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Electric Stunt => Gettin all AMP'ed up! => Topic started by: Ron Hook on May 12, 2011, 06:11:36 PM
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I have notice that some of the prop holders or collets used on electric motors have a shaft that is either that right size or too large for the hole in the APC prop. Is it OK to drill out the hole in the prop to fit the prop holder or collet? If you have done this, any advice on how to do this correctly. I would also like to know what prop holders flyers are using.
Thank you in advance.
Ron Hook
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Ron,
I trust you are looking at APC electric props--- preferably the Thin Pusher ones. All of my APC electric props come with a set of adapters for different sized collet shafts. Usually one of these will fit the shaft and they simply plug into the rear of the prop hub. In the event that the main hole in the hub is itself too small I elect to carefully ream it to the correct size using a tapered ream and reaming from both the front and rear . This keeps the hole centered. I confess I have once or twice grabbed the correct sized drill and drilled the hole on my drill press. If you have a set or numbered drills you can work up to the correct size one number step at a time and it is unlikely that you will drill it off center.
My 2 cents,
John
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Ron,
Wht John says is correct with 1 addition. You can drill out the hub larger than the motor shaft size. Then you must use the included locating rings. Even if the the prop hub has the right diameter hole, you must use a locating ring. Also note that the locating ring has a 2 degree draft to it and the smaller end goes into the hub first. The locating ring goes in the back side ot the motor side of the hub.
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To add to what Crist is saying: the APC prop holes are not necessarily concentric. The back hole (the one that fits all the locating rings) is the precision hole -- the front hole is just for clearance to pass a shaft through. So you don't want to drill out the front hole and use it to locate the prop, unless you're a good enough machinist to bring it into concentricity with the rear hole.
That's why Crist is recommending that you just drill the front for clearance, and use the rear hole (with a bushing) for location.
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To add to what Crist is saying: the APC prop holes are not necessarily concentric. The back hole (the one that fits all the locating rings) is the precision hole -- the front hole is just for clearance to pass a shaft through. So you don't want to drill out the front hole and use it to locate the prop, unless you're a good enough machinist to bring it into concentricity with the rear hole.
That's why Crist is recommending that you just drill the front for clearance, and use the rear hole (with a bushing) for location.
Is this true for all APC props, or just the electric series ?
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Is this true for all APC props, or just the electric series ?
I don't think the other props come with the locating ring, so no, it wouldn't apply. It would only apply if the prop comes with a locating ring.
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I don't think the other props come with the locating ring, so no, it wouldn't apply. It would only apply if the prop comes with a locating ring.
http://www.apcprop.com/v/html/tech_support_notice.html#holealign
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Tim,
Good information, I think could also effect the use of a balancer, we should probably do the balance with one of the sizing rings in place so as to have the prop mounted properly on the balancer shaft.
Best, DennisT