The Hawker Typhoon, a single-seat fighter/bomber, was created by the British.
Originally planned as a medium-altitude interceptor to replace the Hawker Hurricane, several design issues arose that couldn’t be resolved.
Sydney Camm, the designer, started designing the Typhoon’s successor, even before the Hurricane’s production began in March 1937.
There were two preliminary designs, the N and R, named after the engine manufacturers, that were bigger than the Hurricane and designed for the newly developed Napier Sabre and Rolls-Royce Vulture engines, respectively.
Both engines had 24 cylinders and were capable of over 2,000 hp (1,500 kW), with the primary difference being their cylinder arrangement – an H-block in the Sabre and an X-block in the Vulture.
Hawker submitted these designs in July 1937, but they were advised to wait until a formal fighter specification was issued.
In March 1938, Hawker received the Air Ministry’s F.18/37 specification for a fighter capable of reaching at least 400 mph (640 km/h) at 15,000 feet (4,600 m) and had a British engine with a two-speed supercharger.
The armament was to be twelve .303-inch Browning machine guns with 500 rounds per gun, and alternative weapon combinations were allowed.
The Typhoon’s design was a blend of traditional Hawker construction and contemporary techniques.
The front fuselage structure, from the engine mountings to the rear of the cockpit, was made 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 consisted of large, detachable duralumin panels, providing 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) and a wing area of 279 sq ft (25.9 m2).
It had a small amount of inverted gull wing bend, with the inner sections having a 1° anhedral and the outer sections, attached just outboard of the undercarriage legs, having 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 was structurally robust, with ample space for fuel tanks and heavy armaments while allowing the aircraft to be a steady gun platform.
Each of the inner wings had two fuel tanks, with the “main” tanks having a capacity of 40 gallons and the “nose” tanks, built into the wing leading edges, forward of the main spar, having a capacity of 37 gallons each.
The inner wings also had inward-retracting landing gear with a wide track of 13 ft 6+3⁄4 in.
The new design’s wing was very “thick” by contemporary standards, similar to the Hurricane before it, and although the Typhoon was expected to reach over 400 mph (640 km/h) in level flight at 20,000 ft, the thick wings created a significant drag rise, limiting speeds to 410 mph at 20,000 feet (6,100 m) in tests.
The climb rate and performance above that level were considered disappointing.
When the Typhoon was dived at speeds over 500 mph (800 km/h), the drag rise caused buffeting and trim changes.
These compressibility issues led to Camm designing the Typhoon II, later known as the Tempest, which incorporated 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