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post #1 of 29 (permalink) Old 11-03-2008, 12:51 PM Thread Starter
 
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Question Gyroscopic Force

A helicopter was flying over my house just a minute ago, and it got me thinking about turbine engines and jet fighters.... the spin up to 100,000 RPM creating all these forces: air compression, thrust, velocity, and what have you.

Well, remeber the old prop planes of the, the old rotary type? wiki
Quote:
Rotary engine - WW1
.... Rotary engines have all the cylinders in a circle around the crankcase like a radial engine (see below), but the difference is that the crankshaft is bolted to the airframe, and the propeller is bolted to the engine case. The entire engine rotates with the propeller, providing plenty of airflow for cooling regardless of the aircraft's forward speed. Some of these engines were a two-stroke design, giving them a high specific power and power-to-weight ratio. Unfortunately, the severe gyroscopic effects from the heavy rotating engine made the aircraft very difficult to fly....
So when the pilot wanted to turn left, he forced the plane right.... when he wanted it to go up-left he aimed down-right.... basically counter steering the plane (modern marvels teaches you extra things)....


So with these high-end jets of today producing hells amount of thrust and RPM range.... how much would the gyroscopic forces be at play?
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post #2 of 29 (permalink) Old 11-03-2008, 03:58 PM Thread Starter
 
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where's there an aviation forum when you need em ?
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post #3 of 29 (permalink) Old 11-04-2008, 03:37 AM
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Quote:
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So when the pilot wanted to turn left, he forced the plane right.... when he wanted it to go up-left he aimed down-right.... basically counter steering the plane (modern marvels teaches you extra things)....
Umm, no.

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post #4 of 29 (permalink) Old 11-04-2008, 03:45 AM
 
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I dont think gyro's work the way you think they work

http://science.howstuffworks.com/gyroscope.htm



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post #5 of 29 (permalink) Old 11-04-2008, 08:13 AM Thread Starter
 
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well i do remember it from a modern marvels show.... might not be the exact left to right ratio but basically they were backwards in handling which mae the planes have terribly difficult.... but anyways wrong left to right ration behind, would not the jets have to fight these forces too?
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post #6 of 29 (permalink) Old 11-04-2008, 09:47 AM
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Originally Posted by ochoa0042 View Post
would not the jets have to fight these forces too?
No. The forces that made those planes hard to control were torque and p-factor (which is still a factor in most single-engined propeller aircraft).

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post #7 of 29 (permalink) Old 11-04-2008, 09:59 AM
 
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From brief reading about p-factor, why would it be any different in a radial engine as opposed to a rotary one? The propeller is the same either way.



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post #8 of 29 (permalink) Old 11-04-2008, 10:10 AM Thread Starter
 
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From brief reading about p-factor, why would it be any different in a radial engine as opposed to a rotary one? The propeller is the same either way.

nope its not the rotary you're thinking of , the mazda rotary... its completely different.... the radial engine has the propeller attached to the crank shaft.... the rotary has the propeller attached to the engine, and the whole engine spins with the propeller, all that mass from the engine block spinning totally threw off the plane having adverse gyrscopic handling

what's p-factor.... propellers?
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post #9 of 29 (permalink) Old 11-04-2008, 10:15 AM
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P-factor isn't any different between radial and conventional motors, but the additional torque (or whatever the technical term is for the rotational force from the radial motor) makes the aircraft want to turn even more.

It's not going to be enough to reverse controls or anything like that. Remember, airplanes deflect air to change direction, a rotating engine will do nothing but cause a slight tendency to turn or rotate, especially during significant changes in throttle.

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post #10 of 29 (permalink) Old 11-04-2008, 10:18 AM
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Quote:
Originally Posted by ochoa0042 View Post
what's p-factor.... propellers?
P-factor is caused by the asymmetrical thrust created by the propeller (primarily), as well as airflow off the propeller which spirals around the fuselage of the airplane and end up hitting the vertical stabilizer (secondary, much less of a factor); causing a turning tendency that is normally counteracted by a small application of rudder in the opposite direction. The force is most notable in situations where you are at high power, and low airspeed (such as initial climb).

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