One way to find out, but, get down into a pea-patch, roll a few feet, get moving and off the ground, then rotate upward,Rear engine won’t be able to half hover like a Bush plane. There is no vectored thrust over wing and tail. When you see a bush plane nose high, it’s cheating. You are not going to get steep angles like a conventional setup.
Those high CL devices create a huge need for a countering CM devices like a huge tail on a long boom with a lot of up trim. Can't be used on a flying wing.Yes, but I'll probably be going with som self-adjusting L.E. Slats, like are commonly used in Alaska for Bush Planes.
There are numerous flying wings with little, or even no vertical stab, from the Hortons and before, through the B1 Bomber.Those high CL devices create a huge need for a countering CM devices like a huge tail on a long boom with a lot of up trim. Can't be used on a flying wing.
It's more-or-less along the top of the wing, but there is plenty of room to adjust it. This is a preliminary design, I'm learning. If I could find, say, the vertical center of mass and drag, it would be placed better..
Such a high thrust line will require a substantial horizontal tail to counteract pitch-down tendencies .... look at tails of amphibious craft with high mounted pusher props .
best wishes in your experiments.
Does it matter? Maybe, but I'm not second-guessing my design, at this time. It looks right to me, except, perhaps the thrust line. That may take adjustment.I believe he is referring to the slats requirements of normal tail to keep the plane from pitching too much as speed changes. A flying wing has little leverage with the elevators. Think of a tail as a pry bar for the wing. Flying wing has very little leverage; that is why CG is critical. A long tail can have a much wider CG range because of the leverage.
The early stages are the best times to "second guess". Good foundations lead to good final results.Maybe, but I'm not second-guessing my design, at this time.
Actually, wing CG is -0.72 inches..., forward of the LE, in the V. Corresponds closely with your pilot/fuel CG. Hopefully I can get enough balancing moment from the battery, to counter the 1/2 VW, prop and fuselage. May have to be under, or even forward of my feet Wing Calc sheet is posted above.The early stages are the best times to "second guess". Good foundations lead to good final results.
My quick eyeball guess representing the overall CG based on a pilot and fuel being about the same weight as a legal part 103 airframe:
Red circle = pilot CG
Green circle = plane CG
Light blue = overall CG
View attachment 120900
Real numbers would be much better.
My guess for the center of drag would be pretty close to the overall CG. Moving the engine below the wing looks like good idea?
.It's more-or-less along the top of the wing, but there is plenty of room to adjust it. This is a preliminary design, I'm learning. If I could find, say, the vertical center of mass and drag, it would be placed better.
In addition, the high-lift devices make it want to pitch up.
There are no Amphibious Ffying wings, but I supposed someone could try to add floats, or a boat-like hull.
Probably more work to reconfigure than cutting from scratch..
Just had a thought .... lots of (cheap) gyrocopters that have wrecked rotors from low speed rollovers etc .... buy one .... toss out rotor components and install your wing.
YES ... your thrust line is is up on the wing ... (draw a straight line through prop and engine) ... (sideways view)
... your center of mass would be about your chest height (sideways view) ... draw a straight line through it (parallel to thrust line)
... your thrust line would be at least 36 inches above center of mass .... very high .... full thrust wants to push you both forward and nose down .... the exact opposite of what you want on takeoff and for stable flight .
Research early gyrocopters ... many had high thrust lines (8-12 inches) ... no tail feathers .... they tumbled out of the sky on a regular basis .... lowered thrust lines combined with horizontal stabilizers now make them very safe.
In your case the engine mounted behind the seat might work OK (similar to gyrocopters)
Thrust line is going to be high, due to the common 1/2 VW/prop combos. I'd rather not throw more weight on with a reduction drive.
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