M6RV6 wrote:EZ, Just the opposite of the Robertson? Is that what I hear? Sounds interesting, might have to have your personal Phone # before I get done!!
I know on my old J5, it sure did make a big difference if the aileron's were set, up, even, or down 3/4 of an inch!!
Thanks GT
Yes, opposite of Robertson for a reason. Drooping the ailerons downward with the flaps makes more camber across the whole wing, thus maximum lift. No argument about that. But it also means there is a greater risk of tip stall in gusty conditions, where you have the wing making a lot of lift all the way to the tips. If you were flying in smooth air the drooped ailerons would give you the slowest flight possible. But as those 20K hour graybeards in AK will tell you, slowest flight does not always equate to best achieved short field performance. For reliable, safe, predictable short landing required full control and real-world maneuverability down near the stall. And you need lots of drag for the steepest approach without building up speed.
I have no experience with the Robertson mod. It is certified and that means they proved it is safe. But they might have done a lot of other things to achieve that when the ailerons were drooped. And the Robertson ailerons are not drooped as far as the flaps.
What I can say with a little experience behind me is that the "crow" system works, works very well, and adds another level of safety/control/drag. Having t6he ailerons a little bit up, with the flaps a lot down, does several good things on landing. First, it reduces the camber at the wingtip, and greatly increases the effective twist (washout). This reduces or even eliminates tip stalls from gusts, harsh maneuvering at low speed, etc. Chalk up one on the safety side.
The washout lowering the AOA at the tip means that the air flowing over the top of the wingtips remains attached, with a thinner boundary layer. So your ailerons are still very powerful even at low speeds. no mushy softness. Raising the ailerons and making the wing act like it is twisted (like a propeller) crates a lot of drag, giving you a very steep descent but without the speed buildup.
Raising the ailerons in SOME cases will give you back enough otherwise lost control authority and safety, so you can use a larger deflection on the flaps. Large flap deflections can easily "blank out" the tail. So there is some maximum flap deflection, but this is limited by tail blanking and not tip stalls or control authority.
So although I can't say from experience, I would guess that a Franken-Maule with full span drooping flaps and ailerons would be able to fly a tad slower, but that a Franken-Maule with flaps down and ailerons up would be able to make steeper approaches, over trees and hills,and fly slowly in gusty conditions with more control, and have an extra margin of safety against tip stalls.
Now this means you will have an incredible handling airplane for steep short landings, but for short takeoff there is a downside to this, which is that you have a lot more drag than lift. So for takeoff you would want to have mild or moderate flap deflection, matched with just a little LESS droop on the ailerons (like Robertson). That would give you the best climb for the available power, with the least drag.
It's not me you want to talk to on the phone, it's a German guy named Dipl. Ing. Gerhard Waibel in a little Bavarian town named Poppenhausen. He perfected the "crow configuration" in 1976, on the AS-W20 sailplane that was my first love.
