3
$\begingroup$

enter image description here
(Source) Rudder twist on a Saab 91 Safir.

What are the design methods used to balance a propeller aircraft for left turning tendencies? I think it matters more the more powerful the engine(s) is.

A rudder twist seems to be one, not-so-detailed sources mention an offset engine, a slightly longer-, or differently balanced wing.

$\endgroup$
2
$\begingroup$

There are several ways, and the most effective vary their own yawing moment contribution with engine thrust:

  • A trim tab on the rudder which forces it into a correcting deflection. This trim tab can either be adjusted in flight or only on the ground. The flight-adjustable trim tab is set according to flight speed and is used on airplanes with a wide speed range.
  • Mounting the engine at a slight angle to the airplane centerline. This places the propeller at an offset which produces its own yawing moment.
  • Camber on the vertical tail. Since the tail is in the propeller slipstream, it experiences a relatively higher dynamic pressure at low speed and high engine settings, just when the p-factor is biggest.
$\endgroup$
1
$\begingroup$

Rudder twist seems like an exotic and expensive means to solve the problem. Most light aircraft use a pre-set rudder trim tab set during flight test at the factory, like this on a CE-172.

enter image description here(boldmethod)

$\endgroup$
  • $\begingroup$ Set at the factory and adjusted by the operator according to need. $\endgroup$ – J Walters Mar 17 '17 at 1:27

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.