What pressure in a 737 tyre.

[magpienja]

Question for a commercial pilot, I am a truck driver my truck has 16 wheels/tyres gross weight 44.000kgs, a boeing 737 has 6 wheels/tyres that look much smaller than my truck tyres and most of the aircraft weight seems to be on the main bogies, I am not sure of the mtow of a 737 but it must be well in excess of my 44.000kgs, now the question how can 6 smaller tyres carry all that weight and take the punishment of take off/landings.

Regards Nick.

[magpienja]

Mmmm the truck tyre runs at 120psi so are commercial aircraft tyres of a very special construction to take that weight, fully loaded they dont even seem to bulge.

Nick.

[Rainboe]

Truck tyres are pretty stiff. Jet airplane tyres are like rock. It's even very difficult to see and feel if they are deflated. I tried experimenting with my large maglite torch (large tube of aluminium) with striking tyres and seeing if the 'doing' noise gave an indication of deflation. You still almost knock yourself out as it rebounds on you.
All I can say is I find it incredible remoulds are used on all jets, and good for about 200 landings. I stopped using them on cars about 35 years ago.

[TopBunk]

All I can say is I find it incredible remoulds are used on all jets, and good for about 200 landings. I stopped using them on cars about 35 years ago.

Only 200!? they must have been real Howlers;):oh:

[Rainboe]

Well if you saw my landings..........maybe 100 (always bouncers.....infact more like 75- some are triple bouncers)

[BOAC]

It was not unknown for new mainwheel tyres on the BAC Lightning to be replaced after one landing on crosswind limits. I cannot recall the pressure in the tyre there but I think it was around 280psi.

[NudgingSteel]

This reminds me of that fabulous spoof documentary series, "People Like Us" and the episode following a flight crew. The inept presenter is accompanying the captain during the pre-flight walkround:
Captain (patting 767 main gear tyre): "These tyres are inflated to about six times the pressure of your car tyre."
Presenter: "I suppose that's why they're so big...."

[NutLoose]

strange as it may seem the footprint of an aircraft like a 737 is not a bad as the likes of a gulfstream executive jet that has a narrow small tyre so has more weight on a smaller area, therefore there are some airports the gulfstream cannot operate from that a 737 could quite happily fly from.

[D120A]

Quite right, and in the same way that a larger airliner can operate into a field denied to a smaller one because of its narrow high pressure tyres, the same can apply to combat aircraft. BOAC mentioned the Lightning; IIRC, the tyre pressure in the nosewheel in the Lightning was 240psi, and in the mains it was actually a sporting 350psi. The tyres were narrow because they had to fit inside the wing, and the result was that the Lightning needed concrete to operate from because it sank into asphalt in no time at all.

At Binbrook the old Canberra dispersals were asphalt and, on anything other than a hot day, you could get away with taxying a Lightning over them. Parking, however, was another matter, and the solution was to place large mild steel pads, one for each wheel, at each dispersal. The aircraft had to be taxied exactly on to the pads for parking and turn-round. The pads, very heavy and carefully placed, conferred the added advantage that the aircraft was sure to be parked on a safe heading, i.e. with the guns and missiles pointing at something arable rather than residential.

[Rainboe]

.....and did they get loosed off unintentionally very often? And how about ejector seats?

[D120A]

Neither ever, in my experience. Possibly because of all the safety precautions, of which safe headings was just one.

But if it can happen, it will... Hence all the safety precautions.