mstull
R.I.P.
I left Sun-n-Fun, filled with enthusiasm. So I started my next project, a monoplane that pitches the wings opposite each other for roll control, instead of using ailerons. It is well suited for an U/L. My goal is to make a Part 103 legal monoplane, that climbs and glides well, and has a sporty roll rate.
I'm using the outer 12' sections of a previous monoplane wing (see the photo below). That wing's single spar is ideally suited for supporting the wings so they can pivot. I'm using the cockpit, empennage, and engine, off my biplane. So the new plane is made almost entirely of recycled parts. It is taking very little time or money to complete. The fuselage is just a triangle of tubing that everything connects to.
Pitching the wings for roll control avoids the drag and adverse yaw of deflected ailerons. I'm planning for around +and- 10 degrees of maximum wing pitch deflection.
At first glance, you'd think that the wing with the greater angle of incidence would have more induced drag because of its greater Angle of Attack (AOA). That would be true if you mounted the plane solid in a wind tunnel. But in flight, the plane is free to roll. Since that wing will be rising, it's AOA is largely unchanged.
Pitching the wings should have a powerful rolling effect. It's not like an aileron that's having to fight against the rest of the wing area. A friend already programmed my design into X-Plane (computer simulation). It rolls better than the biplane, and climbs and glides much better (on the sim).
One concern is near stall on landing. If I try to lift a low wing, will that wing be likely to stall instead of lifting? There is a split second when the roll inertia of the plane resists that wing's rising... particularly with a sudden, large deflection. I almost never land at full stall anyway.
The other obvious concern is flutter. Flutter is a fickle beast. I'm making the wing control system very stiff and tight. I've learned that lose cables and flexibility can lead to flutter. It's always fun being the test pilot on a new, experimental design.
Practicing stalls in flight, I'll have to be sure to keep the stick neutral, and use rudder to keep the wings level. Deflecting the wings would tend to make one wing recover first, which would roll the plane sharply.
I made no effort to design every last detail of this plane. I'm just solving problems as I build, which I enjoy very much. Since the fuselage is just a triangular frame, the space between the wing roots will need to be filled to prevent air from spilling around the wing roots like it does around the tips. Either that, or I'll have to add end plates (fences) to the roots.
Here's a picture showing my progress so far. I finished hanging and adjusting the wings. The roll control linkage isn't connected yet, so they're both resting at 10 degrees up deflection. They pivot very smoothly on their root and strut pivot blocks. The main gear and cockpit are attached. The cockpit is adjustable forward and aft, to adjust the center of gravity. Expect a first flight this month.
I'm using the outer 12' sections of a previous monoplane wing (see the photo below). That wing's single spar is ideally suited for supporting the wings so they can pivot. I'm using the cockpit, empennage, and engine, off my biplane. So the new plane is made almost entirely of recycled parts. It is taking very little time or money to complete. The fuselage is just a triangle of tubing that everything connects to.
Pitching the wings for roll control avoids the drag and adverse yaw of deflected ailerons. I'm planning for around +and- 10 degrees of maximum wing pitch deflection.
At first glance, you'd think that the wing with the greater angle of incidence would have more induced drag because of its greater Angle of Attack (AOA). That would be true if you mounted the plane solid in a wind tunnel. But in flight, the plane is free to roll. Since that wing will be rising, it's AOA is largely unchanged.
Pitching the wings should have a powerful rolling effect. It's not like an aileron that's having to fight against the rest of the wing area. A friend already programmed my design into X-Plane (computer simulation). It rolls better than the biplane, and climbs and glides much better (on the sim).
One concern is near stall on landing. If I try to lift a low wing, will that wing be likely to stall instead of lifting? There is a split second when the roll inertia of the plane resists that wing's rising... particularly with a sudden, large deflection. I almost never land at full stall anyway.
The other obvious concern is flutter. Flutter is a fickle beast. I'm making the wing control system very stiff and tight. I've learned that lose cables and flexibility can lead to flutter. It's always fun being the test pilot on a new, experimental design.
Practicing stalls in flight, I'll have to be sure to keep the stick neutral, and use rudder to keep the wings level. Deflecting the wings would tend to make one wing recover first, which would roll the plane sharply.
I made no effort to design every last detail of this plane. I'm just solving problems as I build, which I enjoy very much. Since the fuselage is just a triangular frame, the space between the wing roots will need to be filled to prevent air from spilling around the wing roots like it does around the tips. Either that, or I'll have to add end plates (fences) to the roots.
Here's a picture showing my progress so far. I finished hanging and adjusting the wings. The roll control linkage isn't connected yet, so they're both resting at 10 degrees up deflection. They pivot very smoothly on their root and strut pivot blocks. The main gear and cockpit are attached. The cockpit is adjustable forward and aft, to adjust the center of gravity. Expect a first flight this month.
