Q about right thrust

[Psikelly]

When I bought my Mini SS it was setup with the motor slanted to the right which gives right thrust Im told. But, my motor also rotates to the right. Does this sound correct? If my motor rotates right then shouldnt the motor be slanted to the left side to counteract?? And does a small electric like an Eflite 450 even produce enough torque to need the right or left thrust??

[Tom Hastie]

There are two "torque" factors that the right thrust tries to counteract. Spiral Slipstream and P-Factor

Spiral Slipstream is fairly easy to picture. If you picture yourself sitting in the cockpit of your airplane and look at the propeller you'll see it rotating clockwise. This clockwise rotation sets up a clockwise spiral slipstream in the air flowing back over the fuselage. If you follow this spiral down the fuselage you'll see that it hits the left hand side of the Vertical Fin. Air hitting the left side of the vertical fin causes the airplane to yaw to the left. Hence the need for right rudder on the initial take-off roll. Or... hence the need for right thrust.

P-factor is most noticable at high angles of attack. If you picture your plane flying slowly at a high AOA, you'll see that the propeller disk is tilted as it goes through the air. The down going propeller blade actually ends up having a higher pitch angle relative to the airflow than the up going blade. More pitch means more thrust, so the right side of the prop disk makes more thust causing left yaw. So again, you'll need right rudder or right thrust to correct.

Spiral slipstream and P-factor are both worst at low airspeeds. That's why funfly aircraft (like Funtana's) have generous amounts of right thrust. So they don't need as much rudder correction when hovering around.

So yup, a Eflite 450 will have some torque effects. However, with these small aircraft, generally a "that looks about right" method for setting the right thrust is fine. The rest can be removed with the rudder stick while you fly :)

This site (designed for full scale pilots) has a good discussion of the yaw prop effects.

http://www.av8n.com/how/htm/yaw.html#sec-helical-propwash

Hope the above gibberish is understandable.

Tom

[Psikelly]

Great Thanks! That helps a lot. Makes it much easier to understand when i know WHY. Thanks again