randii

The replacement masts I am using seem to have too much play...

Generally, for automotive purposes (much larger parts!), you want a few thou clearance for a slip fit, but more is bad because it can allow the bearings to rock, instead of merely rotating axially.

I can detect a tiny amount of off-axis movement, so I am going to attempt too build up a few thou on the perimeter of the mast with CA. Has anyone tried this before?

Randii

tahustvedt

Which helicopter is this?

randii

It is an Aerohawk, but the replacement masts are generic hobbyshop replacements.

Brand shouldn't really matter -- a 3mm mast is a 3mm mast across most every min-heli, with the only different dimension generally being the length (i.e. same diameter).

Randii

tahustvedt

I'm testing it now and if I move the mast of my new Aerohawk (got it yesterday) back and forth I can feel a little play between the mast and bearings. Not much, but it's there.


Tor Arne
Norway

randii

I stripped the mast bare, then used thick CA to build up the mast a bit where the bearings ride. After allowing plenty of time for the CA to dry, I chucked the mast up in my cordless drill and used a sanding block to level off the built-up sections. I snuck up on the dimension gradually, test fitting the bearing until it was a tight press fit.

This seems to have reduced vibration, and really shows the wiggle inherent in close-but-not-perfect carbon fiber masts. The rotor head runs VERY true where it previously had some wobble... and all this has me lusting after one of the upgraded stainless steel tubular masts available from folks like Walt.

Randii