Blew a Tire - Gettin' out the Fiberglass....

Ironflight · #1 04-06-2008, 08:18 PM

It was a completely normal touchdown after a nice little Acro flight, with a five or six knot direct crosswind and no bumps. Touchdown was smooth, and since I had no headwind, we were going just a tad faster than normal, so I did a little braking with the tail in the air to get off at the mid-field, as usual. There was nothing odd until the tail came down, and then I start getting that galloping feeling and the thump, thump, thump that only means one thing - a blown tire! I added a little power to keep it rolling until I got off the runway - no way did I want to block the pavement on a beautiful Sunday evening with lots of people in the air - and came to rest beyond the hold-short line and clear of the parallel taxiway.

Dang, that felt exactly like when I cut a tire on the wheel pant during Phase 1, almost 700 hours ago! I shut down and crawled out. The cell phone rang - "Hey Paul, you need help out there?" Yeah - and bring some tools! The right tire was completely flat, and there was a nice white trail of rubbed-off fiberglass from the pant parallel to the yellow turn-off line and out on to the runway. Hey, at least I kept it nice and straight! That pant was going to need some work though....

The cavalry soon arrived on a dirt bike, in a golf cart, and with a truck. We quickly got the pant off, and saw that the wheel was pretty much on the ground. One guy went back for a wheel and tire from an RV that was on jacks, and I thought about the last time this happened - we just inflated the tire, it held air, and we taxied back to the hangar. I figured it was worth a try, and miracle of miracles, it worked! The tire held, so I hopped in and lead the parade back to the barn. After jacking the plane up and pulling the tire, we deflated it and split the rim. The tube looked fine, but put some air in, and sure enough, there was a tiny cut. It was about an eighth of an inch long, on the sidewall - but not aligned with the sidewall the way you'd expect if it was cut by the wheel pant. In fact, the tire showed nothing at all. It is still a complete mystery what happened - I sort of lean towards some debris inside the tire that got compressed into the tube - but how come it went a hundred hours since the last tire change, and blew on a normal landing?!

Ah well...time to order a new Air Stop tube, and pull out the fiberglass. Fortunately, the pant just wore down the bottom - it will take some structural work, but that is already setting up in the garage downstairs. Paint is another issue, but again fortunately, it is entirely in the white portion of the pant, and no other colors are involved. I'll call Grady tomorrow and see if I can get some touch-up white, or if I'll have to bring him the pant to shoot .

I'd love to take a lesson away from this that would prevent another flat, but I am in the dark on this one. Nevertheless, a flat tire once again proved to be a non-event from a control standpoint, as I am always hot on the controls on landing, ready to put in whatever inputs are necessary to keep it on the line. Don't let it get sideways, always land to give yourself the most concrete margin you can (on the centerline, or biased for wind), and fly it until all the parts stop moving.

Paul

AlexPeterson · #2 04-06-2008, 08:35 PM

Paul, this sounds just like the mysterious holes in the sidewall of RV nosewheel tubes. My theory is that the tube sort of "walks" as things flex until it stretches a section of the tube to its limit. Don't have a better explanation. I only know that since I put a couple tablespoons of baby powder in there, I haven't had another (had three in about two years before upping the amount of powder).

Ironflight · #3 04-06-2008, 08:52 PM

Quote:

Originally Posted by AlexPeterson

Paul, this sounds just like the mysterious holes in the sidewall of RV nosewheel tubes. My theory is that the tube sort of "walks" as things flex until it stretches a section of the tube to its limit. Don't have a better explanation. I only know that since I put a couple tablespoons of baby powder in there, I haven't had another (had three in about two years before upping the amount of powder).

This had the appearance of a razor-like cut Alex - it actually sealed itself well enough to get back to the hangar - yet when I inflated it outside the tire,we could spread it and get it to leak - is that how the nosewheel leaks were?

I use a fair amount of talc - will try even more - shouldn't hurt much!

paul

Transporter · #4 04-06-2008, 09:54 PM

Paul,
Glad to hear you and the Val are OK. What brand of tires and tubes are you using? I'm getting ready to order the finishing kit so any advice will be welcome! Thanks,
Mike

Ironflight · #5 04-06-2008, 10:03 PM

I'm running Air Stop tubes from Michelin, and Desser retreaded tires. Now before anyone blames the retreads....the first tire I blew during Phase 1 was the stock Van's tire, and this current flat was the first time in 25 years of using Dessers that I have had a probem....

AlexPeterson · #6 04-07-2008, 06:19 AM

Quote:

Originally Posted by Ironflight

This had the appearance of a razor-like cut Alex - it actually sealed itself well enough to get back to the hangar - yet when I inflated it outside the tire,we could spread it and get it to leak - is that how the nosewheel leaks were?

I use a fair amount of talc - will try even more - shouldn't hurt much!

paul

Paul, that is indeed what the nose wheel story is, at least in my case. They look like a little crack might look in brittle material. I recall maybe 1/8" long or so. The air goes out, the tube "rearranges" itself and seals somewhat again. I don't recall ever trying to reinflate one though.

Kind of like a bad pair of socks that want to move around on your foot....

JBPILOT · #7 04-07-2008, 04:53 PM

Just a thought. I had 3 flats in 3 years. I finally bought a new tire guage and realized I was not putting as much air in the tires as I thought. I was about 5 pounds low. Have not had a problem since. I think it flexed the side-walls too much. Never actually found anything in the tube or tire. Just caused stress on the side of the tube is seemed.

John Bender

GrayHawk · #8 04-07-2008, 06:10 PM

Is there a source for 'air stop' tubes for the nose wheel?

AlexPeterson · #9 04-07-2008, 06:16 PM

Quote:

Originally Posted by GrayHawk

Is there a source for 'air stop' tubes for the nose wheel?

Not that I've found... but, the el-cheapo tube seems to hold air quite well. I maybe add air twice per year. Nor is there a source for a higher quality tire available...

Ironflight · #10 04-08-2008, 09:10 PM

Just to let folks know - blown tires and ground down wheel pants can be annoying, but they aren't catastrophic. Sunday night I roughed in the structural repair to the bottom of the pant. Monday morning I ordered a couple of new tubes from Desser (one to use, one a spare), and did some shaping on the pant. Monday night I built up the final shape of the pant with resin and micro. This morning before work I took ten minutes, finish shaped the pant repair, and put on a final layer of resin to create a nice finish. Sanded and primed it after work, ready for paint - but unless you are looking for the damage, you won't see it. The new tubes were waiting on the door-step when I go home, drove out to the airport in the evening, and in an hour and a half, had the new tube on, had flipped both tires on the rims (they were due), and had the pants back on - ready to fly.

Just keep the airplane straight when you blow the tire, don't let it become major damage, and if you built it in the first place, the repair is pretty simple....

Paul