why dont airplane tires disintegrate when the plane hits the runway?

Question

It seems like the rubber tires would disintegrate with the friction and heat and rapid rotation as the tires hit the runway

Answer 1

The aircraft tire is designed to take rapid accelleration up to its stated landing speed due to the thickness and plys of chord. There are a few other reasons as well. The tire does not just fit over the rim like car tires that blow easily when hitting a pot-hole. The wheel is a clam shell and unbolts into two pieces. The rim of the tire is porportionally so thick there is no way possible to stretch it over the wheel. That is why when it rapidly accellerates, it holds its shape at the wheel rim. Most I am aware of too also have an inner-tube inside of the tire. Proper insertion is also as important as the outer tire itself.

The bearings on the wheels allow the energy from friction to be quickly be converted to rotational energy so the screetch lasts for 1 second or less and you have seen teenagers screetch their wheels for 15 seconds without disintigration all the time. This is also why aircraft go through 100 hour inspections and at least an annual. Washing or cleaing an engine with mineral spirits for example can dissolve the grease from the wheel bearings and cause a lot of friction... enough to burn out a tire on landing cause now they can rust without the grease and lubrication.

Tires do come apart but it is not as common as you would think. I use retread tires on my plane because the rubber compound the company uses lasts as long as Michelin Tires and cost about 60% of the Michelins. Airliners carry heavy loads and use heavier equipment also have more than one tire per axle in case this does happen. The weight of the aircraft can still be supported if one goes. Most pilots I know and yes... this is plane specific as well as runway condition specific, try to grease their landings so that their is not an abrupt drop to the runway. Many times when I land you cannot hear any screetch at all... just a quiet spinning up of the wheels.

Usually a maintenence, weather , waiting too long to replace a worn tire,poor pilot technique... landing and not putting the balls of your feet on the floor when operating the rudders on landing can accidentally lock the brakes and dramatically wear a flat in the tire. Weather????.... Taking off in slushy conditions then reaching altitude can quickly change the slush to ice locking the brakes. This happened to a Piper Cheyanne ahead of me on landing locking his wheels ..blew the tire and off into the middle of the grass. I had to divert to a parallel runway.

Answer 2

Nobody expected an airplane shaped cutout but did expect to either find the wings or tail section either broken off or at least cause some damage. The windows right by the hole weren't even broken and even the fuselage alone of a 757 can't fit through a 16 foot hole. This is the most protected building in our country and you honestly believe they couldn't stop that plane that was on course for the Pentagon nearly an hour after the first attack on the WTC. Literally hundreds of security cameras and they can't show 1 video or even 1 still photo of a plane making impact? People need to think a little bit.

Answer 3

They do. Especially when the pilot makes a hard landing or one where the tires are NOT aligned down the runway as in a crosswind landing done poorly.
I am an aircraft mechanic and I have seen many damaged flaps from pieces of tire hitting them. I have heard of engine failures on rear engine planes where chunks of tire were ingested into the intake of the engine.
The big planes don't get many landings on a tire. But the tires have been improved tremendously over the years. Most airlines use recapped tires as long as the core is still usable.

Answer 4

1. More plies: car tires typically have one or two plies (layers of rubber-coated fabric cords), while aircraft tires contain as many as 20 plies. The 737 nose tire in the example has 6 plies.
2. Different components: aircraft tires use nylon fabric (most car tires use polyester) and highly specialized rubber compounds designed for their particular function in the tire.
3. Simpler tread design: tread patterns consist only of tread ribs between several deep, wide cirumferential grooves.
4. Higher deflection: an aircraft tire typically runs at 32 percent deflection, while a car tire runs at only 11 percent deflection.

Another major difference is that 80 percent of aircraft tires are bias-ply tires, which have multiple layers with ply cords at alternating angles substantially less than 90 degrees to the tread centerline. Automobiles use radial tires, in which all plies run in the same direction and 90 degrees to the tread centerline. Radial tires are becoming more common, as aircraft manufacturers take advantage of their lighter weight and additional landings per tread. Radials are rarely retrofitted onto existing airplanes due to the high cost of certification for the airframer.

Answer 5

some times they do just that explode and disintegrate, the tire manufacturers have gotten much better at tire compounds and design than what there was available even as late as ten years back, the last thing they need is a multi-million dollar suit because of a blow out and the ensuing damages, much less the loss of business due to a bad reputation. depending on where and when it hapens, the tires are the first item on the inspection list when they land, and the last thing a pilot checks before take off

Answer 6

at normal landing speeds, the rotational speed of the tire is at a value less than the tires max design rotational speed. Ex the front tires on metroliner rated for 136 knots, normal landing speed is less than that, however, the "rated speed " is also less than the design Max rotational speed to give a good safety margine.

Answer 7

They're designed to take the load of landings. Pure and simple. Nitrogen may be used as it's more stable than ordinary air and may extend the life of the tires somewhat.

I'm not aware that nitrogen has ever been used in fire extinguishers as one poster stated.

Answer 8

Airplane tires are filled with nitrogen, not air. Nitrogen is a gas used in fire extinguishers as it prevents oxygen from feeding the fire. If airplane tires were filled with air, then they would explode.

Also your question regarding disintegration. As far as I know the tyres used on Concorde contained special metal inserts. Im not sure if these tyres were used on other airliners such as the Boeing 747. Finally airplane tires are very large when you stand next to them. They are not penny-sized like they are seen when viewed from a distance. I know this because I used to work at an airport amongst aircraft.

Answer 9

They are tested-tuff for what they do. If you ever watch a jet land
fairly up-close U would see some smoke come off them when they first touch, that is why they are changed very frequently as per number of landings by aircraft. FAA has checks for them
they are routine mainteance.

Answer 10

Airplanes burn some of their rubber when the hit the ground, but otherwise, the PSI of the wheel is fully compressed.