[7] In May 1932 he was appointed personal assistant to the managing director, Robert Bruce, a position previously held by Petter's friend and colleague Harald Penrose.

[6] His father appointed Petter to the board in May 1934, making him technical director (at the age of 26) in preference over more experienced engineers such as Arthur Davenport and Geoffrey Hill.

In July 1935 Ernest Petter convened a shareholders meeting to propose a merger with British Marine Aircraft for the purpose of expanding Westland's workshops.

[12] The Air Ministry was initially reluctant to award Westland contracts due to Petter's inexperience, but his reputation as a successful designer was strengthened after it was demonstrated that the automatic slats on the PV 7 were both effective and reliable.

As a result, and after internal discussion, the Air Ministry added Westland to the list of bidders for Specification A.39/34 (the replacement for the Hawker Hector army co-operation aircraft).

[14] Based on this information, he placed pilot visibility, the ability to take off and land in small spaces, and ease of ground maintenance as the prime requirements.

[18] Later, when these problems had been addressed by a larger, variable-incidence tailplane, it was realised that if a landing was aborted and the throttle opened up fully, the Lysander could rear up and stall.

It was designed to meet Air Ministry specification F.37/35, which called for a single-seat cannon-armed fighter, at least 40 mph faster than a contemporary bomber and not less than 330 mph at 15,000 ft.[22] To obtain this performance Petter and Davenport chose to minimise drag; the two Rolls-Royce Peregrine engines were fitted in closely streamlined nacelles, and their radiators were fitted inside the wing inboard sections (something that would be later copied in the de Havilland Mosquito and the Hawker Tempest I).

[citation needed] The prototype first flew in September 1938, and while it was one of the fastest and most heavily armed fighters of its era, faster than the Spitfire Mk 1, its development was problematic and protracted.

In November 1940, he wrote a memo to Sholto Douglas stating "The Whirlwind is probably the most radically new aeroplane which has ever gone into service... New ideas I am afraid, even with the greatest care, always mean a certain amount of teething trouble...

[27] Shortly after this exchange 263 squadron became operational, but Petter always regretted that the Whirlwind was not available for the Battle of Britain and blamed Eric Mensforth for the delay in production.

[30] One of the problems with the early marks of Spitfire was variability of longitudinal stability, leading to aircraft getting dangerously out of control and contributing to the risk of structural failure .

[36][d] During test flying the effect of compressibility was experienced by Penrose who wrote, "In speed runs at the ceiling the wings and fuselage sometimes shook as though the machine was bumping over cobblestones."

[39] Penrose said later that "At this time Petter's intellect put him ahead of most contemporary designers as shown by his introduction of pressurization and extensive use of remote electrical controls which subsequently became standard practice.

By the time of the Welkin he had learnt the lesson that it takes as long to develop an aeroplane as to design it... [40] Petter was an outstanding organiser and could envisage construction time-scales with greater knowledge than Fearn and Wheeldon.

"[41] Westland's successful manufacture of Spitfires meant that Petter was well thought of by Sir Wilfrid Freeman, chief executive officer at the Ministry of Aircraft Production (MAP) and by N. E. Rowe, its director of technical development.

[44] Also, to avoid the delays in production of the bomber he wanted Mensforth to give him full powers of a chief engineer responsible for every department concerned with its construction.

[55] Of this time at Warton, Beamont said "although Petter was generally thought to be difficult I found him logical and 'ahead of the game' and totally oriented on making an enormous success of the Canberra.

To achieve a small frontal area and reduce wave drag it had two Rolls-Royce Derwent engines mounted one above the other in the fuselage, echoing his earlier Westland P13 proposal.

[64] On 29 March 1949 MoS granted approval for English Electric to start the detailed design, develop wind tunnel models and build a full-size mockup.

Modifications to the Canberra to incorporate a bomb aimer, camera bays and dual seat for the navigation trainer required a redesign of the front fuselage, which caused disruption in the design office and the workshops.

[67] In addition, with the P.1A Lightning design programme ramping up, Petter demanded a separate administration for Warton and an experimental workshop under his control as a condition of his continued service with English Electric.

[74] On 11 July 1951 a delegation from the RAF visited Petter to discuss the requirements for a lightweight interceptor to counter the threat of escorted Russian Tupolev Tu-4 bombers (AST OR/303).

[76][77] With concept design work on the light fighter ramping up, Petter decided not to proceed with the Red Dean and the MoS cancelled the contract in November 1951.

[78] Petter sent a brochure describing the Fo.140 to the Air Staff in January 1952, but beyond this, further development of the light fighters was hindered by the lack of engines with a high thrust-to-weight ratio.

In common with his previous designs, Petter made use of magnesium alloys in the structure, using material surplus from the RTV2 Missile programme in the construction of the Midge prototype.

[83] Colonel Johnnie Driscoll, head of the NATO Mutual Weapons Development Program noted Petter's light fighter concept.

[91] However at the same time the Macmillan government was rationalising the aircraft industry and made the order for Gnat Trainers conditional on Folland merging with the Hawker Siddeley group.

It was during a stay at the McCowan family farm that Petter met his future wife Claude, the daughter of Louis Munier a Swiss official at the League of Nations in Geneva.

"[95] ‌Five years earlier, Claude had been introduced to a 'Father Forget', a former minister of the Reformed Church of France who claimed to be able to cure her Parkinson's disease through communal prayer.