Helicopter Landing Gear
Helicopters may use wheels, floats, or skids.
Each type of landing gear has pros/cons and the best one depends on the mission/application
the helicopter will be used in. In this article, we’ll briefly discuss the various landing gear and the pros/cons of each.
If speed and range are a priority, retractable landing gear are favorable.
Retracting the landing gear reduces drag allowing the helicopter to fly faster and further.
On the downside, retractable landing gear are more complex, adding to the cost, maintenance and weight of the helicopter.
For larger, heavier helicopters the weight/cost associated with a retractable landing gear is
relatively small (compared to the total weight/cost) and hence may be more attractive.
Wheeled landing gear are more popular on larger/heavier helicopters.
Wheels simplify the movement of helicopters around an airfield, allowing them to roll from location to location.
Moving helicopters with skids often requires “hover taxiing”—taking off into a hover and slowly flying to a new location.
It is possible to use other machines to lift/transport skid-equipped helicopters, but of course those machines have their own cost.
Hover taxi operations are less practical for larger helicopters that produce more downwash.
Wheels add weight/cost relative to skids.
However, the cost of adding wheels is relatively smaller for larger helicopters (compared to total helicopter weight/cost).
As a general rule, wheels are used on helicopters weighing more than 4 tons.
Wheels may also improve run-on landings.
There are situations (typically engine emergencies) where a helicopter won’t have enough power
to land with 0 speed and a run-on landing (which requires less engine power) is required.
Wheeled gears can be made to swivel either passively or steered by pilot control.
The former is simpler but less controllable than the latter.
Again here the more costly/complex option is more likely to be used on a heavier, more expensive
Skids are superior to wheels when it comes to simplicity and cost.
There are other advantages to using skids. For example, ground resonance is less likely
to occur with a skid. Helicopters that need to land in softer areas
(e.g. snow or swampy areas) may be equipped with skids and add-on “bear paws” to
prevent excess sinking into the terrain. In fact, this was the motivation behind the
invention of skids by Bell Helicopter in the 1940s—reports of early
wheeled helicopters getting stuck in muddy/swampy terrain.
Of course, skids and wheels are not useful for landing in the water.
These helicopters use buoyant floats to stay atop the water.
In addition, some helicopters have emergency floats that can inflate/deploy
in the event of a water landing. Most of these are highly susceptible to
overturning in high sea states.