turning tendencies

[mayday1]

Yeah, thanks for all the info... this has been very helpful!

 

[minitour]

Yep...its all good now.

I never got the "why" behind it and I just know some day I'm gonna have a student that is gonna want to know why things happen the way they do...which is good....the world needs its share of nerds like me. If it weren't for us nerds, we'd be over-populated.

Thanks again!

-mini

 

[Mr. Cole]

No problem. I love to teach and I love aviation, and since I no longer work in engineering this kind of stuff allows me some opportunity to do what I love doing.
Hey, I read Aerodynamics for Naval Aviators from front to back and just ordered an aerodynamics textbook and a book on wing sections, how much of nerd does that make me?

Dave

 

[nosehair]

makes sense now.. thanks for the responses... not sure why some text books place this under the "left turning tendency" headings.. just causes confusion.

thanks again.

Long, Long ago, Far, Far away, in another space-time continuum, all training airplanes were tail-wheels. All training handbooks grouped the four left-turning tendicies together. Raising the tailwheel during the take-off roll was one of these.

Now, in tri-cycle gear airplanes, the gyroscopic precession causes a right-turning tendency during the rotation of the nose. But only during rotation. As soon as the pitch change stops, the right turning force stops.

All these forces can be explained, discussed, and demonstrated by describing a short-field take-off:

1) Holding the brakes, you apply full power, and notice that the engine/crankshaft/propeller torque tries to roll the airplane left. Notice that the left tire is squashed down a bit. The greater area of contact with the ground causes the airplane to pull left as you release the brakes.

2) As you accelerate, the prop corkscrewing effect of the slipstream striking the left side of the vertical stabilizer causes the airplane to try to turn left.

So, as you are accelerating from zero to rotation speed, you are continually applying more right rudder to compensate.

3) As you rotate, the gyroscopic effect causes the nose to yaw right, requiring you to suddenly decrease the right rudder, possibly adding left rudder, depending on engine size and rotation airspeed.

4) As soon as the rotation stops at the initial climb attitude, the P-factor, along with engine torque and slipstream immediately yaw the airplane more to the left requiring immediate increase in right rudder.

Is that cool, or what?

Oh, and also, this is a good example of why you have to be careful with all aviation technical material. Much of the current "Fundamentals" material is just copied from eons ago and is misleading or downright incorrect.

Check ot the picture of the "Lazy-8" in the new Airplane Flying Hanbook issued 2004, page 9-6. Looks more like a Cuban 8, but not exactly.
Just an example of how often wrong material gets into publication.