Evening star., 1933-01-29

VINO pTeSlCeU. Stll VdAACio ACSAoSo AS
the evening.
and takes photographs measuring nVe
inches square. The smaller lenses serve
to record on the same fllm such de-
tails as height, time to the nearest
second, serial number and such other
information as may be useful for rel
erence.
Determined Automa tically.
That exposures may be made at pre-
determined intervals, variable accord
ing to the height of the machine above
the ground photographed, an electrical
control box is fitted. This allows the
intervals between exposures to be de-
termined automatically and also warns
the pilot, by lighting red lamp on MS
instrument board just before each ex-
posure is made, so that he may keep
the plane on an even Keel.
The camera contains $50 working
parts, such as gear-wheelS and levers,
which must be able to operate prop
erly at temperatures as low as 40 de-
erees F. below zero. The chief reason
for heating the camera electrically is
that Photographic film at low tempera-
lures not only loses some Of its SEN
sitiveness. but becomes brittle as glass.
The electric heater fitted in each flm
magazine has an automatic control to
prevent over-heating at the lower altl-.
tudes.
Oxygen and electrical apparatus con-
stitute a large and important part OF
the flights equipment. The main sup
ply of oxygen will be carried in three
75O-litre cylinders, which should al
ford a sufficient supply for the two oc-
cupants of the machine for about Two
and half hours, even if the machine
remains above the crest OF Everest for
a full hslf-hour. One man uses about
six ltres minute at 10000 feet.
There is also a 750-litre reserve cyl
inder of oxygen, and although the pri-
mary supply is controlled by the pliot,
the reserve system is controlled by
either pilot or observer, so if the main
supply fails and either should faint
the other will not also be doomed to
lose consciousness for lack of oxygen,
but may turn on the stream for his
own and for his companions use
Should the pilot need such help, the
observer may thus restore him to con-
seriousness in time for him to resume
complete control of the plane. Sud-
den deprivation of oxygen at great alti-
tudes induces sensations similar 10
those experienced on being anaesthe-
tizod. There is. therefore, some warn
ing before Inconsistencies supervenes.
Protecting the Pilot.
The electricity for heating purposes
is supplied by a 1,0O0-watt engine
driven generator. 1t Will serve not
only the crew (warming their clothing
and even their goggles so that these
may not become frosted), but also the
valves of the oxygen apparatus and
such instruments as might cease to op-
crate if they become frozen.
The pilot in particular will have
need of this supply for there is no roof
to his cockpit. 1t is equipped with
big hooded wind-screen and is protect
ed against the draughts which often
leak into a pilots cockpit from the Tor
ward part of the machine; yet he Will
still remain the most exposed member
of the crew. and upon his ability 10
continue his work will depend TIE
safety of himself and his observer.
One other important provision Is the
fitting of spring control boxes on the
control cables to take up the difteren-
pared with the duralumin in the plane
structure. The control cables are OF
steel, whereas the wings and most OF
the frame are of duralumin, which
contracts in changing temperatures
about twice as much as steel. the
spring boxes will thus prevent the con-
trolls from becoming sloppy" at high
altitude and should give the pilot COM
plete control no matter how low the
temperature.
E-LzJ:o- Trn nov{reS
The other plane is the Westland
Wallace, the standard r. A. F. general
p,lrpose aircraft. It is also fitted with
a Bristol Pegasus $3.50 h. pD engine. A
similar engine boosted to high de-
gree was used by Capt. G. F. Twins
when he made his altitude record. 1t
embodies two devices-a superchareer
and an automatic boost control-Whlch
so react on each other that the OUT
put of the engine remains nearly con-
slant throughout large part OF the
climb. That is to say. centrifugal
fan congresses the gases before entry
into the cylinder and barograph con-
trolls a servo-motor, which in turn con-
/ trolls the opening of the throttle, ana
thus prevents the fan from overcharg-
ing the cylinders.
The wallace, which is similar in gen.
eral design and in many details to the
Houston -westland, has been adapted
and equipped in exactly the same way,
and it is expected the two machines
will have performances SO nearly equal
that there will be little difhculty IN
their carrying out the expedltlon To-
gether. =.
In the Houston -Westland, which is
| regarded as our first string, the pilot
al, l., Co,,o Jroy, codor ord ClVdeS.
dale and the observer Lieut.. Col. L. v.
s Blacker. In the Wallace, Flight
| Lieut. D. F. Mcintyre and an expert
cinematographer will be the occupants.
| A reserve pilot from the r. A. F. In
India will be available at Purnea.
where the party will also include, IN
addition to Col. P. T. Etherton and
myself. a second cinema photographer
a Photographic expert from Australia,
q ground engineer from both the West
land Aircraft Co. and the Bristol
! Aeroplane Co., and a non-commissioned
officer and five airmen lent by the
R. A. F. in India.
Start Early in Day.
The flight will almost certainly start
early in the day, because the take-on
will be easier in the cool morning air.
and the comparatively bad conditions
| which are found in the middle Of the
! day will be Of less importance when
! the machines are landing light at the
termination of their flight. 1t will be
essential to choose day when the sky
is clear and visibility is good
| In the best of conditions the 29.141
feet actual height of Mount Everest
will, on account Of its southern lati-
tude, represent q standard atmosphere