Wheel Collar Retainer
 

I was going to post this thread a while back but changed my mind. But the subject came up in a thread on another forum so thought I'd go ahead n post.

This is is just a FWIW post. The subject is wheel collar loose and wheel is lost.

I have tried using thread locker but even the blue was too strong. The hex wrench, supplied with the collar, rotated inside the set screw. I finally used a ball wrench that was strong enough to remove the set screw.

My solution: I added a small n tight O'ring on the gear wire to retain a loose collar. I tested this using a disk sander with no sanding pad. Wheel horizontal on top of loose collar and O'ring below collar. Ran wheel up to speed and nothing moved during the test. Time will tell how good or bad it works.

A little slice of appropriate size fuel line often works too

If you file a flat spot on the axle at the place the collar's screw hits, use a good quality screw and a hardened Allen wrench, the wheel collar will not come loose.

And use thread locker. When you want to remove it, just add heat to the set screw with a soldering iron. Loosens just fine.

I have stripped out so many of those set screw I can not count. I have tried every hex wrench under the sun. They always seemed to strip out or for unknown reasons, be stripped when I wanted to take them out. I started using hex head screws in their place. You can tighten them a lot more and use a larger size hex wrench. Plus when you grind away the hardened surface of the wire, you can really lock them in place.

Another way I have seen is to cross drill the wire and use a piece of safety wire like a hair pin to hold every thing on if it comes loose.


Buzz.

When I'm securing a wheel with a collar, I'll take out the set screw, mark the hole location with a fine point sharpie, grind with a Dremel a flat spot, then with threadlocker set the collar (doesn't have to ungodly tight, if it can move, it wont slip off). Never had a problem with this method. When I need to take off the wheel, put a nice hot soldering iron on the set screw, once heated up it will loosen. I used to epoxy collars and set screws, but found out that method is way overkill..

McMaster Car sells a split collar that clamps on the axel,rather than a jam screw.They haven't came loose yet.jeffo

I use these on larger planes. They work very well.

I have found that a wheel comes off in flight
not because the collar gets loose, but because
I didn't notice it. Putting notches in the axle didn't
really help. It just took a few more flights of being
ignored before it fell off. Fuel tubing and O-rings
also fall into this category.

My solution was to solder a washer onto the
axle instead of using a collar. I put a piece
of cereal box between the washer and the
wheel for proper clearance. With a regular
soldering iron and regular solder it doesn't get
hot enough to melt the wheel.

It does take about 5 minutes to do each wheel,
compared to the one minute using collars, but
I find it is well worth the time. Since I started
doing this about 28 years ago, I have never
lost a wheel.

Jenny

Yeah, a good close fitting washer with the slightest amount of solder will hold any wheel on, any scale. I wish DuBro would rethink their wheel collars. I think wheel collars could be made of materials similar to propellers, nylon reinforced with carbon fibers would be enough to hold a wheel on. An extra note, I have ground collars almost dangerously thin just to make them thinner and lighter. But I think you're right Jennifer, a little extra time and work, and a washer and solder is all one needs, and it's lighter.

The secret to making the flat spot work is to make it a notch that didn't keep the flat spot all the way to the end. If you do it right, you can loosen the set screw by a half turn where the collar rattles around and it still won't come off.

Yes, I agree. And with some threadlocker on the set screw, I've never had a failure.

I got to add. When I was in my teens flying controline and used collars, I can remember losing wheels on takeoff. Friends would wave and tell me that I only had one wheel, really fun landing that way. As I progressed, I would epoxy my collars (way overkill). Now with threadlocker and a good notch ground with a Dremel, they never fail. To loosen, just heat up with a soldering iron. But I like the idea of soldering close fitting washers .

I like to put some drag on my wheels to help keep from running off our rather-short runway. It also seems that the wind turns around when I'm on short final! Starting from the inside, I have a wheel collar, metal washer, wheel, fiber washer, O-ring, then the final wheel collar. I use a slip-joint pliers to squeeze the collars together to give the right amount of drag. Because of wear, I have to adjust the tightness every 10 flights or so. Thus, many of the techniques here won't work. I just put a small blob of Goop on the end of the axle. Despite not having tightened the grub screw down adequately more than a few times, I've never lost a wheel.

Every 10 flights? Geez. I have a Cub that I installed the wheels on 5 years ago and haven't touched them since. Wheel retention needn't be complicated.

I adjust the drag on the wheels as the fiber washer wears down. Do you have brakes on your Cub? Especially with a tail dragger, you need to make sure that the tension is not so high as to make it nose over either on take-off or landing but high enough to get maximum braking.

No brakes. I set it down nice and easy and let it stop. If I need to shorten the roll, I just zig zag a little.

Every 10 flights or so is to adjust the drag.

I I would like to say I set my stuff down nice and easy. Maybe once in a while. Anyway, the silver soldered washer has worked well for me, but the plastic wheels are more popular lately. For a short time, I threaded the axles after softening them up with a torch. and used nylock nuts, or soldered regular nuts. Lately, since I don't race much any more, I just dump the setscrew, and put in a regular shortened bolt for more torque, and a tapered flat if I feel ambitious..

For a little bit of drag without needing to adjust
frequently, a light spring inside the collar would
add just a little pressure, and would take up
the slight wear.

An alternative is to put a little toe-in, which will
force the wheels against the collars. The pressure
decreases as the plane slows down so it doesn't
cause nose overs.

An added benefit is that if the plane wants to wander
during takeoff or landing, the wheel that is pushing
hardest gets more drag and pulls the plane back
into a straighter path.

Jenny

Thanks, Jenny. Some good ideas there. I couldn't find a spring that would fit as the axle is quite short, but the O-ring does provide some compliance. I already had quite a bit of toe-in, enough that the tires are worn quite conical. The plane in question is an older WM chippie with a smoke muffler (and thus a lot of lead in the tail) that the original builder installed. It also has retracts so the wheels are back from where one would like them. On a good day with a bit of a head wind and full flap, I can set it down at the start of the runway and stop before the end. The brakes just improve my success rate!

Since I don't use smoke, I plan to replace the smoke muffler with a stock one (Saito 100), remove the lead from the tail, and rebalance by moving the battery. It's a fun plane to fly but making a good landing is a challenge.

The spring doesn't need to be a regular
coil spring like would be in a pen. It
can be conical shaped so that when it
is compressed it looks like a spiral.
If you are creative you can make one
by bending a piece of music wire into
a spiral and then stretching it to the
cone shape.

You can also use a piece of flat spring
steel, like is on the clickers and other
noisemakers you see on new years eve.
Cut a piece the size and shape you desire.
punch a hole to fit your axle. Then give it
a slight bend to make a nice smooth curve.
(If you have a hard time visualizing this think
of a bent penny.) If the edges cut onto your
wheel, bend the very edge back a little to
make a slight lip. This spring will take
VERY little space.

Another good source of material is the "slap
bracelet" if you can still find one.

Jenny

The flat spring idea sounds great. I've used wave washers in equipment I've designed. Didn't think of them. I got the O-ring idea from a post years ago. Something like two Belleville washers back-to-back would be good if I could find ones light enough. Punching a hole in spring steel may be a challenge.

You get my vote for the most consistently-useful posts on RCU.

Wow. Here's what I'm thinking, KISS principle. Keep It Simple Stupid. The more you over engineer something, the worse it gets. Seriously, if you're just trying to keep a wheel on, a notch on the axle and threadlocker on the set screw does just fine.

Well, since it was one of my posts on RCG that ETPilot was responding to, I guess I'm "responsible" for this thread. What I have done to my landing gear is to solder a washer on the inboard end of the axle. The outer 1/2-3/4" of the axle has been annealed, which is a fancy way of saying heated to a dull cherry red with a torch and allowed to air cool. This is done to soften the metal so it can be drilled. The music wire landing gear used in the PT60 is hardened, and you will destroy drill bits trying to get through it.
I destroyed three of them before getting on the internet to find out how in the @#$%&^ to drill this stuff! :mad:
After annealing the wire, soldering on the inboard washer, and marking for the hole to be drilled, I used a 5/64" bit at 1390 rpm, and used a pecking motion to slowly work through the wire. I ground a flat spot for the bit before drilling. I then installed a second washer on the outboard side of the wheel and installed a 1/16x1/2" cotter pin to secure the wheel.
Nice and neat, and I think it looks a lot better than a wheel collar on each side!
One of the inner washer will get a bit more solder, though
.http://www.rcuniverse.com/forum/atta...mentid=2193719http://www.rcuniverse.com/forum/atta...mentid=2193720

Yea flyboy2610. You are just a trouble maker. LOL. Love your threads on the other site.

Lots of good info on this thread. Just learning as I move along this modeling highway.