JAS-39 Gripen Owners/Build Thread
03-20-2015, 03:21 PM
#1178
As such, to get the "recommended control throws", I needed to reduce the servo endpoints to about +/-30% on the Jeti (+/- 38% on JR or Futaba). This is less than I am comfortable with (lose too much resolution) so I modified the 3/4" SWB arms by drilling 1/16" clevis holes at the 1/2" positon.
Jim,
I usually do this as well. But I was wondering, with the new gyros that we have and with their excellent performance, I am wondering if the higher speed (slew rate at the control surface with a longer servo arm) is a better trade off, even with the decreased torque/resolution of the longer servo arm?
Good luck on the test flight!
03-20-2015, 11:52 PM
#1179
Maiden Flight Report
Here is the results of today's maiden flights.
Myself and a couple of buddies went out to the dry lake bed north of Kingman, AZ to perform the maiden flight. It's a 3-1/2 hour drive from home but there is literally square miles of flat hard packed ground so you don't have to worry about runway length, width, or wind direction. See pic. Maiden flights, particularly of complex aircraft, can be stressful so having such a wide open space was well worth the drive.
I had set up the flight controls in take off mode to give me 20mm of up canard as the neutral with the canards also mixed to elevators to give a total of 40mm up with full up elevator. Ailerons are also mixed with elevators in take off mode. In fly mode, the canards are centered and there is no elevator-canard and elevator-aileron mix. I put a 1/2 second delay to smoothly transition going from takeoff mode to fly mode. Landing mode has 13mm of up canard offset with no elevator mix.
The elevators were set up such that, in their neutral position, the inboard edge of the elevator blended with the shape of the fuselage. The aileron neutral was such that the trailing edges lined up. This appeared to be a slight amount of down elevator and down aileron, but it was the best info that I had.
The up canard offset was my brain child and I hope that it would help raise the nose gently without having to use as much elevator to get the plane to rotate, and possibly over-rotate. The 1/2 second mode delay was also my idea.
The result of this setup was nearly tragic.
The takeoff was into a 10-15 mph wind. The plane tracked straight and I put in a bit of up elevator increasing it slightly as the plane appeared to achieve take off speed. Throttle was at approx 70% and the Kingtech 210 performed flawlessly. The plane was in take off mode. The point of rotation was past me so I didn't get a good look at when the plane was getting light on the nose gear but I flipped the switch to fly mode. The plane leaped into the air to approximately 45 degree pitch up in the notorious Gripen leap. The 1/2 second delay likely made matters worse. The plane is now 20-30 feet in the air, nose very high, throttle at 3/4, and threatening to stall. I go to full power, and about this time, fly mode kicks in.
As it turns out, the elevator and aileron neutral were set too low so the plane effectively had lots of down elevator. The plane went from 45 degrees pitch up to 30 degrees pitch down. Holy sh*t! I knew I needed to get the nose up in a hurry so I switched back to take off mode and the plane pulled out before hitting the ground and was now at 30 degrees pitch up with full power. I pushed down elevator, now pitched down but not as bad as before, relaxed the push, now pitch up, not as much as before and climbed to put some margin between the plane and the ground.
The controls were EXTREMELY sensitive and I was at low rate. I did the turn to downwind and, still climbing, I took the advice of fellow Bavarian Demon team mate Dave Brawley and turned the Cortex on with 30% gain as this would soften the controls. That worked great and the plane was controllable though the sticks were still pretty sensitive. I did a few laps to give time to relax. The plane kept wanting to climb and I eventually realized I was still in take off mode. I knew that upon switching to fly mode the plane would dive a bit but I had plenty of altitude and was ready on the trim so I flipped to fly mode, pulled back on the stick a bit, fed in some up trim and got it trimmed level in a few seconds.
In fly mode, it was a joy. Maybe a bit more expo needed (used 30%). I did a few more laps and we noticed a slight tucking tendency in the turns but nothing serious. The plane seemed to really behave at about 1/2 - 2/3 throttle.
The approach was a bit high and I kept a bit of power on. I didn't switch to landing mode. I pulled the power back at about 10 feet, slowly flared, and tried to bleed off speed and let it settle. I over flared (more expo needed) and it gained a bit of altitude then settled down and landed gently at a nice nose high attitude. Taxied back and shut down. Whew!
The landing gear was kept down during the entire maiden flight. That's how it's often done in the full scale world and I had enough on my plate without having to deal with hydraulics, door sequencing timing, and the possibility of a jam and maybe the gear not coming down.
For the second flight, I got rid of the 20mm offset up canard offset, changed the elevator-canard mix to give 40mm up canard at full up elevator but I forgot to get rid of the 1/2 second delay (blonde moment). I left the elevator expo alone (didn't want to make too many changes at one time).
I taxied farther down the lake bed so that the rotation point would be directly in front of me for a good look at the rotation. 75% power, speed building up, a bit of up elevator, nose getting light, flip to fly mode, rotate, Gripen Leap but nowhere near as bad (getting rid of the 1/2 second delay would have made it a lot better) and climbed out. I did a lap and flipped the gear up switch. Nose went in fine, right main went almost all the way up but the door was slightly open. Left main only moved a bit. What the ??? OK, switch to gear down and all three gear were down.
I basically just flew some laps in fly mode to get used to the plane, got a better feel of the tucking in the turns, and did a few 30 foot fly-by's, nothing very exciting, but the plane still looked pretty cool. I did a higher fly by and pull up with a roll to test the roll rate (too fast), and a couple of more laps before the fuel gauge sensor told me the kero was getting low. I set up on the approach a bit father out, and a bit less power, it appeared too slow at one point so I added a bit of power and let the nose down, got a bit more speed, back to nose up, nicely descending, flare, over flared again (should have increased the expo) and it climbed a bit and got really slow, relaxed the stick back pressure, blip of power not quite enough, settled, and touch down on the right main first, a bit harder than I would have liked, then settled on all three gear. Taxi back and shut down.
I inspected the landing gear and found that the rod was bent on the left main gear cylinder and it wouldn't retract the gear more than maybe 10-15 degrees. The right main and nose gear were fine. This damage must have occurred on the first landing (since the left main wouldn't retract during the second flight). After some discussion, we realized the problem was the gear geometry. More on this later.
All in all, it was a successful day with much learned. My "good" ideas on take off mode turned out not to be so good, but that's the way life goes sometimes. The next outing will be even better. As Janne said, this really is "Taming the Beast". Now to fine tune some settings, get the gear cylinder fixed, and start on the sanding, prepping, painting.
Regards,
Jim
P.S.: below is the only photo I took of the Gripen at the lake bed and it didn't even have the wings on yet. We did get shoot video of both flights so I might put something on YouTube.
Here is the results of today's maiden flights.
Myself and a couple of buddies went out to the dry lake bed north of Kingman, AZ to perform the maiden flight. It's a 3-1/2 hour drive from home but there is literally square miles of flat hard packed ground so you don't have to worry about runway length, width, or wind direction. See pic. Maiden flights, particularly of complex aircraft, can be stressful so having such a wide open space was well worth the drive.
I had set up the flight controls in take off mode to give me 20mm of up canard as the neutral with the canards also mixed to elevators to give a total of 40mm up with full up elevator. Ailerons are also mixed with elevators in take off mode. In fly mode, the canards are centered and there is no elevator-canard and elevator-aileron mix. I put a 1/2 second delay to smoothly transition going from takeoff mode to fly mode. Landing mode has 13mm of up canard offset with no elevator mix.
The elevators were set up such that, in their neutral position, the inboard edge of the elevator blended with the shape of the fuselage. The aileron neutral was such that the trailing edges lined up. This appeared to be a slight amount of down elevator and down aileron, but it was the best info that I had.
The up canard offset was my brain child and I hope that it would help raise the nose gently without having to use as much elevator to get the plane to rotate, and possibly over-rotate. The 1/2 second mode delay was also my idea.
The result of this setup was nearly tragic.
The takeoff was into a 10-15 mph wind. The plane tracked straight and I put in a bit of up elevator increasing it slightly as the plane appeared to achieve take off speed. Throttle was at approx 70% and the Kingtech 210 performed flawlessly. The plane was in take off mode. The point of rotation was past me so I didn't get a good look at when the plane was getting light on the nose gear but I flipped the switch to fly mode. The plane leaped into the air to approximately 45 degree pitch up in the notorious Gripen leap. The 1/2 second delay likely made matters worse. The plane is now 20-30 feet in the air, nose very high, throttle at 3/4, and threatening to stall. I go to full power, and about this time, fly mode kicks in.
As it turns out, the elevator and aileron neutral were set too low so the plane effectively had lots of down elevator. The plane went from 45 degrees pitch up to 30 degrees pitch down. Holy sh*t! I knew I needed to get the nose up in a hurry so I switched back to take off mode and the plane pulled out before hitting the ground and was now at 30 degrees pitch up with full power. I pushed down elevator, now pitched down but not as bad as before, relaxed the push, now pitch up, not as much as before and climbed to put some margin between the plane and the ground.
The controls were EXTREMELY sensitive and I was at low rate. I did the turn to downwind and, still climbing, I took the advice of fellow Bavarian Demon team mate Dave Brawley and turned the Cortex on with 30% gain as this would soften the controls. That worked great and the plane was controllable though the sticks were still pretty sensitive. I did a few laps to give time to relax. The plane kept wanting to climb and I eventually realized I was still in take off mode. I knew that upon switching to fly mode the plane would dive a bit but I had plenty of altitude and was ready on the trim so I flipped to fly mode, pulled back on the stick a bit, fed in some up trim and got it trimmed level in a few seconds.
In fly mode, it was a joy. Maybe a bit more expo needed (used 30%). I did a few more laps and we noticed a slight tucking tendency in the turns but nothing serious. The plane seemed to really behave at about 1/2 - 2/3 throttle.
The approach was a bit high and I kept a bit of power on. I didn't switch to landing mode. I pulled the power back at about 10 feet, slowly flared, and tried to bleed off speed and let it settle. I over flared (more expo needed) and it gained a bit of altitude then settled down and landed gently at a nice nose high attitude. Taxied back and shut down. Whew!
The landing gear was kept down during the entire maiden flight. That's how it's often done in the full scale world and I had enough on my plate without having to deal with hydraulics, door sequencing timing, and the possibility of a jam and maybe the gear not coming down.
For the second flight, I got rid of the 20mm offset up canard offset, changed the elevator-canard mix to give 40mm up canard at full up elevator but I forgot to get rid of the 1/2 second delay (blonde moment). I left the elevator expo alone (didn't want to make too many changes at one time).
I taxied farther down the lake bed so that the rotation point would be directly in front of me for a good look at the rotation. 75% power, speed building up, a bit of up elevator, nose getting light, flip to fly mode, rotate, Gripen Leap but nowhere near as bad (getting rid of the 1/2 second delay would have made it a lot better) and climbed out. I did a lap and flipped the gear up switch. Nose went in fine, right main went almost all the way up but the door was slightly open. Left main only moved a bit. What the ??? OK, switch to gear down and all three gear were down.
I basically just flew some laps in fly mode to get used to the plane, got a better feel of the tucking in the turns, and did a few 30 foot fly-by's, nothing very exciting, but the plane still looked pretty cool. I did a higher fly by and pull up with a roll to test the roll rate (too fast), and a couple of more laps before the fuel gauge sensor told me the kero was getting low. I set up on the approach a bit father out, and a bit less power, it appeared too slow at one point so I added a bit of power and let the nose down, got a bit more speed, back to nose up, nicely descending, flare, over flared again (should have increased the expo) and it climbed a bit and got really slow, relaxed the stick back pressure, blip of power not quite enough, settled, and touch down on the right main first, a bit harder than I would have liked, then settled on all three gear. Taxi back and shut down.
I inspected the landing gear and found that the rod was bent on the left main gear cylinder and it wouldn't retract the gear more than maybe 10-15 degrees. The right main and nose gear were fine. This damage must have occurred on the first landing (since the left main wouldn't retract during the second flight). After some discussion, we realized the problem was the gear geometry. More on this later.
All in all, it was a successful day with much learned. My "good" ideas on take off mode turned out not to be so good, but that's the way life goes sometimes. The next outing will be even better. As Janne said, this really is "Taming the Beast". Now to fine tune some settings, get the gear cylinder fixed, and start on the sanding, prepping, painting.
Regards,
Jim
P.S.: below is the only photo I took of the Gripen at the lake bed and it didn't even have the wings on yet. We did get shoot video of both flights so I might put something on YouTube.
Last edited by rcjets_63; 03-21-2015 at 12:17 AM.
03-21-2015, 02:18 AM
#1181
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Jim,
WOW, what a description of your Gripen maiden flights. They were similar to my SM/Xtreme version with a VERY skilled pilot (not me) at the controls. We changed a bunch of things, including moving the CG forward, along with reducing the throw of the canards and aileron function of the elevons. The best setup was to limit the canard movement to stop the tuck in the turns. I'll have to consult my notes for the exact throws in degrees. For landing the beast, we punched in a number of up elevator trim units to maintain a comfortable neutral, level flight path at a reduced power setting with the gear extended. The model is trimmed to fly virtually "hands off" in this configuration and just needs a bit of power added during turns. Landing is performed from a long straight-in approach gradually reducing power and adding elevator to reduce the sink rate. I realize that some of this may not be applicable to your larger scale version but take it for what's it worth. The primary "problem" with the model Gripen is the scale main gear position in relation to the CG. It may need a computer, the same as the full scale, for better handling characteristics. I'm sure you'll sort it all out before TG and the JWM. Good luck in all this and wish to compliment you on your outstanding build of the AW version.
Rgds,
Art
WOW, what a description of your Gripen maiden flights. They were similar to my SM/Xtreme version with a VERY skilled pilot (not me) at the controls. We changed a bunch of things, including moving the CG forward, along with reducing the throw of the canards and aileron function of the elevons. The best setup was to limit the canard movement to stop the tuck in the turns. I'll have to consult my notes for the exact throws in degrees. For landing the beast, we punched in a number of up elevator trim units to maintain a comfortable neutral, level flight path at a reduced power setting with the gear extended. The model is trimmed to fly virtually "hands off" in this configuration and just needs a bit of power added during turns. Landing is performed from a long straight-in approach gradually reducing power and adding elevator to reduce the sink rate. I realize that some of this may not be applicable to your larger scale version but take it for what's it worth. The primary "problem" with the model Gripen is the scale main gear position in relation to the CG. It may need a computer, the same as the full scale, for better handling characteristics. I'm sure you'll sort it all out before TG and the JWM. Good luck in all this and wish to compliment you on your outstanding build of the AW version.
Rgds,
Art
03-22-2015, 12:16 AM
#1186
Thanks guys for your congrats. Much appreciated. There is still lots of work left.
For your viewing amusement, here are pics from the maiden flight.....Hold onto your cokes, the take-off is a real roller coaster ride.
Taxi out, Take off roll
Rotate, Gripen Leap, Fly Mode Kicks In, Pitch Down, Pitch Up, Pitch Down, Climb out
A couple of high fly pasts
Slight tucking of nose coming out of the turn
Approach, flare, almost touching down. I wish I could say that it touched down, but I over-flared....
Ballooning, touch down on right main, on all gear during rollout
Regards,
Jim
For your viewing amusement, here are pics from the maiden flight.....Hold onto your cokes, the take-off is a real roller coaster ride.
Taxi out, Take off roll
Rotate, Gripen Leap, Fly Mode Kicks In, Pitch Down, Pitch Up, Pitch Down, Climb out
A couple of high fly pasts
Slight tucking of nose coming out of the turn
Approach, flare, almost touching down. I wish I could say that it touched down, but I over-flared....
Ballooning, touch down on right main, on all gear during rollout
Regards,
Jim
Last edited by rcjets_63; 03-22-2015 at 12:24 AM.
03-22-2015, 12:41 AM
#1187
Here is the video of the second flight.
https://www.youtube.com/watch?v=nLtJ2630_Dc&feature=youtu.be It still had the Gripen Leap (gotta get rid of the 1/2 second delay between flight modes). Although I selected gear up on climb out (you can see the main doors open), neither of the main gear went up though the nose gear retracted. I guess the retract cylinders don't have enough force to pull up the mains against the air stream. At least they didn't bind and all gear came down OK.
There is still plenty of work left to do to get this plane contest-ready.
Many thanks to Wayne Layne (video) and Brian O'Meara (caller).
Regards,
Jim
https://www.youtube.com/watch?v=nLtJ2630_Dc&feature=youtu.be It still had the Gripen Leap (gotta get rid of the 1/2 second delay between flight modes). Although I selected gear up on climb out (you can see the main doors open), neither of the main gear went up though the nose gear retracted. I guess the retract cylinders don't have enough force to pull up the mains against the air stream. At least they didn't bind and all gear came down OK.
There is still plenty of work left to do to get this plane contest-ready.
Many thanks to Wayne Layne (video) and Brian O'Meara (caller).
Regards,
Jim
Last edited by rcjets_63; 03-22-2015 at 12:44 AM.
03-22-2015, 05:47 AM
#1188
Grate flight ,looks grate and stable for secound flight gripes are one special jets to flight and after some more flights the turn in to grate filing models ,I mis my skymaster gripen it was a blast to fly I hope the new one aviation design will fly as good ,Jim grate work!
03-22-2015, 11:44 AM
#1189
Just checked the lower struts on my gripen mains and they are properly machined. One strut sticks in upper unit because tolerances to tight. Will need to fix with sandpaper.
Roy
Roy
03-22-2015, 09:30 PM
#1192
Sebastian, I look forward to seeing a video of your AD Gripen fly.
Roy, glad to hear that you don't have to get your strut machined. Thanks for the replacement cylinders. I'll get this all sorted out well in time for your build.
Mike, LOL, well this pilot needed an underwear change after the first few seconds of the maiden. I'm just glad that I got it stabilized in a climb.
Thomas, I had your nose wheels installed but the AW mains. Your wheels and rims are just too valued to let them near mud on a lake bed.
Regards,
Jim
Roy, glad to hear that you don't have to get your strut machined. Thanks for the replacement cylinders. I'll get this all sorted out well in time for your build.
Mike, LOL, well this pilot needed an underwear change after the first few seconds of the maiden. I'm just glad that I got it stabilized in a climb.
Thomas, I had your nose wheels installed but the AW mains. Your wheels and rims are just too valued to let them near mud on a lake bed.
Regards,
Jim
03-23-2015, 03:16 AM
#1193
Wow Jim congrats on your maiden... it looks like it took a few years off of your life! 
Your description had me puckering in my chair.
I am glad you were able to tame the beast.
The one photo you have on take off reminded me of my last flight on my Rafael, unfortunately I didn't recover from the stall and it pancaked onto the run way.
Your description had me puckering in my chair.
I am glad you were able to tame the beast.
The one photo you have on take off reminded me of my last flight on my Rafael, unfortunately I didn't recover from the stall and it pancaked onto the run way.
03-23-2015, 07:58 AM
#1195
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Congratulations Jim
You are enjoying all your hard work in the air. Fantastic.
After all it will be perfect.
Pierre Fouché
You are enjoying all your hard work in the air. Fantastic.
After all it will be perfect.
Pierre Fouché
Last edited by Rafale; 03-23-2015 at 08:17 AM.
03-23-2015, 11:04 AM
#1196
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03-24-2015, 09:55 AM
#1197
Many thanks to Horizon Hobby for sponsoring Jet Team USA 2015. We very much appreciate your support.
The Gripen is currently equipped with four A6050 High Voltage digital servos controlling the retracts, doors, speed boards, and brakes. After Top Gun, I will upgrade the flight control servos to A6270 HV digital servos.
Regards,
Jim
The Gripen is currently equipped with four A6050 High Voltage digital servos controlling the retracts, doors, speed boards, and brakes. After Top Gun, I will upgrade the flight control servos to A6270 HV digital servos.
Regards,
Jim
03-24-2015, 06:33 PM
#1198
Radio Programming to Override Gear Door Sequencer
Further to post #1139, I explained the operation of the full scale gear doors as follows:
- The landing gear & doors operate in Mode 2 (the gear doors are normally closed, open for gear to extend/retract, and then close again); and
- when the engine is shut down, the doors open for maintenance purposes. The doors remain open until the engine is started and taxi speed exceeds 20 km/hr and then they close and revert to Mode 2 operation
I also needed to be able to open the doors for maintenance purposes too. I can only reach the fueling connection and manual shut off valve when the main gear doors are open. The plane is equipped with an MBar sensor which measures the air system pressure (rather than an on-board failsafe (eg Tam's, DreamWorks, etc) so I was able to use the transmitter's built-in sequencer to control the gear and the doors.
In order to be able to open the doors manually, I wanted a switch to over-ride the sequencer control of the doors. Here's how it is done:
1) Create a function "Doors" in Function Assignment. Assign a logical switch (in my case L2) to control the doors. Leave the Gear control blank "..."
2) Program the sequencer as follows:
- Q1 "Doors" activated by the gear up/down switch (Sk in my case). Leave the Overwrite channel blank "..."
- Q2 "Gear" activated by the gear up down switch (Sk). Assign the Overwrite channel to "Gear 1"
3) Program logical switch as follows:
- L2 "DrCntrl" Enabled
- Control 1 is the override switch (Se), Condition = AND, Control 2 = Q1 (the door sequencer)
- after selecting Q1, press the Prop button (F2) so that it is proportional
- set the evaluation to Lin (linear).
Now, whenever the Se switch is in the up position, the sequencer has control of the doors. When the Se switch is in the down position, the doors are open.
To replicate the scale functionality, I'll put the Se switch in the down position after shutting down the turbine (allowing me access to the manual fuel valve and fuel fill port). While taxiing out for the next flight, and with the airplane oriented so the doors can be seen by the judges, I will move the Se switch to the up position to close the doors and give the sequencer control.
The same method can be used to override the Butterfly function, for example, using a switch. See http://www.jetimodel.com/en/DC-16-am...sing-a-switch/
Regards,
Jim
Further to post #1139, I explained the operation of the full scale gear doors as follows:
- The landing gear & doors operate in Mode 2 (the gear doors are normally closed, open for gear to extend/retract, and then close again); and
- when the engine is shut down, the doors open for maintenance purposes. The doors remain open until the engine is started and taxi speed exceeds 20 km/hr and then they close and revert to Mode 2 operation
I also needed to be able to open the doors for maintenance purposes too. I can only reach the fueling connection and manual shut off valve when the main gear doors are open. The plane is equipped with an MBar sensor which measures the air system pressure (rather than an on-board failsafe (eg Tam's, DreamWorks, etc) so I was able to use the transmitter's built-in sequencer to control the gear and the doors.
In order to be able to open the doors manually, I wanted a switch to over-ride the sequencer control of the doors. Here's how it is done:
1) Create a function "Doors" in Function Assignment. Assign a logical switch (in my case L2) to control the doors. Leave the Gear control blank "..."
2) Program the sequencer as follows:
- Q1 "Doors" activated by the gear up/down switch (Sk in my case). Leave the Overwrite channel blank "..."
- Q2 "Gear" activated by the gear up down switch (Sk). Assign the Overwrite channel to "Gear 1"
3) Program logical switch as follows:
- L2 "DrCntrl" Enabled
- Control 1 is the override switch (Se), Condition = AND, Control 2 = Q1 (the door sequencer)
- after selecting Q1, press the Prop button (F2) so that it is proportional
- set the evaluation to Lin (linear).
Now, whenever the Se switch is in the up position, the sequencer has control of the doors. When the Se switch is in the down position, the doors are open.
To replicate the scale functionality, I'll put the Se switch in the down position after shutting down the turbine (allowing me access to the manual fuel valve and fuel fill port). While taxiing out for the next flight, and with the airplane oriented so the doors can be seen by the judges, I will move the Se switch to the up position to close the doors and give the sequencer control.
The same method can be used to override the Butterfly function, for example, using a switch. See http://www.jetimodel.com/en/DC-16-am...sing-a-switch/
Regards,
Jim
03-25-2015, 02:37 AM
#1199
Jim, did you also set it up to replicate this?
"The doors remain open until the engine is started and taxi speed exceeds 20 km/hr"
The reason I ask is I had an idea about a speed brake deployment where if we had an input from the wheel sensor (need to design one
) then a condition could be created where the speed brakes are deployed at wheel speeds above a trigger set point and retracted when the speed is below the trigger set point (Landing Flight Mode). Of course you would want an override (arming switch) to turn off in case of a go around (bolter).
"The doors remain open until the engine is started and taxi speed exceeds 20 km/hr"
The reason I ask is I had an idea about a speed brake deployment where if we had an input from the wheel sensor (need to design one
) then a condition could be created where the speed brakes are deployed at wheel speeds above a trigger set point and retracted when the speed is below the trigger set point (Landing Flight Mode). Of course you would want an override (arming switch) to turn off in case of a go around (bolter).
Last edited by RCISFUN; 03-25-2015 at 02:40 AM.
03-25-2015, 06:38 AM
#1200
Hi Rich,
No, I'm going to manually move the switch rather than programming it to close when the scale speed exceeds 20 km/hr because:
- it is very convenient for maintenance or test purposes to be able to open/close the doors at will
- I can ensure that the doors close in view of the judges. This might give a bit of a bump to the realism score
- scale speed of 20 km/hr is model speed of 4 km/hr (2.5 mph) and I'm not sure that the airspeed sensor is very accurate at such a low speed and, if it is, then pointing the nose into a slight breeze would close the doors.
Regards,
Jim
No, I'm going to manually move the switch rather than programming it to close when the scale speed exceeds 20 km/hr because:
- it is very convenient for maintenance or test purposes to be able to open/close the doors at will
- I can ensure that the doors close in view of the judges. This might give a bit of a bump to the realism score
- scale speed of 20 km/hr is model speed of 4 km/hr (2.5 mph) and I'm not sure that the airspeed sensor is very accurate at such a low speed and, if it is, then pointing the nose into a slight breeze would close the doors.
Regards,
Jim