Their attraction lay in the limitations of propeller-driven aircraft above 450mph (722.4kph). Whittle formed Power Jets Ltd in 1936, tried to interest Armstrong-Siddeley but met with skepticism, and it was not until BTH (British Thomson-Houston) agreed to produce his drawings for the Whittle Unit (WU) 1, that he made progress.
The resulting experimental power unit still made formidable demands on the available metallurgy. Heat and stress in the combustion chambers were twenty-five times what existing materials could cope with, yet an engine was built and ran on 12 April 1937. Despite his first engine running out of control and threatening to blow the test house to pieces, Whittle persevered, and in December 1940 the Air Ministry paid for an improved W.1X. This was followed by a contract for a practical flight engine, the W.1, which first ran in April 1941, and flew in the Gloster E28/39 aircraft from Cranwell on 15 May, with 850lb (385.6kg) of thrust at 16,500rpm. The engine weighed 623lb (282.6kg), and the aircraft’s maximum speed was about 338mph (543kph) in level flight.
Demand for production remained urgent and led to Rover making some of the world’s first aircraft jet engines. By late 1941 Rover, BTH, and Power Jets were building versions of the W.2 Mark 4 and the W.2B. A second Gloster aircraft, with a production Rover W.2B, inadvertently exceeded maximum revs, and attained an astonishing 466mph (748.1kph) probably the fastest speed of any aircraft up to that time.
Had it not been for the war a Rover engine might have gained the world’s absolute speed record. Complications with Whittle continued. The Wilks brothers and Rover engineer Adrian Lombard, later Rolls-Royce aero engines’ director of engineering, contributed more to the development of the engine than Whittle gave them credit for. However, the brittle relationship ruined any hope of Rover manufacturing jet engines. The inventor blamed Rover for delays, claiming it had failed to keep to its agreement not to re-design anything. Rover asserted that Whittle was obstructive, and promptly re-designed the W.2B into the W.2B/26, with straight through instead of reversed combustion chambers. The leading Rover engineers on the project were sworn to secrecy, literally over a Bible, and segregated in a private area converted from the directors’ dining room at the old Helen Street factory.
A guard was posted on the door, and only people directly connected were allowed in, even though most of the engineering work on the turbines continued at Lode Lane. Matters came to a head in November 1942, when Rolls-Royce engineer SG Hooker persuaded Lord Hives to intervene. Rolls-Royce was concerned at the difficulties between Whittle and Rover, which threatened to keep British jet aircraft out of the war.
It was worried about equipping the Royal Air Force with the best aircraft, although it was certainly eager not to be left out of new aero engine development. Rolls-Royce was committed to piston engines. Its work on turbofans and turboprops in its Derby experimental shops had been disappointing. Hives were keen to gain a share of the jet work and set up staff at Derby to build a W.1. Rolls-Royce got on better with Whittle, and when Hives and Hooker met managing director Spencer Wilks, for a wartime dinner at the Swan & Royal in Clitheroe, Hives suggested that jet engines were not in Rover’s line.