New 16/15/5, do I grind a flat spot on the shaft? - RC Groups
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May 20, 2003, 04:34 PM
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Captain Carlton's Avatar

New 16/15/5, do I grind a flat spot on the shaft?

I got my first Mega. Do I grind a flat spot on the shaft for the set screw for the prop adapter, or do i leave the shaft perfectly round?

Thanks, Rick
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May 20, 2003, 04:43 PM
Registered User

I left mine alone...

the friction of the grub screw should be enough...
May 20, 2003, 04:44 PM
Tacoma, WA, USA
William A's Avatar
Same here.
May 20, 2003, 04:51 PM
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pda4you's Avatar
I just use friction and have not had any issues.

May 20, 2003, 05:21 PM
Registered User
Mmmmm, can't agree about just counting on the friction of the grub screw. My hayfield is littered with props and adaptors that came off in flight. 99% of which I've never found. At least use a little Loctite, not on the screw but on the shaft. Helps keep the adaptor from creeping on the shaft, which loosens the screw.
Better yet use a collet-type adaptor.
May 20, 2003, 05:24 PM
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pda4you's Avatar
True - I did loctite the screw - but I have 60 or so flights with no issues.

May 20, 2003, 07:27 PM
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Dr Kiwi's Avatar

Collet adaptor

I second uscra112 - I'll never use a grub-screw adaptor again after having a prop fly off my Phasor and another off my AXI during bench-testing. I had tightened them fully, and put Loctite on, but they still tried to go through me, then the wall. I have no idea why the machining of a flat on the shaft is not standard practice among manufacturers of these potent motors.

Be careful out there! Cheers, Phil
May 21, 2003, 04:49 AM
(aka Cliff Lawson)
Wright Flyer's Avatar

I use a Graupner collet type adpator on my 16/15/6 to mount APC props which effectively grips the whole shaft, not just a single spot where a set screw contacts it. Once you tighten the bolt then there's absolutely no way that prop adpator is coming off there.

May 21, 2003, 08:01 AM
small electrics r BIG FUN
I gave up on prop adaptors with screws before I went brushless. The collet type that tighten with a nut in front don't wobble or come loose, and no shaft grinding.
May 21, 2003, 08:23 AM
Registered User
Andy W's Avatar
Collett is always better, but even 27-cell F5B setups can have a screw-type adapter stay on a round shaft when properly installed. Dieter has posted the procedure here a few times..