Prop effects in FU3...

[Guest R_Driscoll]

I think there may be two effects with the swirling slipstream - one on the rudder, one on the wings/ailerons. Below v2 I suppose the wing effect is small since the ground counterbalances, but close to takeoff it might add to the the net effect causing the plane to fly Wun Wing Lo. I think both effects would be in the same direction (same as propellor) and opposite to the propellor reaction force. I don't know if FU3 models this.And I speak from my 'vast' experience in real flying here. Zero hours total so far and counting. So I've probably got this totally wrong.RobD.

[Guest JakeInHartsel]

Well Hans & Rob,I have flown a number of airplanes and in all that I have flown you have to hold some right rudder to keep it straight on the runway. Note that I have only flown airplanes with clockwise (As seen from the cockpit). Most airplanes in the US have propeller rotation in that direction. The effect in an airplane with a nosewheel is much less noticable than one with a tailwheel.For some reason in FU it is necessary to hold left rudder on all except the Russian Planes. I don't know why this is I suspect there was an error in their model. A lot, if not most, of the Russian planes hpropeller turns counter clockwise and on a real plane such as this you would need to hold left rudder to keep it straight on the runway durring takeoff. I have never flown a Russian paln, but friends that have confirm the need to hold left rudder.I hope this helps.JakeInHartselSitting in front of my computer at 9,700 ft. msl

[Christopher Low 5,354]

Jake,I am puzzled by your comments here. Surely a clockwise rotating propellor would force the nose of the aircraft towards the left ? That would require RIGHT rudder to compensate, which you have clearly stated elsewhere on this thread.Please enlighten me :-)Chris Low.

[Guest JakeInHartsel]

Sorry Chris, I confused my self, which is not hard to do.You are right on a regular airplane with a clockwise rotating propeller the nose tends to move to the left, necessitating some right rudder.What I should have said on the other was that FU1, during takeoff with all but the Russian Plane the nose tended to move to the right necessitating left rudder to keep it straight.But like any airplane, especially taildragger, you just give it what ever rudder inputs you need to keep it straight.

[Lars Peter 0]

Hello.I can give you some interesting info about propeller slipstreams thatI have noticed during the years with RC-flying.At low speed with taildraggers this can be a big "RC"problem.With this small aircrafts the effect is huge.The slip strem goes in a bowe from the nose, and hits the rudder area with great forces and sometimes opposite rudder is not enough to get a strait line on the runway.With some models the engine had to be mounted in with a pull angle 2-3 degrees from the fuselage centerline to compensate some from this effect. See the illustrated picture below and see the turning direction of the propeller.In this case the slipstream will hit the left side of the rudder.Lars Peter.:-wave

[Guest JakeInHartsel]

Thanks Lars Peter, similar things can happen with real planes. Generally you overcome them by advancing the trottle slowly so that you get to a higher speed where the rudder is more effective when you get to the higher P effect which high trottle settings bring.I am just get back into flying RC, after a very long time. the last time that i flew it was with rubberband escapement.JakeInHartselSitting in front of my computer at 9,700 ft. msl