Skids or wheels ?
Wrote for the Helicopter History Site by David Gibbings and Taylor Cox
Skids are used mainly because they weigh less than wheels. On larger, more powerful helicopters,
wheels are used because the utility and convenience can be more important than the savings in
weight. In order to move a skid-equipped helicopter on the ground, one has to attach a set of
ground-handling wheels, jack up the helicopter, and roll it (into the hangar for maintenance, for
example). If your helicopter already has the wheels as a
permanent feature, it is more
convenient to move around when the engine is shut down or the pilot has wandered off.
The design decision between retractable or fixed wheels becomes a trade-off between the
complexity/weight but increased aerodynamic efficiency of retractable gear and the simplicity of
fixed gear (and increased drag/reduced efficiency).
It really depends on the primary use of the
helicopter; if you are logging, skids make sense because you can lift larger loads and are more
concerned with hovering performance. If the primary mission is medevac or air transport,
retractable wheels allow greater speed and increased fuel economy over long distances.
So the main factor is one of simplicity, a skid landing gear needs very little maintenance but there is a drawback.
Ground handling is a bit more difficult, so it follows that it is the smaller machines that use them.
Once you get above say 8,000lb or 4 tons, you really need some built in wheels to move the thing around, a
Bell UH-1 must be somewhere near the practical limit, especially if your trying to get it under cover in a hurry.
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