The myth of Gyroscopic Precession.
Joined: Jul 2001
Posts: 1,084
Likes: 1
From: the cockpit
I agree Joe, GP is a useful tool to enable easy understanding of the rotor dynamics for basic users, much the same way the term centrifugal is used. Neither are actually at play in the rotor disc, although GP is actually a phenomena where as centrifugal is ficticious.
When teaching this subject, I like to use the rotor head of the UH -1H / B212. It has a rotor disc that is subject to aerodynamic precession as well as a stabilisation bar that is subject to gyroscopic precession. It is then easy for the student to see why one acts as a gyroscope as it is rigid, and why the other doesn't because it is free to flap.
When teaching this subject, I like to use the rotor head of the UH -1H / B212. It has a rotor disc that is subject to aerodynamic precession as well as a stabilisation bar that is subject to gyroscopic precession. It is then easy for the student to see why one acts as a gyroscope as it is rigid, and why the other doesn't because it is free to flap.
Joined: Dec 2001
Posts: 1
Likes: 0
From: Aberdeen
Excuse me for butting in here, just a couple of points about your discussion, that have probably already been put to bed, but anyway....
Surely if a rotor system was at working speed in a vaccum, movement of the disc would be impossible, therefore gyroscopic properties are not present. As opposed to a gyroscope which is fully functional in a vaccum. The fact that phase lag is taught as always being 90 degrees appears to be inaccurate from other posts, for a system to show gyroscopic properties surely the angle must be exactly 90 degrees always.
I'm sure you guys will tear my long thought out theory with zest.
Surely if a rotor system was at working speed in a vaccum, movement of the disc would be impossible, therefore gyroscopic properties are not present. As opposed to a gyroscope which is fully functional in a vaccum. The fact that phase lag is taught as always being 90 degrees appears to be inaccurate from other posts, for a system to show gyroscopic properties surely the angle must be exactly 90 degrees always.
I'm sure you guys will tear my long thought out theory with zest.
Thread Starter
Joined: Nov 2000
Posts: 452
Likes: 0
From: Vancouver, BC, Canada
Lu
You can feel a little more at ease with Gyroscopic Precession.
A syllabus on 5-day Aerospace courses from the University of Kansas arrived in the mail today. One of the courses on rotorcraft (not Prouty's) covers 37 topics, of which 3 are;-
- Gyroscopics.
- Gyroscopic characteristics of rotors.
- Pseudo-gyroscopic effects.
<img src="eek.gif" border="0">
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Move here from another thread where it was off topic.
You can feel a little more at ease with Gyroscopic Precession.
A syllabus on 5-day Aerospace courses from the University of Kansas arrived in the mail today. One of the courses on rotorcraft (not Prouty's) covers 37 topics, of which 3 are;-
- Gyroscopics.
- Gyroscopic characteristics of rotors.
- Pseudo-gyroscopic effects.
<img src="eek.gif" border="0">
------------
Move here from another thread where it was off topic.
