statistic Final Glide switch 8 up to S position The majority of the recorded data is available for display during the flight The displayed menu matrix already familiar from the normal or Cross country mode has been expanded with a 3rd dimension A descriptive illustration is shown in the three dimensional statistics matrix in Appendix Al Contrary to menu matrix
5. 37 11 01 97 For this reason it is very important to familiarize your self with all possibilities of the altimeter adjustment Of notable importance is the QFE altitude the adjustment is performed automatically when powered up and no correction is required The other important altitude is the QNH altitude A This agrees with the altimeter information if you adjust this to the airport altitude before takeoff The QFE altitude is the reference altitude for final glide it can be adjusted during flight in menu position 0 1 if the barometric pressure changes In order to enter the changes it is temporarily necessary to leave the final glide mode but this should not cause problems since all current data remains in the memory The potential energy is equivalent to 121 feet altitude which is necessary for the total energy altimeter to guarantee a minimum arrival speed of 54 knots h It is accounted for automatically when the unit is turned on O ft translates therefore into 121 feet on the total energy altimeter calculated to standard atmosphere and without temperature correction The altimeter information helps especially in the mountains to scan for obstacles passes etc Therefore you should pay attention to it before takeoff Make sure the QNH altitude menu position of 0 2 DL is set on the altitude of the takeoff airport An exact altitude adjustment does pay off especially if your destination airport has a different altitude
6. to the right The appear if no GPS reception is available e a a RUP CREDI Speed difference 0 9 DR h only available with GPS reception The difference between the air speed and the ground speed V in linear flight this value is a measurement for the instant wind component This value is evaluated with a relatively short integration time 5 seconds The computer can only give valid information if during the integration time a straight flight path is flown to the turn point This Wind component is especially valuable if it is compared with the wholly independent long time integration wind component received in the position 0 9 DL EMEN CNN eee Lol adum I ER at GPS reception 2 10 E120705 This display quadrant displays the coordinates of the momentary position The information is displayed in degrees minutes seconds but without punctuation between the values rer ee NUR PEN Bat Battery voltage V 0 5DL Bat 0 0 12 4V This display quadrant displays the charge condition of the battery It should be checked with simultaneous activation of the radio transmit button ESSE QUE TUMPENIECECECENCNEEINE JOUER a o Bearing is always understood as the bearing on the activated turn point always identical with Sn n being an active route number PX MMC NEM a ere MT Distance n 1 n DL D6 without GPS reception 23 8 programmable 20 Distance is always understood as the yet to fly route It is
7. D40 DG200 GF402 ClubAs Janti LSif SB5 DG2i7 GF604 SpeedA Jan Ls3_ SB9 DGS300 Homet TwinAS StdJan LS3a SBi DG400 kesti9 Twins SZD55 LS3 17 DG47 Kest SZD56 LS39td NENNEN 1 f DG5i8 Moqi tS 1 j DGs20 jStdib fise L1 St es a ee ee 1 93 11 01 97
8. Gi 3 0 0 50 0 4050 1200 11 18 05 00 B 2 50 0 1 8 2250 3300 11 23 10 00 G 4 51 0 29 0 4050 3300 11 33 20 00 B 3 80 0 Tou 750 3000 11 531 10 00 G 5 80 0 40 013750 150 12 03 05 00 Ck COO Kk ck ck Ko KO Ko Kk Ko Ko KK Kk Kk Kk KK Ko KK KK Kk Kk Kk KR X KC kockck k ko ck ck ck ck Start route 2 CK COO Kok ck ck Ko KO Kk okockockokokockck ck ko ko ok ockock ck ck k ck kock ok ck ck k ck kokok G 6 120 0 30 0 3300 850 12 08 05 00 B 4 1 150 0 2 b5 50 750 T12213 05 00 G 37 170 0 30 0 3000 750 12 18 25 00 p db db db di dir dir dir db db db dir dir dir db dir dir dir dir di dio di dir dir dir dio di db dir dir dir dir di dio dio dir dir dir dir dir d Landg 200 750 12 43 81 11 01 97 Dr s Westerboer Hofhansel GmbH Weiden Fig of 5 2 1 Expression the statistics of a flight In the first length of the expression you find a form part to the registration of general data of the flight The second part shows all TIMES absolute in hours minutes and relatively in percent The next length covers the ROUTES and SPEEDS of the single route lengths and the total route In the last display mode of this real reached prints Glide number The fourth length includes following data Altitude gains altogether in all registers number of the registers number of the Cruise sections Average Climbs all registers Maximum Climbs strongest register with No the register Altitude gains into the strongest re
9. Hofhansel GmbH Weiden VW of 921 statistics Date Thursday 12 September of 1993 Way of the fly Pilot Airplane Takeoff 1 Turnpoint Landing TIMES Flight time total 2 00 h 141 Boute flight time 1 25 h 7 1004 Climb portion 0 25 n 29 Glide portion xbs00 boy LIS ROUTES SPEEDS route TAS GS nm knots h knots h Total route S tot 108 0 355 22 76 2 Route S of 1 64 8 OA 71 8 Route S of 2 43 2 68 6 74 0 Mc trip 87 knots h Glide ratio E 41 CLIMBS Thermal No Altitude gains total 11550 ft Jall 80 Number of the thermals 4 Cruise sections 7 Average Climbs 420 ft s all Maximum Climbs 660 ft s 1 Altitude gain w M max 3000 ft 1 Max Altitude gain 3300 ft 2 B climbs dAmax 360 ft s 2 THERMALS CRUISE SECTION dS alt dA Time dT No nm ft ft mm ss Takeoff 0 0 750 3000 208 G 0 0 0 0 1250 3000 53 15 00 B 0 03 3 2501 3000 08 05 00 G 2 0 0 0 0 3750 1800 13 05 00 Ck COO Kock ck ck OK Ko Kok ko KK KKK ko ko ok ockockock ko ck ck kockock ck ck k ck kokk Start route 1 Ck COO Kok ck ck Ko KO Ko KK o Ko Ko Kok Kk ko KK KR KK KK Kk Kk KK KR X Kk Kk ko Kk ko ko kc kck ck
10. displayed with these three symbols inactive leg distance between Turn point of n 1 and Turn point n _ active leg as a track over the ground v active leg distance of momentary position to the active turn point n er DL 84 9 case characters ea we ee aaa Total distance aa 1 10D 32 8 The Total distance is the sum of all partial distances In this category the total route length is found It includes your current leg what you previously flew and what is programmed but not yet flown The same nautical miles value received into the final slide as AE Ee Sree ee ee ee et programmable t DL The programmed Wing Loading can also be used as a correction algorithm Chapter 3 3 2 and the programmed value modified ed QFE altitude 0 1 DL h programmable 0 0 OR 0 0 DL 1 2 11 01 97 The QFE altitude is the relative altitude referenced to the base airport altitude resets automatically to 0 ft at power up this automatic 0 ft of the QFE altitude must be programmed with the airport altitude and stays on the programmed value until power off after take off and reaching a total energy pressure from the air speed of 54 knots h a reference value of 131ft is added 131 ft equivalent altitude this altitude is the reference altitude for the final glide it can be adjusted during the flight in menu position 0 1 if the barometric pressure changes Eo MENU ee INE ONE A QNH altitude ft 0 2DL
11. eene 28 3 5 The final glide mode eene 36 3 6 The Altimeter none eee 37 4 Measuring Distances eeeeeeseeeeeeeeeneennnnnnnnnns 40 AT Distance2S1Zes iiie peine betta teet ea 40 4 2 General Operation kee ee ae a un Eens eE nennen 42 42 Start ota TOUte nara aeea ve ean ARE 42 4 2 2 Reactivating a route ceesseseseeeeeeeeeen eren 43 4 2 3 Erasure of the Distance storage eeeeee 44 4 3 Management of the routes eee eeeeeeeeecsneeceneeseseeeeeeeeesaeeesneers 45 4 3 1 The route mode with GPS linkage ees 45 4 3 2 The distance mode without GPS linkage 51 5 Fihal glide erre 54 Sok The Setup Process te teet tt ore tetto eet 55 5 2 Applications for the final glide mode 57 5 3 Final glide without active GPS linkage sesssss 60 5 4 Final glide with active GPS linkage eee 66 2 5 5 Final glide in the Task mode eene 66 4 4 Case examples Cruise flight mode esee 68 4 4 1 Triangle flight in the GPS task mode 68 4 4 2 Multiple legs and GPS Goal Flight Mode 68 4 4 3 Cruise with intermittent GPS Dropout 68 4 4 4 Programming of curses with multiple laps
12. you can select a glider model with a worse polar despite the short power off the flight data stays stored The Wind component is selected with the rotary knob 6 Turning it to the left select a maximum range of 25 knots h head wind and to the right a maximum range of 25 knots h back wind The raster resolution value is 1 knots h For correct wind component selection for the VW921 has different recommendations that are available to help in choosing the correct wind component that should be supported For several reasons the final decision is left for the pilot In well known wind shear i e in valleys or mountains deviations from the recommended values are already in the setup to be regarded In final glide over the last turn point the last leg in most cases has a wholly different wind component as the momentary value The wind component can be used as an additional security component In that one can select more or less head wind Bad news for last Calculation mistakes detour mistakes etc can lead to an unrealistic wind component setup The end result is a total over or under calculation of your final glide altitude reserves Out of these introduced final glide components the VW921 immediately calculates the glide angle of your glider and over the total distance you also receive the altitude required for a successful final glide For security reasons the VW921 adds 300 ft to this altitude Now you only
13. 113 is followed by 114 At the statistics menu position 89 5 you are able to set the preferred flight number The setup procedure is only required for the first time It is recommended that you select the next available number from your sail plane log book To set the flight number select S9 5 with switch 8 to S position the MENU rotary switch to position 9 and the MC rotary switch to position eg Pressing switch 10 twice to the ENT position you set the number for the last flight to 1 74 C 0 0 Log 135 FlightNr 1 To set the flight number to a preferred number you have to enter the correction mode by pressing switch 10 to KORR position The display will blink with the message Flight no C 0 0 Log 135 FlightNr 135 Now by pressing switch 9 to or position you modify and by pressing switch 10 to ENT you select the preferred start flight number for the last flight All the previous flights will be renumbered respectively 6 1 3 2 The flight date For each flight number you can find the flight date in the statistics menu position S9 0 dd mm yy C 0 0 Log 135 Date 12 09 93 6 1 3 3 The takeoff time For each flight number you can find the associated take off time in the statistics menu position S9 1 C 0 0 Log 135 TakeOff 10 43 01 6 1 3 4 The Time of Landing For each flight number you can find the associated landing time in the statistics menu position S9 2 7
14. 43 Management of the routes 4 3 1 The route mode with GPS linkage In cases with GPS linkage there are two different GPS operation modes possible that also affect the handling of the routes in the VW921 flight computer The first mode uses consecutive input of different turn points titled in the handbook goal flight mode When you have reached a turn point the consecutive is automatically switched and displayed In the computer language and GPS world we frequently find the concept of a GOTO function or turn point function In the second mode the whole task is programmed into the GPS memory subsequently named task mode While it appears simpler and more user friendly to work mainly with the task mode the goal flight mode is nevertheless frequently used especially with modifying e g decrease the task The VW921 flight computer automatically recognizes if it has been connected to a GPS receiver It also recognizes if the GPS receiver is programmed in the goal flight mode or in the task mode The task mode gets a higher priority As soon as the task mode is activated in the GPS receiver the VW921 takes over the entire task and locks on to that task In this way the GPS receiver has a second complete navigational computer to use The VW921 holds the original task this allows the GPS receiver to do other tasks in the non function mode For example the next turn points can be executed or just to experiment in a Double seated glider
15. A special advantage is the help function emergency function nearest way points with that you can receive instant data for final glide or the next closest airport 45 11 01 97 1 Task mode N N Fig 4 3 1 1 Schematic depiction of the indicated sizes at active route of leg 1 S1 distance D1 TRK track course over ground P1 BRG bearing bearing to the turn point of TP2 distance D2 distance from TP2 to the turn point TP3 yet not active bearing of P2 is the bearing between both these points In the task mode the first programmed point is the start or origin point all other turn points are to be programmed sequentially For multiple laps way points must be entered multiple times into the GPS receiver Computers with the software version C there are only 9 turn points in the VW921 that can be managed Unfortunately a triple go around with takeoff out of the middle is not easily programmed Software version D Up to 15 part routes programmable whereby this task variation is possible As soon as the start line is flown over press the switch 10 to ENT position for more than 11 2 seconds this starts leg S1 The course over the ground goes from the start turn point 1 to turn point 2 on the task list For the route arithmetic only the route component is regarded which lies parallel to the course line The route speed derives itself out of the route component The distance to the turn 46 point is the d
16. analogously How can you check if the VW921 works with the right turn point data First of all in column 0 of the distance row menu position 1 or route display mode display mode 3 you can find out which route is active the number after the lowercase letter Turn the menu selector knob 4 to this position With the active route no 3 approaching the third turn point the following is displayed N 0 7 xo 3 1 3 D3 73 8 P3 112 In the status display row the active route D3 and the turn point P3 is displayed Non active routes would be displayed with a double apostrophe In the top right display quadrant the approaching turn point with name and the coordinates underneath are displayed In the next menu knob 4 position you receive the goal coordinates from the GPS receiver While both are identical this is displayed twice consecutively You can change the coordinates in GPS receiver without problems the VW921 will still lead you on the original coordinates When coordinates of the following turn point are inputted in to the GPS receiver they change themselves after a delay to the inputted coordinates In the distance row the distance between turn point 3 and turn point 4 is displayed in this example after D4 and after P4 of the course angle between both these points If the GPS receiver is pointing right to the next turn point it also matches the information for the photo sector At start of the next route in this case
17. bisector as well as the photo sector Contrary to your original plan because the flight necessitates you intend to approach a point in the terrain with a distinct altitude i e with the following possible events 1 In the mountains you want to cross over a valley with a fixed arrival altitude above the opposite ridge 2 You can not find more thermals You break off your task and want to land on the next airport and therefore change the goal 3 A long glide lies before you over a thermal dead area which you want to traverse with a fixed arrival altitude 4 While in a cruise flight during the local championship you realize that the planned task can t be completed in time and you want to go back the fastest way to your home airport last turn point into the task mode The first three cases use the following method to solve the task In the GPS receiver the next intended turn point is invoked with the goal flight mode This function is supported differently in GPS models In the GARMIN receiver the next closest turn points are displayed through the function NEAREST WAY POINTS The Filser GPS at the Emergency function chooses the next flight places out of the total list After activation of the GPS goal you wait a moment about 2 seconds so that the data is transferred right into the flight computer Thereupon by pressing ENT and for about 1 5 seconds the hitherto existing assignment is deactivated and the GPS goa
18. interested on flight 134 the incomplete triangle task To reach the statistics data for flight 134 you select with switch 8 the S mode turn the MENU knob to position 9 and the MC knob to position 4 you selected the statistics menu position S9 4 The display shows C 0 0 Log 135 in memory Pressing switch 9 to position selects flight 134 To make sure that you selected the right flight number turn the MC knob through positions 0 to 3 and check the flight date flight time for take off and landing After re selecting MC position 4 the display again shows C 40 0 Log 134 in memory Briefly press switch 10 to the ENT position then the display shows the message C 0 0 Log 134 in memory Now you are able to browse through the flight 134 data see chapter 3 4 or you are able to print the same data through the serial port see chapter 6 2 6 2 The serial interface The flight computer is equipped with a serial interface for the various communication assignments that can be used These assignments include Printing of statistics data in the statistics storage Printing the flight data from the last 15 flights reception of the GPS data from a GPS downloading turn point data to the VW921 as of version D 78 output of the basic data from the flight computer in one second intervals time coordinates variometer signal altitude while at flight to a data recorder with
19. lengths before the flight The counting of the miles occurs backwards towards null or the flown routes become negative In this event the displayed values for the route S and the distance D are identical except for the minus sign In the second event you give up the information as far as the route yet to fly The programming of the route mileage is 51 11 01 97 only possible in single distances of D1 through D15 Df the sum of the programmed distance is stored automatically in DX The programming procedure is the same as making a correction see Chapter 3 3 2 You choose the distance row with the help of the toggle switch 9 With the menu selector knob 4 select the single distance in the display and program correct this by pressing the KORR toggle switch 10 to the KORR position and with the toggle switch 9 enter the programmed value by pressing switch 10 to the ENT position This procedure should be repeated for each single distance that you want to put into your route Prepare the map with the course route and distances marked this will help you orient yourself quickly This will help you to better estimate the flight time so as to avoid unnecessary risk due to flying too fast You can check your engaged wind component on the respective route length by comparing the route lengths and the distance markings After each distance correction the flight computer displays a calculated wind value compared to the wind setting of
20. max 8 2240ft Climbs S1 3 Average climb in the registers with maximum altitude gain C 0 0 Climbs d x100 C Amax 3 6ft m Climbs S1 4 Altitude gains in the climb register with 29 11 01 97 maximum climb and associated Lift number C 0 0 Climbs A AACmax 3 1417ft Climbs S1 5 Average climb in the climb registers with maximum climb C 0 0 Climbs dx1o0 C Cmax 7 6ft m Climbs S1 6 Thermalling time during cruise flight in hours and minutes and relatively to the total cruise flight time C 0 0 Climbs t Cl 1 04 23 Climbs S1 7 Number of the recorded thermals C 0 0 Climbs Thermals LE Climbs S1 9 Average climb while in cruise flight with the respective number of the thermals C 0 0 Climbs 4 x100 C 12 4 6ft m Climbs S1 10 Average climb of the last 3 thermals C 0 0 Climbs d x100 C X 3 4 8ft m 30 Row 2 Cruises registers In menu position 2 the Cruise statistics is recorded for each single cruise distance With the toggle switch 9 the single cruise distance of the statistics flight register is selectable S2 0 Nautical miles of the total route length at the start of the Cruise distance C 0 0 Cruises AL Anf 18 116nm S2 1 Nautical miles of the total route length at the end of the Cruise distance C 0 0 Cruises AL End 18 134nm S2 2 Completed route in Cruise section No 18 C 0 0 Cruises AL Nr 18 18 8nm S2 3 Start alt
21. not implemented for the VW92 computer 6 2 3 Data output format during the flight Additional possibility exist to output and store flight data to an external equipment like laptop computer or flight recorder using the serial port 83 11 01 97 The TxD output pin of the female D sub connector has to be connected to the serial port of the recording equipment The data is transmitted in 4800 baud 8 bit no parity mode Each transmitted block holds the following information 1 Byte 1 byte for the Synchronization 2 Byte R data block recognition 3 Byte Flight state Bit 1 Bit 0 Bit of 0 Bit of 1 Airplane in the flight Bit of 2 Airplane lands Bit of 3 Speed to fly mode Bit of 4 climb mode Bit of 5 Bit of 6 Bit of 7 4 6 3 bytes in Time in hours minutes seconds BCD code 7 8 Signed total energy compensated standard pressure altitude Integer Number 9410 Signed average climbs in the last 20 seconds multiplied with 10 Integer Number 11412 Signed exact variometer value multiplied with 10 Integer Number 13414 True Air Speed TAS multiplied with 10 15 16 Unsigned Compass course at option compass linkage Integer Number 17 18 Signed Over ground speed multiplies with 10 at option compass Integer linkage Number 19 20 Unsigned Course over ground Track only at option GPS linkage Integer Number 21 28 Floating Position in length and width only at option GPS linkage Point figure The numbers are carried over in
22. route 4 route 3 at this point is finished and route 4 is determined as the new route between present position and the current GPS goal At the moment of activation of a new route the goal of the VW921 and the GPS receiver is updated so that in the turn point display mode this turn point appears at least twice Once in the active column of the turn point display mode and Once in the next column with the turn point of the GPS receiver This stays up until input of an other turn point into the GPS receiver 49 11 01 97 is received A further advantage of these handling algorithms is the possibility of leading a final glide over a turn point Please note You have two independent units making calculations of the next turn point while you can select and discard any new turn points with the GPS receiver the VW921 flight computer holds steadily towards the old goal until you have selected a new goal with the GPS receiver and validated it through entering the new route In this way you attach a new route to the other and consequently also put a new route together When the turn point is reached it will be logged into the route list as end point of the last route and as start of the newly activated leg The radius is chosen large enough so that it takes into account inaccurate coordinate information to define the turn point as valid The route calculation is applied even if the turn point data incorrect The goal flight mode in the flight co
23. that on the computer display the menu row 3 is selected for to the Menu selector rotary switch Position 2 Matrix column 2 Example N 0 7 c 3 2 S2 0 v2 0 Whit the leg of the flight S2 and the average speed on the section V2 this selection equals to the matrix position in the Menu selection Table 14 3 3 2 Correction of Stored Data Initial values must be entered correctly e g Wing Loading and Airport altitude You will always be dealing with the same routine First select the Display Menu positions with help of the MENU selector knob 4 and the toggle switch followed by the ENT toggle switch Correct the values with the proper knob position and the toggle switch e g the Wing Loading with WingLoad the airport altitude with APT AIti position etc By pressing the KORR toggle switch 10 in the up position the correction mode is selected Toggle the switch 9 to correct the stored value to the preferred current value The correction process is concluded by pressing the toggle switch 10 to ENT The corrected data is now stored in the memory and will not lost by powering down the computer e g the stored airport altitude remains in the memory until you are at another airport and newly reprogram the altitude Example You take off with the standard menu position 0 0 A wing loading of 8 lbs sqft was programmed prior to takeoff Under way the thermals get weaker and you therefore empty the water ball
24. the following numerical format unsigned or signed integer numbers 84 consist of 2 bytes LSB carried over first floating point numbers consist of 4 bytes l st byte Exponent 080H 2 nd byte bit 0 6 Mantissa positions 2 8 bit7 sign 3 rd byte Mantissa positions 9 16 4 th byte Mantissa positions 17 24 The mantissa position 1 behind the decimal point is basically 1 85 11 01 97 7 Miscellaneous 7 1 Installation The glider wiring system must not be live during installation Before starting work disconnect the battery Warning Before any electrical connections are made it is essential that the variometer is switched off i e on off volume knob 1 turned fully contra clockwise Both units are designed to standard dimensions so installation is very easy There is no need for a compensation bottle because of the principle on which the pressure sensor works It is recommended that the computer be located top left on the instrument panel or perhaps in the middle so that it is easy to reach with your left hand see Appendix 9 3 If the compass is mounted in the panel it must be at least 3 2 inches away because of the magnetic field of the variometer If the compass is mounted on top of the pedestal i e on the horizontal surface above the instruments there should be no discrepancies caused by interference Tubing connections are made as follows O the pitot is connected to the DYN static pressure
25. to the magnetic field The sensor produces a voltage signal proportional to this travel in a bridge circuit The signal is up to 100 times stronger than 3 11 01 97 that of the sensors currently available resulting in reduced interference more stable zeroing and excellent reliability The membranes are adjacent to each other and so compensate for any travel resulting from accelerations and prevent corruption of the signal We have developed these sensors ourselves so they are not available in any other vario system Patent No P3023719 5 09 The Variometer signal is derived from the absolute pressure sensor which produces the altitude signal using electronic differentiation A second sensor provides the pitot pressure signal by measuring the reduction of pressure in accordance with the barometric pressure altitude formula To ensure that error free compensation is maintained the altitude signal corrects the pitot pressure signal value This means that compensation is achieved without a total energy compensation jet and is exact at any altitude An electronic filter with a time constant of 1 2 seconds smoothes out both the Variometer display and also the audio Variometer output dual tone audio vario 1 Q 3 2 2 4 5 6 7 8 mode 9 Description of Controls VW910 Variometer see Fig 1 On Off Volume knob Compensation Zero setting without audio signal VW921 Flight Data
26. will keep a certain security altitude and you must find thermals on the back wind leg on each event For this case it is possible to use the final glide mode For monitoring the security altitude there are two possibilities one you fly generally on a altitude difference AA that is equal to the security altitude i e you must climb that much higher until you can read at least this security altitude as a positive value in the AA Two you set the airport altitude on this security altitude and fly with the goal AA 0 You already know that at the end of the turn point activate the remaining distance by the simultaneous pressing ENT and the airport altitude will be set to the correct value For a flight to a turn point and back to the last thermal source 64 DISTANCE 10 5 ALTITUDE 4590 MC 2 0 WD 2 7 WL 6 1 07727 dA 1670 D 5 3 s Turn point dA 1670 D 0 0 Fig 5 3 2 Flying on to a turn point Example the distance is 5 nm and your altitude is 4590 ft above ground you are programming for a glide of 10 5 nm 0 5 nm for the turn around The AA the displayed altitude 4 300 ft 1s then your return altitude In our event Fig 5 3 2 Flying on to a turn point MC 2 0 WD 2 7 WL 6 75 the results is AA 1670 D 10 5 With the constant of AA other values can be estimated to make sure if your glide path stays within the performance capabilities of your airplane 65 11
27. 01 97 5 4 Final glide with active GPS linkage A comparison between sections 5 3 and 5 4 will assure you that there is practically no major difference in flight with and without active GPS linkage The usage is identical excepting the internal functions distance programming as such and the total reference calculations all distances over ground speeds wind etc In distance programming there is a difference for the task mode or the goal flight mode In the task mode the calculation of the final glide is always referenced to the entire route up until the last programmed turn point While during the goal flight mode only the next or at best the very next turn point is acknowledged so that the final glide can only be predicted up to this point 5 5 Final glide in the Task mode In the task mode it is always possible to get the distance to the last goal AE DX and at the same time for the selected setting MC value Wing load value FP altitude and wind the required altitude If the VW921 is correctly compensated and the above values are set correctly then the negative glide path difference is equal to the required altitude to be gained by thermalling So there is no difference when the final glide mode is invoked before the start before the activation of the first leg in the middle of any legs or during the last leg It is always a good idea to call up the final glide mode after down loading the task from the GPS receiver You can ch
28. 5 11 01 97 C 0 0 Log 135 Landing 12 43 01 If the flight is still in progress the displayed time is 0 C 40 0 Log 135 Landing 00 00 00 6 1 3 5 The flight time For each flight number you can find the associated flight time in the statistics menu position S9 3 C 0 0 Log 135 Fl Time 2 00 00 It is available and continuously updated during the flight 6 1 3 6 Managing the statistics storage The additional flight log book option is located in statistics menu position S9 4 It performs the statistics control and loading the logged flight data into the statistics storage area In chapter 2 2 it was mentioned that in the statistics storage area there is always only one flight data loaded and analyzed Selecting S9 4 during the flight will always display this message C 0 9 xLog 135 no memory The reason is that during flight the present data from the flight occupies the statistics storage area Selecting and reloading old flight data is not possible at this time Before take off or after landing you can find the status of the appropriate flights in this menu position In cases where data in the statistics storage area is loaded from the selected flight number the lower row displays the following 76 C 0 0 Log 135 in memory This information can appear only once only by the flight number presently loaded into the statistics storage area Selecting all the other flight numbers where the flight data
29. 7 WD 0 0 5 4 0 0 EA WDi 4 o X V x Se dA 3630 D 43 0 RD me MC 2 0 7 DISTANCE D 33 5 E F i DISTANCE D 32 4 HA 3410D 27 0 DON i WIND WD 5 4 Hm 27 0 w UN WIND WD 0 0 parse ET SN dA 2880 D 180 MC 1 5 uh 43 NM 32 NM 27 NM 16 NM 0 NM Distance E 5 2 E 3o f 3 3 a E 3 3i 2 3 9 z 4 Where the 43 nm distance circle on the map crosses the canal we start with the final glide On the right bottom display quadrant already appears the final glide distance AE of 43 0 nm This is identical with the remaining distance on d3 D3 60 43 0 nm For an exact final glide analysis it is possibly required to correct the 43 nm value press KORR and or again and at exact over flight of the canal check through lateral control enter the programmed value by pressing ENT Here we get a first orientation which wind until now prevailed We could forget about the altitude value if during the flight no big pressure changes are given and our takeoff airport is identical with the destination airport It is sufficient to compare the displayed altitude with the mechanical altimeter We can ask the nearby flight service station or air traffic control service for information about the barometric pressure using the radio transceiver If a stronger change during the day is entered the altitude correction is performed on the basis of each 0 1 inches of mercury is equal to 100 ft altitud
30. A 823 programmable before the flight The QNH altitude is the total energy compensated altitude over MSL without temperature correction calculated as sum of QFE altitude and airport altitude Elevation the airport altitude is programmable only before flight a programming of the airport altitude during the flight is interpreted as the airport altitude of the destination airport and does not change the QNH altitude but the QFE altitude over this destination airport ae ee Lee altitude Altitude over the 1013 15 mbar level real altitude value of the total energy altimeter calibrated at the factory Pn ee eee ee altitude Also total energy compensated altitude over the 1013 2 mbar level agrees with the real flight altitude i e a displayed value 6000 agrees with a flight level FL of 60 You will find more information regarding altimeter functions in chapter 3 6 The Altimeter 22 MC McCready value ftm OR MC 2 5 temporar 100 Temporary display of the McCready knob position which is shown for approximately 2 seconds to each MC alteration with the MC Knob 5 in the top right display quadrant HONDA ee MEN Bearing n 1 n UR P6 216 only with GPS reception The bearing always gives the right course from turn point to turn point in dependency of the 3 signs lt inactive leg the bearing between Turn point of n 1 and Turn point n _ active leg as a track over the ground
31. Computer 10 position rotary Menu selector switch MC MacCready Value selector rotary switch from 0 0 to 5 0 in steps of 0 5 Wind Component selector rotary switch from 25 knots h to 25 knots h in 2 5 knots h steps Polar Selector Switch P1 Bug contaminated polar P0 Measured polar P2 Rain polar Flight mode Speed to fly Menu selector switch Ss Thermal climb Statistics Mid position Cruise mode EA Final Glide mode Input toggle switch Function 1 Moving the cursor between Display lines 5 11 01 97 Function 2 Increasing reducing of correction values 10 Enter and Correction toggle switch KORR Entry of a correction action ENT Entry of the corrected value 11 Electric vario zeroing screwdriver adjustment for dial instrument and audio 12 Selection of polar see Appendix 9 1 3 Operation 3 1 Powering up the instrument After Power On 1 set up the following one after the other 3 1 1 The VW910 Variometer If the Flight mode Menu selector switch 8 is on S Statistic Thermal position the indicator will deflect fully counter clockwise and subsequently home in on zero in about 20 30 seconds If the Flight mode Menu selector switch 8 is in mid position Cruise mode there will bea deflection of the pointer into the minus sector depending on the MC value and the Polar The audio signal also behaves similarly 3 1 2 The VW921 Flight Data Compute
32. RR position programming mode is then selected It is dependent on the menu selector knob position which glider manufacturer group is displayed for 2 seconds To select a different glider manufacturer group you have to rotate the menu selector knob 4 and with the toggle switch 9 press to select the glider model To enter the selected glider model press switch 10 to the ENT position For each glider model there are three polar curves 1 The normal polar is the optimal polar curve The polar selector switch 7 is in PO the mid position 2 The bug infected polar takes a linear degradation from the normal polar 5 degradation at 43 nm hr and 10 at 86 nm hr Switch 7 position for the bug polar is P1 3 The rain polar takes more degradation from the normal polar 15 at 43 nm hr and 30 at 86 nm hr Switch 7 position for the rain polar is P2 In case you find the degradation higher then the rain polar you can select a polar from a glider with lower performance 92 To do that during the flight turn off the power of the VW92 briefly and choose a different glider model If the power off period was shorter than 1 minute the computer will keep the collected data it will not reinitialized Manu Akaflieg Glazier Glass Grob Polish Rolladen facturer Gliders Dirks 1 fl gel Gliders Schneider Led D38 DGt00 Lib30 AstiCS Cobra lStc D39p_ DG100C GF304 JeansA Janti LSid
33. VW 910 921 Advanced Programmable Flight Data Computer User s Manual English German Translation by Peter Mate of 1994 wh 11 94au th Dr rer nat Aeronautics instruments Westerboer Medicine technology Pr Blstr 18 Hofhansel Industry technology 92637 Weiden i d OPf Tel 0961 26916 amp Cie GmbH Telecommunication Fax 0961 61866 Contents 2 Description of Controls eere eere 5 2 1 VW910 Variometer see Fig 1 5 2 2 VW921 Flight Data Computer eene 5 3 OpetatlOn enn It 7 3 1 Powering up the instrument sese een 7 3 1 1 The VW910 Variometer eene 7 3 1 2 The VW921 Flight Data Computer eene 7 3 2 The Variometer D t 4 tede rte etd 9 3 3 The Normal or Cross country mode eee 13 3 3 1 Display Mode in the Normal or Cross country mode 13 The Menu position 3 2 meant that on the computer display the menu row 3 is selected for to the Menu selector rotary switch Position 2 Matrix column 2 eeeeeeeeeeeeeeeen rennen 14 3 3 2 Correction of Stored Data sseeeeeee 15 3 3 3 Freely programmable display menu position 0 0 17 3 3 4 Display quadrants in the Cross country mode 19 3 4 The statistics mode eeesssesese seen 26 3 4 1 Statistics Matrix Display ROWS
34. a can be loaded for these flights into the foreground and analyzed 6 1 1 The record storage For reconstruction of the flights for statistics purposes the computer has to store all incidents during the flight with location altitude and time The stored data for each flight includes the following events take off time landing time the beginning and ending of each part distance legs the entry and exit points for thermals the start and end points for each glide complementary to each thermal entry and exit point 70 All single events will be stored sequential as raw data into the record storage memory A complete flight has the followine memorv storaee structure apa Ttt N j E EJE x 8 18 88 8 93924 8 z z z sa sajajjia jajlala s a SoProdelfox xF 9 3 o x x x 9 3 Fig of 5 1 1 1 Structure of the record storage The record storage is designed as a ring storage The storage memory is filled with the flight data sequentially until the storage is filled up The new flight data will overwrite the first stored data in the beginning of the memory The record storage capacity is 256 events and it can hold several flights OcA GG O UOsru tu 2 6262 00 TOO YOY w ANAS NUN Tm AM o5 gt a A End Flight 142 i Flight 143 Flight 132 Flight 141 l Start 142 Flight
35. a particular program on a PC or other data recorder 6 2 1 Printing of the statistics data All VW921 computers with the statistics option have a facility for connecting a printer via the serial interface Any printer which has a V24 V28 serial interface can be connected and used for printing out the statistics data Suitable cables are available from the manufacturers The procedure is as follows e After landing turn on the VW910 921 or leave it turned on e The last flight data is in the statistics storage or load the selected record number for printing e Notice that statistics menu position 9 selected in the display then you will print the flight book data and not the flight statistics e Turn off the printer power switch e Connect the serial cable between the VW921 and the printer serial input e Turn on power for the printer The printer handshake will start the printing process The flight statistics data is printed by which all operation steps of the flight computer statistics menu final glide normal or route mode pages in the display mode The printing performed in the background mode and the VW921 is continuously available for other functions If second copy requested the printer stays connected Powering the printer off for gt 10 seconds and repeated power on the computer prints a new copy of the same flight Statistics And so the printout of a flight looks like 79 11 01 97 Dr s Westerboer
36. ack on the stick and shows too little sink or even shows climb It is tending to operate like an uncompensated variometer dashed line 3 in Fig 8 The cause is too little compensation Compensation is increased by turning the compensation adjustment knob 2 anti clockwise e The vario reading falls off when the stick is pulled back and during the transition from V1 to V2 continues to show exaggerated sink values dashed dotted line 4 in Fig 8 The cause is excessive compensation The cure is to turn the compensation adjustment 2 in a clockwise direction NB This adjustment is sensitive even small movements affect the degree of compensation considerably 91 11 01 97 7 3 Compass Compensation Only for flight computers with optional compass linkage Not yet available 7 4 Selecting the Glider Model and its Polar Your VW921 glide computer stores the polar for a wide variety of gliders in its memory Selecting the glider model automatically sets the correct polar In cases where your glider model is missing from the list you can select a glider model with a similar polar The resulting error for the speed to fly value is minimal The pre programmed glider models stored in the VW921 memory are listed in table 7 4 1 Selecting the glider model is performed in the following manner Within the first 10 seconds after powering on the VW92 and the display shows the presently selected glider model press switch 10 to the KO
37. al time clock includes the Time and Date By pressing KORR the programmable value will be displayed Side 1 Hour minute Side 2 weekday day month year and by selecting ENT the corresponding side is stored V True Air Speed TAS knot h 0 6DL v 93 0 0 DL 24 Momentary True Air Speed TAS is the altitude corrected speed in the air Note If you fly higher and faster than the TAS will deviate more from the air speed IAS indicated air speed Vg Leg speed knots 3 n DL or 2 nUR V2 83 The achieved average speed over the ground attained from the respective partial legs altitude variation will correspond to the achieved average Climbs inactive leg active leg no flight signal active leg in flight E m I pue uper eiu vn active leg speed knots h 3 0 UR v2 78 or 9 2 0 UR Active leg speed is displayed only after 15 minutes in the new leg After beginning a new leg for the first 15 minutes the average speed of the last leg is shown 1 The active route has yet no usable results 2 Average speed over ground archived on the last leg eu Average Leg speed sround speed on the previous legs flown and recorded i ea ee ieee ek are ee M NAME WD Wind component knots WD 15 temporar h_ OR Preset the wind component with the Wind knob 6 Following a three second delay the selected value appears on the display after that the display is updated more frequently pe d h
38. are chosen either by the pilot with the SG switch or by the installed magnet switch on the flap push rod see Chapter 6 1 Installation In the first case Thermal and Cruise shows the Variometer round indicator momentary climb or sink rate The display range is of 15 0 feet sec the acoustic range is of 30 0 feet sec At sink rates higher than 30 0 feet sec the tone 9 11 01 97 abandons completely This is not a Variometer error but a warning in an extreme flight situation for example during a wave flight On the top left field of the flight computer display the averaged climb during the last 20 seconds is displayed M 2 4 xxxxxxxx XXXXXXXX XXXXXXXX Current standards in competition flying make a digital display with this type of information necessary An improvement of only 0 2 knots in average rate of climb during a 300 km flight means a gain of about 7 minutes An analog display cannot provide the same degree of accuracy In the second case cruise speed to fly the speed to fly is represented visually by the variometer and acoustically by the audio variometer If the variometer reading and the audio tone are in the minus range fly faster inthe plus range fly slower You are flying at the optimum speed when zero is displayed and the audio tone is intermittent We have intentionally not left a window of silence around the optimum speed to fly The pilot would not know whether he should fl
39. ast thereby reduce wing loading to 7 Ibs sqft The flight computer is set to menu position 0 and needs to be rotated with the menu selector knob to position 0 10 full right turn easily selectable The display depicts C 0 5 gt 3 0 10 WL 8 0 By pressing the toggle switch 10 KORR WingLoad appears with a blinking question mark C 0 5 gt lt 0 10 WingLoad 8 0lb Pressing the toggle switch 9 up down respectively increases decreases the value with 0 1 Ib sqft increments The other method is to move to the desired value press and hold 15 11 01 97 the toggle switch 9 up down until the value is reached In the example you therefore press and hold down the toggle switch 9 until the value Wing Load 7 0lb appears on the display Then you release the switch to the center position and by pressing the ENT toggle switch 10 down your desired value is programmed gt lt 0 10 Corrections are possible only for glider model programmable display mode menu position 0 0 QFE altitude airport altitude distance and final glide distance only without GPS reception Time and date Compass Compensation option Menu Display 1 Correction 2 Correction 3 Correction select Mode platform platform platform Soa ur Line dl Line dr Display quadrant upper right down left down right QFE Altitude a QFG Altitude QFE atmospheric pressure QFH Altitude A Airport QNH Altitude atm
40. back on the stick To avoid acceleration effects the change in direction of flight should be smooth rather than sudden During the transition from V1 to V2 the variometer display is observed Ideally the display would follow the aircraft polar exactly continuous line 1 in Fig 8 but there may well be small deviations in the transition phase dotted line In this phase the angle of attack and the coefficient of lift changes Naturally this also affects the drag coefficient Consequently it is generally not possible to avoid a small deviation from the ideal when conducting flight tests TAS kn h 92 49 Varia fis I Ideale Compensation 200 2 Real Compensation 400 Fig 7 2 1 Total energy Compensation 90 If you have reason to believe the compensation to be in adequate then the cause may be the static pressure source We have had good results with pressure taken from a tube at the rear of the fuselage which is used purely for the variometer The pitot tubes which some manufacturers build into the fin as standard have proved to be excellent You can also adjust compensation 2 at the vario itself Using this adjustment compensation can be set during the test flight To do this you do need however to recognize the possible errors which may be displayed and be able to interpret them Fig 8 represents typical errors and these can be recognized and corrected as follows e Variometer reading rises when you pull b
41. cation over the photo sector is only as good as the coordinate information of the turn point At a deviation of turn point coordinates and a photo object of around nm this notification is naturally wholly unusable When reaching the last turn point finish line the photo sector is magnified to 180 When invoking the final glide mode with the mode select switch 8 and sometime during the route the remaining flight distance and the associated required altitude gain if less than 47 11 01 97 5 4 nm is is given E g before takeoff make sure all turn points are correctly entered this way the deviation between the route length in the VW921 and the task position is a maximum 0 5 1 nm based on different calculation formula s there will always be small differences How does one program a task with multiple laps Of course it is always possible to either use the goal flight mode or the task mode and consecutively program all turn points redundantly As of version 2 0 there is a new possibility only program one round and through using an invocation algorithm attach more rounds If the last route has already started and in the GPS receiver the task is still activated you simply start a new route If only two or three turn points belong to the round the VW92 assumes that a new turn point has started and attaches just one more round At 4 or more turn points it assumes however a start off on the middle of a leg and attaches the start po
42. display the speed difference AV Vg TAS This advises that the selected wind on the wind knob 6 is essentially larger or smaller than the calculated wind component AV and your wind attitude strongly deviates from the short time wind recommendation 3 with active GPS linkage and with matching wind attitude the angle between the bearing and course over the ground with direction pointer is shown The three display value is for an exact direct final glide without detours this is especially advantageous If you hold this angle on Zero you are guided by the flight computer directly to the turn point coordinates Note in stronger wind during circling based on constantly shifting wind component the display between the above display modes alternates between 2 and 3 The display quadrant on the bottom left shows a non adjustable value for the glide path deviation AA In the bottom right quadrant of the display the remaining distance AE is displayed It is identical with the yet to fly total distance DX More information about the final glide mode in chapter 6 36 3 6 The Altimeter You may receive the following altitude information in feet from the flight computer the standard pressure altitude AS the QFE altitude a relative altitude over the start up airport the QNH altitude A airport altitude above Mean See Level the Glide path deviation AH There is only one altimeter in the VW921 the total energy compensated a
43. e The 9 pin D sub socket connects to the flight computer the 9 pin D sub plug is a one to one serial interface extension of the flight computer serial port and serves as the connection to the printer serial port a personal computer serial port or a data logger This plug can be installed on the instrumentation pedestal providing an easy access for printer or laptop computer The other lead of the double cable connects to the optional panel mount GPS receiver Mark the cutout for the plug with help of the included template Over this external serial port connection it is not only possible to speak to the VW921 with a PC but also to the GPS receiver For example you can download to the GPS receiver with all turn points from the PC 88 Attention If over this plug a third unit i e a printer or a PC is installed the unused instrument must be turned off Only two active accessories can be linked simultaneously with each other While connecting a printer to the flight computer the GPS receiver must be powered off While connecting a PC to the GPS receiver the VW921 flight computer must be powered off A suitable cable for connecting a PC to the flight computer is a 9 pin cable of the RS 232 type The same cable is also suitable for the PC to the GPS receiver connection For this connection any 1 1 RS 232 cable with 9 pin D sub connector is usable In gliders with accessible connectors to the VW921 the single lead cable set w
44. e change By international agreement a standard pressure is defined as having a barometric pressure of 29 92 Hg 1013 2 millibars at sea level and with the temperature of 59 F 15 C The sea level pressure may vary between the extremes from 28 50 to 30 50 Hg We did not observe any major change in wind strengthening only for safety reasons we select a head wind component of 10 knots h We retain the MC value at 1 5 The Glide path deviation amounts in our event to dA 3630 i e we are 3630 feet under the required altitude for the final glide with MC 1 5 and 10 knots h head wind component Our tactical flight considerations aim on two questions 1 Where can we gain the missing 3630 feet of altitude 2 Is the estimated wind component approximately correct For the first decision the negative glide path deviation it helps to have the following considerations Can we gain the required altitude in a thermal Is this possible at all at the present day cloud base Do we have a promising cloud street We decide for the direct speed to fly flight 61 11 01 97 Now we must check the wind influence A prominent start line on our prepared map are the 32 4 nm circle at the highway Neumarkt Regensburg northeastern the place Neumarkt Until that point we can rely instead on the remaining distance D If we fly a search circle the travel distance calculation will not be influenced because in this phase only the wind shift has an e
45. e data so that the pilot always gets the exact route calculation as measured This information helps the pilot with navigation checking wind strength and in making tactical decisions 4 1 Distance sizes The Flight computer can store up to 9 sections or partial sections of a flight and total route SX a speed sensor route Sio total over the total flight Each route section has corresponding route data that belong to it that describe the flight on this leg Review the following section for concept details and an overview 40 Term Symbol with Explanation GPS onl aa Leg Sors __ amalready flown distance Distance Dord yetto be flown distance teste Wore D the flight time on the active route Route speed Vorv the speed achieved on the route Me Sal ta Bearing Porp the bearing of the location respectively the start to the end point of the route Exit S point the start point of a route with names maximum 8 char and coordinates Goal point X the end point of a route with names maximum 8 char and coordinates A more detailed explanation of the single concepts and symbols are available in chapter 3 3 4 The display rows for Normal Cross country mode A yet not activated leg Sn is always set to null A completed leg m will be set on the original distance Vice versa the yet not activated distance Dn corresponds with the distance of the route length and the distance Dm which i
46. eck if the total distance equals the task this way you have the single turn point xxx coordinates In case you forget a turn point or you entered an incorrect coordinate value then the distance value comparison will be negative To make the difference clear for a final glide without GPS receiver lets assume the same circumstances as in the example in the chapter 5 3 You fly the last leg of the task around 43 2 nm from the goal Weiden and you have the same weather condition You do not need to perform any fine tuning on the distances since you have the GPS for that purpose You know that the readable distance d4 D4 DX AE 80 4 km from the fourth and last leg short for the Rhein Main Danube channel must be located and 66 compared to the top view which the map confirms The wing loading readable in menu position 0 10 is equal to the true wing load Over the radio you acquire the QNH pressure and if there is a required correction the difference can be input in menu position 0 2 by pressing the KORR switch twice you can adjust the QNH pressure directly In case you did not check the wind component in menu position 0 9 you are able to see the wind set direction since the last turn point The difference from the true air speed TAS and speed over the ground Vg zAV XXXXX Since the wind increased by 3 km h the AV moves between 1 and 6 km h You can adjust the wind knob to 5 km h The MC selected value remains unchanged o
47. eiden We have plenty of spare altitude for the arrival altitude of 300 ft and 1590 ft at the point where we reset the MC value to zero At the double track railroad Amberg Sulzbach at AA 90 we check the wind component again In case the difference is not too big 54 nm we can continue the straight final glide 62 Remark Display resolution with 0 1 nm interval steps is very helpful for the distance comparison It allows the precise adjustment of the controls through interpolation especially for short distances Besides the generally valid final glide example we need to consider some special cases Distance flight without preprogrammed distance In this case for the final glide distance there is no value given AE 0 and because of that no glide path deviation result Because of the missing distance entry the computer will request these distances when entering the final glide mode After entering the distances the computer activates these as the last partial distance D1 and last leg Flying to a special goal point or turn point ridge end distance of a thermal dead weather You program a complete task A task with three turn points The distance D1 to D4 is programmed The second leg is 64 8 nm long and at the distance of 40 5 nm there is a 10 8 nm long valley You arrive at 8700 ft QNH to the valley and to cross over it you would like to use the final glide mode The goal is to arrive above the ridge with 600 ft of altit
48. eld altitude doesn t change the QNH altitude but the QFE altitude has been modified to this corrected altitude correspondingly Atmospheric pressure changes during the flight are corrected with the corresponding alteration of the QFE altitude 39 11 01 97 4 Measuring Distances The basic flight computer model already processes data provided through the high precision piezo electric pressure sensors necessary for the exact calculation of a final glide It makes sense therefore to use this precision for the rest of the flight so that distances flown and height corrected average cruise speeds TAS can be displayed as digital read out taking account of the wind Using the additional options like GPS Navigation and or compass linkage the user friendliness of the flight computer through the greatly simplified positions and distance determination of more displayed altitudes and the accuracy and reliability of the derived values e g Wind final glide altitude again further improves and reduces pilot workload The utilization of satellites and other navigational aids necessitates however a sophisticated software which differentiates between signal sources derived from the GPS unit compass linkage or data out of the pitot signal It is normal to have longer pauses at the reception of navigational data bad reception of the GPS satellite feed powering off the GPS receiver because of high power consumption etc the computer links th
49. er 6 2 73 11 01 97 6 1 3 The flight log book storage The VW921 flight computer is equipped with an integrated real time clock This way all the flights are logged with a date and take off and landing times The logged time and date enables you to log the flights and the log book for the sail plane precisely The flight computer has a separate storage area for log purposes the last 15 flight are logged The log works on the FIFO first in first out principle if the log buffer is filled with data from 15 flights starting with the 16th flight it pushes out the number 1 flight and the new flight will be logged as flight number 15 The flight log book storage was designed to be big enough to store a large 14 day competition with eventual multiple starts You will quickly get used to this convenient future This future relieves you from inconvenient reacquisition of flight data from the contest manager and all the flight data is stored and separated apart The log book is accessible in the statistics menu row 9 in menu positions S0 0 S9 5 and stores the 15 flights in the following manner 6 1 3 1 The flight number In the top right display quadrant the selected flight number is displayed Selecting the statistics mode with switch 8 to the S position you enter the last activated flight log area To move to other logged flights you have to press switch 9 or The flights are numbered in growing sequence i e flight number
50. ermalling time during the active cruise flight Also see S1 6 C 0 0 Times t Cl 0 25 29 S6 3 Glide time during cruise flight in respect to the total flight time t tot corresponding to thermalling time t ClL C 0 0 Times t Cr 1 00 71 S6 4 Flight time of the legs t L1 Part route lengths n are selectable with the toggle switch C 0 0 Times t L1 0 50 59 The statistics menu position 7 and 8 are not used on the VW921 flight computer In display mode 9 and 10 no statistics data is portrayed but in display mode 9 the flight logbook administration is displayed see the detailed description to the flight logbook in chapter 6 1 3 Flight Logbook Storage In display mode 10 exact information from the wind sector is displayed only in versions with compass linkage otherwise this display mode is empty 35 11 01 97 3 5 The final glide mode The last of the three display modes is selected by pressing the mode select switch 8 to the down EA final glide position In this mode the display has only one mode and no option for selection The display quadrants show the following information top left the selectable Variometer display with the average or net climb The display value on the top right quadrant displays information in the following manner 1 Without active GPS linkage used as an altimeter display selectable on the ground as to which altimeter mode is displayed 2 With active GPS linkage used to
51. ffect If we forget to activate the thermal straight flight switch for the following straight flight this will be automatically performed when reaching the speed of 55 nm hr at the wing load of 7 2 Ibs sqft as required for the calculation of the remaining distance We can now focus on the meteorological navigation By approaching the mentioned highway of the control distance we compare at over flight with the remaining distance AE It is obvious that the head wind has died down or is non existent at all the flight computer displays D 33 5 nm and not the expected 32 4 nm So at the exact over flight we press the switch 10 to KORR position and we correct with the switch 9 to 32 4 nm Finally we enter the value with switch 10 by pressing it to the ENT position At the same time at the display bottom right section the true wind component appears and the top right quadrant displays a blinking XXXXXX Now we reduce the wind component with the WIND knob 6 Then the glide path deviation changes to AA 2880 ft Above the city of Lauterhofen at 2100 ft altitude above the ground we find a cumulus cloud with 400 ft min average lift In that condition we set the MC value of 42 0 and the newly calculated glide path deviation displays AA 4320 ft We can observe while circling in the lift how the AA value is getting smaller Finally if the AA reaches the value of 0 or a positive value you can start your final glide in the direction of W
52. gister Biggest Altitude gains with No the register Average Climbs in the register that the biggest Altitude gains brought The last length offers an overview all glide and climb phases of the row to with the most important data 82 Cruise section G number of the Cruise sections Nautical miles S at the start covered on the total route completed kilometers dS altitude at the start H Total energy altitude loudly standard atmospheric pressure altitude difference dh Time in hours and minutes duration of the Cruise sections in minutes and seconds climb phase B number of the register Nautical miles at the start of the climb phase covered on the total route Average M into m Climbs s start altitude of the register Gained altitude into the register Time in hours and minutes climb time in minutes and seconds Comment The absolute information of route S start altitude H and Time always cover on the commencement of the circling respectively itself glide phase the recorded is with the commencement of the next phase always identical 6 2 2 Printing the Flight Log book The printing the flight dates take off and landing times of the last 15 flights is analogous to the printing the statistics storage It requires the connecting of the serial printer to the serial port The display mode selection is in the statistics menu row S9 6 printing the flight log book Presently the function is
53. he relationship between route length and gained altitude C 0 0 D total Glide Ratio 41 Row 4 D Single registers The statistical data identically organized like Row 3 in these registers each single leg information is stored individually The toggle switch 9 picks the individual legs Example 4 0 Leg 1 distance from takeoff to turn point 1 C 0 0 D singl Leg1 120nm Row 5 Maximum registers In statistics menu position 5 miscellaneous maximum information is displayed Only 4 registers are used 33 11 01 97 S5 0 Altitude gain in the thermal with the maximum altitude gain AAmax with thermal number information Also see S1 2 C 0 0 Maximum AAmax 2 3608ft S5 1 The climb in the thermal with maximum Altitude gain M AAmax also see S1 3 C 40 0 Maximum d x100 C AAmax 3 6ft m S5 2 Altitude gain in the thermal with maximum climb and the associated thermal number Also see S1 4 C 0 0 Maximum AACma 3 1417ft 5 3 Average climb in the thermal with maximum climb Also see S1 5 C 0 0 Maximum x100 C Cmax 7 6ft m Row 6 Times registers Here the summarized times are displayed S6 0 The flight time t tot with percent information The percent information references the total distance of the flight time C 0 0 Times t tot 2 00 141 S6 1 The total cruise flight time t LY Also see S3 1 C 0 0 Times tL 1 25 100 S6 2 Th
54. ical however with the restriction that the GPS version with active GPS reception inserts the bearing to the next turn point into the distance row When operating without active GPS reception only the distance of the part routes is displayed The values of the route length distance and route speeds are calculated and are dependent on GPS reception The calculations are run automatically whether missing GPS reception i e By turning off the GPS receiver or a VW92 without GPS option When reception of the GPS signal is newly established these values are modified with the updated coordinates So in principle it is possible to turn off the GPS receiver 1 e to save battery power the calculation of the values always happens in the most precise form The following section applies to the VW921 without GPS connection as well as with GPS connection The following summarizes both events without GPS linkage The following are differences if there is an active GPS linkage This is especially noticeable in menu position 1 the distance row Without GPS linkage there is no bearing angle displayed so that the right bottom quadrant stays empty In this event when pressing the KORR toggle switch 10 nothing happens In contrast when a GPS linkage is active there should be a reaction correction of the current values The single route lengths allow themselves to be programmable or correctable at this point You have the ability to program the route
55. ill be used The connection to the printer will be established immediately before printing If direct access to the rear of the VW921 is not possible the double lead cable should be used The part with the 9 pin D sub plug must be installed solidly The D sub plug of the VW921 should be connected and locked The 5 pin round female connector should be mounted in a reachable place in the airplane e g Instrument panel The other cable included with the VW92 is for connection to the 5 pin round female connector to the serial device i e printer or PC Also see chapter 6 2 Serial interface 7 2 Compensation We have had no reports of pilots finding compensation a problem Test bench adjustment has proved itself in practice In cases where there were unsatisfactory pitot results the electrical compensation was working well However meticulous test bench adjustment may be a check is needed in the aircraft itself to detect any minor errors in static pressure or measured pressure This can only be carried out on a test flight of course There follows a description of the pull up case converting speed to height as it 1s relevant to cross country flying 89 11 01 97 This test requires stable weather with an absence of thermal activity if possible The test sessions are always started at a fixed initial speed V1 leg as in Fig 8 at 92 knots The test consists of rapidly reducing the speed to a lower speed V2 leg 49 knots by easing
56. ime C 0 0 Thermal At 11 03 15min Thermal S0 5 Position nautical miles of the total flown distance C 0 0 Thermal S Nr 11 183nm The Thermal register stores sampled data in circling mode which lasted longer than 30 seconds Data sampling is triggered automatically by speeds lower than circling glide switch over 28 speed Wing load dependent see table C displays the same value as the Variometer round instrument Also if circling in a sink negative values are registered as thermals It is important to use a flight style which clearly separates straight distance flight and circling This results in concise and clear statistic data The flight computer has 99 thermal registers to store data from thermals enough for any long flight With this detailed data recording you have a new more exact and also more comfortable note pad for flight analysis Row 1 Climb registers Climb register selection is performed at position 1 of the Menu selector knob 4 in the statistics mode This displays all global information that involves the climbs e g Total altitude gains total climb time etc In the columns you will find Climbs S1 0 Total altitude gain C 0 0 Climbs AA total 10540ft Climbs S1 1 Averaged rate climb from all registers C 0 0 Climbs 9 x100 C total 4 2 ft m Climbs S1 2 Altitude gains in the climb registers with maximum Altitude gain and associated Lift number C 0 0 Climbs AA
57. in the same way the display for quadrant 3 Line dr down right In case you would like to change the layout again at a later time you simply press the KORR switch while in menu position 0 0 After turning off your VW92 the last programmed layout will remain stored in the memory Display mode 0 0 selections for upper right quadrant Line ur Description Symbol Flight computer configuration in the Display options 17 11 01 97 37 X LL OP 14 15 Px x x x EHE S RE SEE Battery Display Bat X X X X X Target Turn Point Nam x x x Bearing P CT x x x Display x x x x x Main Climo c XxX Xx Xx Xx x Thermal Clim c Xx Xx Xx X X Display mode 0 0 selections for bottom left quadrant Line dl Empty x x x x x x Display St x x x x mas v x x x x x x OFE altitude a x x x x x x Bearing P ST x x x x Temperature T x x xx x x x x x KXXX I PS OS amp KXXX x x x x x EBERSIFPSRISIRIREIHSS x x x Display mode 0 0 selections for bottom right quadrant Line dr Empty 0 Tx x x x x x Distance __ x x x x x x Wwrack TR amp x xe x Av Display Av x x x x Mc Speed J x Gesam V Ev x Wind Emp winde x Grose E
58. int at the next goal out It leads you directly to the first target point You can find an example of the multiple laps in chapter 4 4 4 2 Goal flight mode For some tasks e g POST FREE DISTANCE or ZIGZAG shaped courses the route will be determined during the flight Therefore you can fly without the task mode Because this route mode is also applicable for parts of the task mode some pilots generally fly in this mode The advantage is in the consequent flight mode there is no transition necessary Before takeoff the first turn point is entered into the GPS receiver Depending on the update rate of the GPS receiver one or two seconds the VW921 flight computer needs a little time to calculate the data Now you can start the first route with the VW921 as described above by pressing longer on the toggle switch 10 to the ENT position In the goal flight mode there is no start point programmed the current coordinates are taken as the start point and the exact course line is drawn to the first turn point At the approach of the first turn point before that turn point is reached the GPS receiver can be switched to the next turn point The VW92 leads you with distance and bearings on the first turn point In the flight 48 computer the following turn point is already input the up coming departure point is well known and offers you the same photo sector notification as during the goal flight mode AII other turn points are proceeded
59. irect distance over the ground and the bearing is the takeoff line between your airplane and the turn point Note this peculiarity at bigger deviations of the course the sum of the distance can be bigger than the original distance between both points Schematic depiction of the indicated sizes at active route 1 with route S1 distance D1 TRK track course over ground P1 BRG bearing bearing to the turn point TP2 distance D2 distance the turn points TP2 and TP3 yet not active bearing of P2 is the bearing between both these points In flight with the task mode as opposed to the goal flight mode with a fixed set assignment offers the following advantages The operation is simpler when reaching the turn point start the next route by pressing the switch 10 to ENT position This mode abstains from making an automatic switch over to the next part route First after reaching and photographing the valid turn point only then is the leg finished in the VW921 In this way you can compare the bearing BRG to the to approaching turn point towards a bisector This comparison is displayed in the flight computer additionally with the information a photo sector is supported A photo sector is inserted at the turn point fly around Activated for the sector at 45 to the bisector and displayed within a distance of 8 nm of the turn point through a blinking display Photo in the top right display quadrant Keep in mind that this notifi
60. is still stored in the storage area not deleted you will be asked C 0 0 Log 134 in memory Answering the question with a yes by pressing switch 10 to ENT you load the data from the selected flight number into the statistics storage area The previously loaded data is removed from the statistics storage area In cases where the selected flight was performed a long time ago the flight data maybe overwritten with the new flight data then the display shows in menu position C 0 0 Log 128 no memory Certainly for early flight numbers the data is not available either Example the utilization of the statistics storage area You fly a large triangle task For the flight the computer assigned flight number 134 The thermals weaken and you are not able to complete the task You try to avoid an out landing risk and you land at a nearby airport At that airport you have the opportunity to get an aero tow back to the home glider port before sundown When returning to the home glider port you would like to analyze the incomplete task You did not have the time to printout and analyze the flight before the tow to the home port Flight 134 ended at the neighboring airport and the take off for the tow back to the home glider port starts flight 135 even if the computer is turned off After landing on the home airfield your computer finishes flight 135 with nothing but useless data stored during TT 11 01 97 the tow Now you are
61. istics storage With the title statistics storage we cover all data required to process the flight analysis The statistics storage can always hold only one flight which is available through the display mode during or after the flight printable and downloadable to a PC A printout or download thru the serial port can only be performed after the flight is finished The loaded flight data remains in the statistics memory until something is newly loaded The newest happens automatically at every new take off but it is possible to load older flight data as long it is still available in the record storage The last mentioned possibility is only available on the ground in flight it is locked and the statistics storage is occupied with the current flight data In case you are not reloading any earlier flights from the record 72 storage memory the statistics storage holds the data from the last flight After the flight you are able to connect a printer and print the statistics data of the last flight The printing of earlier flights requires the usage of a algorithm see chapter 6 1 3 The Flight Log book Storage You can access the flight data stored in the statistics storage memory in three different ways on the display through the statistics menu selections see chapter 3 4 printing through the serial port connected printer downloading to a PC through the serial port These possibilities are handled in detail in chapt
62. itude of Cruise section No 18 C 0 0 Cruises A In 18 4100ft S2 4 Altitude after ending Cruise section No 18 C 0 0 Cruises A Out 18 820ft S2 5 Altitude loss on Cruise section No 18 most a negative value C 0 0 Cruises AA Nr 18 3280nm 31 11 01 97 S2 6 Cruise Time for section No 18 in minutes and seconds C 0 0 Cruises At 18 15 00min S2 T Total number of Cruise sections C 0 0 Cruises Cruises SPA Row 3 D Total registers In menu position 3 of the display mode the total distance values are shown The statistics register positions are S3 0 The total of the leg distances takeoff to landing C 0 0 D total Leg X 108nm S3 1 The total time t L used for flying the total Leg hours minutes This is 100 of the total flight C 0 0 D total t 1 25 100 3 2 The achieved average ground speed GS LY on the total route GS LY Leg t LY C 0 0 D total 9 knots hr CAD 76 1kn S3 3 The achieved average air speed TAS L on the total route C 0 0 D total 9 knots hr TAS L 142kn 32 S3 4 The total altitude gain on the total route C 0 0 D total AA total 12631ft S3 5 The average climb on the total route C 40 0 D total 9 x100 C total 4 2ft m S3 6 Out of the average climb on the total route theoretically attainable McCready speed MC speed C 0 0 D total 9 knots hr MC speed 46 kn S3 T The Glide ratio is t
63. l is activated as the next turn point In both the cruise mode as well as the final glide mode you are directly led on your intended goal Incidentally you can go back anytime to your old route by pressing of ENT and for 1 5 seconds Naturally the here described algorithm is useful not only in cases with active GPS linkage but equally good without GPS linkage with the difference that no turn points have to be inputted but always the distance on the 58 respective legs to be programmed see chapter 5 4 Event examples without GPS linkage In case 4 in the task mode with GPS linkage by pressing the ENT up to the last route and skipping through all the other turn points your home goal is selected without inputs to the GPS receiver 59 11 01 97 5 3 Final glide without active GPS linkage The first example demonstrates the application practice near of the final glide The technical handling is already well known we will concentrate more on the tactical applications example final glide see fig 5 3 1 Event example final glide We are flying with an ASW 20 on the return flight from the Swabische Alps to Weiden EDQW a triangle flight and approaching the Rhein Main Danube channel south of Freystadt on a 5400 ft altitude QFE Weiden Before takeoff we already had the single leg with its distance pre programmed Fig of 4 3 1 Event example final glide DISTANCE D 43 ALTITUDE A 5400 MG 15 MCuLS 15 20 WL i6
64. le and double row display models The matrix in the table assists you in selecting the appropriate menu and works with the computer during the flight If you have a desire to portray a certain information on the display you select the item out of the laminated card The menu selector knob 4 corresponds to the table column and the toggle switch 9 selects the wanted menu mode line In order to quickly orient yourself the menu matrix displays information status on the top right quadrant exceptions Menu position 0 0 in menu row 2 with selected turn points in the top right quadrant You can find more exact information regarding the status line in Chapter 3 5 Example The display reads C 0 7 c 3 2 S2 0 v2 0 To check the Battery voltage with the momentary menu position currently at 3 2 check the menu matrix to find 0 5 denoting battery voltage To check the voltage you must turn the menu knob to position 5 and toggle the switch so that the display reads 0 5 The display then displays C 0 7 gt lt 0 5 Bat 13 2V 76 3 F 13 11 01 97 The temperature information appears only on systems with optional temperature measurement You can find more exact information about display programming possibilities in subsequent chapters Incidentally menu line 0 is always displayed after power up so that you do not have to search for this important information 1 Vos x The Menu position 3 2 meant
65. ltimeter which provides reference for the calculation of the other altitude values This altimeter measures the energy compensated barometric pressure compares it with the standard barometric pressure of 1013 2 mbar and converts it into the standard pressure altitude AS This information is parallel to the altimeter information at an adjustment on standard pressure of 1013 2 mbar Through adjusting the altimeter pointers to 0 ft you get the QFE atmospheric pressure of your position momentary airport barometric pressure The VW92 automatically engages at 0 ft QFE altitude when the unit is turned on The QNH altitude A in menu position 0 2 is at the same time automatically set to airport elevation If the atmospheric pressure changes during the flight you must compensate for the pressure change and adjust the altimeter i e the flight computer expects the same correction That happens with the simple correction algorithm on the menu position of 0 1 where the QFE altitude can be found Press the KORR button only once so you can change the QFE altitude as altitude over your destination airport immediately By receiving barometric pressure data from nearby reference airport you can adjust the computer to the exact atmospheric pressure by pressing the KORR switch the second time For the final glide the QFE altitude alone is relevant Only the altitude over the destination airport is the reference altitude for the glide path deviation
66. mputer is converted immediately into the task mode as soon as you activate the task mode 2 ROUTE TASK in the GPS receiver Before takeoff the complete task is programmed During the flight three different variations are chosen with following priority and the goal point storage is set corresponding to the valid variation The route agrees with the start point to the present goal exactly like the route before Thereupon the route is copied identically with the goal point storage For example turn point 4 in the GPS receiver and turn point 4 in the VW921 display stay respectively 2 The start of the task position goal point 0 is identical with the activated turn point So that the concatenation algorithm is utilized and all the GPS receiver programmed turn points are flown in the preset sequence 3 If neither 1 nor 2 apply the task position in the GPS receiver simply attaches to the existing turn point sequence In chapter 4 4 3 you can retrace a detailed example of the multiple back and forth switching between task and goal flight mode 50 4 3 20 The distance mode without GPS linkage The VW92 flight computers without GPS option version type 1X and with GPS option Versions type 3X differentiate themselves in their normal display mode by missing the turn point display mode the first version type has a single display row and less data is displayed in menu position 0 Both remaining menu positions are generally ident
67. n 1 5 m s 67 11 01 97 4 4 4 4 1 4 4 2 4 4 3 4 4 4 Case examples Cruise flight mode Triangle flight in the GPS task mode empty Multiple legs and GPS Goal Flight Mode empty Cruise with intermittent GPS Dropout empty Programming of curses with multiple laps empty 68 6 Statistics and data storage The VW92 flight computer captures and stores all important events of a flight in a data storage This recorded data is available immediately or later for extensive analysis The organization of this data storage is in a direct relation to the statistics mode as to down loading and printing over the serial interface and getting the flight data see chapter 6 3 so that in this chapter both topics are treated together To utilize the full potential of the statistics option of your flight computer a knowledge of its storage organization is imperative The statistics display mode was already introduced in chapter 3 4 You might infer that in the statistics storage agrees with as to the storage of all analyzed flight data like route lengths average speed flight circling glide times all registers cruise distances and much more you could recall flight data from a previous flight however this is not the case because current and previous flight data cannot simultaneously occupy the data storage While the data of a flight is in record storage storage of all events takeoff landing route start climb glide s
68. need the altitude over the destination airport as comparison value correctly adjusted so that the flight computer can provide the exact Glide path deviation You already know that this QFE altitude menu position 0 1 adjusts itself automatically at power up to the altitude of the takeoff airport If a correction during flight is necessary due barometric pressure changes this adjustment is performed either through alteration of the QFE altitude or through correction of the goal airport altitude on the QNH 56 menu position 0 2 As soon as the flight computer is programmed with the distances all components for the final glide are calculated so that this mode is displayed without annoying pre adjustment simply by pressing the mode select switch 8 down to position EA 5 2 Applications for the final glide mode Standard application of this mode will be the final glide on the last leg You want to arrive on your destination airport with a specified speed and preferably no altitude waste In the event of an active GPS linkage it is always exactly predicted out of your location and your goal distance Alternatively without GPS linkage this distance is calculated out of the air speed TAS z True Air Speed the Climb Glide switch s activation and the selected wind component In the first event with incorrect wind component selection only the glide path deviation is calculated incorrectly In the second event you must compare the
69. nu position 0 10 of the route mode This value shall always be set to the real wing loading Before the takeoff check the wing loading for each event set the value dependent on the pilot weight and on the water ballast During the flight correct them after dumping the water so that this always reflects the actual wing loading The glider polar can be checked or modified immediately after power up For more details about the polar curve s and how this is selected check chapter 7 4 Selecting the Glider model and it s Polar Curve A polar deterioration is selected with the polar switch 7 In middle position PO the correct polar curve is selected for your glider model The bug contaminated polar PJ is selected in the upper switch position and regards a polar deterioration of about 5 at 43 knots h While the rain polar P2 in the bottom switch position is a polar deterioration of about 15 at 43 knots h Because at higher speeds of a stronger influence of contamination or raindrops can be expected a linear increase of the polar deterioration over the speed sector was used At 86 knots h this value amounts to therefore 10 P1 30 P2 55 11 01 97 respectively of the polar fall at this speed If you don t have these calculated polar values for contamination state for your glider we recommend the use of a polar curve from a different glider model By turning off the flight computers and variometer briefly 2 seconds and powering up again
70. on Then adjust the position of the magnet until the computer switches over from speed to fly N to vario C at that flap position Now the magnet can be secured in position If a second automatic switch over position is required a second magnet should be fitted Option of external speaker The loudspeaker is supplied in a 60 mm diameter round case For best effect it should be mounted in the side of the instrument pod or in the instrument panel if there is a vacant 87 11 01 97 space Avoid mounting the loudspeaker pointing upwards as it will very soon collect dirt on the cone and the sound will be distorted The speaker is connected with a 30 inches long lead which terminates in two flat connectors of the same width Duplicate instrumentation Option For two seaters a second vario is available in 60 mm or 80 mm diameter versions Electrical connection is via a 79 inch lead which terminates in connectors designed to prevent incorrect polarity Finally the electrical connections and the tubing are checked the battery is connected and the equipment is switched on using switch 1 as described in Section 3 Operation Printer Serial Interface Connection There is a 9 pin D sub socket on the rear of the VW921 for connecting a printer personal computer or GPS receiver via the RS 232 serial interface The cables supplied include an option of single or double cable connection In some gliders the rear of the VW921 will be accessibl
71. ospheric pressure Power On Display glider model eoa 0 4 0 10 Wing Load Wing Load WL WL 1 0 1 9 Legs S1 S9 Legs S1 S9 9 5 Correction of the Flight number flight number Final glide active Leg Sn so that final glide distance AE and DX 16 Figure 3 3 2 Possible Correction Combinations 3 3 3 Freely programmable display menu position 0 0 The display layout corresponding to this menu position can be freely programmed according to your needs Most likely it will be the page you will select most often in flight and it can therefore also be brought up for display very easily The menu page 0 0 appears automatically after the unit is turned on and is quickly selected by rotating the menu knob all the way to the left The only preprogrammed and fixed display is the average rate of climb C the net vario reading on the top left quadrant If you would like to change the information displayed on the other quadrants you press the KORR switch and the lower display line will for example show C 0 0 XXXXXXXX Line ur QFE alti Using the switch you can select from the table 3 3 3 Layout possibilities for the programmable display page in menu position 0 0 the information you would like to have on display on quadrant 1 Line ur upper right and use ENT to confirm it After that you are in the correction mode for quadrant 2 Line dl down left and after confirming it you will be able to program
72. r On the Display the following appears for about 10 seconds VW921 DG 100 Version 34 1 4US On the first row of the display beside the Flight Data Computer model VW921 your glider model should be displayed or a type with a similar Polar A correct Polar selection is a requisite for the proper function of the Cross country mode and the final glide mode calculation If a change is required to the Polar selection e g a wingspan change with Winglets you can make the change only in the initial 10 seconds You enter the correction mode by pressing the KORR switch 10 7 11 01 97 within the 10 sec time window to select the glider model See paragraph 7 4 The second display row displays your flight computer version The double digit number shows your version The two digit number is determined by the configuration as follows Basic flight computer with single row display 00 Option Value double row Display 10 Temperature sensor 01 Compass linkage 02 Statistics 04 GPS linkage 20 ISO country code for U S A model US For example the configuration figure of 34 agrees therefore with US version with the options double row display statistics and GPS linkage but without compass and without temperature sensor The letter 1 4 shows the software version of your flight computer software followed by the ISO country code for USA is US Following the initial display the upper right display quadrant will display the c
73. remaining distance with your map position and correct accordingly In both events you get a wind component recommendation with that selection you can enjoy the last miles of gliding and you will be surprised how exact the calculated glide path matches with reality But do not forget to check the remaining distance without GPS the wind recommendation with GPS respectively Wind plays a strong role with the unfamiliar vertical wind component It is also equally possible to check the final glide before reaching the last turn point In case of an entire task position task mode with active GPS linkage programming all partial distance of D1 to Dn without active GPS linkage the information always references itself on the entire remaining distance Contrary to the above with active GPS linkage and goal flight mode flight the next turn point is the final glide goal until the turn point is in the GPS receiver and the turn point in the flight computer is the same The turn point in this mode is newly programmed in the GPS receiver Then the final glide route leads you around the flight computer activated turn point on the turn point of the GPS receiver It is 57 11 01 97 recommended to input the GPS receiver a while before reaching the next activated turn point so the turn point is already there it only needs to be activated Then when reaching the respective goal the courses for the turn points are already well known and so is the
74. rror mus fe 18 Compass com x x Gesamt Total Table 3 3 3 Layout possibilities for the free programmable display page in menu position 0 0 x possible 3 3 4 Display quadrants in the Cross country mode In the following you will get an extensive overview of the Cross Country mode information The information is organized in alphabetical order of the abbreviation 1st column The 2nd column displays the basic meaning the 3rd column displays the unit types and the 4th column displays which menu quadrant of the cross country mode contains the displayed or desired information Example The upper right UR quadrant displays 3 4 which signifies menu column of 4 menu Knob menu position 3 amp toggle switch selectable bottom right display quadrant In the 5th column an example is presented Name PO Remarks Remarks gt 0 6 The left arrow always points to the currently activated leg for example at the start of the third leg 3 will be displayed If no leg is active instead of a number a second arrow pointing into the opposite direction is displayed gt ee a ECCE Angle 0 1 DR gt 21 0 0 UR 0 0 DL gt sse 19 11 01 97 The angle is analyzed by GPS reception The angle difference between bearing and programmed course is given with or which signifies a command to correct the course to the right or left The example above signifies Correct 21
75. s a finished route is set to null Meanwhile with GPS linkage these distances are set through the GPS receiver and should be programmed into the GPS receiver before the flight More exact hints are in chapter 4 3 2 The route mode without GPS linkage The section Sto total starts and stops automatically by pitot pressure The measuring starts when airspeed exceeds more then 32 knots h for more than 10 seconds and ceases when speed is reduced to less than 22 knots h The total route SX is the sum of all partial flight routes of S1 to S9 41 11 01 97 The routes of SJ to S9 can be started and stopped in conjunction with each other i e starting a new section stops the current one This has the advantage that when flying a triangle for example you only need to start 7 when crossing the start line SX is automatic At the first turn point you start S2 and S stops automatically but SX continues to measure Only when the last section SZ S9 is stopped does the total SX stop You can program the sections before take off so that the distance count is cumulative or a countdown You either know how much ground you have covered or how far you still have to fly Distance programming is only possible in S to S9 the cumulative total of the programmed sections is held in S Le the route of S5 is activated only after route of 4 is completed If you prepare your map by marking distances along the route you can easily find your position e
76. selection here the Menu knob 4 selects the display row and the column selection is performed with the MC Knob 5 The toggle switch 9 selects the third dimension of the matrix in which thermals and glide section data is stored To separate the statistic display values from the normal mode in this manual the statistics display menu position is displayed with the character S as a prefix Le the menu position 3 4 signifies that Statistics matrix Only with Statistics Option 26 display mode of 3 Menu knob on position 3 and column 4 MC Knob on position 4 respectively on a value of 2 In order to find the statistics data during the flight quickly designation for the VW921 display position statistics matrix is provided on a laminated card Portrayed as a two dimensional level of the statistics matrix you will find a detailed description of each of the display rows of this statistics matrix in the following chapter 3 4 1 27 11 01 97 3 4 1 Statistics Matrix Display Rows Row 0 z Thermal Registers In this display mode you receive all the stored information relating to thermals Example for Thermal No 11 Thermal S0 0 Total climb of the thermals C 0 0 Thermal d x100 C Nr 11 6 4 f m Thermal SO 1 gained altitude C 0 0 Thermal AA Nr11 2050ft Thermal S0 2 Thermal entry altitude C 0 0 Thermal A ln 11 2759ft Thermal S0 3 Thermal exit altitude C 0 0 Thermal A Out 11 4810ft Thermal S0 4 Circling t
77. ssed again 4 2 3 Reactivating a route In case you inadvertently activated a part route or for some other reason want to reactivate your last turn point tap the switch 10 to ENT and the input switch 9 to for about 1 5 seconds Notice that in this event the flight time and speed sensor route in route of Sn 1 again on the now active route Sn is added So is the old distance Dn 1 set back again to the original value of the route the time of tn 1 and the speed sensor route are deleted This reactivation is possible only once and also only if the previously activated route has not yet been finished That means the distance of this route must be greater than 2 7 nm from the next turn point What if you have to return to the turn point because of a wrong photo 43 11 01 97 4 2 3 Erasure of the Distance storage With a simultaneous keystroke 10 to the down position and 9 to the up position you will delete all pre programmed routes which have not been activated yet This procedure is always recommended if you have programmed an entire flight plan before the flight and now during the flight you want to change the task The already flown routes remain with all the data in the storage only the pre programmed routes not flown are deleted Comment Computers with the software version C displayed at power up route storage and distances are entirely deleted in this version all routes begin again at null 44
78. stimate flying times and perhaps avoid the unnecessary risk of pressing on too fast Section Sn can be started or stopped at any time without affecting the other sections This means that you can record part of a section or leg of a task In terms of distance and speed 42 General Operation 4 2 1 Start of a route The start of the legs always takes in place with the same procedure and is independent of your display value respectively of the activated display mode Press the toggle switch 10 to ENT position for approximately 1 5 seconds on the right upper quadrant of the display you will see the activated flight section Start S3 for 3 seconds 42 As of this moment the leg time is displayed fn the speed sensor route is started at null and the flown route Sn measurement in direction of your next turn point is activated In the upper example the route time of t3 0 sec and the route of S3 0 Nm If until now there was no active route by pressing the toggle switch 10 to the ENT position for a longer duration the first leg Sl and also the total route S is activated Otherwise if you press the toggle switch to the ENT position a new leg will be activated and the previously active route of S will be halted Only one route can be active at one time Incidentally it is harmless to depress the toggle switch 10 to the ENT position for a longer duration and it will not be activate the next leg until the toggle switch is depre
79. the Wind knob 6 for a short time The VW92 furthermore notices this suggested value and displays it permanently on menu position 0 9 up to the next correction If you use this feature of the distance comparison and adjust the derived wind value with the Wind knob 6 you already have an extensive idea of the actual wind situation long before the final glide This way the flight computer serves as a good navigational aid For example you know quite exactly when you will reach the next turn point The activation reactivation and erasure of routes happens as described in chapter 4 2 in which naturally only the distance and route storage s are involved One more remark regarding the programming of partial routes with the GPS version Maybe your GPS receiver is defective or you have a VW92 GPS version without your own GPS receiver You could borrow for a short time a friends receiver that wants to fly the same route You only need the GPS receiver for the programming of the VW921 You only need to connect the GPS receiver once for a short time max 10 12 seconds before the flight to download the distance storage with the exact values and also the entire turn point list Then you can return the GPS receiver and you used the faster form 52 of programming The rest of the route management works as described before 53 11 01 97 5 Final glide The computer is particularly useful when used in Final Glide mode It is designed so that
80. then your takeoff airport Example You fly cross country from California City airport elevation 2437 ft to Lone Pine airport elevation 3680 ft The displayed takeoff airport altitude is yet to be set on a value of 2430 ft before the takeoff the altitude resolution is 30 ft So on the display of the VW921 a QFE altitude a 0 ft and a QNH altitude A 2430 ft should be displayed before takeoff These values are independent of the current atmospheric pressure because this is stored only internally in the flight computer as a reference pressure value for the entire flight After takeoff the QNH altitude and QFE altitude maintain a constant difference value of the airport altitude E g At 1800 ft over the airport the computer displays a 1800 ft and A 4230 ft Any time during the flight preferably before the final glide you want to set the QFE altitude on the altitude of your destination airport You can perform that through a direct 38 alteration of the QFE altitude this possibility already exists before the flight but then your QNH altitude at the moment of takeoff is incorrect It is best to make the correction during the flight by selecting menu position 0 2 QNH altitude invoking the correction mode and putting the airport altitude on the target airfield In the case of our example 3680 ft Lone Pine The QNH altitude stays exactly on the previous altitude It is airfield independent thus an alteration of the goal airfi
81. this particular air mass Vario S itdi OE peed to fly Vario 4 C 2 5 M 1 2 ad ratu eE 2 1 distance sT 2 average rate of climb is measured 3 4 Fig of 3 2 1 Average Rate of Climb start of data capture If you decide based on the positive rising air reading and the encouraging speed to fly indication when approaching thermalling speed to start circling simply switch the flight mode switch 8 to S Climb position The computer will immediately give you the average rate of climb over the last few seconds because the integrator immediately takes into account the current rate of climb excluding any previous sink With this you receive immediate information on the rate of climb likely to be archived in this thermal Fig 3 2 1 This is perhaps the best time to mention the optional second speed to fly vario instrument In this case switching the vario to speed to fly only affects the audio tone 12 3 3 The Normal or Cross country mode 3 3 4 Display Mode in the Normal or Cross country mode As soon as the Statistic Final glide switch 8 is switched in the mid position the other 3 display quadrants are programmable to display preferred information You select the menu information out of a two dimensional menu matrix using the menu selector knob 4 and the toggle switch 9 The charts for selecting the menu programming are on separate laminated cards one each for sing
82. to STAT The connectors are at the rear of the VW910 variometer The power supply is taken from the glider 12V system O red wire to positive O blue wire to negative 86 If the wires are connected incorrectly and polarity reversed the equipment will not operate It is protected from reverse polarity damage but it is prudent to ensure correct polarity in any case Then the VW92 computer and the VW910 variometer are connected The 15 pin connector marked R 1s equipped with a slide lock and connects to the computer unit When slid about 0 1 inches to connect the slide lock prevents the plug from becoming disconnected The variometer is connected in the same way The 15 pin connector to the variometer is marked with a V The slide lock for securing the connector is mounted on the variometer case Next run a wire through to the speed sensor switch Take care to ensure that it is not laid adjacent to the radio antenna cable The speed sensor manual switch SG switch is best installed closer to hand e g in the control column In flapped gliders the speed sensor magnetic switch should be fitted in a suitable position next to the flap control rod The magnet is to be fitted directly on the flap control rod and its position should be adjustable The distance between the switch and the magnet should be approximately 0 2 inches Select the flap position which the manufacturers recommend as the optimum thermalling positi
83. ude the map shows an altitude for the ridge of 5700 ft First delete all the remaining distances which do not belong to this route length This happens by simultaneously pressing ENT and then all the routes above the active route are deleted Because of that D3 and D4 fall out in this example It is now D2 d2 DX AE 24 3 nm the remaining distance of D2 up to the second turn You correct the distance of D2 with the intended final glide value of 10 8 nm because of which all other distance values also change Additionally correct the airport altitude to 6000 ft by pressing KORR at QNH altitude The altitude is 6000 ft because 300 ft of arrival altitude was already integrated This results in a QFE altitude of 2700 ft See 5 3 1 Valley over crossing MC 2 0 WD 8 1 WL 6 6 After crossing the valley you reset to the previous task by simultaneously pressing ENT and D2 will be set back to 13 5 nm 24 3 nm 10 8 nm 63 11 01 97 D3 and D4 will be set back to the start up value the FP altitude will be set back to the original value because the original goal is the valid goal This process may reoccur multiple times Furthermore the following variations are possible A final glide to a turn point is programmed immediately by simultaneously pressing ENT and You want to finish a leg against wind on a specific altitude while climbing you want to use the back wind leg to minimize outlanding risk you
84. urrent values for the following in 3 second intervals MC McCready value WD WinD component WL Wing Loading Now you may adjust 1 for acceptable loudness Then the MC value 5 for null The actual Wing Loading including water ballast Menu position of 0 10 correction procedure and the wind component 6 likewise to null In the second row set all switches 7 10 in the center position For extensive and clearly arranged information the display is divided into quadrants each with 8 digits Top left top right bottom left bottom right While the top left quadrant of the display always shows the variometer reading as a function of the flight mode selector switch position or respectively of the flaps position sensor The information in the 3 other display quadrants depends on the display mode selected You have basically three different menu options to select the information to be displayed 8 1 the Normal or cross country mode switch 8 in center position menu page position selection of the VW921 see section 3 3 The normal or cross country mode 2 the statistics mode switch 8 up position S menu page position selection of the VW921 statistics see section 3 4 The statistics mood 3 the final glide mood switch 8 down position EA fixed final glide side see section 3 5 The final glide mood 3 2 The Variometer Data The functions Thermal and Cruise
85. witch over etc are captured and has not been over written it can be loaded into the statistics storage so that now the flight is in the statistics storage What was previously in the statistics storage has now been overwritten But all to this stored flight data is however kept in the record storage so that it can be restored later The third form of storing flight data is in the flight book storage The flight book storage holds only short data from the previous 15 flights It holds the most important flight book information like takeoff landing and flight time and the flight date are loaded and displayed You can familiarize yourself with how the statistic record and flight book storage interact with each other in the following chapter 69 11 01 97 6 1 The VW921 Storage Memory Organization For a detailed overview of the VW921 glide computer data capture the chapter is subdivided into three sub chapters 6 1 1 The Record Storage 6 1 2 The Statistics Storage 6 1 3 The Flight Log book Storage Chapter 6 1 1 The Record Storage is valuable for you only if you would like to have a deeper knowledge of the memory structure of the VW921 For understanding statistics storage you do not need to read this section You only need to know that the record storage is dependent on flight duration and a certain number of flights with all statistic data stores in the background Using the statistics display mode the stored statistics dat
86. with GPS coupling is discussed in Chapter 3 Chapter 3 explains all display indications including those for the final glide mode section 3 5 This chapter concentrates on proper selection of the initial final glide settings and the interpretation of the various indications Many examples will be provided in order to demonstrate the available capabilities 54 5 1 The Setup Process In the VW92 all components of the final glide are either directly or indirectly adjustable but there are also parameters that are automatically set In the following all final glide parameters and the associated setup stages are explained again The Final glide distance AE is the sum of all the unflown part routes and so is also identical with Total distance DX The programming or correction occurs only indirectly over part routes With active GPS linkage the single turn points are programmed in the GPS receiver and from this the final glide distance is calculated Without active GPS linkage the partial distance must be programmed Choosing the correction mode during final glide the changes to the active partial distance dn simultaneously change the total distance DX In chapter 3 5 the final glide mode is explained in detail The McCready MC 5 number setting is dependent on the actual weather situation For higher MC number selected with the MC knob you need more altitude and from this a resultant higher speed The Wing Loading WL corrected in me
87. y faster or slower if there was a window of silence This would apply no matter how narrow the window of silence Needless to say speed to fly is related to the MacCready value set and also to Wing Loading You can check the MC value on the control knob position or you can easily turn the sensor knob 5 slightly and for three seconds the MC value is displayed in the top right quadrant 10 XXXXXXXX MC 1 5 XXXXXXXX XXXXXXXX It is important when you are making the selections with the rotary switch that you are sure that it is latched otherwise the computer does not know which of the two values to display and will alternate between the two The Wing Loading selection performed at the 10 position of the Menu selector knob 4 C 0 0 gt lt 0 10 WL 32 5 e press the toggle switch 10 to KORR position e with the toggle switch 9 change the value e press the toggle switch 10 to ENT lt to enter the value So that you have an indication of the vertical speed of air masses independent of the speed to fly the computer offers a digital readout of Net Climb and Net Sink That is the rate of climb and sink of the air mass through which you are flying at the time without taking into account the glider s rate of sink N 3 0 XXXXXXXX XXXXXXXX XXXXXXXX 11 11 01 97 A net reading of 3 0 knots means that your glider will actually climb at approximately 2 0 knots should you decide to circle in
88. you can check the interaction of all the factors involved wind component MacCready value altitude degree of bug encrustation on the leading edge etc quickly and easily In this way it is easy to optimize the final glide The final glide is estimated most to a time usually commenced when the pilot is already familiar with the day s gliding weather The pilot knows cloud base altitude average rates of climb and will have some idea of what the wind is doing This enables the pilot to make certain decisions whilst planning the final glide probably with a higher MacCready value because that represents additional safety 5 and with the estimated wind component 6 only the head wind or tail wind vector is of any importance In addition the pilot must state the distance from his home base airfield as exactly as possible and for this purpose it pays to use an air map which has been prepared in advance with concentric circles representing distance from the destination see Appendix 9 2 The computer does not require a special operating state to perform the final glide calculations these are continually performed in parallel with other tasks Selecting final glide mode changes only the display format The display is designed to allow you quickly and at any time to call up all the information vital to a successful final glide The interpretation of the most important information glide path deviation distance remaining and course deviation

VW 910/ 921 - Dr. Westerboer

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