Since you have asked: I would strongly favor a fixed angle of incidence for the rear wing, the configuration that has proven to work well. No need for rare earth magnets, a changed control input scheme if the plane enters a dive, etc.Which of these options - "a", "b", or "c" do you think is better? Or can you think of a better solution?
Hi Vigilant1,Since you have asked: I would strongly favor a fixed angle of incidence for the rear wing, the configuration that has proven to work well. No need for rare earth magnets, a changed control input scheme if the plane enters a dive, etc.
This fixed incidence rear wing is a built-in design flaw of all Fleas.
That is why most airplanes fix the incidence of the wing that provides the majority of the lift, and vary the incidence of the other for pitch control.the issue of flight attitude and the ability to pull out of a steep dive. I think the only solution is the one Jean de la Farge of Argentina settled on - a separate elevator.
But if it's used as a takeoff flap, you can reduce the AOA of the rear wing. Then it's only something you have to use during takeoff and landings.The Cosandey Flap only went went up lessening the rear wing lift, it was to trim the nose down pitch that Fleas have as speed increases, as Duncan has described
Not only simpler but also easier and safer!Cosandey put a flap on the rear wing to accomplish the speed/trim change, it is a much simpler addition.
Hi Martin,By the way: In the context of our thread the whole chapter 6 is very interesting.
Absolutely - no issues there.<snip> If you move both, it only has a net effect.
No. You are wrong there TFF. The basic reason for moving both wings is to maintain the 60/40 lift split, and to completely remove the tendency for the rear wing to overpower the movable front wing. Your contention is exactly what traditional Fleas do, and they all have a tendency to nose over at higher speeds.No different than if you move one double and the other is fixed.
Exactly. But because the third surface is a symmetrical airfoil which is free-floating, it has little or no overall effect on the main flying surfaces. The point is, we WANT this third surface to fight the natural tendency to nose over at high speeds. It starts fighting only this scenario.If you add a third, no matter if in front or rear, it’s job is to fight the natural configuration of both surfaces.
The main wings ARE doing doing their job. But as I've outlined before, doing their job eventually raises the tail, drops the nose, requiring the pilot to pull back on the stick. Flight speed has been limited. Any significant increase in speed will see the nose dip significantly, and there is a race to get the nose up before the rear wing takes command completely. And this is where the third surface comes in. Pull up on the control lever, and the nose lifts. Once in safer territory, let go the tail control, and the third surface pivots freely again, minding its own business.Why not make them do their job in the first place.