The Hawker P.1072 was the designation given to the single P.1040 Sea Hawk prototype when it was given an auxiliary rocket engine in an attempt to improve its take-off performance. Early trials with the Sea Hawk had showed that it was a promising naval fighter, but that its high take-off speed was a limitation when operation from fighters. Standard Rocket Assisted Take-Off gear could be used, but an alternative solution was to fit a rocket engine into the tail of the aircraft.
Hawkers had carried out some work on this idea in 1947, and it was suggested that a new P.1040 prototype should be built to test it out. Nothing was done about this idea, and so when the existing P.1040 (VP401) completed its part in the flight test programme it was decided to use that aircraft instead. After winning the SBAC Challenge Cup on 1 August 1949 with the Hawker test pilot T. S. Wade at the controls VP401 was returned to Hawkers, but a series of problems then delayed progress, and the rocket engine was not installed until June 1950.
The rocket chosen was the Armstrong Siddeley Snarler liquid-fuel rocket. This was mounted in the lower part of the rear fuselage, with the rocket nozzle below the rudder. The wings were reinforced to carry the extra weight, the rudder was modified to maintain its size despite the bottom being cut out, and a large bullet fairing replaced the acorn at the junction of the tail plane and rudder. Jet fuel was reduced to 120 gallons while the rocket carried enough fuel for a 2min 45sec burn.
The P.1072 made its maiden flight on 20 November 1950, making it the first British high-performance manned rocket-powered aircraft to fly, the first British mixed-power prototype to fly, and rather surprisingly Hawker's first twin engined aircraft to take to the air! A total of six flights were carried out between November and January 1951, but on the last trip a minor explosion in a pressure gauge transmitter caused damage to the fairings around the rocket. The aircraft was repaired, but never flew again.
The test flights had mixed results. On the positive side the rate of climb was impressive, and it was calculated that the aircraft could have reached 50,000ft in 3.5 minutes. On the negative side that would have placed the unpressurised aircraft 10,000ft above its safe operating ceiling. The most significant problem was that the rocket was uncontrolled. Once fired, it quickly accelerated the aircraft towards its Mach limits, inducing buffet. The only way to lose this speed was to pull into a climb, which quickly brought the aircraft up to 40,000ft. The project was abandoned in favour of work into jet reheat.