The Hawker P.1040 was the direct precursor to the Hawker Sea Hawk, and the single aircraft built acted as an unarmed, un-navalised prototype for the later fighter. The P.1040 evolved from the P.1035, which was a design for a jet-powered version of the Hawker Fury. This earlier design had retained the elliptical wings of the Fury, but had moved the cockpit to the front of the fuselage. The jet engine was to be mounted behind the cockpit, with the air intakes on the side of the fuselage and a single exhaust pipe below the rudder.
The P.1035 was submitted to the Air Ministry in November 1944. Work on improving the design was carried out in November and December, and on 22 December the first drawings of the P.1040 were completed. In the intervening period Hawkers had designed a bifurcated exhaust pipe that allowed the tail pipes to emerge on either side of the fuselage, just behind the wing roots. This meant that the thickness of the wing had to be increased near the fuselage, allowing the air intakes to be moved from the sides of the fuselage to the front wing roots. The P.1040 also had a clearer fuselage than the P.1035, and the elliptical wings of the Fury and P.1035 were replaced with straight edged tapering wings. A nose wheel undercarriage was also adopted. The altered air intakes and exhaust pipes also allowed fuel tanks to be installed in front and behind the engine, giving the P.1040 longer range than the Meteor, and possibly saving the entire project.
By October 1945 Hawkers were ready to build a prototype, and the company issued a Production Order to its Experimental Department, but early in 1946 the company received bad news when the Air Staff announced that it was no longer interested in the type. Fortunately the Naval Staff retained their interest, and on 21 February 1946 placed an order for three P.1040 general purpose and long range naval fighter and strike support aircraft. The first of these would be built as the P.1040 (serial number VP401), without guns and folding wings, while the second and third would become the navalised N.7/46.
Specification N.7/46 was issued, to Operational Requirement OR.218. This called for an aircraft that would reach its highest speeds under 15,000ft, with a strike radius of 400 nautical miles, a normal all-up weight of 14,000lb, and armed with four 20mm cannon but with the possibility to use two 30mm cannon instead. At about the same time Hawkers also received a contract to build a single swept-winged version of the aircraft, the P.1052, an aircraft that eventually led to the Hawker Hunter.
Progress on the P.1040 was slower than the Naval Staff had originally ordered. In June 1946 Hawkers were told that the prototype should be ready to fly by February 1947, but at that date they hadn’t even received the first Nene flight engine, which only arrived on 14 April 1947. Like many aspects of British life work on the P.1040 was affected by the harsh winter of 1947 and the crisis that followed, but work speed up during the year. The Nene engine was installed in June, but the first engine run showed up some problems with the bifurcated exhaust pipes. Taxing trials were carried out while the pipes were being modified. On 18 August they were returned from Rolls Royce, and the aircraft was moved to Boscombe Down. Finally, on 2 September 1947, with Bill Humble at the controls the P.1040 made its maiden flight.
The early trials revealed some minor problems. Lt. Cdr Eric Brown, a more experienced jet pilot, was called in to investigate. He found problems with vibration and snaking when engine revolutions were changed and a violent shaking during high speed dives at 10 degrees (but not in steeper dives). These problems were solved by installing leading edge mass balanced elevators on the wings and an acorn fairing at the junction of the fin and tail plane, and by April 1948 the aircraft was flying well. The excellent visibility from the cockpit made a particularly favourable impression, and the aircraft was considered to be ideal for deck landings. By 1949 VP401 had completed its role in the flight test programme, and so it was returned to Hawkers to be given an auxiliary rocket engine, under the new designation of Hawker P.1072. More extensive trials were carried out using the two N.7/46 prototypes, before the aircraft entered service as the Sea Hawk.
Engine: Rolls-Royce Nene RN.1
Power: 4,500lb static thrust
Wing span: 36ft 6in
Length: 37ft 7in
Empty Weight: 8,660lb
Max Overload Weight: 11,200lb
Max Speed at Sea Level: 522kts
Max Mach Number in level flight: 0.815
Max Mach Number in dive: 0.835
Service Ceiling: 43,500ft
Absolute Ceiling: 47,500ft
Endurance: 2hrs 18mins