How to describe the Gyroscopic System

[CougarAviator]

What's an easy way to describe the gyroscopic system to a student pilot?

 

[Monkeyfist]

Buy a gyroscope --> principles
Then go to the airplane --> plumbing

 

[minitour]

What about it?

Vacuum pump, filter, relief valve, "hoses", engine, gyros, rigidity inspace, precession, earth turning, uh...I dunno...I'm probably missing alot, but I don't know what about it you want to explain.

-mini

 

[PropsForward]

Are you talking about the rigidity in space thing? Where a weighted spinning object resists movement against its axis? If so, buy a toy gyro and demo it to him.

 

[minitour]

Followup:

Actually, if someone could explain the WHY behind Precession for me,I'd appreciate it. I understand the principle and how it affectsus, how to explain it, etc...but I don't know why you push "here" andthe force comes out over "there"...maybe even a website or book I couldlook at?

Thanks!

-mini

 

[CougarAviator]

I'm trying to explain to a student pilot. I know about rigidity in space and precession, but what about the actual operation of the instruments: Attitude indicator and DG....

 

[uwochris]

mini,

Check out the following: http://www.av8n.com/how/htm/motion.html#sec-gyro

If you want to understand why precession occurs, the best thing to do is pick up a physics textbook. These books also explain the "why" behind a lot of other important concepts to pilots.

Chris.

 

[EMB170Pilot]

oh my God! COME ON I didnt get that much into detail with my students


Precession: Any force applied to a spinning object will react 90 degress from which the force is applied. Spin a quarter and apply a force to it and watch what happens AMAZING explained

anything else let me know

 

[Stifler's Mom]

I need to stop reading threads in this section. You guys give me a headache from thinking too hard.


PS Go find a bicycle tire, mount it on a handle, spin it and move it around.

or

Think about what leaning into a turn while riding your bicycle does?

 

[A Squared]

Actually, if someone could explain the WHY behind Precession for me,I'd appreciate it. I understand the principle and how it affectsus, how to explain it, etc...but I don't know why you push "here" andthe force comes out over "there"...maybe even a website or book I couldlook at?

OK, I'll take a stab at that. Let's use the example of a taildragger taking off. When you raise the tail on the takeoff roll, gyroscopic precession makes the airplane want to turn left (on an airplane on which the prop is turning clockwise viewed form the cockpit, MP-14 powered aircraft turn right) As you are no doubt aware, the precession behaves like a force applied in the direction of the tilt, at a point 90 degrees later in the rotation. With me so far?

OK, now imagine this. instead of a prop you are sitting in an airplane which has a firehose attatched out front, directing a stream of water straight up, right at the same place where the prop blade would be coming straight up. Now you reach out the pilot's side window (left side) with a ping-pong paddle and stick the paddle in the stream of water (you have real long arms) and you hold the ping-pong paddle at such an angle that the stream of water is deflected such that, instead of going up, it is now going up and forward. So the ping-pong paddle is defecting (accelerating) the water forward, and because of Newton's laws, there is a reactive force pushing back on the ping-pong paddle. That force pushes back on your arm, and if you keep your arm stiff (in addidtion to being long, your arms are also pretty strong) that force would tend to turn the airplane to the left. That is pretty much what happens to the prop when you raise the tail, you are "bending" the path of travel of the prop tips forward as they rise, and that action causes a reactive force. On the descending side of the prop, the same thing is happening in reverse, as you tilt the tail up, you are "bending" the path of the descending prop tips "back" and this creates a reactive force *forward* on the airplane at the right edge of the prop disk, which again tends to turn the airplane to the left. Note, I used he word "bending", but it's not really that you are bending it, it's that you are deflecting the path of travel from the direction established. Some might point out that the prop does bend, a little, but that is irrelevant, the same principle would hold true if, instead of a prop, there was a rigid flywheel. I used the example of a taildragger, as it's easy to visualize (I hope) but if you can grasp my explanation, you can transfer it to any spinning mass.