How to balance EDF fan ?

[solentlife]

OK ... so how to do it ?

DIY set-ups particularly looked for ...

[400blade]

this might be worth trying as its cheap and simple to set up http://www.youtube.com/watch?v=VAL7MJkTv...re=related

[solentlife]

(14-10-2011 10:42)400blade Wrote:  this might be worth trying as its cheap and simple to set up http://www.youtube.com/watch?v=VAL7MJkTv...re=related

Yep ... saw that before .. about the only vid that goes anywhere near to showing it ... others are lacking ...

I'm hoping that some can come up with posts with items they use to create balance rigs ... along with tips / tricks.

I'm thinking to buy rare-earth magnets on ebay and create a balance rig ... so looking for anyone else who may have done it.
I have a heli blade balancer .. shaft with 2 cones screwed on ... hoping that can be used.

[Richard]

That video was good, I like how the magnets worked it was simple and effective.

I have a finger balancer for props which uses two cones, not sure it would hold a fan but I'd like to try how that magnet trick sometime.

[solentlife]

The finger balance as my heli blade balancer ... problem is getting a no friction pivot. The magnets give a near no friction. But will it work ?

I've read that the 2 cones and shaft balance item often - the cones are not perfectly machined and out of balance enough to affect an EDF fan. Given that the fan is small blades and many of them, unlike a normal propellor or heli blades ... I can see the point.

So the question is ........ can a shaft / 2 cone balance rig be sorted to be true before checking an EDF fan ? Problem as I see it ... the cones are not fixed and therefore can vary ... BUT if the fan can be mounted on the shaft and put to magnet as video shows without cones ?

Interesting ... I have to say - I like the drill bit idea ... at least you get a lot of sizes to fit various shaft size fans !!

Any other ways or ideas ??

[Richard]

You could balance the cones too

[400blade]

i cant see the cones being out of balance if there machined maybe if they were cast

[solentlife]

(15-10-2011 12:21)400blade Wrote:  i cant see the cones being out of balance if there machined maybe if they were cast

I think maybe the problem lies not so much with the outer machining but possibly the drilling and tapping thread in centre.
With heli blades and normal props ... it's not so critical. But an EDF fan is a high rpm item with small blades etc. The slight imperfection of the cones may be as much as the inbalance of the fan ?

But I think the shaft would be used without the cones anyway. Looking at the youtube vids ... it's shaft only with magnets.

So the question is ... what size magnets to use .. ebay has loads ranging from 1mm x 3mm up to and beyond 5mm x 20mm ....

I guess that you need to be careful that magnet is not too strong ... actually thinking .. the fan spins on the shaft ... so strong magnet is no problem.

Ideas ??

[400blade]

old speaker magnet should do the job

[solentlife]

(15-10-2011 16:38)400blade Wrote:  old speaker magnet should do the job

mmmmmmm .... was thinking more along lines of those button rare earth magnets on ebay .... couple of quid gives you a number of them. The spares can be used for canopy magnets etc.