seanreit

My Feedback: (60)

I was asked "What would be the holy grail of how to attach a tire to a rim if we were starting over to make new wheels, tires brakes".

All opinions are requested, open discussion.

Shok

My Feedback: (28)

Maybe air pressure like the full scale?

ianober

My Feedback: (12)

I would prefer the 2 piece hub and screws through the tire, just not as many as BVM uses. I like this design for 2 reasons, 1 it elimates the need for glue or any adhesive and 2, it lets you use a solid rubber tire. I think this is the only way to get a long lasting tire, air filled is too thin a rubber and if you over inflate then you have to take apart the hub again to get the air out.

GSR

My Feedback: (145)

I have absitivley posilutley no problem with the BVM design. With the hot T pin method it takes me 10 mins from start to finish to change a tire and they NEVER come off. Also if you are just abjectly lazy you can only put in every other bolt and it will still work fine. Scotty

Gordon Mc

My Feedback: (11)

I don't mind bolts through the tire as BVM uses, however I would still prefer a 2-piece hub so that you can disassemble the hub to put the tire on without having to stretch it over the rims.

The problem I found with the BVM mounting method is that once you stretch the tire it can stay stretched for a little while. The first time I did tire replacements on my Bobcat I did the bolt holes immediately, and ended up with much less "meat" on the inside of the bolt area ; this in turn caused the tire to rip through the bolt-holes after a while.

2nd time I replaced them, I put the tire on and noticed that it was staying 'oversized' and not closing on the rim even when I tried clamping it. After I let it sit for a few hours it was fine. A 2-piece hub would have eliminated this issue.

seanreit

My Feedback: (60)

Any drawbacks anyone can think of to the two piece hub?

Is everyone on board with ball bearings at the axel?

DocYates

My Feedback: (102)

I like the two piece rim, and do not mind screws thru the tire. I would prefer the female part of the hub to be threaded, so there is no need for a nut on the other side. I tto don't like to have to scretch a tire to get it on the hub, so to me an ideal unit would be a hub that comes aprt, threaded on one side for the screws that pass thru the tie, and a tire that fits the rim with no need for an additional tool to put it on the rim. Solid rubber tires as well.
Tommy

ChuckC

My Feedback: (24)

I think ball bearings may be over-kill and would have to be sealed so you didn't have to have yet another maintenance point.

Sintered bronze bushings seem to be just fine and much cheaper.

Like the two-piece hub idea...

drdoom

My Feedback: (9)

I have no issues with JL's 2 piece Hubs on the F-16, they really spool up on takeoff and touchdown.

digitech

My Feedback: (10)

look at the manufacturers who never looses a tyre and weighs less.

secondly find a good tyre supplier who can make you loads for less...

Vincent

My Feedback: (61)

Two piece hubs for the robart tires would be nice. All sizes to choose from and you can put a section of nylon rope inside the tire to beef it up. I had a set on my Avonds F-16 and they lasted a long time and were easy and reasonable to replace.
V..

ravill

My Feedback: (11)

Yup, screws through the tire that are MOLDED in at the factory would be nice. Having replaced enough BVM wheels (I'm too lazy to even try to squeeze a tire over the old rim [] ) so I just buy new ones. That's getting expensive..[sm=greedy.gif]

Raf

seanreit

My Feedback: (60)

How much extra would you guys pay for a two piece rim with screws to hold the tire on?

u2fast

My Feedback: (37)

i have often thought about tires and wheels. to me the perfect set up is to have a lip machined into the inner side of the wheel. on both halves. then mold a tire with the same groove but 5 to 10 % smaller. screw the wheel together and nothing through the tire. just the compression of the rings on an undersize groove. wa la, i shall patent the idea. barry

Wayne22

My Feedback: (2)

Spark has a metal ring moulded into the hub side of the tire, and the two piece hub clamps it in place...no stretched tires, no tires blowing of the rims, and no burning rubber when changing tires. For additional security flanges could be moulded in either radially or horizontall for a more secure fit, though I doubt this is needed.....

Might was well make them out of titanium too..

Skip the ball bearings, one speck of debris would toast them, and a tire too..

Gordon Mc

My Feedback: (11)

Hard to say ... in general the way I tend to look at this kind of thing is : if I need to buy the brakes separate from the wheel+tire combo, that's less appealing than a one-stop shopping solution, and the extra shipping & handling required to buy from 2 sources instead of one already takes away some of the extra margin.

Ball park guess - maybe 10% more for the better solution. I only replace my BVM tires every 200 to 300 flights anyway, so the inconvenience that I'd be paying to overcome is pretty minor.

Gordon

KC36330

i gave this some though several yrs ago and thought the best idea was to make a rim that clamped around the tire and the center of the tire have a bead molded into it for the clamping. here's a quick and dirty MS Paint of the two pc rim with the groove for the tire. on the brgs I'm most satisfied with the bronze bushings, self lubricating and allot less hassle, cheaper too.

seanreit

My Feedback: (60)

We're going with a two piece design as Barry suggested above. I have a prototype here made today with bearings in it. Very nice unit. It is a converted BVM T33 wheel/ brake.

We'll be making a mold for the tire sometime next week if I had to guess.

Thanks for the input guys. If the bearings dont' hold up to my landings, we'll go to bushings, if the bearings do hold up to my landings, none of you will have problems with them at all

Randy M.

My Feedback: (38)

If you go with the two piece hub with screws through ala BVM, make sure to have a way to line up each half. Some kind of interlocking pin. Having to line up those holes would be a pain.

seanreit

My Feedback: (60)

There won't be screws to hold the tire, the tire will have a flange as per Barry mentioned that fits into the RIM sides preventing the tire from spinning off through RPM's or other means. In addition to this flange, there will also be compression against the Tire itself as you put the two halves together.

We are thinking roughly 3 screws attaching one side of the rim to the other, but that part is still in the air.

Another consideration is a threaded wheel sides, reverse thread on one side, this part we are still working on, so too early to tell.

I'm sure something can be worked out. I just thought such a wonderful question, what would the best design look like?

This is going to be a damn good one that's for sure.

Gordon Mc

My Feedback: (11)

A downside with that approach is that you are specificaly making the wheels left- or right- sided. That means needing 2 spare rims instead of just one, means that you can't swap the tires from left to right to balance out uneven wear for aircraft that don't track perfectly straight, etc. You'd also need to make both left and right nose-wheel tires depending on which side of the strut the axle attaches to. Last but not least, the forst time someone puts a left wheel on the right hand side and it unscrews and messes his aircraft up, you (rather than the mistaken user) are going to be blamed.

Side neutrality would be better IMO.

Gordon

u2fast

My Feedback: (37)

kc36330, the bead is a good idea. the problem with this idea, is it allows the entire tire to grow and stress the very center. i use to have an aviation design f16. it used 4 screws to hold the tires on. they were near the center. on take offs, you could see the tire grow and eventually the tire would explode. i had some custom wheels machined and used 6 screws and placed them much further out in the tire and the issue was resolved. all be it, the adjet f16 tire was soft, but the only difference between the soft tire and a hard tire is the time it will take to break the tire down. sean, good luck on the wheel, tire design. i do like bearings in wheel. the adjet 16 had them and it rolled so smooth and you didnt get the slop an oilite bushing gives you over time. but consider a medium to large size bearing, some times the side loads can be great when you consider the speed and the weight of a model. barry

KC36330

I'd be tempted to say that the solid bead around the tire would completely prevent any ballooning at anything under oh let's say 200,000 RPM (unless you make them from a soft material and then they wouldn't be much of a tire anyways) and the tire would wear out long before the bead failed. after all it's a 360ΒΊ of secured contact, not 4 little screws, but unless Sean is gonna make a couple pairs for me to test out i guess we'll never know.

seanreit

My Feedback: (60)

First set goes to me to abuse and find out what we did wrong. Second pair will probably go to one of the CA boys, as they don't know how to land, yet fly 50 flights a day.

Perfect wheel abuse

Gordon Mc

My Feedback: (11)

What counts as a flight ?