gyroscopic effect

The gyroscopic effect is demonstrated with a battery-powered gyro. When the gyro is not spinning it is really hard to pick up, but when it is spinning the precession makes it easier to pick up - but there is no weight loss. For more go to http://www2.eng.cam.ac.uk/~hemh/gyroscopes.htm
Thanks to Reka Domokos camera-woman

Category:

Science & Technology

Tags:

• gyroscopes
• boomerangs
• precession
• weight
• loss
• spin
• Hugh
• Hunt

[nullflux8is]

Just one more question, if I may. How fast does a gyroscope need to spin inorder for it to be effected by the gyroscopic effect. My intitial thoughs would be that the reaction moments would need to exceed more than half of its weight. or is there a predictable spin rate? Thanks for all your feed back

[spinfun]

@nullflux8is The answer is not simple - involves some math. Bear with me:

1. Gyro moment = J * OMEGA * omega where J is the rotor moment of inertia (approx J = m * r * r / 2 where m is mass, r is radius), so for a 1kg rotor, radius 5cm then J = 0.0013.

and omega is the spin rate = rpm/10 (approx) so for a 5000rpm rotor omega=500

and OMEGA is the precession rate, ie how rapidly you will be turning the gyro, again RPM/10. I'm running out of characters in this reply so, to be continued...

[spinfun]

@nullflux8is So for instance if the gyro is to be turned through a full 360 degrees in, say, 20 seconds that's 3RPM os OMEGA = 0.3

In this case then the gyro moment = J * OMEGA * omega = 0.0013*0.3*500 = 0.2 Nm. How big is 0.2Nm? It's the same as a 1kg weight at a distance of 2cm, so this would be small compared with the weight of the rotor. But suppose OMEGA is 3 (360 degrees in 2 seconds) then the moment is 2Nm which is now 1kg at 20cm really very noticeable.....to be continued again....

[spinfun]

@nullflux8is So the bottom line is that you have to do the sums for your particular spin speed and precession rate. The higher these are the more noticeable is the gyro effect.

[nullflux8is]

I've always been interested in the gyroscopic effect in that, as you mention, the reaction moment tilts or throws its weight out/upwards. Can I have some of your insight in regards to...when a flywheel is setup in a double gimble fashion, spinning at, lets say, a thousand rmp, how is it that the resistance/pressure to keep it somewhat stable is very much in excess of the total weight of the mechanism. The gimbled mechanism doesn't lose or gain weight but the resistance is much greater?

[spinfun]

@nullflux8is if you swing a ball around your head on the end of a string the forces acting on the ball are much greater than gravity - the string is nearly horizontal. This is what happens when accelerations are high, because of F=ma. The same high forces occur with gyroscopic precession, but they combine to form a moment. The fact that the apparent forces exceed gravity is indeed comparing apples with oranges - you'd reach a different conclusion if you did the experiment on Jupiter.

[mannibajimaya]

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[codocodocodo1]

filmed with a calculator

[HybridWaterMan2]

fascinating! So even though the weight stays the same, isn't the relative weight changed by virtue of the gyroscopic precession?

[nullflux8is]

To make things a little clearer, to my previous comment. When you take a Dynabee exercise ball and spin it, the total resistance exceeds the weight of the Dynabee ball. I may stand corrected in that the Dynabee may not be a double gimble setup but that is what I'm referring to. And comparing weight and resistance in this example is like comparing apples to oranges. Facinating and a courious effect as well, would'nt you agree?