Flight, January 1936

A ROOMIER PERCIVAL
The Vega Gull: Seats for Four and a Speed of 170 m.p.h. With a Gipsy Six Engine: Many Practical Detail Modifications

   ESSENTIALLY the new Percival Vega Gull follows standard Percival practice, and might, in fact, be regarded as a scaled-up and cleaned-up Gull. It is notable chiefly because it carries four people, with a high degree of comfort, at a speed barely 5 m.p.h. less than that attained by last year's three-seater Gull. An increase of 15 sq. ft. in wing area keeps the landing speed down to the 45 m.p.h. of the smaller machine.

Cabin Comfort

   The fuselage, which is 9 in. longer than that of the Gull, has a spruce framework and plywood covering. A thin cotton fabric known as nainsook, or madapollam, is applied, protecting the ply and forming a base for the Titanine finish. The cabin is 44 in. wide and its four seats are arranged in pairs, the two front seats being of the bucket type. The rear pair is luxuriously upholstered and provided with armrests. Soundproofing - which, like the upholstery, is the work of Rumbold - is incorporated, and from all viewpoints the cabin is comparable with that of a saloon motor car. There is a door on each side of the cabin and windows of splinterproof glass.
   Dual controls are optional, as are the electric starter and sun blinds fitted to the machine demonstrated the other day at Gravesend Airport by Capt. Percival. Luggage is carried in a separate compartment behind the cabin. Smith's instruments are fitted, and there is a Reid and Sigrist Gyorizon. As in the 1935 model of the Gull, fresh air is taken to the cabin from a small scoop on the starboard wing. Provision has been made for the installation, if necessary, of a simple heating system from the exhaust.
   In span the wing of the Vega Gull measures 3 ft. 4 in. more than that of the Gull. Structurally, however, it is identical, having spars of spruce and plywood, lattice bracing of spruce, ribs of the same material and fabric covering. The locking device for the folding wings has been improved and now embodies a disappearing tommy-bar in place of a fixed extraneous handle.

Cleaning-Up

   Two 20-gallon petrol tanks are housed in the wing, as in the Gull, and allow a range of 620 miles. The external actuating levers for the ailerons have been done away with in the name of aerodynamic cleanliness. Cleaning-up is also apparent in the undercarriage (which, incidentally, now has a 6 1/4 in. travel, compared with the 5 3/4 in. of the older model), the small bracing strut from the compression leg to the spar having been eliminated a la Mew Gull. Wheels and tyres, as previously, are Dunlop and Bendix respectively. The pneumatic tail wheel is completely orientable and self-centring and is carried in a fork.
   A Gipsy Six engine of 200 h.p. is fitted as standard, and a De Havilland or Ratier controllable-pitch airscrew is optional. The installation of one of these benefits take-off and cruising speed.
   The split trailing-edge flaps are generally similar to those of the Gull (this means that they do not extend across the bottom of the fuselage and are worked by a lever on the port side of the pilot), but are increased in span and chord. Not more than a 10 lb. pull is required for their operation.
   Such beneficial features as the new type of undercarriage are being incorporated in the 1936 model of the Gull, the maximum speed of which has been increased about 4 m.p.h.

PERCIVAL VEGA GULL
Four-seater Cabin Monoplane
D.H. Gipsy Six, 200 h.p.

   Span 30 ft. 6 in. (12,04 m.)
   Length 25 ft. 6 in. (7,77 m )
   Wing area 184 sq. ft. (17,1 m2.)
   Tare weight 1,575 lb. (716 kg.)
   Gross weight 2,750 lb. (1 250 kg.)
   Maximum speed 170 m.p.h. (274 km/h.)
   Cruising speed 150 m.p.h. (242 km/h.)
   Stalling speed 45 m.p.h. (72 km/h.)
   Range 620 miles (1000 km.)
   Service ceiling 18,000 (5 600 km.)

Flight, April 1936

MODERN LIGHT AIRCRAFT REVIEW

PERCIVAL

   LATEST of the Percival Gull series, the Vega Gull may be described as an enlarged Gull, though the comparison does not end there. It is both scaled-up and cleaned-up, and carries four people in considerable comfort at a speed barely 5 m.p.h. lower than that attained by the standard three-seater. An increase of wing area has kept the landing speed down to the same figure as before, and the area of the split flaps has been increased. Electric starters are an optional fitting, as are a cabin heater and an R.T.E. homing equipment, and luggage is carried in a separate compartment, behind the cabin, which is reached from the outside.
   The majority of low-wing cabin machines tend to become uncomfortably hot without some form of ventilator, and that on the Vega Gull is fed from an aperture well outboard in the wing, so that the air is fresh. Two doors are fitted, so that there is less of the clambering, which is so irritating to the no-longer-young, and the seats are arranged in two pairs with provision for dual control if this is required. The rear pair of seats is provided with armrests. Cleaning-up is apparent in the undercarriage, and this has a travel of more than six inches.
   In the case of the Gull the pilot sits alone in front with the two passengers in slightly staggered seats behind. This machine is normally fitted with a Gipsy Six engine, but a Major can be fitted if required, and in this case the cruising speed is 133 m.p.h., against the 155 m.p.h. of the normal type.
   The specification of the Vega Gull is as follows: Weight empty, 1.575 lb.; disposable load, 1,175 lb.; span, 39ft. 6in.; length, 25ft. 6in.; maximum speed, 170 m.p h.; cruising speed, 150 m.p.h.; stalling speed, 45 m.p.h.; ranges 620 miles; price, ^1,550.
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Flight, October 1936

VEGA VICTORIOUS
The Specification of Scott’s Percival Vega Gull and Its Gipsy Engine

   THE Percival Vega Gull is a development of the standard Gull, built on generally similar lines, but with a wider fuselage designed to accommodate four passengers, though in the case of the race-winning machine the two vacant seats were sacrificed to extra fuel tank space. A low-wing monoplane, it is of the normal Percival wooden construction, with trousered and spatted undercarriage and fitted with trailing-edge flaps. The cruising speed of the standard model with the 200 h.p. D.H.Gipsy Six engine is 150 m.p.h., but the Series II Gipsy Six and D.H variable-pitch airscrew, as fitted to Scott's machine, increase this figure very considerably. The winner's special tankage arrangements consisted of two tanks in the outer wing panels containing 20 gallons each, two more in the centre section holding 14 gallons each, and a fifth in the cabin of 28 gallons capacity ; this made a total of 96 gallons, which was calculated to give a theoretical range of 1,500 miles.
   The Series II Gipsy Six engine with which the machine is fitted is a version of the successful and well-tried Gipsy Six, but adapted for use with V.P. airscrews and utilising high-octane leaded fuels. The outstanding feature of its performance is a higher consistent output over the cruising range and a notable increase in take-off power, made possible by the use of the V.P. airscrew.
   The six cylinders have a total capacity of 9.186 litres and a compression ratio of 6:1. The crankshaft runs in eight main bearings, with a ball thrust bearing at the front end. The valves - the exhaust valves are of the Stellited type - operate on steel seats having a high coefficient of expansion, made necessary by the emplovment of high octane fuel.
   Two downdraught carburetters each supply three cylinders and draw warm air from around the cylinders at cruising speed, a flame trap being interposed. When the throttle is fully open a change-over flap is moved and air is taken from outside the cowling. This obviates any risk of freezing at cruising speeds, yet there is no loss of performance at full throttle. A gear-type oil pump supplies oil at a pressure of 40 to 45 lb./sq.in., the main stream going via the crankshaft and subsidiary streams lubricating the valve gear and auxiliary drives. Two scavenge pumps draw oil from each end of the crank case.
   With a V.P. airscrew the engine develops a rated output of 205 b.h.p. at 2,400 r.p.m. Fuel consumption is 11 1/2 gallons per hour, cruising at 2,100 r.p.m., or 16 gallons per hour at full throttle (2,400 r.p.m.). Oil consumption is 3 to 5 pints per hour at 2,100 r.p.m.
   The proprietary equipment of the machine included the following: Smith's engine instruments; two Husun compasses, types P3 and P4; Reid and Sigrist turn and bank indicator; Sperry artificial horizon. A Rotax battery supplied current for the Vickers landing light and Demec navigation lights. The wheels and tyres were Dunlop, and Bendix brakes were fitted. The Percival undercarriage embodied legs by Automotive Products. In the construction of the airframe the spruce was by Bamberger, and plywood was by Flexo and Aeronautical and Panel Plywood. Reynold's special tubing was also employed. The finish was in Titanine dope. Upholstery was by Rumbold, the cabin top was Rhodoid, and the windscreen was of Splintex.
   Proprietary engine components and accessories included a crankshaft made of steel supplied by the English Steel Corporation, a camshaft by the Weyburn Engineering Co., and white metal bearings by Hoyt and the Eyre Smelting Co.; Wellworthy piston rings were fitted, and the valve springs were Salters'. B.T.H magnetos, driven through Simms flexible couplings, supplied current to K.L.G. plugs via cables made by British Insulated Cables, Ltd., and the H.T. terminals were by Chater-Lea An Amal petrol pump supplied fuel to the Claudel-Hobson carburetters, to which Amal flame traps were fitted. Other ccessories included gaskets by Hall and Hall, and Cooper's Mechanical Jointing; Robertson's "Jubilee" hose clips; oil-resisting rubber by the Northern Rubber Co., Dermatine Co., and Lyne Hancock; liquid jointing material by Held Glue and Compounds, Ltd., and the Kenilworth Manufacturing Co.; and engine paint by Pinchin Johnson. The 87-octane fuel was Shell (supplied via Vickers four-way petrol taps), and the oil was Castrol.

Flight, March 1938

British light aircraft

PERCIVAL

   NOW that pilots are becoming accustomed to the use of such items of necessary equipment as split flaps and v.p. airscrews, a high-efficiency machine such as the Vega Gull can no longer be considered as one solely for the expert. This best known of the Percival range is the descendant of a line of Gulls which originally carried two passengers and a pilot. The Vega Gull carries four people and their luggage at a cruising speed, with a Series II Gipsy Six and living at optimum altitude, of 170 m.p.h. At lower levels the necessity for keep­ing the boost pressure and the fuel consumption within reasonable limits some­what reduces this speed, but even at 1,000ft. or so the machine can still be cruised at 150 m.p.h.
   As far as the internal arrangements are concerned, there is plenty of leg room both in the front and the rear seats, and there is a wide door on each side. To some extent a machine such as the Vega Gull must obviously be treated as one would treat any fairly large aeroplane, but there is nothing difficult or unusual about its flying characteristics, and anyone with a reason­able amount of flying experience would find no difficulties. The figures given below are those for the Series II-engined type, but the Vega Gull is, of course, still available in its original form with a fixed pitch airscrew.
   SPECIFICATION: Span folded, 16ft.; length, 25ft. 4in.; all-up weight, 3,250 lb.; weight empty, 1,740 lb.; maximum speed, 175 m.p.h.; cruising speed, 170 m.p.h.; landing speed, 45 m.p.h.; range, 660 miles; price, £1,995.
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Flight, October 1938

British Sport and Training types

PERCIVAL

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   Nowadays the Vega Gull, which was first introduced as a four-seater luxury version of the Gull Six, is usually fitted with a Series II Gipsy Six and v.p. airscrew. Pilots are becoming accustomed to the proper use of the throttle and mixture control with this unit, and a comparatively high-efficiency type, such as the Vega, can no longer be thought of as being one for the use of experts only. Like the Gull, this machine has a long list of distance and speed successes to its credit, the most recent being Broadbent’s Australia-England flight in 5 days 4 hours 21 minutes in April of this year.
   Both the structure and the finish have proved themselves in service over the last few years. The former is of wood with the wing built round two box spars of equal depth. The outer sections fold, and the centre section is built into the fuselage. The latter is of box structure with spruce members and plywood panelling, and has been designed so that the four-seater cabin is entirely free from struts or cross-members. The tail unit is fully cantilever. When a Series I engine is fitted a metal airscrew is used, while with a Series II engine either a D.H. or Ratier v.p. airscrew may be fitted. The cabin has a large door on each side, and the seating is arranged in two pairs, full dual control being provided for the front occupants. There is a baggage locker at the rear, and this is accessible from the outside.
   Vega Gull (Series II engine) data: - Span, 39ft. 6in.; length, 25ft. 4in. (folded 16ft.); all-up weight, 3,250 lb.; weight empty, 1,740 lb.; wing-loading, 16.5 Ib./sq. ft.; power-loading, 16.4 lb./h.p.; maximum speed, 174 m.p.h.; cruising speed (7,000ft.), 170 m.p.h.; and cruising range, 660 miles. With a fixed-pitch airscrew the cruising speed is 150 m.p.h. at sea-level, and the range is 630 miles.
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Flight, November 1939

Britain's Civil Aircraft

PERCIVAL

   The Percival Vega Gull is a four-seater low-wing cabin monoplane with a single Gipsy Six engine. Like the Q6 it has efficient trailing edge flaps; these reduce the landing speed to 44 m.p.h. When the Series II version of the Gipsy Six is fitted, the machine has a top speed of 174 m.p.h. and will cruise at 170 m.p.h. at 7,000ft. The range with standard tankage is 600 miles.

Percival Aircraft, Ltd.. Luton Airport, Beds.