Come back Globalti - all is forgiven

ColinJ

Puzzle game developer
@Globalti, I see you have made a bid for freedom today, to the letter pages of Cycling Weekly ...

I agree with your point that bicycle tyres should not need to be deflated before flying because the pressure differences when flying are only like those experienced when cycling over a big Alpine pass! :thumbsup:
 

Globalti

Legendary Member
Eh? Did they publish me? Cool !
 

Brandane

Rain; It's not big and it's not clever!
Location
Costa Clyde.
The proof is in the pudding. I flew to Orlando last week with my bike. Conti gatorskins 700x28 (on a hybrid) pumped to 100 psi before I left.
They were in shreds when I took the bike out its bag.



Only kidding; 40000 ft of altitude for 9 hours did them no harm. I'll be doing the same on the way back, although that won't matter as I have access to a track pump when I get home
 

Globalti

Legendary Member
The proof is in the pudding. I flew to Orlando last week with my bike. Conti gatorskins 700x28 (on a hybrid) pumped to 100 psi before I left.
They were in shreds when I took the bike out its bag.

Only kidding; 40000 ft of altitude for 9 hours did them no harm. I'll be doing the same on the way back, although that won't matter as I have access to a track pump when I get home
Pedant mode/

The effective altitude in the hold would have been somewhere between 8,500 and 10,000 feet though. However bike tyres DO explode when left inside hot cars, I don't know why that is - maybe because they expand and come off the rims?

/pedant mode.
 

Globalti

Legendary Member
The fuselage of an aircraft is a big sealed aluminium cylinder with a convex wall at the rear end like an aerosol can. The hold and the cabin are both "pegged" at around 8,000 -10,000 feet of pressure by the engine-driven compressors as the 'plane climbs. Any difference between hold and cabin and the floor would collapse upwards or downwards. If cabin pressure was allowed to drop to outside pressure at 35,000 feet the passengers would die from lack of oxygen; life starts getting uncomfortable by 15,000 feet and I've seen unwell old folk blue around the lips at 4,000 feet on Cairngorm, having come quickly up the funicular. Not sure why there would be a sudden "drop" in a chopper though - the aerodynamic effect of the rotors perhaps?

If the seal fails in a 'plane the pilot has to descent to around 10,000 feet quickly. People who have experienced this talk of mist forming in the plane as the atmosphere loses the ability to hold moisture. Oxygen masks drop down automatically and when you pull the tube you activate a chemical reaction that generates a few minutes of oxygen in a small reactor. Sudden explosive decompression can allow such big volumes of air to exit the fuselage that objects or people can be sucked out: http://en.wikipedia.org/wiki/British_Airways_Flight_5390
 

green1

Über Member
Not sure why there would be a sudden "drop" in a chopper though - the aerodynamic effect of the rotors perhaps?
Yep its called ground effect, you have the rotors pushing all the air down in the ground and it can't escape quick enough so you get a build up of air pressure. The Russians played around with Ekranoplanes to take advantage of ground effect.
 
Location
Loch side.
If the pressure in the hold was different from that in the cabin, all the animals in the hold would die. They don't.
The airplane's own tyres don't explode, do they?
The hold and cabin shares the same recirculated air. My brother often flies Airbus A320s with goats in the hold and he says you can smell them. I presume they can smell us. Apparently cabin air on long flights is bad enough for airport personnel on the tunnels to stand back and hold their breath as the doors are opened.

I used to travel with a MTB with sealant in the tyres and once you've deflated those tyres you have a mess. I kicked and screamed (internally) against the ground personnel insisting on deflating my tyres but soon realized I'm farting against thunder. Now I jam the valves and put a label on the wheels that say "Gel Filled."

Edit: Good on you Globalti for raising the issue. I hope it has effect.
 

Smokin Joe

Legendary Member
Pedant mode/

The effective altitude in the hold would have been somewhere between 8,500 and 10,000 feet though. However bike tyres DO explode when left inside hot cars, I don't know why that is - maybe because they expand and come off the rims?

/pedant mode.
I'm glad that's not only me. Back it the day I've arrived at a race start with a knackered inner tube on more than one occasion before I twigged that I'd better let the pressure down before I put the bike in the car. Only ever happened with clinchers though, never tubs.
 
OP
ColinJ

ColinJ

Puzzle game developer
Was the reason you wrote to the magazine rather than start a thread not to prevent the dullfest that has now ensued?
Now you see, when I spotted the 30-odd threads today that I could see were going to turn into what I would describe as 'dullfests', I quietly clicked on 'Ignore Thread', left, and closed the virtual doors behind me.

Why would you stick around to check how dull this dullfest had become, and do you make a habit of commenting on how dull you find every dull thread to be? If so, I find that a rather dull way to spend your time! :laugh:
 

subaqua

What’s the point
Location
Leytonstone
Now you see, when I spotted the 30-odd threads today that I could see were going to turn into what I would describe as 'dullfests', I quietly clicked on 'Ignore Thread', left, and closed the virtual doors behind me.

Why would you stick around to check how dull this dullfest had become, and do you make a habit of commenting on how dull you find every dull thread to be? If so, I find that a rather dull way to spend your time! :laugh:

cos he is a miserable canute
 

Brandane

Rain; It's not big and it's not clever!
Location
Costa Clyde.
Pedant mode/

The effective altitude in the hold would have been somewhere between 8,500 and 10,000 feet though. However bike tyres DO explode when left inside hot cars, I don't know why that is - maybe because they expand and come off the rims?

/pedant mode.
So; if the tyres were in an unpressurised environment at 40,000 feet, would they explode?
If so, I will be deflating mine next week. If the plane I am on breaks apart at that height, I would hate to think that my bike tyres are going to be damaged. :ohmy:
 
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