Gyro build problem

Here it is : **LINK**

All comments noted but even looking at Clicksprings video again I have done everything as per his drawings & process yet am still not seeing how his works perfectly yet mine ( ours ) does not . I have now put both my attempts to rest for a while & contemplate doing something else.

George.

..unless some other phenomenon is at play?

At one job the only way i could get a readable ECG trace was with the patient positioned N-S. Any other direction and the baseline oscillations on the trace made it unreadable. The proximity of ley lines, my boss's antimagnetic personality or the electrified railway at the bottom of the garden were all considered causes..

Where i live now there's a 600ft ridge just across the field. One day i shall find the energy to climb it and recover all those small parts missing from my shed. I'm convinced of the mass attraction that causes them to vanish.

Fast spinning objects may well be communicating with an alternative reality.. why in some places you can put a pair of socks in the spin drier and only ever recover one sock. It's no stretch to consider a perfectly spinning gyroscope can also exhibit abberant behaviour <s>

Take a look at www.gyroscopes.org and the maths tab. I plugged the 'as spec' numbers for your gyro wheel and chose 5000rpm and then entered the 'as scaled' (with a bit of guestimation). To get the same gyro couple it seems the rpm need to go to about 20000 or more. A bit of a problem with windage and bearing loss. This fits with my experience, I made a smallish gyro and the performance was pretty disappointing. I ended up mounting it in double gimbals as a demo. So, 75mm OD looks about the minimum in brass.

Slightly off topic; but the Sperry Mk.XIV gyro compass of the 1950/60s had a 56lb wheel and it spun up to 7000 rpm. The compass was mounted as near to the centre of gravity of the vessel as practicable in order to reduce movement of the 'machine' due to roll and pitch. Quite a fearsome beast when it was running at full chat!

Dave
The Emerald Isle

Interesting experiment in low gravity. Not much effect from a small spinning plastic disk but interesting all the same.

Thinking about my toy gyro, the problem looks like it's simply too heavy to get it up to speed easily with a bit of string. You need it to go as fast as possible but you can only put a given amount of energy in with one string pull, so a relatively slender flywheel with a modest rim you can really get shifting will work better than a fat one you can only get to a fraction of the speed.

It's all proportional to the V^2 rather than the M.

A home made Gyroscope and a novel way to get up running speed. Here

Mike.

As others have indicated; Clickspring's Gyro doesn't look suitably proportioned for scaling-down: At reduced scale it will need to be run much faster than a string-pull can provide.

Missile guidance Gyros were [before things went solid-state] typically spun-up by gas pressure, operating on turbine notches cut in the periphery of the 'wheel'. Have a look at the two monochrome photos on this page, and consider the possibility of milling notches in Clickspring's wheel ... a short blast from a CO2 cylinder should do the trick.

MichaelG.

I'm not sure it would be a good idea to spin these things, with plain bearings, to high speeds. I saw what happened when someone spun a ball-race up using the compressed air gun. I think this is the first cautionary tale I've posted.

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Duly noted Gordon

Thanks for the prompt and very wise response.

My post should really have said 'consider the possibility, and the implications'

MichaelG.

Here's an aircraft instrument gyro.The turbine/ gyro wheel is either brass or bronze, and the conical point runs in a cup with three(I think) ball bearings, each end. The ball races are adjustable. Ian S C

Tried an experiment, span up a toy gyro with 3/16 shaft using string. On the tacho this got to 4500rpm but dropped fairly quick to 3000. I reckon you would be lucky to do much better. Using the criterion of a gyro that will sit horizontal and do 1 rev/sec with a rotor speed of 2000rpm the 75mm diameter rotor is marginal - OK if turning a bit faster but losing energy fairly quick.

The snag is that a toy gyro to sit horizontal on a little tower is pretty challenging, the weight (mass) cannot be too much but you need the mass to get the gyro couple - and the practical rpm achievable is in the 2000 to 3000 region. This design criterion is quite different from designing a gyro compass.

As a kid I remember a pretty good gyro that was about 70mm diameter with a thin ish rim - but made of lead painted in shiny brass lacquer - probably not allowed now....

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Ian,

Yes that's an excellent bearing arrangement [also once popular on 'unipivot' pick-up arms and some electric clock balance wheels] ... Can't recall the proper name for it though.

You might find this Patent of interest ... same concept on a much larger scale.

MichaelG.

The bell crank on one of my hot air engines uses the bearings from a tone arm, mainly because they were there and needed using. the bearing on each side is in the brass bit with the lock nut. This motor(similar any way) appeared in ME a number of years ago as the winner of the Gnat power section, it was published first as a BETA type, then later as a GAMMA. It has a 5/8" bore, and will drive the generator with enough power to run a 3v radio.

Ian S C

Anyone remember the linaze giroscope that used to be advertised in model engineer quite a few years ago, it had ball bearings.?

Interestingly I picked up a rather large (old) external HDD yesterday while it was running, and I could feel it twisting in my hand.