I'm getting to the detailed programming part of my motion platform, but I'm lacking some real flight experience.I would appreciate if anybody can give me some details on actual small / medium GA aircraft motion during the following events: 1.When extending flaps: what do you feel during transition and after extended? 2. When lowering gear: what do you feel during transition, lock, and flying with gear down? 3. When extending airbrakes / spoilers: what do you feel during transition and after extended?4. What is the actual duration of the buffeting after rotation takeoff? What does the buffeting amplitude depend on? 5. Does anyone have a good trigger event during flight (vertical speed?) for activating motion platform turbulence? Although my motion cues drive only pitch and roll, with the right algorithm you can get some nice effects. See http://www.simprojects.nl/motion_software.htm and the subchapters. Thanks for your help!Roland

Hi Roland,Not actually flown in GA a/c lately (last time was about 30 years ago), but I have noticed some of the things you mention in an airliner. Of course it all depends on each specific a/c type. On some the effect is greater, on others hardly noticed.>1.When extending flaps: what do you feel during transition and>after extended? A small upward motion known as ballooning. Also a little bit of forward motion (like breaking) from the extra drag. More noticeable when extending flaps during descend.>2. When lowering gear: what do you feel during transition,>lock, and flying with gear down? Noise! A lot of noise! And sometimes (haven't noticed everytime altough I was looking for it and waiting) a tiny fwd motion from the extra drag. More noticeable in 737s.>3. When extending airbrakes / spoilers: what do you feel>during transition and after extended?Light rubble and a small dive effect.>4. What is the actual duration of the buffeting after rotation>takeoff? What does the buffeting amplitude depend on? Depends on the pilot!!! I have been in take-offs that if you don't look outside you would wonder if you are still running down the runway!!! Especially in A320s!>5. Does anyone have a good trigger event during flight>(vertical speed?) for activating motion platform turbulence? Can't answer this one.George DorkofikisAthens, Hellashttp://online.vatsimindicators.net/811520/1704.png

I think it's quite hard to explain these like this - perhaps you could find someone at the local airport to take you for a small test flight? Preferably an instructor, so you could fly yourself?//T

i find the hardest to simulate in GA motion would be the unstableness in certain aircraft. i flew the piper warrior and there were occassional air pocket( weightlessness and drop upon takeoff and other times)The balloning effect is true on lowering flaps but its actually a little unpredictable with regards to how it moves.i too suggest to take a flight yourself and try to replicate what you feel.

Thanks guys, You are right, I should take a flight myself get the experience first-hand. I will check with the nearby airports. Indeed what I remember most from a flight taken about 10 years ago were the airpockets. I would love to simulate these, but vertical motion (heave) is quite complicated to implement.

you would need a 6 DOF platform. Costly and complicated to implement. but if its good enough for a Level-D sim, everyone would love it.

Hi Roland,I also think a ride would be worthwhile. How you considered adding active seat cushions?Mikewww.mikesflightdeck.comwww.mikesflightdeckbooks.com

Hello Mike, Active cushions, do you mean the ones that inflate and push you down, to simulate continuous G's? For adding heave I had some ideas: (not sure if they'd work)Actually for heave the most intense feeling is suddenly going down. Since gravity is helping here, it would not take a lot of power to trigger a falling motion. Here's the idea: I would make a device that lets my platform fall for an inch or 2 (landing on the innner tire), then slowly 'wind' itself up again. Since I have a platform hanging in cables, mechanically wise it would not be too hard. The trigger for falling could come from a sudden amount of negative G's. I think this would be a reasonable compromise. Ideally, I would let the complete platform fall down, but for a simple trial version one could have only the chair going down. Not sure how that experience would be, as the motion would only be in your body, not your legs. For mechanics, pheumatics could be a good option, as it's a simple in/out action. What do you think?

having you chair fall only would have to make sure your screen follows too. if not, you would have orientation issues after the fall, screen would be higher.

I guess you're right. The whole platform including visuals should move together. Thought of a new way: use the rubber inner tube below my platform as a lifting device by partly depressing it. I wonder how much force it will take... So many ideas, not enough time to try them all...

i get a rubber inner tube would be best as an alternative to simulate the air pockets. I saw a video doing that somewhere.