New rotorcraft concepts

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dukkbutt

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Joined
Jan 9, 2021
Messages
10
Location
Spokane, WA
Can't find a reference about stability of a flying wing and pusher props. I'm sure I read it years ago but I'll just withdraw the statement.

If a tractor prop airplane is displaced nose up during flight but still moving in its original direction due to inertia, the thrust vector is above the line of flight, in front of the cg, pulling the nose up which is destabilizing. The pusher prop in the same circumstance has an upward thrust component but it is behind the cg thus pushing the tail up and the airplane back toward level flight.

These are relatively small forces and easily overcome by normal aircraft stability design so they are not typically a consideration.
 

D Hillberg

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Joined
Nov 23, 2010
Messages
1,718
Location
very low low low earth orbit
Can't find a reference about stability of a flying wing and pusher props. I'm sure I read it years ago but I'll just withdraw the statement.

If a tractor prop airplane is displaced nose up during flight but still moving in its original direction due to inertia, the thrust vector is above the line of flight, in front of the cg, pulling the nose up which is destabilizing. The pusher prop in the same circumstance has an upward thrust component but it is behind the cg thus pushing the tail up and the airplane back toward level flight.

These are relatively small forces and easily overcome by normal aircraft stability design so they are not typically a consideration.
When thrust/drag & weight/lift are equal it doesn't take much to upset the apple cart.
Add inertia and you get some interesting flights
 

EzyBuildWing

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Joined
Sep 23, 2009
Messages
581
Location
Sydney NSW Australia
Simple "Rat Rod" VW-gyro makes a big statement.........what could be simpler?
Might fly and look better with a dirty/rusty old reliable Rotax 4-stroke with open rusty noisy-pipes, and tundra-tyres.
Love the Rat Rod look......and especially the leather saddle-bag!
Maybe Rat-Rod enthusiasts would go for towing it around on "Rat-Rod trailers" behind their "Rat-Rod cars"?
Mad Max Gyro Silverton Museum.jpg
 

piolenc

Member
Joined
Feb 17, 2013
Messages
12
Location
Mindanao, Philippines
Tractor gyroplanes are much more stable then pushers, PIO PPO are nearly nonexistent in early tractor designs
Flying wings are unstable due to center of pressures and C/G limits being exceeded and not thrust.
Short coupled flaperons and spoilers are not as effective as tail feathers on a stick.
no difference in jet thrust or pusher prop thrust.
Old engineer saying "Easier to pull a rope then push it" pulling is naturally more stable
There may be something about gyroplanes that conceals the stabilizing effect of a propeller behind the center of gravity, but the notion that pulling is just naturally more stable is invalid for all aircraft. A pusher stabilizes in both yaw and pitch.
 

U+fly

Active Member
Joined
Nov 25, 2021
Messages
38
There may be something about gyroplanes that conceals the stabilizing effect of a propeller behind the center of gravity, but the notion that pulling is just naturally more stable is invalid for all aircraft. A pusher stabilizes in both yaw and pitch.
Thank you for confirming this fact, explained earlier as good as possible.
 
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