Following the thread about my travails to replace a wheelchair inner tube, I started wondering if there's any risk of putting said wheelchair in the baggage hold of an airliner, with the tyres fully inflated ?
Practical question, since we're flying in December. Last time we flew there was no problem, but that was a previous wheelchair with bigger tyres and lower pressure (40 psi).
Inflate the tyres to 105psi. Then, even if the pilot gets lost and flies to the outer reaches of the solar system thus ensuring a complete vacuum the differential pressure will only be 120psi.
Well I have always assumed that the aircraft's own wheel have air tyres, they do OK, usually!
That crossed my mind, but then the pressure could be lower.
As the previous answer suggested, my knowledge of gas physics is rather poor (I never really enjoyed it, along with optics) - I preferred electrickery and nuclear ;)
Some carriers request that bicycle tyres are deflated and as noted in the other thread some have quite high pressures which means such a precaution may not be unreasonable. If you already know who the airline is they will be the best to ask, and also see if they can help with the logistics of reinflating them, or if you need to take a pump with you which may be awkward.
G.Harman
Always had to deflate them on the bikes in the '80s. Damned nuisance, as the vibration/knocks could cause punctures. Tried letting them down to about 30 - 40 psi but the idiots let out the rest. I've had a tub. at about 110 go bang when it was at the top and I was on the drops - ages before I could hear again. Low volume at high pressure, OK; high volume at low pressure, bad (Stanley proved this with his 'dangerous' boilers - the low pressure one destroyed the set-up. Years ago I saw a report by the HSE about a tractors rear tube that had gon bang. Apprentices were mucking about and seeing how big it would go. It killed one of them. Tyres should be OK at usual pressure but to be sure they could be let down by 1 Bar, but the airlines don't understand.
IIRC you are supposed to inflate tractor tyres in a cage - according the the photocopied article I read in a tyre equipment workshop years ago.
The aircraft (including the hold) will be pressurised to around 8,000 feet, which is less than a 4 psi drop in air pressure, when compared to ground level.
They actually use dry nitrogen to inflate the tyres of airliners, to avoid the problem of ice forming inside the tyre at high altitude and creating unbalanced tyres. Main tyres on a Jumbo are at about 200 psi, with the nose wheels slightly less.
There is a particular danger with wheels that are 'bolted'. If bolts get corroded they may fail... A long time ago I saw a report of a man who was ejected through the roof of a building. He was standing on said wheel, inflating the 'tire' when the bolts failed... Don't they do stupid things on other side of the pond...
Jim
pressure would be no problem. You are just removing one atmosphere from outside it.or about half an atmo.
Cold might not be too kind, however.
It would make MORE difference to LOW pressure tyres, actually.
IIRC aircraft tyres on jets are pumped up to high pressures with inert gasses.
But of course once off the ground the pressure drops a little as the tyres dont have to bear the aircrafts weight, and its cold up there which drops them a bit more..
Not necessarily. There are unpressurised holds as well.
In a modern airliner, the only unpressurised areas in the hull are the wheel wells, the area behind the aft pressure bulkhead and the radome, which is ahead of the forward pressure bulkhead. The hold may not be heated though.
Was out with friends on mountain bikes and there was an ear-splitting bang whilst we were all going down a hill. This was probably only 40-50 lb/sq inch. Took a moment to work out what had failed - it was the wheel rim. It had been worn too thin by the brake pads, and gave up.
Sister-in-law had one explode on a push-chair. In that case, she had worn right through the tyre, and inner tube exploded when it made contact with the ground. That push-chair went through inner tubes at an incredible rate, which was a widespread problem as the manufacturer kept running out of spares in the UK, and they were a completely non- standard size, or course. Fortunately, only one case of an exploding one though.
Not sure the wings are pressurised or the tail...and whether holds exist in the tailcone or not...
None of the flying surfaces are pressurised, but they are not part of the hull. The tailcone is usually attached to the rear pressure bulkhead. On a wide bodied jet, the hold is below the cabin floor and it is much simpler to pressurise it than to make the floor a pressure bulkhead. At one time, the rear pressure bulkhead could be a lot further forward and there could be an unpressurised hold behind it, but I can't think of any modern airliner where you will see that.
Would that be sufficient to allow the tube to cope, reasonably safely, with sudden depressurisation at altitude? I liketo think that in such an awful situation, there wouldn't also be a peleton of bicycle wheels exploding. Or do the airlines actually understand this and try to avoid the problem?
Would that be sufficient to allow the tube to cope, reasonably safely, with sudden depressurisation at altitude? I liketo think that in such an awful situation, there wouldn't also be a peleton of bicycle wheels exploding. Or do the airlines actually understand this and try to avoid the problem? /q
If there was a sudden depressurisation at altitude would we be bothered about a few bike tyre inner tubes exploding?!
Jim K
Why not? At least one aircraft has depressurised at altitude because the pressurisation system was switched off by a spurious command from another faulty piece of equipment. It was recoverable by diving the aircraft to a safe altitude. It might not have been had there also been explosions in the hold.
Well I'd ask an airline, surely they must know. Brian
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