Captainbob

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I have a BVM F-100 which i've been flying for about four years now. Have probably used about 110gal of K-1 by now. The biggest problem i've had so far is keeping tires on the airplane. i'm on my fourth set now. at last years DOGS show one rolled off of the rim during t/o.
It seems to me that the inside diameter of the tires is larger than the bolt circle diameter of the rim so that when mounting the tires and drilling for the screws you completely miss the rubber. Comments anyone??????????

Cooper

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Well Captain Bob

On my BVM F-100 I can assure you all the tire was drilled for the little retaining screws through the rubber so possibly there is something amiss in your set up. Are you possibly not using BVM wheels and rubber?

Best regards

Greg Anixter

S HARRIS

My Feedback: (6)

Capt Bob, I have also noticed this on my big Sabre tires. On the last set I applied bit of pressure on the tire to assure that the screw goes thru the tire. You may need to rotate a bit sooner also, (high rpms will destroy almost anything)Hope this helps. Scott

jetpilot

My Feedback: (48)

I had this happen to me at Top Gun last year. The tire flew off on takeoff. The bolts need to be periodically checked for tightness and use a drill press when installing the tires as this helps not to miss the other side. Also use the smallest drill bit necessary to get the bolt through. I just installed another set of bolts on a F100F im taking to Top Gun this year and the tires seem to fit perfect to me, but i noticed the larger hole opening on one side will make one want to use a large drill bit to ease of the bolt installation, but will probably give the tire too much play on the bolt. You might also notice the tire comes off on one side more than the other?
I believe the bolts want to rotate on braking.
I also noticed one main had a slight bit of tension as compared to the other and this might also shorten the life of the tire.
I also always use takeoff flaps too shorten the distance of takeoff. The airplane will come up much quicker with takeoff flaps and this will definately help out the tires.
Do you use takeoff flaps?
What engine are you using?
Do you apply brakes before tuchdown?
Also, I definately did drill through rubber when i installed the bolts.
Scott

Captainbob

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Thanks for all of your replys. i just made an accurate measurement of the tire inside dia. and the screw circle dia. tire inside dia is 2.00 inches, screw circle dia is 2.10 inches. This means that the center of the screw is only into the rubber .050" from the inside edge of the tire. this only leaves a thin membrane of rubber (less than .020" thick) between the screw and thin air. It seems to me now that i think about it that what is happening is that at high speed, there is enough centrifugal force to cause the tire to expand enough that the screws tear through this thin layer of rubber.
looseness of the bolts couldn't be the cause since if even one backs out it's going to jam against the strut. i also use a drill press to drill the rubber before putting the screw through. i don't see that the size of the drill bit has anything to do with the problem though since the size of the hole in the rim limits the size of the drill bit that can be used. the nature of rubber being what it is causes the hole to close up once the bit is removed. you'd have to use a much larger drill bit than the hole will allow in order to have an oversized hole in the tire.
I do use flaps on takeoff. have never used brakes before touchdown. using an AMT netherlands Pegasus at 35lbs thrust. i have made some pretty hot landings though and maybe this is causing the problem- thinking about the tire expanding on the rim at high RPM's. THanks again for your help - youall.

DavidR

My Feedback: (1)

Something else you can do it chuck a straight pin in your drill press. Heat the pin red hot with a torch and the run it thru the tire and rim. As Scott mentioned you may also want to comress the tire slightly while you "drill" it.

DR