Martin-Baker Aircraft Co. Ltd. was founded as an aircraft manufacturer in 1934. The factory was established in 1929 and was initially called Martin's Aircraft Works. Four aircraft prototypes were produced: MB1, MB2, MB3 and MB5.
The first design of the MB1 was a low-wing monoplane design and this in itself was heresy, for the first British monoplane, civil or military, had yet to fly operationally. Also unconventional was the installation of the Gipsy engine, mounted in the fuselage behind the seats, driving a fixed-pitch propeller through a shaft running horizontally between the pilot and passenger, who sat side by side.
This arrangement and the general configuration of the aeroplane gave the pilot excellent all-round visibility, making it, with its low stalling speed, a very safe machine. At the same time its low structure weight and simple construction would have made it economical to operate and easy to maintain. Unfortunately, slender financial resources prematurely terminated work on this project, at a stage when all but the wings were completed; engine runs and other ground tests had been carried out in the astonishingly short time of three months
It was at this stage, too, that the Company took on the construction of an interesting autogyro design by Mr. Raoul Haffner, which was later tested by Captain Valentine Baker at Heston. With some financial aid from a business friend with an interest in aviation, Martin now turned to the design and manufacture of a small, cheap two-seater aeroplane to exploit a simple but highly ingenious method of construction, using round-section thin-gauge steel tubing throughout the structure. The fuselage strut ends were flattened brazed, and drilled holes picked up on bolts supported in the steel longeron tubes. Machined, flanged steel sleeves, fitted on the longerons at focal joints, provided, by holes drilled around their periphery, a means of attachment of fuselage struts, the whole being faired by light metal hoops of near-oval shape. Based, like the fuselage, upon simple construction, the wing was built around a pyramidal spar consisting of three large-diameter but thin-gauge booms, braced by smaller tubes and converging towards one another at the wing tip. The wing struts and ribs, and also the tail unit components, were fastened to the spars in a similar way to the fuselage construction.
For economy of storage space the wings were designed to fold rearwards. Wing folding was a one-man operation, the front pin being on a screw operated by a handle, whilst the rear hinge was designed to prevent the wing falling backwards into the fuselage when the front pin was released; the wing in the closed position came finally against a stop. Long triangular welded-aluminium fuel tanks, designed to be quickly detachable, were carried in the centre of each wing spar. This machine became the MB1 and was powered by a neatly cowled Napier Javelin engine, a 6-cylinder in-line unit producing 160 h.p., flexibly installed in a tubular mounting with all parts accessible for easy servicing, electrically started and driving a fixed-pitch wooden propeller. A sturdy, yet light, tubular-construction undercarriage carried low-pressure tyred wheels and employed shock-absorber struts of simple design. Although the main interest of this aeroplane was in its simple design, much forethought was given to its cockpit layout and general facilities. A contemporary aeronautical journal reported, "The seats are comfortable and the cockpit is totally enclosed with an oval transparent hood. The windscreen is a sharp vee, with vertical front panes, which should not collect fine rain or snow and should obviate any reflection from internal or external lighting."
Aerodynamically a straightforward design, when flight tested in April, 1935, the MB1 was found to possess sound inherent flying qualities which later became a characteristic of the Martin breed of aeroplanes. Top speed was 125 m.p.h. Although the MB1 did not go beyond the prototype stage, many valuable lessons were learnt during its design, construction and testing, which were to be used in the production of the Company's next design.
The international looking glass of the period immediately before the Second World War reflected a need for fighters rather than for private aeroplanes, thus Sir James Martin decided to design a military machine utilising the simple basic structure employed and developed in the MB1. Even in these early days, to formulate a requirement and write a specification was not novel, but to translate this into an effective machine needed further effort, technical skill, resources and time. But in less than no time Martin, with his small band of workers, had produced the MB2. Like its predecessor, the MB2 was constructed of steel tubing, but many detailed improvements were made which further simplified production as well as repair and maintenance.
The MB2 was powered by a special Napier Dagger III 24-cylinder H-type engine of 805 nominal bhp, but capable of operation at plus 13 lb boost to give over 1,000 h.p. for take-off, driving a fixed-pitch two-blade propeller. The undercarriage was, for simplicity, fixed and cleanly faired in two trouser-type fairings, the port one carrying the oil-cooler. Later a scheme was worked out for making the undercarriage retractable to improve performance. The fuselage lines were square cut and exceptionally clean, with almost constant depth from nose to sternpost. An unusual feature, at that time, was that the fuselage was slightly longer than the span of 34ft 6in, a feature contributing to good stability and control in the yawing plane, and which was retained in later Martin-Baker designs. The wing carried eight Browning .303 machine-guns, disposed in two groups outboard the undercarriage, which made the MB2 the first British eight-gun fighter.
The clean and orderly cockpit was set well back, allowing a good view downwards behind the wing. A crash post was fitted, which automatically extended to minimise structure damage and injury to the pilot in the event of a nose-over landing. A small tapered tail-plane was mounted on the top of the fuselage well forward of the sternpost, while the fin and rudder combination was roughly triangular in side elevation. This arrangement placed most of the effective rudder area below the tail-plane, thus providing an adequate balance to the keel surface and assuring good recovery from spins. In earlier designs, there was no fin and the rudder had lacked entirely the part above the tail-plane, lateral stability being provided by the fuselage and the undercarriage trouser fairings. However, this was found to be not entirely satisfactory, and the fixed fin was later added.
The lessons learned in the design and construction of the two previous low-wing monoplanes were embodied in a new design, the MB3, which was powered by a 2,000 h.p. Napier Sabre 24cylinder H-type engine, driving a De Havilland variable-pitch three-blade propeller. MB3 was projected to meet an Air Ministry fighter specification. It carried six 20-mm cannon, each with 200 rounds of ammunition, which made it the most heavily armed fighter in existence at the time. The armament installation was very good from an operational point of view, and a quick turnaround was ensured by the excellent accessibility of guns and ammunition.
While retaining the essential characteristics of the earlier designs, MB3 included many new features. The fuselage primary structure was still the round steel tube arrangement, but metal panels had taken the place of wood and fabric of earlier models. The wing, of torsion-box construction about a laminated steel spar, gave a remarkably strong and stiff structure in which flexing was not perceptible. A pneumatically controlled undercarriage was simple, sturdy, effective and notably reliable. As the wing flaps were also pneumatically operated, the need for hydraulics, with all their attendant operational hazards and maintenance problems, was eliminated. Radiators were installed underneath the wings, the coolant radiator on the starboard and the oil-cooler on the port side.
This aeroplane proved to be highly manoeuvrable and easy to fly, and could have been developed into a good fighter aircraft. It was a double tragedy when, on 12 September, 1942 the engine failed soon after take-off, and Captain Baker, in an attempt to save the aircraft whilst executing a difficult forced landing, crashed in a field and was killed. The personal loss to James Martin was immeasurable. It has already been stated that a deep friendship had grown up between these two men. James Martin never forgot the fearless, skilful and resolute pilot, and many consider that it was this painful tragedy that really fired the passionate interest in the safety of aircrews, which was later to become the very pivot of his life. At the time, the material loss was also a bitter pill. The MB3 was completely wrecked, and building to the same design would have resulted in immense loss of time - that commodity so essential to the successful production of a new aeroplane - so it was decided to design another prototype with a Rolls Royce Griffon engine, to be the MB4. In the event, this project was eventually dropped in favour of a new design, which became the MB5.
The MB5, a low-wing monoplane, fitted with a 2,340hp. Rolls-Royce Griffon 83 engine driving a pair of three-bladed conta-rotating propellers, was an aircraft of sleek and pleasing lines. Underslung radiators were placed beneath the belly of the fuselage, aft of the cockpit. This arrangement, as well as reducing the cooling drag, led to a slim and clean nose which, with the long spinner enclosing the propeller hubs, gave an exceptionally good view over the nose and leading edge of the wings. Fighter pilots flying this aircraft for the first time were full of praise of this essential tactical feature.
"Mr Martin’s Memorable M.B.5" – Reprinted from Air International, 02/79
The fuselage primary structure of MB5 was of the now familiar steel tube construction, covered and faired with light, detachable metal panels, which offered exceptional accessibility to the equipment installations and for servicing. The engine-mounting consisted of two molybdenum-steel tapered cantilever booms, and here too the layout provided easy access to engine components and accessories. The engine was neatly cowled with panels which could be removed easily to lay bare the engine in a few minutes.
The wing was of the single-spar type, with the spar and leading edge forming a torsion-box of remarkable stiffness and strength; primary wing structure details were simple to produce and easy to repair. Flying controls were operated by torsion bars, which gave excellent positive control coupled with light operation. A sturdy wide-track undercarriage gave exceptionally good taxiing qualities, whilst its pneumatic operation was simple, effective and entirely trouble free.
It was, however, in the pilot's cockpit that one of MB5's main attractions lay. The cockpit was exceptionally well laid out, with all controls coming easily and readily to hand, within the pilot's reach. Instruments were grouped in an orderly fashion, allowing routine cockpit checks to be done in logical sequence. Fuel control was centred in one lever - a feature dear to the hearts of fighter pilots. Accessibility for servicing was provided by mounting the instruments on hinged panels, which opened into the cockpit. A special primary control-unit was neatly installed in a manner economical in space, yet effective in operation, and having the advantage of bringing vital control components within the easy scrutiny of routine inspection. The cockpit was cleanly floored, an unusual feature then in British military aircraft, which gave a pleasing impression of spaciousness combined with business-like utility.
Official reports of the day stated that the cockpit could advantageously be copied as standard for fighter aircraft. A one-piece transparent tear-drop canopy of neat design was fitted, provided with wheel control for operation by the pilot. The mechanism was perfectly balanced and easy to operate, whilst jettisoning was clean, safe and effective. The four-cannon installation, utilising Martin-Baker flat belt-feed mechanisms, was exceptionally well arranged. The functional efficiency and destructive power of this weapon was noteworthy among contemporary aircraft, whilst the excellent accessibility of the installation permitted easy servicing and ensured a quick turnaround under operational conditions.
Not all its virtues rested in the excellence of its engineering, for in the air MB5 was unquestionably ahead of contemporary piston-engined fighters, with a top speed of 460 m.p.h. Early flight trials, in the capable hands of Bryan Greensted, quickly established it as an exceptionally good aircraft, and some older readers will remember the polished demonstration of MB5 by Squadron-leader Zurakowski as an outstanding event at the SBAC AIr Show at Radlett in 1946.
Pilots liked the ease of taxiing provided by a wide-track undercarriage, the excellent all-round view, the absence of swing on take-off and landing, the spectacular rocket-like climb, the surge of power, quickly responding to throttle openings, with a corresponding bite into the air urging the aircraft forward, and the feeling of confidence given by a robust structure. They also liked sitting in a clean cockpit from which the aircraft could be flown effectively with precision and safety.
Why this aircraft was not put into production remains one of the aircraft industry's minor mysteries, and one which is often the subject of interesting speculation. Some will say that, as a piston-engined aircraft, it came too late to be acceptable in the advent of jet fighters. However, had a decision about its future been taken early by the authorities, it could have gone into production soon enough for it to have reached squadrons in sufficient numbers to have been engaged effectively in World War II. Disappointment in failing to put MB5 into production was felt keenly by all at Martin-Baker and shared by many Royal Air Force officers and other officials.