70
Diagrammatic
representation of a typical
layout of the steam
catapult.
Note how
the power cylinders
are housed beneath the
deck, and the location
of the steam receivers
in which steam from the
boilers is stored.
STEAM SUPPLY
FROM BOILER
i
THE NAVY'S STEAM
A
LTHOUGH the British-invented, American-adopted steam
aircraft-catapult is already being applied to eight carriers of
^ the U.S. Navy, Britain's first operational installation will be
in H.M.S. Ark Royal, the fleet carrier expected to be completed by
Cammell Laird and Co., Ltd., of Birkenhead, early this year.
Catapults of this type are being built and developed for the
Admiralty by Brown Brothers and Co., Ltd., of Edinburgh. They
will be fitted in H.M.S. Hermes and H.M.A.S. Majestic, both of
which are being built by Vickers-Armstrongs, Ltd., of Barrow;
in H.M.C.S. Bonaventure, under construction by Harland and
Wolff, Ltd.; and in H.M.S. Victorious, now undergoing extensive
modernization at H.M. Dockyard, Portsmouth. It is the intention to replace with steam catapults the existing hydro-pneumatic
catapults in all other operational carriers of the Royal Navy as
production and Service commitments permit.
The steam catapult works on a principle quite different from
that of the hydro-pneumatic types at present employed. The
shuttle, or trolley, to which the aircraft is connected by its towing
FLIGHT
CATAPULT
bridle, is propelled along a track in the deck by two pistons which
are directly connected to it, and which slide in two cylinders
placed side by side under the deck and extend the whole length
of the track. An ingenious flexible-steel sealing strip, opened by
the shuttle driving key and closed by a "sealing block" immediately
behind it, prevents loss of pressure in the cylinder,. The comparatively light pistons and the shuttle assembly are the only
moving parts. The cylinder and piston assembly, and certain other
features, are the subject of patents.
Illustrated on this page is a typical layout, showing the power
cylinders housed under the deck and the steam receivers in
which steam from the boilers is stored ready for the launch. Also
shown is an aircraft secured by its towing bridle to the shuttle
and restrained by a "hold-back" which is hooked in a suitable
fitting on the deck. ' When the accelerating force is applied to
the shuttle this, added to that of the turbojet, causes a calibrated
breaking link in the holdback to break, leaving the aircraft free
to move forward under the accelerating pull.
FRANCE DESCRIBES THE ORPHEUS
PRODUCTION CONFERENCE
T is by no means unusual nowadays to find preliminary descriptions of new British engines being published in foreign journals.
The French paper Aviation Magazine, for example, has recently
published the photograph reprinted here, which apparently shows
a mock-up of the Bristol Orpheus turbojet, although we are naturally unable to confirm or deny its accuracy. The French journal
has also given a number of details of the engine, including the
following: diameter, 32in; length, 97in; dry weight, 850 lb; sevenstage compressor (pressure ratio 5:1), indicating that the engine
is not a two-spooler; eight combustion cans in an annular space,
and a single-stage turbine, the whole rotating assembly being
supported by only two bearings, one at either end.
The prototype Orpheus, which first ran on December 17th last,
is reported to have delivered 3,900 lb thrust at 10,500 r.p.m. with
a specific of 1.1 lb/hr/lb; later on, over 4,400 lb is to be reached.
Thrust-weight ratio and dirust/frontal area are given as 0.22 and
0.296 (achieved) and 0.193 and 0.205 (theoretical targets),
respectively.
"TNTEGRAL construction contrasted with traditional methods"
-*- was the theme of the third annual conference on aircraft
production organized by die Institution of Production Engineers
(Southern Section).
The conference was held at the University of Southampton on
January 14th and 15th, and papers were presented by Mr. A. E.
Woodward-Nutt (M.o.S.), Mr. G. W. Richards (High Duty
Alloys), E. D. Keen and A. Menzies (Armstrong Whitworth),
S. Radcliffe (Wadkin) and W. E. W. Petter (Folland). Speakers
at the conference luncheon were Alderman R. E. Edmunds, Mayor
of Southampton, and Sir Edward Boyle, Parliamentary Secretary,
M.o.S. Full reports of the papers, speeches and discussion will be
given in an early issue.
I
Presumably showing a mock-up of the Bristol Orpheus turbojet, this
photograph was recently published in France. A note on this remarkably
light and compact single-spool engine appears above.
- I :
CANBERRA INQUEST
A T an inquest at Hertford last week on two R.A.F. officers who
**• were killed in an accident to a Canberra on December 20th,
verdicts of accidental death were recorded. The aircraft was
stated in evidence to have got out of control and to have crashed
on the lawn in front of a children's home at St. Margarets, near
Ware, Hertfordshire. The officers who lost their lives were P/O.
Raymond H. Sholl and F/O. Hubert E. Thorne.
The diird occupant, F/O. C. B. Crombie, said that the accident
occurred half an hour after the take-off from Bassingbourn. The
aircraft had reached a height of 32,000ft and encountered "tremendous turbulence." It went out of control, performed "various
manoeuvres," and in the end went into a dive, turning left, from
which F/O. Crombie was unable to recover. The aircraft had
been difficult to control, he said, because of the bad weather, and
at one stage the navigators had asked what had gone wrong. At
more than one stage they had "got on their backs." He ordered
the two navigators to abandon the aircraft.
As for his own escape, F/O. Crombie said that he was unable
to release the control column "owing to the tremendous g-forcc."
To release the column it was necessary to move his hand downwardd to the releasing mechanism. "In the end," he said, "I
knew I couldn't get my hand down, but I lifted my hand up
and it was knocked back against the handle which operates the
ejecting mechanism. I just ejected through the canopy."