drooped ailerons

[swoeric]

I was wanting to know if anybody had any experience in using drooped ailerons. i know some have them level for max speed and others hang a tad bit lower. has any body rigged them 3/4 or more lower. has anyone flown a plane that has adjustable droop and no flaps.

[Mark Julicher]

Re: drooped ailerons

I have occasionally flown a Kitfox with full span flaperons. Obviously the full span droops when flaps are deployed. The adverse aileron yaw with full flaps down is an eye opener.

Radically drooping only the ailerons, (i.e., wing tip only), risks a tip-first wing stall and very likely some ugly spin entry characteristics.

[Hank Jarrett]

Re: drooped ailerons

Drooping the ailerons is NOT a good idea! It will change the lift distribution adding a little extra lift at the tips but at the cost of allowing the stall to start at the tip instead of the root. That is most likely to happen when you trip the stall at low speed by moving the controls slightly in roll. Kind of like what you are doing on every landing. So here you are, low and slow and one wing suddenly stalls. Even trying to recover with rudder (since the ailerons will make the stall worst at this point) will not be enough. You are going to be a pile of smoldering wreckage at the end of the runway.
Only good thing about this scenario is you are close to the runway threshold and the rotation tends to throw the wreckage off to one side a little so the planes following you can see them pulling the bodies out of the wreck.
Short answer, this is something that will give you about 3 knots faster cruise and a sudden death in the near future. DON'T DO IT!
Hank

[mike lutz]

Re: drooped ailerons

Some years ago I played around with my ailerons on my 1940 bc65.My findings were that with both ailerons up a quarter inch I could get slightly more cruise.(4-5mph).any more than that it went the other way.Stalls with them up just that much were not good ,as the tips would stall first do to the loss of lift from a deformed boundry layer over the wing.End result NOT RECOMENDED.Then I drooped the ailerons a quarter inch and found a slightly shorter take off,slightly better climb,and 4-5 mph less cruise.Stalls were much better than raised,but it didnt just fly quite as nice as when they are in line with trailing edge .The bottom line is this,its not worth your time and effort to play around with it.It flys so much nicer the way it was desighned to be.I would leave it alone.Just my two cents worth.
Mike

[Hank Jarrett]

Re: drooped ailerons

Quick correction (hey, it's early). DROOPING the ailerons should slightly increase CLIMB, not cruise. RAISING the ailerons will increase cruise, but BOTH will mess up handling and drooping will cause tip stalls that can kill you.
If you got a significant improvement in cruise from raising the TE of the aileron (more than 5 knots) I would suspect the plane might be out of trammel (bent) someplace. Raising them too far will actually reduce cruise speed at any equal power setting. Raising them at all will have a negative effect on smooth roll control that will probably add drag from the constant inputs, negating the 5 knots anyway.
Same results. Lower them and risk death for an insignificant increase in climb, or raise them for poor handling and no effective improvement.
Hank

[swoeric]

Re: drooped ailerons

Thank you guys much. This was exactly the information i come here for. I was also worried about the stall effects. I knew that this wasn't an issue with the flapped planes but unsure here. thank you again.

Eric

[N96337]

Re: drooped ailerons

I would imagine that you'd run the risk of 'aileron reversal' at the stall if only ailerons are drooped, Hank? I remember talking to Del Benjamin about the Gee Bee and him telling about aileron reversal if you used much aileron landing that thing. Didn't sound like much fun!
John

[Hank Jarrett]

Re: drooped ailerons

Long time ago we did some analysis of aileron reversal and that time it turned out to be because the wing was actually twisting. At high speeds the aileron was actually acting like a trim tab and twisting the wing the opposite direction. IT was evidently a common problem on several WW-II planes when the wing wasn't stiff enough.
On a low and slow Taylorcraft I would have to look at it to see what would happen if one drooped aileron tip stalled that wing while the other was deflected up. Whichever wing was producing the most lift would roll the plane over and I am guessing it would roll into the lowered aileron suddenly and violently.
Hank

Just a guess, I'm not going to volunteer to do the test flight!

[flyguy]

Re: drooped ailerons

Moved to Cruise Speeds. 30Nov10.
DC

[flyguy]

Re: drooped ailerons

On a low and slow Taylorcraft I would have to look at it to see what would happen if one drooped aileron tip stalled that wing while the other was deflected up. Whichever wing was producing the most lift would roll the plane over and I am guessing it would roll into the lowered aileron suddenly and violently.
Hank

Just a guess, I'm not going to volunteer to do the test flight!

Yep, it's called, "Precision spin entry." Use a little power (torque left), rudder left, nose up, right aileron to maintain heading, BOOM, breaks left precisely every time. Let off on everything and pull back power coming over the top and it will reverse heading 180 degrees, 1/2 turn spin.
DC

[Hank Jarrett]

Re: drooped ailerons

I'm afraid I don't fly much aerobatics and I think some turkey just came up in my throat.
Hank

[crispy critter]

Re: drooped ailerons

It's actually a pretty fun and easy manuver to perform in a t-craft...it does it very nicely however not recommended for anyone not comfortable or compitent with spins,rolls,etc.
If you really want to watch the world go'round then just as she breaks over pull full back elevator,stand on the left rudder,maintane the right aileron and see how fast you can count......bet ya can't keep up,lol. Make sure you don't try this without proper spin entry/spin recovery training and very vigirous aircraft inspections!

[guns68]

Re: drooped ailerons

My plane's ailerons are rigged 1/2 inch low and I have not noticed anything good or bad. That being said the only other T'craft I have flown was an F19 (mine is a 65hp BC12D) and it's ailerons were level. I have noticed that it's not an uncommon "mod" up here for planes to be rigged 1/4 to 1/2 inch low. I'm bringing mine down for maintenance soon. Maybe I'll change things back to level and see if I notice a difference. Either way she fly's pretty well as is.

[Hank Jarrett]

Re: drooped ailerons

Check the wash-out/in while you are at it. You might just have a droop that counters excess wash-out.
Hank

I also have had spin training. Got to the point where it wasn't that bad, just not really that fun either. I REALLY believe in spin training! You don't want to learn how to recover when you weren't expecting it the first time.

[guns68]

Re: drooped ailerons

Thanks Hank,I'll be sure to check the wash out. I had not even thought about that.

I agree about spin training. The funny thing about me is that I really do not like the sensations when entering the stall, but once I get through that I found spins to be pretty fun.