Quote:
Originally Posted by Tristan Lall
On most aircraft using tricycle gear, the nose wheel is unpowered, unbraked and mechanically or hydraulically steered.
There are numerous exceptions, however. Some early Boeing 727s had nose gear brakes, but they were omitted on later aircraft (and often removed on early ones) because the added braking capacity was of little use compared to the weight penalty (something like a hundred pounds). There was an aftermarket kit being evaluated by Air Canada on one of their Boeing 767s which added an electric motor to the nosewheel for taxiing. While saving wear and tear on the main engines was a good idea (I believe it could run on the APU's generator), again, it weighed too much, and there was concern it could lead to higher maintenance costs for the nose gear assembly. On a few small aircraft (Diamond's DA20, for example), the nose wheel is freely castering. Steering is accomplished with the toe brakes controlling the main wheels (differential braking), and the rudder pedals at higher speeds.
Incidentally, the suspension on the nosewheel of most aircraft is not located beside the wheel like that—it's usually in the strut. (Gas-over-oil is common.)
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Another exception would be the Boeing B-52 Stratofortress Which has a quadracycle undercarriage and 4-'module' crab steering to facilitate landing the behemoth of an aircraft in high crosswinds conditions. Most aircraft have to approach flying sideways and straighten out after they land to roll down the runway instead of off it, the B-52 simply rolls sideways
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