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The Westland Wallace (Flight May 4th 1933)
THE WESTLAND " WALLACE " : This three-quarter front
view shows how closely the service machine resembles
the version used on the Houston-Mount Everest flight. The engine is a Bristol "
Originally designed as a private venture known as the " P.V.6
" the version used in the British Royal Air Force has been given the name "
Wallace," and is of the class known as " General Purpose." As the class title
indicates, machines must be adaptable to a great variety of purposes, and the
demands made are by no means easy to meet, as will be realised when we point out
that "G.P." machines must have a flight range of at least 5 hr., must be ca
pable of carrying a fairly heavy bomb load, must be equipped for taking
photographs and for radio communication with ground troops and guns, must carry
oxygen apparatus for high flying, must carry fixed and movable machine guns, and
must be fitted with dual flying controls. Yet in spite of all these demands the
"G.P." machine must have a good performance. Thus, somewhat paradoxically, the
design of a general-purpose aeroplane has become very much a specialised task.
The Westland Aircraft Works of Yeovil have had exceptional experience in the
production of "G.P." machines. and it may be recalled that the "Wapiti" (Bristol
"Jupiter" ) has been built in very great numbers (more than 500) for the R.A.F.,
the R.A.A.F., and the S.A.A.F. The" Wallace " incorporates everything that was
found completely satisfactory in the" Wapiti," and a number of improvements
How great an improvement on the "Wapiti" is the "Wallace " can best be indicated
by a few figures. The "Wapiti" has a tare weight of 3,180 lb while the weight of
the " Wallace " is 3,520 lb. The gross weights are 5300 lb. and 5,750 lb.
respectively. The fuel and oil carried is the same in both cases, i.e 105
gallons of petrol and 10 gallons of oil, so that the useful loads (crew.
military load and equipment) are comparable. That of the "Wapiti" is 1,213 lb.,
while the " Wallace " load is 1,323 lb. In other words, the " Wallace " carries
about 100 lb. more than the " Wapiti." Thanks to the extra
power of the Bristol " Pegasus" M3 engine (555 b.h.p. as compared with the 460
b.h.p. of the " Jupiter ':.') and the improved aerodynamic design of the"
Wallace;" the latest machine has a very much better performance. For example,the
maximum speed of the" Wallace " at 5,000 ft. is 161 m.p.h., while that of the "
Wapiti " is 139 m.p.h. at the same height. In the matter of climb also, the "
Wallace " is very superior. For instance, the time to 10,000 ft . is 8.8 min.
The "Wapiti" takes 11.5 min. The service ceiling of the "Wallace" is 22,800 ft.
That of the "Wapiti" 19,300 ft.
The photographs, general arrangement drawings, etc., which we publish herewith
show the general lines of the "Wallace." It will be seen that there is
considerable similarity between it and the " Wapiti," but dimensionally the two
differ a good deal. The only thing which they have in common is the wing span
and area. The former is 46 ft. 5 in. and the latter 488 sq. ft.
Structurally also the "Wallace" follows tile principle and methods which have
been found so successful in the "Wapiti" The machine is an all-metal biplane,
and can be supplied equipped with a number of alternative power plants, such as
the Bristol " Pegasus, "the Armstrong Siddeley" Jaguar " or " Panther," or the
Gnome -Rhone" :Mistral." The Royal Air Force version is, as already stated,
fitted with the Bristol " Pegasus "M3.
The fuselage is constructed in the familiar Westland manner, of tubes of
approximately square section. Joints <Ire made by flat pitch plates and tubular
steel rivets. In the forward portion of the fuselage the structure is of the
rigid type, with bracing formed by diagonal tubes, while the rear fuselage
portion is braced by swaged rods. This type of construction is extremely simple.
and has been found very easy to maintain and repair. The biplane wings are of
the staggered, two-bay arrangement, and are of equal span and chord. They have
corrugated steel strip spars of box section, and are detachable at top
centre-section and fuselage. Ailerons of the Frise type are fitted to upper and
lower planes, and Handley Page automatic wing-tip slots are fitted to the upper
The inter-plane struts are of streamline section, and built up steel
construction. External bracing is by RAF wire. The tail organs are of duralumin
construction. The covering of the front portion of the fuselage is of aluminium,
arranged in the form of easily detachable panels. In the "Wapiti" this covering
was corrugated for stiffness, but in the "Wallace" a .slightly heavier gauge has
been used, and the corrugations are omitted. The rear portion of the fuselage is
covered with doped fabric, as is also the wing covering. An undercarriage of the
"split" type is fitted, and from some of the views it will be seen that this is
of relatively narrow track. It has, however, been found that the stability on
the ground is sufficient. The telescopic legs of the undercarriage are of a
special Westland patented type, and possess great shock absorbing qualities. The
undercarriage wheels are provided with brakes, and these are so arranged that
they can be used together or independently. They are operated by toe pedals on
the rudder bar, and can be locked on by a hand brake lever in the cockpit. A
reduction of 50 per cent in landing run is gained by applying the brakes
The wheels are partly enclosed in "spats." A low-pressure castoring tail wheel
takes the place of the old type of tail skid, and in conjunction with the wheel
brakes makes manoeuvring on the ground quite easy, and avoids the need for a
separate tail trolley.
The "Wallace" can also be produced as a twin-float seaplane, and the fittings on
the fuselage are arranged to take either wheel or float type. Skis can also be
fitted if the machine is to be used in localities where snow-covered ground or
frozen lakes are found. The floats are of duralumin construction . with straight
rounded top and stepped vee bottom. Water rudders are fitted to the heels of the
floats, and are connected to the rudder bar. At 5,850 lb. gross machine weight,
the excess buoyancy is 100 per cent.
The Bristol "Pegasus" engine is fitted in the nose of the fuselage, and is
provided with a radial exhaust ring which, in conjunction with the Townend
cowling ring, materially decreases the drag of the engine. The petrol tanks are
of welded aluminium, anodically treated against corrosion and painted.
The main tank, which is of cylindrical shape, is placed in the fuselage,
approximately on the centre of gravity, so that as its contents are consumed the
trim of the machine is not altered. The auxiliary petrol tank and the oil tank
are placed farther forward in the fuselage. A combination of pressure and
gravity petrol feed is employed. The total tank capacity is 131 gallons, and the
oil capacity 14 gallons. The oil is cooled by an oil radiator. If the " Wallace
" is required for long distance work, a considerable extra quantity of fuel can
be carried. In that case the bombs under the lower plane are omitted, and
streamline petrol tanks fitted instead, each of 60-gall oil capacity. The range
then becomes 1,000 miles.
The pilot's cockpit aft of the top plane is so situated that a very good view is
obtained. The deck fairing in front of the pilot, it will be seen, slopes away
to the engine, and from the cockpit the upper part of the Townend ring is seen "
edge on," so that it does not obstruct the view greatly. The pilot's seat is so
arranged that it can be raised and lowered, and the foot bar has an adjustment
to enable pilots of different height to be suited.
Particular care has been taken to exclude draught from the cockpit. To relieve
as much as possible the pilot during a long flight, provision has been made not
only for trimming the machine in a fore and aft sense by means of a trimming
tailplane operated by a wheel in the cockpit, but the machine can also be
trimmed directionally by a rudder bias gear on the rudder bar.
In the observer's cockpit, close behind that of the pilot, there is a Scarff gun
ring for the movable machine gun. The observer's seat is of the "tip-up "type,
and the floor can be moved out of the way when the prone bomber's position is
used. The field of fire from the rear gun is very wide, and by using the firing
steps on each side of the floor, the gunner can fire vertically downwards on
EASY INSPECTION: "Zip" fasteners are used in the
fabric covering of the rear portion of the fuselage.
Parachute and ammunition racks are fitted, and a camera may be mounted on the
fuselage floor, behind the cockpit, and operated by remote control. To leave the
cockpits as unencumbered as possible, especially with parachute jumping in view,
the control cables are taken, in the vicinity of the cockpits, through the
inside of the fuselage fairings , i.e., between the primary structure and the
outer covering. To trim the machine when no observer is carried, there is a
small stowage space just in front of the tail, into which suitable weights can
be loaded. The total weight of bombs which can be carried is 500 lb. in normal
service. But for special purposes this load can be, and has been, increased to
The forward air-cooled gun is, of course, fixed and fires through the airscrew
disc, a Constantinesco interrupter gear being fitted. The gun is completely
enclosed in the port fuselage fairing, but is within reach of Ěthe pilot for
clearing stoppages, etc." An automatic air-cooled gun is normally fitted on the
Scarff gun ring in the rear cockpit, but duplicate guns call be mounted if
THE" WALLACE " IN PRODUCTION: On the right a small
section of the works at Yeovil, with fuselages in various stages of
construction. On the left a view through the Townend ring which surrounds the"
Pegasus " engine.
In conclusion, it may be pointed out that the" Wallace " has, of course, been
designed to the load factors laid down by the British Air Ministry, and complies
with these factors both for normal flying at a gross weight of 6,300 lb. and for
aerobatics at a gross weight of 5,650 lb. The original machine was type-tested
at the Aeroplane and Armament Experimental Establishment at Martlesham Heath. so
that foreign purchasers may .place orders for the " Wallace " with all the
confidence which "passed by Martlesham" engenders.
WESTLAND WALLACE -
Bristol Pegasus M.3
|Wing area sq ft.
||438 sq ft
|Fuel (105 Gallons)
|Oil (10 Gallons)
|Crew - Load & Equipment
at 5,000 ft 161 m.p.h. (259 kmh.)
|Top speed at
10,000 ft. 157 m.p.h. (253 kmh.)
|Top speed at
15,000 ft. 150 m.p.h. (242 kmh.)
speed 60.5 m.p.h. (97 kmh.)
ceiling 22,800 ft. (6950 m.).
ceiling 24,300 ft. (7400 m.)
5,000 ft. 4 mins
Time to 10,000 ft . 8.8 mins
Time to 15,000 ft. 15.8 mins
Time to 20,000 ft. 28 mins
The performances given above refer to standard atmosphere. The
effect of bombs or other equivalent resistances will slightly reduce