Puncture preventing sealant in light aircraft tyres?

[Mechta]

Punctures and under inflated tyres seem to be a common problem on gliders, particularly on tailwheels, given the relatively thin tread and low volume of the tube. As a result, I asked my technical examiner if I could put a pre-emptive sealant of the type used on bicycles and baby buggies in mine to prevent smaller holes causing a flat. His reply was that this would constitute a modification and invalidate the insurance. Fair enough, I won't do it then, but I just wondered if anyone in the UK has experience of trying to get approval to use the stuff in their aircraft tyre?

Is anyone aware of any issues that sealants could have on tubed tyres apart from the possibility of putting wheels out of balance?

Have you tried a sealant in an aircraft tyre and did it work?

[dubbleyew eight]

the best thing for punctures in aircraft tyres is a bitumen surface, or concrete, kept clear of foreign objects.

you need a compresser in the hangar and a tyre pump attachment.

putting "slime" in a tyre? why would that be a problem?

fly in dry country with double gees around and you will find "slime" used quite often. tyres going out of balance from it is baloney. the stuff remains liquid in the tyre.

[Ka6crpe]

I have a similar product in my K6 glider tyre and have no issues.

On my favourite club glider (Jantar) I did suffer a flat tyre on a land out onto an airstrip that was still under construction, and nearly ground looped it. The club used slime in that tyre after that also with no issues.

[Mariner9]

Most (if not all) products of that type require you to immediately drive/ride your car/bike for 20 mins or so in order to distribute the product around the tyre by centrifugal force.

I suppose you could fast taxy around for 20 mins but you might get some engine overheating issues!

[Mechta]

I suppose you could fast taxy around for 20 mins but you might get some engine overheating issues!

Its a glider, so if I could persuade the other club members to push it around for that long, overheating would be very likely and it could take quite a lot of beer to bring temperatures back to normal! Maybe I would be better off borrowing a treadmill from a gym, and run the tailwheel on it until the stuff is evenly spread.

Thanks for all the replies. I think an enquiry to the BGA (British Gliding Association) is in order. Punctures of this sort are evidently a problem, and if it can be shown that the benefits outweigh the risks, they might be able to come up with a way of approving the use of the stuff.

[mad_jock]

take the wheel off and attach it to the end of a drill. Then spin it.

I can't see how anyone would know if you had put it in to be honest.

Is it tubeless or does it have a tube in it?

[Mechta]

Hi Mad Jock,

The tailwheel has a tube in it. Not sure about the mainwheel, though. Yes the electric drill option is the most sensible ( the tread mill suggestion was tongue in cheek), although to be honest, by the time the glider has travelled to the launchpoint the mainwheel would have done enough revolutions for it not to be an issue.

I don't know if the stuff, once distributed to a thin layer around the inner tube, stays where it is, of if it would head back to the lowest point if left for a week or more in the hangar.

I've spoken to my regional technical examiner, and he thinks its is unlikely that the BGA could give approval as this is an EASA transitioned glider (it would be different if it was an older 'Annex 2' vintage glider).

He agrees that it is unlikely anyone would know if the sealant was in the tube but if it was found out after an accident he says it could give the insurance company a get out. Maybe the next step is to speak to the insurance company themselves, as a ground loop resulting from a flat tyre seems a far more likely scenario than any I can think of caused by the sealant being present.

I've since noticed that Skycraft actually advertise 'Slime' on the tyre page of their on-line catalogue. They don't actually say it can be used in aircraft tyres, but the fact that it is on the same page as aircraft-specific tyres, infers it.

[mad_jock]

I can't see anyone caring.

I think the stuff just drys and coats the inside.

Try it on one then cut it open if you cant see a difference just use it.

[abgd]

If that's how it works, why not just fit thicker tyres?

ISTR issues with some types of valves gumming up on bicycle tyres.

[cockney steve]

Maybe I would be better off borrowing a treadmill from a gym, and run the tailwheel on it until the stuff is evenly spread.

we need to know, if the treadmill speed is infinitely variable, will you take off:}

The sealant is, I think, Latex....this has the peculiar property of remaining liquid when under pressure....
remove pressure and it solidifies hence it "seeks and seals"

I know a transport operator who used to ship liquid latex to a carpet factory at Dundee when they closed (folded?) he got paid to empty the tanks and transport the latex back again. Road tankers had to be cleaned out before they could revert to non-pressurised loads.

@abgd the latex would probably be lighter and not affect the tyre resilience as much.
take valve out, inject liquid, repressurise immediately. as far as i know, the stuff is thick enough to not drain to the bottom,but there's not sufficient to cause a balance problem anyway.