Motoring
| Author | John Gott |
| Published date | 01 March 1964 |
| Date | 01 March 1964 |
| DOI | http://doi.org/10.1177/0032258X6403700308 |
| Subject Matter | Article |
JOHN
GOTT,
M.B.E.,
G.M.,
B.A.
Chief Constable
of
Northamptonshire
Our Motoring Correspondent discusses research into a dangerous wet
weather possibility and gives his impressions
of
Britain's latest new-
comer to the small family saloon class.
Aquaplaning
Aquaplaning, as applied to wet roads, rather than to water, first
attracted attention in the daily Press a year or so ago, when it was
put forward as a possible cause of some bad accidents on the London-
Birmingham motorway. The phenomenon, if not, however, then
known by that name, was no new thing to competition motorists, even
in the 'thirties, especially to those who had driven fast cars at
Brooklands where the special track tyres carried very little tread
pattern.
The reason for the aquaplaning effect is simple enough. Unless
the tyre tread can wipe away the water lying between it and the
road surface, that layer
of
water will build up until it is eventually
acting as a sort of wedge lifting the tyre clear of the road.
The possibilities
of
that situation need little elaboration!
The first warning signal to a driver that his car may be beginning
to aquaplane is a sudden, frightening lightness in the steering. At
this point an experienced driver realizes instinctively that his front
wheels are no longer in proper contact with the road and that a
sudden movement on the steering wheel may cause him to lose
control. A less skilled driver, however, may well make that move-
ment, all too often probably with fatal results.
Recently the technicians of the Dunlop Rubber Company have
been looking into the reasons for aquaplaning and have come up with
some startling conclusions.
To arrive at these a mechanical rig was first devised which per-
mitted an accurate analysis of the factors producing aquaplaning,
without risking a skilled driver. A tyre, under a load equivalent to
that which it would have to take on a road, was pressed against a
drum sprayed with water, the speeds of rotation, both of drum and
of
tyre, being shown on gauges.
This rig clearly showed that the
"wedge
effect" of the water
increased with the speed of the drum and that the tyre's speed and
grip decreased accordingly.
126 March 1964
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