The Hawker Typhoon was a British single seat fighter/bomber.
It was intended to be a medium high-altitude interceptor, as a replacement for the Hawker Hurricane, this was not to be due to several design problems that were encountered, and these problems couldn’t be completely ironed out.
Even before Hurricane production began in March 1937, Sydney Camm had embarked on designing its successor.
Two preliminary designs were similar and larger than the Hurricane.
These later became known as the “N” and “R” (from the initial of the engine manufacturers), because they were designed for the newly developed Napier Sabre and Rolls-Royce Vulture, engines respectively.
Both engines used 24 cylinders and were designed for over 2,000 hp (1,500 kW); the difference between the two was primarily in the arrangement of the cylinders – an H-block in the Sabre, and an X-block in the Vulture.
Hawker submitted these preliminary designs in July 1937 but were advised to wait until a formal specification for a new fighter was issued.
In March 1938, Hawker received from the Air Ministry, Specification F.18/37 for a fighter which would be able to achieve at least 400 mph (640 km/h) at 15,000 feet (4,600 m) and specified a British engine with a two-speed supercharger.
The armament fitted was to be twelve .303-inch Browning machine guns with 500 rounds per gun, with a provision for alternative combinations of weaponry.
Camm and his design team started formal development of the designs and construction of prototypes.
The basic design of the Typhoon was a combination of traditional Hawker construction, as used in the earlier Hawker Hurricane, and more modern construction techniques; the front fuselage structure, from the engine mountings to the rear of the cockpit, was made up of bolted and welded duralumin or steel tubes covered with skin panels, while the rear fuselage was a flush-riveted, semi-monocoque structure.
The forward fuselage and cockpit skinning was made up of large, removable duralumin panels, allowing easy external access to the engine and engine accessories and most of the important hydraulic and electrical equipment.
The wing had a span of 41 feet 7 inches (12.67 m), with a wing area of 279 sq ft (25.9 m2).
It was designed with a small amount of inverted gull wing bend; the inner sections had a 1° anhedral, while the outer sections, attached just outboard of the undercarriage legs, had a dihedral of 5+1⁄2°.
The airfoil was a NACA 22 wing section, with a thickness-to-chord ratio of 19.5% at the root tapering to 12% at the tip.
The wing possessed great structural strength, provided plenty of room for fuel tanks and a heavy armament, while allowing the aircraft to be a steady gun platform.
Each of the inner wings incorporated two fuel tanks; the “main” tanks, housed in a bay outboard and to the rear of the main undercarriage bays, had a capacity of 40 gallons; while the “nose” tanks, built into the wing leading edges, forward of the main spar, had a capacity of 37 gallons each.
Also incorporated into the inner wings were inward-retracting landing gear with a wide track of 13 ft 6+3⁄4 in.
By contemporary standards, the new design’s wing was very “thick”, similar to the Hurricane before it.
Although the Typhoon was expected to achieve over 400 mph (640 km/h) in level flight at 20,000 ft, the thick wings created a large drag rise and prevented higher speeds than the 410 mph at 20,000 feet (6,100 m) achieved in tests.
The climb rate and performance above that level was also considered disappointing.
When the Typhoon was dived at speeds of over 500 mph (800 km/h), the drag rise caused buffeting and trim changes.
These compressibility problems led to Camm designing the Typhoon II, later known as the Tempest, which used much thinner wings with a laminar flow airfoil.
12 machine guns.
4 x 20 mm Cannon.
Night fighter conversion of one aircraft.
31 ft 11.5 in (9.741 m)
41 ft 7 in (12.67 m)
15 ft 4 in (4.67 m)
279 sq ft (25.9 m2)
8,840 lb (4,010 kg)
11,400 lb (5,171 kg)
Max take-off weight
13,250 lb (6,010 kg) with two 1,000 lb (450 kg) bombs