Why Do Some Helicopters Have Wheels and Some Have Skids?

The landing gear of helicopters determines how the body of the vehicle rests on the ground at the moment of landing. Here are some of the key members of this team. wheel and sledhelps us understand how the helicopter will land on the ground.

So what are the differences between the sled and the wheel, or which one is more advantageous? Let’s look at this together.

The skids have wear strips that are resistant to friction caused by slips during take-off and landing.

The skid set in helicopters is generally produced from hollow tubes. Cross pipes mounted in front and back of the vehicle’s hub (you can think of it like the body) are lined up. These pipes are laid wide in the body part and suspension mechanism (tire that connects a vehicle to its wheels and allows relative movement between the two) is designed at their ends. This mechanism is then mounted elongately by the helicopter fuselage, perpendicular to the cross tubes. to sled tubes is connected.

The reason for the robustness of the sleds during landing and take-off depends on this design. Also, since this system is bolt-on configuration, mounting them on the helicopter does not require great effort. Sledges to the helicopter imposing gives a structure. These suspensions, already mentioned above, take the weight of the vehicle during the descent, thus providing a lighter landing. In fact, we can say that the design and construction of the sleds is so simple that it increases their preferability.

Wheels are used on larger and more powerful helicopters.

This is because these types of vehicles are more comfortable and it is not considered important to save weight while producing them. For example, sleds are preferred because they are lighter than wheels, so savings are at the forefront. In this type of vehicle, it is quite easy to move the vehicle when the engine is turned off and the pilot is away from his seat.

Because during the construction of the helicopter, a balance has been established between the retractable and fixed wheels so that the vehicle can easily move from its place. In this context of aerodynamics (the effect of air on a moving object) is also taken into account.

Transporting the Skid Helicopter to the Hangar with a Tow Truck

In short, we can say that the maintenance of wheeled helicopters is more luxurious than skids for this reason. One of the downsides of skids is that they run the risk of snagging on cables when flying at low altitudes. Also, they can’t taxi on their own (this is also called a rule, meaning that an aircraft travels on the ground using its own power). For example, in order to be able to move the skid helicopters at a standstill, it is necessary to attach extra wheels (one of those later mounted tractor wheels) under them. Then jack up the vehicle and place it where the vehicle will be stored. take to hangar needs.

Of course, there are usage differences between them.

Image Source: Andrew Doran

Whether the helicopter will be used for large cargo transportation or for air transportation changes its preferability. For example, wheeled ones are more suitable for carrying cargo and air transport operations because they can stay in the air longer. They can also travel long distances at high speed. Sled ones cannot carry large loads, such as carrying a small number of passengers. light duties has.

When we look at the ones with wheels, we see that they concentrate the weight of the loads they carry only where the tires are. Therefore, landing surfaces are places made of asphalt, such as a single helipad. In skid helicopters, as the load is distributed along the length of the fuselage, as we mentioned above, the balance of the helicopter does not deteriorate. Therefore, they can land on both asphalt and non-paved surfaces (grass, gravel, etc.). The differentiation of these features is due to the helicopter center of gravity placement in the fuselage design of both. (CG) The difference in design is effective.

Wheeled ones have a wider body to keep the CG centered, while sleds don’t. Because their bodies are smaller than other parts due to their bolt-mounted and dismountable structures. The reason why their bodies are small is because the body is wide or the addition of an extra skid has a negative effect on the friction coefficient of these vehicles. of airplanes or helicopters in body design Landing gear designs are crucial to account for their aerodynamic effects.

Sources: Science ABC, Helix