Intended as a heavy, high-speed fighter/bomber, Dornier's Do335 Pfeil (Arrow) was a radical design by the standards of its day. Despite this, relatively few complications were experienced during development. Claudius Dornier had worked on the tandem engine installation since the late 1930s and the extension shaft and pusher propeller, which could have been awkward, gave few problems.
The only real cause for concern involved baling out. To solve this an ejection seat was to be fitted as standard. To further improve the pilot's chances of escape, the rear propeller and dorsal fin would be jettisoned before ejection by explosive bolts. In the event of a wheels-up landing the ventral fin could also be jettisoned.
After modifications to cure tail buffeting experienced during initial flight tests, the Do335's handling was considered to be good, in part aided by a hydraulic-boosted flight-control system. It was also possible to fly the aircraft on one engine, with the best performance obtained in the "pusher" mode. By the war's end 37 had been built, including two B-series aircraft (with increased armament), together with over 70 partially completed airframes.
The UK's Royal Aircraft Establishment (RAE) at Farnborough identified three Do335 airframes for testing during 1945, an A-1, an A-12 and an incomplete B-series airframe. Only the A-12 and B made it to the UK, following the A-1's landing accident at Merville, France. At Farnborough the A-12 was test flown only three times before crashing in January 1946, killing the test pilot.
Initial test flights had been undertaken by the renowned Capt Eric "Winkle" Brown in his role as head of the Aerodynamics Flight and Royal Navy chief test pilot at the RAE. As with all Luftwaffe aircraft, the Do 335's brakes were unreliable, prone to overheating and sometimes caught fire, says Brown, but this was in part compensated for by the reversible-pitch tractor propeller, which could reduce the landing distance by 183m (600ft).
The aircraft was less responsive at low speeds, but at high speeds the controls were well harmonised and effective. "The 335 had good stability, and the powered ailerons weren't as fidgety as many of its Allied counterparts," says Brown. Despite this, for an aircraft of it size the Do335 would not have been a match "out in the open" for the late-war Allied fighters, he says, but "if it had been restricted to an all-weather and night-fighter role, it would have given a good account of itself".
A top speed in the region of 410kt (760km/h) was always going to be the Do335's main advantage, "and while it would not of outfought the Mustang or Spitfire, they would have had to work hard to nail it", says Brown.
Source: Flight International