torque question

[hotcoffe]

How to figure out the direction of the torque in any plane?

[Toad]

Turn off auto takeoff, push the power up, keep your feet off the rudders and see which way it goes.

[pangea]

Turn off engine to determine which way the prop rotates.  Torque will be in the opposite direction.

[hotcoffe]

Thnx.

[Latrobe]

For the most part, the torque is always to the left. The planes that have torque to the right are: Yak's, Typhoon (Tempest too I think), and Spit 14. I don't think there is another with torque to the right but I'm sure someone will correct me if I'm wrong.

[guncrasher]

p38's


semp

[Triton28]

p38's


semp

With both screws turning, the 38 has no torque due to counter rotating props.

[hitech]

Trivia question,

Does engine torque create a roll or a yaw force?

HiTEch

[Triton28]

Trivia question,

Does engine torque create a roll or a yaw force?

HiTEch

Both!   

[Skyyr]

Trivia question,

Does engine torque create a roll or a yaw force?

HiTEch

That's sort of a trick question. Taken completely on it's own, torque creates rolling force in single-engine, single propeller aircraft, but not yaw. Yaw is induced from the aerodynamics of airflow rotating around the fuselage due to prop mass airflow and from a non-neutral control surface configuration.

That is to say, torque itself does not induce yaw, but airflow from a turning propeller (which itself causes a rolling tendency) and the trim required to cancel out the effects of torque will cause a yawing tendency, which itself needs to be trimmed for.

That said, there are a few factors of propeller aerodynamics that contribute to yawing tendency.

Airflow from the descending propeller blade will spiral around the aircraft and strike the aircraft's tail, usually on the left side, inducing further left-turning tendency (known as "prop wash").

Lastly, P-factor also produces a yawing tendency due to assymetrical lift produced by the propeller. The angle between the relative wind and the propeller blade differs for the ascending and descending blades when the aircraft is not in a straight-and-level orientation to the relative wind (such as during a climb or descent). During a climb, the downward-moving side of the propeller (as viewed from the rear) has a higher angle of attack than the upward-moving side. This higher angle of attach causes the lift to be greater on the descending side of the propeller, causing the aircraft to yaw towards the opposite direction (again, typically the left). This effect is greatest when angle of attack is large and forward airspeed is low, typically the takeoff phase of flight. The opposite also happens during a slow descent, where the ascending blade has a greater AoA, producing an opposite yawing tendency.

These combine to produce a pronounced yawing tendency (in addition to the rolling tendency), usually to the left (viewed behind the aircraft/propeller).

EDIT: Cuz I had a brainfart and started writing about adverse yaw

[guncrasher]

it's a trick.  hitech already asked this question a couple of years ago.  look it up.



semp

[Randy1]

I would say both roll as a counter to the torque and yaw because the roll creates a vector perpendicular and forward to the planes center of gravity

[morfiend]

I would say both roll as a counter to the torque and yaw because the roll creates a vector perpendicular and forward to the planes center of gravity

  I would have guessed the opposite,the torque induces yaw which causes a roll effect...  but I'll leave it to the experts to answer.



   

[projoe]

IL2 has torque to the right as well.

[Ack-Ack]

p38's


semp

Only if flying with a single engine and the torque if flying on a single engine doesn't roll the aircraft like in single engine planes, it produces a yaw effect instead.  I'm guessing that's most likely due to the 2nd engine.

ack-ack