Flight, March 1936
TWO BRITISH NEWCOMERS
Monoplane Trainer and Fast Transport Monoplane: Interesting Designs by C.L.W. Company at Gravesend
FROM Gravesend Airport comes news of a new British make of aeroplane, to be produced in contrasting types. The constructors
are the C.L.W. Aviation Co., Ltd. (well known in connection with the C.L.W. patented wing), the directors of which are Messrs. S. Wilding-Cole, O.B.E., W. P. Mackinson, A. Levell, F. S. Welman, and Sqn. Ldr. F. W. H. Lerwill, O.B.E.
The first two machines are a two-seater low-wing trainer - of a type which should be particularly suitable for instruction preparatory to flying modern high-performance military and other machines - and a twin-engined transport monoplane. The former will be the first to appear (the transport will be built only to order), and, all being well, it should be flying next month.
Sqn. Ldr. Lerwill, lately retired from the R.A.F., has had extensive experience in the training of Service personnel which has proved greatly advantageous in the planning of the T.1, as the new two-seater is known.
Both the cantilever wing and the fuselage are of quite unusual interest. The former is of the patent C.L.W. type, which is said to possess abnormal qualities of lightness and simplicity and, at the same time, to be very stiff in torsion. Broadly speaking, this type of wing, which tapers both in plain form and thickness and has a single main spar, consists of an open box-like structure, the front and rear members being inter-connected and affixed to the spar with cantilever ribs. Diagonal cross-bracing is provided on both upper and lower surfaces. As originally planned, a straight centre section was to have been embodied, but the prototype machine will have a dihedral angle which originates on the centre line on the under surface of the fuselage. The covering of the main wing panels is of fabric. Split trailing-edge flaps extend from aileron to aileron.
The fuselage, a stressed-skin monocoque structure with Alclad covering, is of commendably simple and apparently sturdy design, with the tail plane, elevator, rudder and fin all readily detachable. Of wide track and relatively high to minimise danger of damage to wing tips, the undercarriage is in two separate halves. Sqn. Ldr. Lerwill does not recommend the fitting of brakes for early training.
Normally the machine will be fitted with either the D.H. Gipsy Major of 130 h.p. or the new 90/95 h.p. Pobjoy Niagara III radial. The latter installation will include the newest type of deep chord hinged cowling without the customary Pobjoy "helmets." Petrol feed is by dual engine pumps.
It is the contention of the manufacturers that it is advisable to put the pupil in the front cockpit, as this more closely simulates conditions in normal Service machines to which he will graduate. The rear cockpit is of sufficient diameter to permit the installation of any normal gun ring. When provision is made for gunnery training and similar duties the Gipsy Major engine is recommended, due to its greater power.
It is expected that with the Pobjoy the maximum speed will be in the neighbourhood of 135 m.p.h., and with the Gipsy Major about 150 m.p.h.
Flight, April 1936
MODERN LIGHT AIRCRAFT REVIEWED
THERE are those who require something rather "snappier” than the ordinary run of light, open two-seaters, and for these there is, or soon will be, the C.L.W. Trainer. This type is intended primarily for instruction preparatory to flying modern high-performance military types, and, in consequence, is likely to be "a real aeroplane," as opposed to those types which have some of the flying characteristics of a feather. The 90 h.p. Pobjoy Niagara III is being specified for the prototype, but the 130 h.p. Gipsy Major will be optional.
Structurally, the machine is of quite unusual interest because it embodies a metal stressed-skin fuselage and a new form of wing construction. With the Pobjoy the maximum speed should be 135 m.p.h.; the Gipsy Major will add another 15 m.p.h., with a slight increase in landing speed.
The manufacturers contend that the pupil should be put in the front cockpit, as this will accustom him to the sensation of flying with no one in sight.
Makers: The C.L.W. Aviation Co., Ltd., Gravesend Airport, Kent.
Flight, September 1936
PRIMARILY for TRAINING
C.L.W. Curlew Flying at Gravesend: Original Features of Design: Excellent Control Apparent
WITH the aptly chosen type-name of Curlew, the little T.1 training monoplane built by the C.L.W. Aviation Co. Ltd., of Gravesend is now completing preliminary test flights which promise to excel the most sanguine hopes of its constructors. Although at the time of the demonstration at Gravesend last Thursday the machine was flying under a restricted licence, which permitted no aerobatics, its performance promised quite exceptionally well. Capt. A. N. Kingwill was the demonstrator, and his exhibition of fast and slow flying left little to the imagination in assessing the qualities of control at both ends of the speed range. Loaded to about 14 lb./sq. ft., the Curlew stalls, with flaps down, at 38 m.p.h., and the measure of control which persists at speeds of that order evoked plenty of favourable comment. The gliding angle is claimed to be about 4:1. At the upper end of tie speed range (125 m.p.h. is being obtained with the Pobjoy Niagara III driving an airscrew of unduly fine pitch) the short span and Frise ailerons permit changing from one bank to another with commendable smoothness and celerity.
Structurally, it will be remembered, the Curlew is a cantilever low-wing monoplane with a wing of patent design. Tapering both in plan form and thickness this is built round a single main spar and consists of an open box-like structure, the front and rear members being inter-connected and affixed to the spar with cantilever ribs. Upper and lower surfaces are provided with diagonal cross bracing. The manually operated flaps extend from aileron to aileron.
Alclad covering is used for the stressed skin monocoque fuselage from which the tail plane, and fin, are readily detachable. Metal covering is employed throughout except for the main wing panels.
The undercarriage legs have a 3in. compression and 6in. travel and there, without a doubt, lies the reason for a seemingly longer take-off than one might have imagined, for the machine is actually air-borne before the wheels leave the ground. Sqn. Ldr. F. W. H. Lerwill, one of the directors of the C.L.W. Aviation Co , Ltd., who knows far more about flying training than most people, does not advocate brakes in a primary trainer, reasoning that they result in more gadgets and are liable to lead an embryo pilot into trouble.
The design has been planned for almost any engine up to 140 h.p. and it is likely that the Gipsy Major will be fitted in some future machines of the type. The 90/95 h.p. Pobjoy Niagara III has the new model deep-chord Pobjoy cowling and dual engine-driven pumps.
The tare and gross weights of the prototype are respectively 970 lb. and 1,500 lb.