Norwich bulletin., 1909-11-23
THE AWASH" OF AN AERoPLANE
MAY BE DISASTROUS.
Rules Of Aerial Road Likely to Be
Important. as Some Accidents Have
Shown.


Those of our readers who have sat
In a racing shell, or stood at the wheel
of q racing yacht, will remember how
troublesome is the wake" of a COM
petitor, whether 1t takes the form of
the wash Of his SOULS, or Of the
disturbance of the air as 1t sweeps
from the leach of the mainsail Of a
weatherly yacht that Is beating out to
windward some distance ahead.
n the case of two racing yachts that
are thrashing it out on the same tack
in struggle to windward, there is a
certain relative position OF the two, in
which the disturbance Of the air, caus-
ed by its passage over the sails Of the
leading yacht, will prove exceedingly
troublesome to the second boat. espe-
cially If she be but a few lengths
astern and sailing close to the wake
of the other.
When this occurs there is nothing
for it but to put about on the other
tack, and so get clear of the interior
ence.
With the rapid development of me-
chancal flight, the remarkable extent
of which was shown so clearly In the
recent brilliant performances at
Rheims, it has become evident that the
wash" or interference, which is in
convenient to a sailing yacht, may be-
come positively disastrous to that
yacht of the air. the aeroplane.
1t was not until the Rheims contests
that an opportunity was presented to
determine the effect of one aeroplane
upon another, when. in meeting or ov-
ertaking, they passed in rather close
proximity. 1t is quite possible that
the question of interference had never
occurred to the aviators at Rheims,
but it is certainly a surprising fact
that the existence of such interference,
and it's evidently serious character as
shown when several machines were in
the air at once, should not have ex-
cited more attention. both at the time
and in subsequent expert discussions
of the Rheims contests.
When such large body as an aero
plane, spreading several hundred
square feet of surface, and weighing
from a quarter to half a ton. is driven
at so miles an hour by propellers that
are revolving at from 1000 to 1900
revolutions per minute, II is certain
to leave in its wake a complicated Sc
ries of aerial cross currents, whirl-
pools and worthless.
Now, judging from the description
of eye witnesses of the Rheims races,
the behavior of the aeroplanes, when
they swept into rather close proxim-
ity to one another, indicates that these
artificiaHy- created wind storms were
present, and that they seriously af-
fected the equilibrium of any aero
plane that came within their influ-
ence.
The wash" from propellers, driven
as in the case of Bleriot's monoplane,
by an S0-horsepower engine. and the
air waves set up by the passage Of
his planes must be very serious in
deed; certainly. the air will not. re-
gain it's equilibrium until long after
the machine has swept by.
Two notable instances of this inter-
ference occurred when several aero
planes were in the air together.
During one race. when Farman was
rapidly overhauling opponents who
were flying at the same level, he en-
countered the wash" of the machines,
and his own aeroplane was thrown in
to rather violent oscillation. Before
he could pass, it was necessary to
make wide detour to the right or left,
or swing up to higher level into dis
turbed air.
on another occasion when Latham,
flying high, overlook a competitor
who was travelling at lower level, IT
was noticed that his own aeroplane
made a sudden dive, as though drawn
downward by the suction of the ma
chine below him.
"Leeway" as the sailors call II, will
become even more necessary to the
air yacht than 1t is now to the sailing
yacht. Woe to the aviator who, fly
ing low, with scant clearance between
himself and the ground, is overtaken
by some aeronautical scorcher, who
sweeps up from behind and with the
characteristic snort of triumph whirls
onward, giving him his aerial dust.
Happy for him If he recover his rude
Iy disturbed equilibrium at the ex-
pense of a broken wing and not of
broken neck.
Perhaps, after all, we have been a
little too previous" in felicitatina
ourselves upon the unlimited roomJthat
will be afforded for flight through the
air; evidently the clearance demanded
by our 60-mile an hour aeroplane must
be measured by something far wider
than the stretch from tip to tip of
the planes or the length from head to
tail