Skids versus Wheels

I remember this being discussed at some point but can't find it and can't remember what the reasoning was behind having one over the other.


I'd been thinking of Lynx but suppose the principles apply to all.

 

I may be wrong, and I'm sure someone will correct me, but I'd have thought that skids would be better on a softer surface, as it will spread the weight over the ground? Wheels may dig in a little?

 

skids good for unprepped ground.

wheels good for moving on prepped ground.

 

How about skids with half tyres cable tied to them to stop them being damaged.

 

I'm going back a while but if I remember correctly.

Skids are:
Simple
Spread the weight
Reduce ground resonance problems (less factors affecting it)

Wheels:
If retractable can reduce drag- hence higher speeds
Are pretty much required for ship-landings, or at least make it easier and safer - allow the use of the harpoon locking system.
Make life moving around on the ground simpler.
Can reduce fuel required for takeoff - rolling taxi and takeoff.
Can do wierd things to ground resonance.

There are bound to be other issues, but the basics are skids are simple and effective, but wheels give some significant benefits in certain areas which is why lots of helicopters use them.

S_R

 

Skids-
don't have locating pins for the groundies to shear.
don't have tyres that pop off because the pilots forget to land with forward speed.
don't make the cab look like a wheelie bin.

 

Sympathetic_Reaction, I'm not going to argue with any of that.

ditto Zapped

 

It's also size thing. Small helicopters with skids are fairly easy to move, but the task becomes more difficult as the aircraft grows. Imagine trying to move a Sea King/Merlin with skids.

Wheeled undercarriage, especially when retractable, is heavy and expensive. So, with smaller aircraft the weight takes up a high percentage of the aircraft's weight and cost. As the aircraft get bigger, that percentage gets smaller so becomes more viable.

I think you'll find that the crossover point is around the Lynx/Bell 412 size.

 

How do the wheels allow the use of the harpoon, over skids?

 

Compression of the oleos and the ability to swivel around the mast to gain a 'green' wind.

 

Having been onboard a UH-60 that sunk belly deep in the mud in a training area near Uijonbu, ROK... I can strongly attest to wheels being bad for unprepared LZs.

 

Wheels are my preference. Much easier on the nerves following loss of the tail rotor in flight. Thankfully, it doesn't happen too often.

 

Sorry to butt in with nowt to add to the original thread, but would it be feasible to have some sort of 'nose cone' that gets placed in front of fixed wheels during flight, in order to reduce drag?

 

Pardon my naivety, but what's the problem with putting little wheels on the skids - as was the case with the Sioux and Scout?

Or putting oleos on skids?

Would putting air-bag-like emergency floats on skids be a new invention - or has it already been done?

 

I'm sure the skid floats have been done.