Group Captain Arthur H. Donaldson, DSO, DFC, AFC, RAF, Ret.
The design of the Whirlwind started in 1935 in response to Air Ministry Specification F .37135 under the direction of W.E. Petter, Chief Designer for the Westland Aeroplane Company (Mr. Petter also designed the Canberra Bomber, the Lighting Fighter, currently RAF Fighter Command's front line defense, and the Folland Gnat, the RAF's present trainer), The low wing, twin engine monoplane was of all metal construction with stressed-skin covering. It was just over 32 ft. in overall length and had a wing span of 45 ft. Overall empty aircraft weight was 8300 lbs, while the loaded weight varied between 10,000 and 11,000 lbs, depending on the mission and weapon stores carried.
Test flown in October 1938, the first orders from the Air Ministry were placed for 200 Whirlwinds in January 1939. It entered RAF service in June 1940 when the initial deliveries were made to 25 Squadron at North Weald, but these planes were shortly after reassigned to 263 Squadron at Drem. Due to production delays of the engines, full squadron strength was not reached until early 1941. Although basically designed as an interceptor fighter, the Whirlwind arrived in service at the same time as the later modified versions of the Supermarine Spitfire. As an interceptor fighter, its performance was very similar to the Spitfire, though it could not quite reach the same altitude, and having twin engines it could not compete with the Spitfire from an economic standpoint. However, the Whirlwind had one vital asset which, at that time, no other aircraft possessed; its armament consisted of no less than four 20rnm cannons fixed in its nose and firing forward. This armament was superior to any other aircraft in the fighter role (the Hurricane and Spitfire started with 303 caliber guns, though the later Spitfire had two 20mm cannons fitted). In addition, the Whirlwind could carry two 500 lb bombs under the wings. Thus, the Air Ministry realized that its true value was as a Ground Attack Fighter or Fighter Bomber.
The Whirlwind had excellent one-engine performance, though it was a little handicapped in this respect in that each engine had its own fuel supply system so that in the event of engine failure, it was impossible to use the fuel from the tank of the dead engine on the remaining live engine. It was a very robust aircraft. On one occasion I was shot up by ground flak, 40mm Bofors type. My helmet was torn from my head and I received head injuries; the cockpit canopy was smashed and there were over 100 holes in the aircraft, yet it brought me safely home across 120 miles of sea, although I had to land with my undercarriage up because it was too damaged to let down.
The speed of the Whirlwind was similar to the Spitfire and the Luftwaffe's Fw 190. It was certainly as maneuverable as the 190, and probably more so. I can remember being attacked from the rear by a Fw 190, which I had no difficulty in shaking off by turning steeply. Another advantage enjoyed by the Whirlwind over most other fighters were the slats fitting to the leading edge of both wings. These came out at slow speeds thus increasing the lift and reducing the stalling speed. The aircraft was therefore able to land in a much shorter space than most fighter aircraft of that period. The obvious advantage in a dog fight was that as soon as one pulled back hard on the stick, the slats came out and one could tighten the offensive or evasive turn even more.
The Whirlwind had two Rolls-Royce Peregrine 12-cylinder liquid-cooled engines, each developing 850 hp. Westland could have fitted a more powerful engine and improved the performance of the Whirlwind, but by then the jet engine had been invented and the Gloster Meteor fighter was entering service, so that the cost was considered prohibitive. All in all, I can honestly say that I consider the Whirlwind to be the finest plane I have flown, and I must have flown over 100 different types, both British and American. The Spitfire was nicer in some respects, but the fact that the Whirlwind had two engines made one feel very safe, especially when one had been hit over enemy territory.