Jgore From Argentina, joined Feb 2002, 550 posts, RR: 2 Posted (12 years 8 months 3 days 11 hours ago) and read 4424 times:
hi everyone. i've always thought that it would reduce the rubber-burn cost on each landing every plane makes: setting a kind of engine that can rotate the wheel to the same speed the aircraft is flying.
the technique would be one engine for the left main gear, so with a chain it could move as many wheels the column would have, another one in the right main gear, and a last one in the nose gear.
In light that the average time a wheel can land, about 10 landings, this technique would improve the durability of each wheel on an aircraft.
i know that everything is already thought, already invented, and already discussed, since i'm talking about an industry that every technical matter is involved.
would it add more weight to the airplane ?, so might be there any chance of less passengers?, and in fact, less profit for the airline by setting those engines in the landing gear?
is just a matter of cost-benefit that is not necessary 'cause replacing a wheel each 10 landings, is cheaper than investing in a couple of engines to the landing gear ?
i don't know, hope you reply me with your ideas, or juist any reason to explainme why it doesnt exist in the airline industry.
VirginFlyer From New Zealand, joined Sep 2000, 4579 posts, RR: 40
Reply 1, posted (12 years 8 months 3 days 10 hours ago) and read 4378 times:
Wheels replaced every 10 landings? Are you sure of those figures???
The idea seems overly complicated - it would be prone to technical failures, it would require maintenance, it would add weight, it would increase the drain on electricity (and thus increase fuel usage). It would be more trouble than its worth.
"So powerful is the light of unity that it can illuminate the whole earth." - Bahá'u'lláh
FBU 4EVER! From Norway, joined Jan 2001, 998 posts, RR: 7
Reply 3, posted (12 years 8 months 3 days 1 hour ago) and read 4274 times:
Our MD-80's in SAS average about 80 landings per tire.
This idea has been tested in the early fifties.They used vanes on the hub to allow the airstream to rotate the tires during approach.The plane in question was the B-36 prototype with single tire mainwheels.Problem was that the rotating tires created gyroscopic forces because of their huge size.On the bogies that replaced the single wheel installation,it was thought that the rear wheels would not receive enough airflow so the idea was dropped altogether.
On present day jetliners,the ground spoilers activate by wheel spin-up on touchdown and /or weight on wheels.Rotating the wheels in the air prior to touchdown would remove the first means of spoiler activation,the plane relying on weight on wheels only.And if that ground shift mechanism fails,well.....
Duff From New Zealand, joined Oct 2001, 118 posts, RR: 1
Reply 4, posted (12 years 8 months 3 days 1 hour ago) and read 4262 times:
It has already been thought of. However, it was quashed because the wheels are unable to penetrate water or any other runway contamitants. The wheels were prone to aquaplane. That is one reason. I am sure there are others.