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Automobile Tire Hydroplaning (Aquaplaning) 1964 NASA
🕑 Added 2019-11-05 19:08:30 +0000 UTCmore at http://quickfound.net/
'Shows how and why automobile tires lose contact with wet pavements and the relationship between speed, tire wear, and water depth. The dangers of hydroplaning are emphasized... Produced jointly with the Bureau of Public Roads.'
Originally a public domain film from the National Archives, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.
The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original).
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19640000612.pdf
NASA TECHNICAL NOTE NASA TN D-2056
PHENOMENA OF PNEUMATIC
TIRE HYDROPLANING
by Walter B. Horne and Robert C. Dreher
Langley Research Center
Langley Station, Hampton, Va
When runway or road surfaces become flooded or puddled with either slush or water, both aircraft and ground vehicles such as automobiles can at some critical ground speed encounter the phenomenon of tire hydroplaning. The effects of hydroplaning can be serious to these vehicles since tires under hydroplaning conditions become detached from the pavement surface and the ability of tires to develop braking or cornering traction for stopping or guiding vehicle motion is almost completely lost. Tire hydroplaning was first noticed and demonstrated experimentally about 1957 during a tire treadmill study. (See ref. i.) This investigation had been prompted by the low values of tire-to-surface friction found during wheel spin-up in landings of a large airplane on a wet runway (ref. 2) and by a rash of military aircraft overrun landing accidents on wet runways. In this tire treadmill study a small pneumatic tire riding under free rolling (unbraked) conditions on a water covered belt was observed to spin-down to a complete stop at a critical belt (ground) velocity. Later studies by the National Aeronautics and Space Administration on full-scale tires (refs. 3 to 9) along with actual operational experience gained from aircraft take-offs and landings performed on very wet runways have further substantiated the fact that hydroplaning can create a very serious slipperiness problem to most pneumatic-tired vehicles...
https://en.wikipedia.org/wiki/Aquaplaning
Wikipedia license: http://creativecommons.org/licenses/by-sa/3.0/
Aquaplaning or hydroplaning by the tires of a road vehicle, aircraft or other wheeled vehicle occurs when a layer of water builds between the wheels of the vehicle and the road surface, leading to a loss of traction that prevents the vehicle from responding to control inputs. If it occurs to all wheels simultaneously, the vehicle becomes, in effect, an uncontrolled sled. Aquaplaning is a different phenomenon from when water on the surface of the roadway merely acts as a lubricant. Traction is diminished on wet pavement even when aquaplaning is not occurring...
Causes
Every vehicle function that changes direction or speed relies on friction between the tires and the road surface. The grooves of a rubber tire are designed to disperse water from beneath the tire, providing high friction even in wet conditions. Aquaplaning occurs when a tire encounters more water than it can dissipate. Water pressure in front of the wheel forces a wedge of water under the leading edge of the tire, causing it to lift from the road. The tire then skates on a sheet of water with little, if any, direct road contact, and loss of control results. If multiple tires aquaplane, the vehicle may lose directional control and slide until it either collides with an obstacle, or slows enough that one or more tires contact the road again and friction is regained.
The risk of aquaplaning increases with the depth of standing water and the sensitivity of a vehicle to that water depth...
