Hydroplaning

Dec 16, 2003 13 Replies

A question for debate:



Is it possible for a car to hydroplane in deep water?



Picture a car hydroplaning on a road surface. We gradually increase the depth of the water in the direction of travel. Can we get the car to hydroplane across a lake? (with only the bottom of the tires touching the water)



Assume:


1) We have a propulsion method (prop or jet) that keeps the car moving at whatever speed we want.


2) The rear track width can be wider than the front so that the rear tires see undisturbed water.


3) The tires are normal width.

Yes, there are regular competitions held for it, just keep watching the various

4 wheel drive programs on the Discovery, Travel or History channels. The cars use wide tires with paddle-type treads and hit the water going fairly fast. The best ones bounce right across the water like a skipping rock! The ones that fail to make it sink pretty quick.

DT

Course you can when its frozen over.

I don't think you could consider turning the car into a missile skimming across water as hydroplaning. Even so I think unless the car is fitted with suitable skis (and the weight balanced) it will sink.

Hydroplaning is when the tyres are rotating on the road and a wedge of water builds up in front of the tyre. If the rotating tyre cannot disperse the wedge of water quickly enough it will climb on top of the water and lose traction and you skid out of control. The hydroplane cannot be sustained and the tyre will eventually make contact with the road again (if you're lucky enough to still be on the road).

don't see why it wouldn't be--it gets done with snowmobiles quite regularly; the phenomenon is commonly referred to as "skimming".

On the other hand, "skimming" also generates a handful of fatalities each year....darwinism at work.

Light airplanes do it easily.

Rick

There is no need for debate. The answer is an unequivocal "yes". But there's always a "but" The speed required is way high: recall the excess speed needed to carry a barefoot skier?

Light aircraft have rolled barefoot across smooth lakes (but the pilots were very,very bold) and they do not allow any large fraction of the aircraft weight to set down.

Brian Whatcott Altus OK

Quite the opposite, you have to apply considerable down elevator to plant the tires.

Rick

I am an old pilot, so I wouldn't rightly know. I'll take your word for it.

Brian

One wants to wonder... What is going on in the mind of a pilot who would purposefully take a flimsy aluminium structure, with a big whirling hunk of propeller on the front.. and touch his wheels onto a lake?

Can you say "disconnected from reality"?

Al...

Dear Al Adrian:

You've obviously never heard of fly fishing!

;>}

David A. Smith

To counter any ground affect ?

Surely this will only apply to certain aircraft some A/C ditched beautifully others you were better to hit the silk than to try and ditch,but in (I believe )all cases ditching was a wheels up affair (retractbles obviously).

A VERY good pilot could probably fly an A/C across a lake at zero feet so the wheels were just touching the water and thus give the "impression" of hydroplaning.

Hydroplaning,

Id imagine the friction-resistance on the wheels creates a torque that makes a puller prop want to face-plant in the water that would have to be counter-acted by some serious aerodynamic forces. Water IS about a thousand times denser than air, so it can have thousands times greater viscous forces for the same velocity, Cd and A.

I betcha you could make some sort of "snow-shoe" for a planes wheels, but I dont know if it would help enough.

-mike

No, to hold the wheels down on the water. That is how "wheel landings" are performed with taildraggers.

Yes, I should have mentioned that, it only applies to tailwheel aircraft. Trying that stunt with a nosewheel aircraft would have undesired consequences.

Rick

Have no experience of this myself but weren't the aerodynamics of the "Lancaster" such that if you tried to do "wheeler" landings you could get into all sorts of difficulties, they (there I go antropomorpising again) much preferred three pointers .

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