Oct 02, 2012, 12:05 PM
Andy2No's Avatar
I've been thinking how I could make a prop adaptor that would let the shaft go all the way through, so I can use the nice shiny plastic spinner with one of my wooden props with a 5mm diameter hole.

Eventually I settled on turning down an M3 hex nylon support post (for project electronics etc). They're 5.5mm across the flats, like an M3 nut, and the ones I have are maybe 3/4 of an inch long.

I used an old Tower Pro bell motor, with the same sort of M3 threaded shaft, as a makeshift lathe. I found nylon is actually quite hard to file or sand down like that but I managed it eventually, by pinching it with a piece of 80 grit paper til the paper got quite hot. I used a watt meter to keep an eye on it. It doesn't take a lot of current, compared to flying.

Once I got the prop to fit on it, I cut the excess off and left it in. I can push it out if I need to, or make another, if I find the patience.

As it screws on to the shaft, getting it tight against the nut at the back behind the spinner is tricky, but it can be done. I had to put the prop on with the top of the shaft just showing through the spinner. As it's a push fit, the last little bit of tightening works out okay.

Incidentally, the washer that came with my spinner and prop is really sloppy on the shaft so it's next to impossible to get it centered. That can't be helping with the balance and vibration problem. I'll find a better one.
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Oct 02, 2012, 12:48 PM
Flying is Freedom
Sky_Captain's Avatar
Nice effort Andy,
All that work and no pics?
Oct 02, 2012, 12:55 PM
Andy2No's Avatar
Just shrinking them down and choosing the best ones now, as it happens... No pics of the prop adaptor though. I think you can imagine that
Oct 02, 2012, 01:02 PM
Andy2No's Avatar
Sod it. I can't choose. Here's most of them

I'm not quite sure if the nose is lower. It might just be sinking into the mattress a bit. I do have the same wheels for the mains in 70mm diameter instead of the 75mm ones I've used there. I'll fit those if it's a problem.

I still need to tidy up the bolts for the main axles. I used half threaded 40mm M3 cap bolts, so the wheels are running on smooth metal instead of screw thread. I'll fit lock nuts, maybe use some thread lock, and saw off the bits that stick out, when I've finished.

Although the 4mm axle steering arm block I've used to attach the nose wheel castor is a bit ugly, it balances nicely - the wheel hangs straight back with the nose up, so it may get left like that.

The steering arm that's sticking out may get sawn off, or I might want to use it to attach a spring to encourage the wheel to go to the centre, or follow the rudder servo - at the moment, it doesn't steer with the rudder, but I don't see that as a big problem. It takes some of the load off that servo too.
Last edited by Andy2No; Oct 02, 2012 at 02:13 PM. Reason: annotating pics
Oct 02, 2012, 03:46 PM
Andy2No's Avatar
This looks like the same undercarriage set I used. The legs are really flimsy (for a lightweight park flyer, I guess), but I only used one of the larger wheels and the bracket for it... actually, one side of the bracket is a leg, but I cut it off just above the top fixing pin.

Last edited by Andy2No; Oct 02, 2012 at 03:51 PM.
Oct 02, 2012, 06:21 PM
Andy2No's Avatar
Okay. I give in Here's some pictures of the prop adaptor, and the bits I used to make it.

I've put it on the bottom half of the spinner, with an M3 nut behind it, but I've left off the washer and lock nut so you can see it properly.

I've photographed it fitted to the Tower Pro motor I was using as a lathe, because it's less fiddly. When I've found somewhere to keep the plane fully assembled, I'll take more pics of it all put together. I've got another kit to finish though, so it might not happen straight away.

The M3 hex nylon posts are actually 12mm long, or about half an inch. For the benefit of anyone in the UK (probably buying the Corvalis as an ST Model Cessna 350), the posts are Maplin part number QT87U (12mm, which is what I used but had to cut down) or QT86T (8mm long, which should be plenty):

Oct 02, 2012, 06:52 PM
Flying is Freedom
Sky_Captain's Avatar
Looks way better than what I did
Oct 02, 2012, 07:34 PM
Andy2No's Avatar
I'm not quite sure what I'm looking at there, Sky_Captain Have you turned down the big nut on the front of the bell to make a big prop adapter? Or is that what you use as a lathe?

What sort of Cub is that? I have a little 95cm wingspan CC Lee 3CH Cub that would benefit from a wooden wedge motor mount like that. I replaced the direct drive brushed motor with an inrunner, because it fitted in the same bracket, but it's not an ideal solution.
Oct 02, 2012, 07:40 PM
Flying is Freedom
Sky_Captain's Avatar
That's one of those old Turnigy outrunners. The not was stock. I was just showing a pick of the piece of wood I used as a mount.
It's an Exceed J-3 Piber Cub.
Oct 02, 2012, 07:51 PM
Andy2No's Avatar
Looks like a good plane (I found a review on Youtube). I like the piece of wood. I ought to do that to my CC Lee Cub, instead of having a 6x3 prop doing about 20,000 rpm
Oct 02, 2012, 08:17 PM
Flying is Freedom
Sky_Captain's Avatar
It was a very good plane. DId that youtube video have Journey Wheel in the Sky playing in the back ground? I posted a video years ago.
Oct 02, 2012, 11:21 PM
Andy2No's Avatar
The one I saw was just part one of a build log by someone called MrRCflying.
Oct 03, 2012, 07:11 AM
Flying is Freedom
Sky_Captain's Avatar
Nope, that wasn't it. I watched several flight reviews of it before I bought it.
Oct 03, 2012, 02:57 PM
RC Enthusiast
YarSmythe's Avatar
Just finished the first flight with the new motor. Great response and power. Exactly what I wanted. Ran a 2200 pack with 1/4 ounce weight in the tail for perfect balance. In a word: SUCCESS!

Needs some control surface adjustments and the nose wheel aligned . Tail has some twist in it that needs removed and we'll be set.

...then a paint job!

Oct 11, 2012, 04:42 PM
I put stickers, neon orange under the wings. It helps, I find this plane easy to lose orientation.

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