How do you balance a spinner?

[IanN]

 

I hadn't really thought about this before, but have seen recent references to the subject both on this forum and in the mag

 

It makes perfect sense to do this. After all, why go to the trouble to balance your prop if you then put a spinner on without also checking that for balance? However, how....? 

 

What method do people use to balance spinners?

[Engine Doctor]

Hello Ian I balance all spinners especially Ali spnners . I use a home made balance consisting of a hard balsa frame with two uprights approx 6 inches high and about 6 inches apart . These have powerful magnets mounted facing each other mounted near the top ( these are available at various model meetings or on the web) The spindle is a piece of 8 gauge piano wire ground to a point at each end . These points need to be pretty central or the shaft itself will be out of balance. This is approx 3mm shorter than the gap between the magnets. The prop or spinner is held on the shaft by tapered tufnol/ nylon sliders . these need to be a tight fit on the shaft. ( you could use a lenght of 4mm studding and make tapered nuts to hold prop etc) Mount the spinner on the shaft and mark the front and backof the spinner  so they always fit together in the same position. Now mout the shaft between the magnets. One end will touch a magnet and the other will float in the air . Let the spiner or prop settle and mark the low spot . You can the either grind alloy off the inside of the spinner or Using a large drill , drill indentations on the back plate removing alloy until yo get a balance . Take small amounts off as you can overdo it and end up with a backplte full of holes . You wont get it exactly right but will improve the balance considerably.

It really makes a world of difference . Hope it helps.

E.D

[Hugh Coleman]

I've a mate who has just finished building a 1/5 scale Spit Mk 22.  He is having substantial balance issues.  His prop is balanced but his spinner (home spun), not.

 

I believe he needs to balance it longitudinally as well as radially, otherwise the principle axis of inertia will be slightly askew of the prop shaft axis.

 

Any ideas how to do this?

 

Cheers,

 

Hugh

Edited By Hugh Coleman on 28/05/2010 13:17:30

[Craig Carr]

Hi,

 

It took me a little while to find it but back in 2004 an article was published in the BMFA news detailing exactly how to do this.

 

Its availiable on line at the BMFA site.  click the link below and go to the bottom of page 7 - the article "spinning out fo control".

 

LINK

 

It was written by the late Steve Purvis who enrolled me into Blyth Model Club many many moons ago. One of the best things I ever did. 

 

Craig

Edited By Craig Carr on 28/05/2010 22:47:24

Edited By Timbo - Administrator on 28/05/2010 22:58:52

[Ross Clarkson]

Top stuff Craig, cheers.