torque question

[hitech]

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

Actually the torque produced by the engine on a twin with only one engine running,  works  the exactly same as a single engine plane does. Physics 101, torque is torque no matter where you apply it to an object.

Thrust on the other hand does produce yaw with a one engine twin.

HiTech

[Ack-Ack]

Actually the torque produced by the engine on a twin with only one engine running,  works  the exactly same as a single engine plane does. Physics 101, torque is torque no matter where you apply it to an object.

Thrust on the other hand does produce yaw with a one engine twin.

HiTech

Thanks for the explanation, wondered why the Lightning yawed like it does with a single engine.

ack-ack

[mthrockmor]

African or European?

[HL117]

The Deadly P-51 Torque Roll:


The only direct contribution that torque makes to yawing in the early part of takeoff roll is perhaps a slight increase in the rolling friction of one main wheel because the torque is causing it to carry more weight than the other wheel. Strictly speaking, torque applies a rolling moment to the plane, NOT a yawing moment.

[Vraciu]

Trivia question,

Does engine torque create a roll or a yaw force?

HiTEch

Roll.  Yaw comes more from p-factor, gyroscopic precession, and to a lesser degree, spiraling slipstream.   Some people reject the latter.  In a climb the descending blade takes a bigger bite of air due to its higher AOA than the ascending blade which causes yaw.   Precession comes into play with pitch changes, particularly when the tail lifts off the ground for takeoff.  (Force applied to the prop is felt 90 degrees ahead in the plane of rotation.   Nose comes down.  Plane yaws left for Pony, Jug, etc. and right for Spit, Typh, etc..)

[Vraciu]

The Deadly P-51 Torque Roll:


The only direct contribution that torque makes to yawing in the early part of takeoff roll is perhaps a slight increase in the rolling friction of one main wheel because the torque is causing it to carry more weight than the other wheel. Strictly speaking, torque applies a rolling moment to the plane, NOT a yawing moment.

P-factor and gyroscopic precession are still an issue for yaw on takeoff, particularly with tail daggers.  

[Mongoose]

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

A twin engine plane flying on a single engine will yaw because the engine is pushing on one side of the aircraft.  With the engines on the wing, the single engine is applying its force to one side of the center of gravity. 

[Vraciu]

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

Accelerated air flow over the wing will increase loft on the side with a running engine, adding roll.  Torque also factors in.  Depending on which engine has failed it can help or hurt.   

[hitech]

Roll.  Yaw comes more from p-factor, gyroscopic precession, and to a lesser degree, spiraling slipstream.   Some people reject the latter.  In a climb the descending blade takes a bigger bite of air due to its higher AOA than the ascending blade which causes yaw.   Precession comes into play with pitch changes, particularly when the tail lifts off the ground for takeoff.  (Force applied to the prop is felt 90 degrees ahead in the plane of rotation.   Nose comes down.  Plane yaws left for Pony, Jug, etc. and right for Spit, Typh, etc..)

Agreed, except that at the start of the take off roll the slipstream is the biggest contributing factor to yaw.

HiTech

[Vraciu]

Agreed, except that at the start of the take off roll the slipstream is the biggest contributing factor to yaw.

HiTech

No argument from me on that.

[colmbo]

Precession comes into play with pitch changes, particularly when the tail lifts off the ground for takeoff.

Pick the tail up too soon on a B-17 (real life) and that will be well demonstrated…..and if you have any left crosswind you might find you don't have enough rudder (you do still have adverse yaw and differential power if needed).

[hitech]

Pick the tail up too soon on a B-17 (real life) and that will be well demonstrated…..and if you have any left crosswind you might find you don't have enough rudder (you do still have adverse yaw and differential power if needed).

Yep you havn't lived unless you understand what happy feet on rudder pedals with pinched but cheeks feels like. I bet once that mass gets rotating in the B17 the lag in stopping it could be quite interesting. Plus I assume hardly any prop wash on the rudder to speak of. Does it like to swing much when setting the tail down after a wheels landing?

HiTech

[guncrasher]

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

actually what I was pointing out was the prior reply where that posting that most planes turn left and rest turn right.  which left out the p38.


semp

[colmbo]

Does it like to swing much when setting the tail down after a wheels landing?

HiTech

Not enough to make it memorable, but that was usually more gentle than raising the tail so that might be part of it.

You're right about mass. It's a 60000 pound tail dragged, if you ever let it get pointed the wrong way you are probably going for a ride.

[rabbidrabbit]

The Deadly P-51 Torque Roll:


The only direct contribution that torque makes to yawing in the early part of takeoff roll is perhaps a slight increase in the rolling friction of one main wheel because the torque is causing it to carry more weight than the other wheel. Strictly speaking, torque applies a rolling moment to the plane, NOT a yawing moment.

What if the wheel was on a treadmill?  I've heard this has a dramatic effect.