Can't fly default 172

[BigEdWND]

Glenn is correct when he says that torque causes the aircraft to turn when full throttle is applied SUDDENLY, but it's always to the left. Propeller(s) turn clockwise (when viewed from the rear), which attempts to induce a roll to the left (counter-clockwise), but this is not likely while still on the ground), so the result is a tendency to yaw to the left. A bit of right-rudder during the takeoff run is normal.

Because of the tremendous torque generated by the Allison or Rolls Royce engines and the huge propeller, this was a significant factor with the P-51 Mustang. It was no problem at all with the twin engine P-38 Lightning because the engines turned in opposite directions.

I disagree with Glenn that weight distribution is a factor. Two 400-pounders in the right seat would make no difference while the plane is still on the ground. After takeoff, at crusing speed, any tendency to roll to the left would be corrected by a slight amount of right AILERON trim. Setting rudder trim to "neutral" may also be necessary.

Most of my flight simming is done in helicopters (nearly 2 dozen in my "fleet"). If you think torque is a problem while still on the ground in a Cessna, you might want to check out the significant action/reaction characteristics of a helicopter. Unless it's a Chinook (with counter-rotating twin-rotors), that big overhead "propeller" generates a LOT of torque which must be controlled with the "rudder" pedals.

Ed

[Kimber]

Is this problem only with these two aircraft?? It looks like it could
be a joystick problem??

What stick do you use??

[ladamson]

>Glenn is correct when he says that torque causes the aircraft
>to turn when full throttle is applied SUDDENLY, but it's
>always to the left. Propeller(s) turn clockwise (when viewed
>from the rear), which attempts to induce a roll to the left
>(counter-clockwise), but this is not likely while still on
>the ground), so the result is a tendency to yaw to the left. A
>bit of right-rudder during the takeoff run is normal.

Well, not always. Some turn counter-clockwise such as the RealAir Spitfire with the Griffon engine, and you'll find numerous two-cycles on ultra-lights turning to the left, as well as those Russian radials on several aerobatic aircraft as well as kit planes.

>I disagree with Glenn that weight distribution is a factor.
>Two 400-pounders in the right seat would make no difference
>while the plane is still on the ground. After takeoff, at
>crusing speed, any tendency to roll to the left would be
>corrected by a slight amount of right AILERON trim. Setting
>rudder trim to "neutral" may also be necessary.

I may have missed it somewhere in this thread, but yes, aileron trim will even out a none or heavy passengers weight, and rudder trim will counteract the spiral "slipstream" effect from the prop. Some aircraft just have a fixed rudder trim tab, to cancel the effect at cruise speeds. Most engines are also mounted at angles, and vertical stabilizers may be mounted at angle too, to counteract slipstream.

Ladamson