Simon Chaddock Posted November 20, 2008 Share Posted November 20, 2008 QuestionWhy should pointing the engine to the right (a sideways force) compensate for engine torque (a twisting force)?An answer to the above might also clarify if the same result is achieved when flying inverted.I would have thought it was aileron trim that counters engine torque which would indeed be the same when flying inverted. Perhaps I am also missing something. Quote Link to comment Share on other sites More sharing options...
Erfolg Posted November 20, 2008 Share Posted November 20, 2008 Could the use of engine side thrust have something to do with the rotating mass of air from the propeller, impinging (that is a nice friendly word) on the airframe imparting a side force, in addition to the longitudinal force?If the force were torque or gyroscopic force, it would effect both DF and pushers. Are they so affected?Erfolg Quote Link to comment Share on other sites More sharing options...
Former Member Posted November 20, 2008 Author Share Posted November 20, 2008 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted November 20, 2008 Share Posted November 20, 2008 I seem to have opened a right can of worms here! The subject of engine offset has always been very debatable. The circulating propwash could well account for the left roll tendency because I have not found thrustline offset to be necessary on a couple of pushers I have made, but these were not intended to be very aerobatic.I have always endeavered to get a model to fly straight up, down, upright, inverted and in knife edge. Look at the torque roll - the model has no forward speed and if left alone rolls to the left. The propwash must be far more effective here.Now look at a (toy) gyro. If you push it in one direction it does not go away from that direction but responds at 90deg. to the force applied, so an engine offset to the right will not necessarily make the model yaw right. Try fitting a smaller prop to a model and you will find that it tends to lose sense of direction and has a mind of its own. This is frequently demonstrated on el*ctr*c models which have a high revving motor turning a small prop. Right thrust is not really pulling to the right as you look at an upright model but countering the forces which are trying to roll it to the left - whichever way up it may be. What does this have to do with airfoils? Sorry Eric. Quote Link to comment Share on other sites More sharing options...
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