Motor/prop adapter question.
I am a firm believer in silly questions, and this may very well be one of them...:red:
I have no experience with small electric motors for airplanes. I've used the larger ones, and found them quite straight-forward.
I recently purchased a Park 250 from HK. It came with a prop adapter and motor mount. This one here: http://www.hobbyking.com/hobbyking/s...dProduct=19031
My question is this - what's the best/most logical/least damaging way to reverse the shaft, so I can use the prop adapter and motor mount?
The adapter quite obviously mounts onto the long shaft... but the long part is sticking out the back end of the motor, and I can't for the life of me figure out how to remove the shaft and reverse it. Or if this is even necessary.
I've tried removing the set screws on the bell end, and the small circlip at the bearing end. The shaft refuses to budge. I'm afraid to apply too much pressure...
Any other outrunners I have, the long part of the shaft sticks out the front... and the motor mount fits to the back.
I look forward to your responses!
You don't "reverse" the shaft normally... you mount the motor reversed, with the shaft coming through a hole drilled in a "firewall" mounted further forward in the aircraft.
You can reverse the shaft in many outrunners. There should be one or 2 set screw(s) and one to 3 C clips. Loosen the set screw(s) and pop the clips and you should be able to pull the shaft out. Sometimes one of the clips is between the motor bell and the stator bearings.
If they used locktite or similar to help hold the shaft in the motor bell it can be difficult to get the shaft to pull out even with the clips and set screws removed...
The shafts are all removable/replaceable on outruners (that I have seen so far).
YA, I can see how that would work... but that puts the motor mount at the front of the motor, which is just wrong to me. Old habits die hard.
In the installation I have for this plane, I'll have to modify the front of the plane, and build a firewall/motor mount and mount the motor in this 'reverse' layout - which will add complexity and weight.
Or figure out how to reverse the shaft. Which will make it so much simpler. Of course, then, what would I do with the circlip - I didn't notice a groove, but I suppose there must be one.
Hi O & S
I looked at the replacement shaft near the bottom of the page and it only shows one groove for the clip. I looks like the shaft just needs to move forward after you remove the clip and loosen the screws at the front. I use a drill press as an arbor press to move the shaft. Make sure everything is supported well. Often a socket is the right size to support the motor and let the shaft move. The worry is that only the magnets will hold the bell on. Please test the system with a prop to see if the bell stays put.
I may press the shaft out, and make one that has the groove in the right place, say, 1/16" from the end - so I can reverse the shaft.
Surely I'm not the only one who thinks this is odd. The larger outrunners I've purchased from HK aren't like this.
I can't imagine that pressing out the shaft, and reassembling the motor without a circlip - and relying on the magnets to hold the motor/prop together - would result in a positive outcome! But I can't say for sure... ;), and I'm not so sure I wanna be the first to try it!
I just did a quick fix to my turnigy SK3. Similar situation. Everything was backasswards because of the mounting holes for the x mount were opposite of where they needed to be. I know it's not according to Hoyle, but I removed the c-clips and lightly tapped the shaft through in the other direction. The new rear part of the shaft had enough space to mount a collar w/ grub screw. This collar came with the motor.
The only problem I had was when tightening the provided collet adaptor, I over torqued it and sheared off the threaded part where the nut holds the prop on. New 5mm collet adaptor arrives today. Always something.
Now that's a pretty good idea. I'm going to try that. Should work, if I can find a collet small enough.
Appropriate wheel collars are available. I would recommend grinding a flat on the shaft for the set screw.
Even if the C-clip slot position wasn't an issue I'd recommend the wheel collar.
I have had a motor shear the C clip and spit the bell, shaft, prop (22X10) and spinner over 75 feet when I hammered the throttle from a standing start. The 13 lb plane only went forward 5 feet.
Not as small as your motor, but it makes you think about these things.
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