The Percival Mew Gull, by David F Ogilvy
Before the war Motor Sport had a regular Air Feature. We do not intend to revive this at the present time but we do feel that private flying deserves the support of all motoring enthusiasts in the gallant effort it is making to survive, and if possible to prosper. Consequently, when space is available, we intend to publish articles about the sort of aeroplanes which appeal to the sporting fraternity, from the pen of David F Ogilvy, Hon Secretary of the Vintage Aeroplane Club and a keen light ‘plane pilot. The first of these articles, dealing with the single-seater Percival Mew Gull racer which won the 1938 King’s Cup Race at an average speed of 236 mph for over 1,000 miles, follows.—Ed.
Flying as a sport and air racing in particular have never thrived on such a large scale as have their counterparts in the motoring world, so special aircraft for the game have always been a comparitive rarity : for example a present-day meeting would find a proponderance of Austers, Proctors and Tiger Moths that between times probably warrant their existences by thrashing out circuits and bumps for the local flying club.
It is a pleasant change, therefore, to handle something of the calibre of the Percival Mew Gull. a diminutive single-seater built round the engine and pilot and tailored specifically for one purpose, that of speed. As with cars, a good aeroplane has breeding and the Mew is no exception.
Ancestry can be traced to 1929, when a prototype low-wing monoplane, the combined efforts of Captain Edgar Percival and Mr B Henderson, reached fruition as the Hendy 302, registered G-AAVT. Subsequently this was developed into the Gull, twenty-three of which were built by Parnall Aircraft Ltd. at Yate, near Bristol, fitted with a variegated assortment of engines, both reliable and otherwise.
By 1934 Percival was on a more sound footing with his own factory at Gravesend, where the theme was varied with the Gull Six, in one of which, G-AIWR, Miss Jean Batten carried out some memorable flights.
Later in the same year the original Mew Gull appeared, but this was somewhat ungainly in appearance and not entirely satisfactory in operation although capable of 205 mph on the level. However, much modified and remotored from a Napier Javelin to a Gipsy Six, this prototype, G-ACND, reached sixth place from scratch in the 1935 King’s Cup.
Four further examples were completed and each of these achieved considerable fame, notably G-AEKL, which won the 1937 King’s Cup at an average of 233 mph, and G-AEXF, in which Alex Henshaw was first home the next year, managing 236 mph over a course of more than a thousand miles. For this success a specially tuned high compression Gipsy-Six R, giving an output of 224-hp replaced the standard 200-hp engine. The last Mew to be built, G-AFAA, came to an untimely end after being set ablaze as a practice target by an aerodrome fire service !
At the end of the war there was, alas, no intact Mew Gull in existence in this country but concerted efforts to find one eventually led to the discovery of G-AEXF at a small French aerodrome near Lyons. After a few days’ repair work and paying a bill to the rightful(?) owner ‘XF was flown home to Blackbushe on July 2nd, 1950.
A few words about this outstanding machine and its no less remarkable pre-1939 owner should prove that the Mew as a design with Henshaw as pilot must have made the most successful combination ever put together.
Initially this aircraft bore the South African registration ZS-AHM, but after an abortive attempt at the 1936 Slesinger Race to Johannesburg in the hands of the late Major Alistair Miller, who was forced earthwards through fuel starvation, it returned to its native land and was allotted the lettering by which it is known today.
A short spell with William Humble, the well-known Hawker test pilot, and ‘EXF fell into the hands of the man for whome it might almost have been conceived. The Henshaw-Mew combination achieved its first success by winning the 1937 Folkestone Trophy Air Race, After which the machine was docked for a number of moditications by Essex Aero Ltd. In its new form with a Gipsy Six R, that had been removed from one of the original Comets, and fitted with a variable pitch propeller and very pointed spinner, the Mew reached second place in the 1938 Hatfield-Isle of Man Race at the phenomenal average of 247 mph, after which it returned for some drastic alterations ; these included the removal of four inches of fuselage top-decking and a similar lowering of the cockpit roof.
The King’s Cup of the same year was the next major achievement, as ‘XF finished nine minutes ahead of the second machine to average 236.25 mph over twenty laps of a fifty-mile circuit. After this even more modifications were undertaken, when the rather temperamental Gipsy Six R was replaced by a standard Six 2 and the tankage was increased to give a total of 87 gallons, sufficient for more than 1,500 miles.
With the Mew in this form Henshaw set off from Gravesend at dawn on February 5th 1939, and reached Capetown 39 hours 25 minutes later, using some very rough undeveloped airstrips en route, some of them at night. After 24 hours on the ground ‘XF was airborne for the journey home, and the round trip of 4 days 10 hours and 16 minutes stands as a record today, thirteen years later.
The last success was that of taking second place in the Hatfield-Isle of Man race in May 1939, after which ‘XF was aquired by one Victor Vermorel, of Lyons, spending the war years under German Surveillance ; fortunately, however, no harm resulted apart from the loss of the journey log-book, which remains untraced.
Since returning home, G-AEXF has received a fresh C of A and was entered for both the King’s Cup anal Daily Express Air Races in 1951 but, alas, was flown in neither. Weather cancelled the former, and a landing accident, causing damage which so far has not been repaired, occurred just prior in the other event.
It is natural for a racing aeroplane to be a trifle unusual in layout and it is no surprise, therefore, to find no seat in the cockpit ; the process of clambering inside is a minor gymnastic feat, but once within it is possible to wriggle into some vague semblance of comfort before juggling with the very necessary Sutton harness. The entire hood hinges on the starboard side and clamps in position with two suitcase-type clips, but when the lid is closed a small ventilating panel can be opened as required.
Internal equipage is sensibly presented and comparatively easy of access. Taking stock from the left there is a four-position manually operated flap lever, which is moved forward for the “up” position ; on the floor in the centre is the fuel selector cock with settings for off, auxiliary and main tanks, and under the combing on the right is the pitch control, which operates in the reverse order to accepted practice, with “fine” at the back stop ; however, a clearly-marked red arrow prevents this forming a serious trap for the unwary. The array of knobs and levers. apart from the throttle and mixture controls which are in their customary places level with the top left longeron, is completed with an elevator trim wheel on the extreme right.
The instrument panel has a number of positions blanked, but the present facia incorporates an airspeed indicator, sensitive altimeter, cross-level, clock, rev-counter, oil pressure and boost gauges, and a compass of unusually generous dimensions. The empty spaces could usefully be filled with a turn and slip indicator and directional gyro, each of which is a necessity for serious work in doubtful weather.
There is no starter or internal primer, so the metal propeller must be swung by hand after external carburetter flooding. Warming should be carried out in fine pitch and the usual run-up procedure applies, during which the oil pressure settles at about 50 lbs/sq in, where it remains indefinitely.
The lowered windscreen allows no forward view, so taxying is not the easiest of pastimes ; in fact, Henshaw formed a habit of walking alongside the aircraft with a hand on the throttle and manually heaving to change direction, but this is by no means necessary, especially if someone is available at the wing-tip when in more confined spaces.
Vital actions are quite standard, with the trim slightly backward of neutral ; no fuel gauges are fitted, but as the present all-up weight of 1.850 lb allows up to 42 gallons, a moral provides the answer so long as the pocket allows.
During the take-off, which surprisingly is devoid of any tendency to swing, there is a pronounced rolling inclination caused by the narrow track of the undercarriage, and this creates an erroneous impression that things are not quite as controlled as they should be, however, the Mew unsticks happily at 85 IAS and the speed builds remarkably quickly to the recommended climbing figure of 140-mph, which at 2,100 rpm (there is no constant speed unit) gives an ascent of about 1,500 feet per minute.
Under most conditions of flight and especially on the climb it is necessary to trim well back, due probably to the fuel tanks being positioned in the fuselage forward of the pilot. One might expect an aeroplane of the Mew’s calibre to possess some unpleasant low-speed characteristics, so I climbed immediately to 3,500 feet to put my mind at ease or otherwise. Here I throttled back at 150 IAS, after which there was a long and tedious wait for the speed to fall off ; with flaps up, at 100 the controls became rather sloppy, at 92 there was an audible warning in the form of whistling round the cockpit, and at 80 IAS the nose dropped slowly but firmly. I took recovery action almost immediately, but afterwards I learnt that if the ‘stick is held back there is a very pronounced flick, although I experienced nothing of this nature.
The three controls (a spadegrip column is fitted) are quite normal in operation and effective throughout the speed range, and even during a dive to the airframe limit of 205 mph, there is no undue stiffening or fore-and-aft loading. However, harmonisation is not as good as one would imagine, for while the rudder and elevators are equally light and sensitive, the ailerons are rather stiff and too restricted in their travel, resulting in a lack of that fighter-like crispness that one would expect to associate with a low-wing racer ; a combination of static friction and the fact that the ailerons are of wooden construction with only fabric covering contribute much towards this.
A C of A in the normal rather than acrobatic category should, strictly speaking, hamper one’s style, but it is no secret that a Mew was seen frequently performing slow rolls in public in pre-war days ; however, I was reasonably content not to put ‘XF on its back, indulging merely in a number of steep turns which can be made within a satisfyingly small radius.
It is perhaps in the circuit that the problems of forward view presents itself most noticeably ; sideways and even downwards leave nothing to be desired, but as the cockpit is raised hardly above fuselage level there is a blind area of about 30 deg forwards–remembering, of course, that the other Mews and, in fact, ‘EXF in its earlier days, had a normally-shaped hood which allowed quite normal vision.
Selecting fine pitch and throttling back to dispose of surplus speed, 110 mph feels right for the end of the downwind leg, from which a curved fighter approach should be made if anything of the aerodrome is to be seen. The flaps can be lowered in stages or in toto, but are singularly ineffective even when fully extended, so careful handling is necessary to reduce to a comfortable 95 IAS over the hedge.
There is a long float during which the ‘stick is held central, as the approach is made almost in the three-point attitude, there is a strong tendency to balloon owing to the sensitivity of the elevators, so the procedure is to sit and wait for the touchdown, after which the run is quite straight under into-wind conditions ; the brakes, however, are of little use in bringing the machine to a standstill.
After the comparatively long period of taxying to the clubhouse at White Waltham, where I carried out the handling flight, I was accustomed to both the poor view and the inefficiant brakes, so manoeuvring on the ground is not so tricky as might at first be imagined. Clambering out, slightly deaf due to the rather above-average noise level, I considered the Mew Gull in its true perspective ; such excellent performance on so little power, combined with a docility that one normally associates with an average light aeroplane, make something that cannot be measured by accepted standards, as there is nothing flying today with which to make a comparison.
It can only be hoped that G-AEXF will be fully restored to health in readiness for the coming season and that it will achieve continued success whether in the hands of its present ‘maitre, Hugh Scrope, or with whoever is fortunate enough to be its owner in the years ahead.