The Do-335 was one of a small group of aircraft marking the pinnacle of international piston-engined development. It was the fastest production piston-engined fighter ever built, attaining 846 kilometers per hour (474 mph) in level flight at a time when the official world speed record was 755 kph (469 mph). Powered by two 1800-hp engines in a unique low-drag configuration and weighing 9600 kg (21,000 lb) loaded, it was an exceptional heavy fighter. This very innovative design also featured an ejection seat, for pilot safety, and a jettisoning fin.
The unconventional layout of the Do-335 -- one engine "pulling" in the nose and another "pushing" in the tail - was patented by Claudius Dornier in 1937. The configuration provided the power of two engines, but with reduced drag and better maneuverability. The German Aviation Ministry (RLM) was interested in the design, but initially wanted Dornier only to produce bombers. By 1942, Dornier was still continuing design work and the war situation was worsening. The Luftwaffe now needed a multi-purpose fighter, and the prototype Do-335V-1 ("V" indicating "versuchs" or "experimental") flew in fighter form in September, 1943 - six years after its conception. Orders were immediately placed for 14 prototypes, 10 A-0 preproduction aircraft, 11 production A-1 single-seaters, and 3 A-10 and A-12 two-seat trainers.
The aircraft was quite large for a single-seat fighter, with a cruciform tail and a tricycle landing gear. The two massive liquid-cooled Daimler-Benz DB-603 engines were used in four different versions, each displacing 44.5 liters (2670 cu in) and weighing 910 kg (2006 lb). The engine produced 1750 hp from 12 cylinders in an inverted V layout using fuel injection and an 8.3:1 compression ratio. The rear three-bladed propeller and dorsal fin were jettisoned by explosive bolts in an emergency, to allow the pilot to bail out safely using a pneumatic ejection seat. The seat, inclined 13 degrees to the rear, was ejected with a force of 20 times gravity. The ventral fin could be jettisoned for a belly landing.
Unlike a normal twin-engined aircraft, with wing-mounted engines, loss of an engine on the Do-335 did not cause a handling problem. Even with one engine out, speed was a respectable 621 kph (348 mph). Because of its appearance, pilots dubbed it the "Ant eater" ("Ameisenbar"), although they described its performance as exceptional, particularly in acceleration and turning radius. The Do-335 was very docile in flight and had no dangerous spin characteristics. Many Do-335 prototypes were built, as the Reich strained desperately to provide day and night fighters and fast reconnaissance aircraft to the failing war effort. One of the many RLM production plans, issued in December 1943, called for the production of 310 Do-335s by late 1945. Initial production was at the Dornier Manuel plant, but this factory was bombed heavily in March-April, 1944, and the Do-335 tooling was destroyed.
Ten Do-335A-0 preproduction aircraft were then produced at Dornier's Oberpfaffenhofen plant in July-October 1944, by which time the Allied bombing campaign was delaying arrivals of engines, propellers, radios, and structural subcomponents. This had a serious effect, because the Do-335 was not a simple aircraft: installation of the electronics alone took 60 hours of assembly, and the electrical parts list was 112 pages long. Production of Daimler-Benz engines, for example, was switched to factories set up in underground salt mines and gypsum mines, but high humidity caused corrosion problems and production dropped 40 percent. Although several preproduction aircraft were issued to combat conversion units some 10 months before the war ended, no Do-335s actually entered combat. Deliveries began to the 1st Experimental Squadron of the Commander-in-Chief of the Luftwaffe ( I/Versuchsverband Ob.d.L.) in late July 1944 for operational trials.
The first of the Do-335A-1 production version left the Dornier line at Friedrichshafen early in 1945, one of only four produced in 1945. It was armed with one 30 mm MK-103 cannon (70 rounds were carried) firing through the propeller hub and two 15 mm MG-151/15 cannon (200 rounds per gun) firing from the top of the forward engine. Even with the fighter situation as desperate as it was, these aircraft were still equipped to carry 500 kg (1100 lb) of bombs internally. Further operational testing, including use of air-to-ground guided missiles, began in Spring 1945 with Trials Unit (Erprobungskommando) 335.
The Do-335A-6 was to be a two-seat night fighter version with the advanced FFO FuG-217J Neptun radar having triple "trident"-like antennas (hence the name "Neptun") on the fuselage and wings, but only a prototype was completed. A total of 37 prototypes, 10 A-0s, 11 A-1s and 2 A-12 trainers were built, although nearly 85 additional aircraft were in assembly when U.S. troops overran the Friedrichshafen factory in late April, 1945. The Vienna-Swechat plant of the Ernst Heinkel AG was also scheduled to build the Do-335 beginning in February, 1945, but production never started.
The NASM aircraft is the second Do-335A-0, designated A-02, with construction number (werke nummer) 240102 and factory registration VG+PH. It was built at Dornier's Rechlin-Oberpfaffenhofen, Germany, plant on April 16, 1945. It was captured by Allied forces at the plant on April 22, 1945. After checkout, it was flown from a grass runway at Oberweisenfeld, near Munich, to Cherbourg, France. During this flight, the Do-335 easily outclimbed and outdistanced two escorting P-51s, beating them to Cherbourg by 45 minutes. Under the U.S. Army Air Force's "Project Sea Horse," two Do-335s were shipped to the United States aboard the Royal Navy ship HMS "Reaper" together with other captured German aircraft, for detailed evaluation. This aircraft was assigned to the U.S. Navy, which tested it at the Test and Evaluation Center, Patuxent River Naval Air Station, Maryland. The other aircraft, with registration FE-1012 (later T2-1012), went to the USAAF at Freeman Field, Indiana, where it was tested in early 1946. Its subsequent fate is unknown, and this is the only Do-335 known to exist.
Following Navy flight tests in 1945-48, the aircraft was donated to the Smithsonian's National Air Museum in 1961 but was stored at NAS Norfolk until 1974. It was then returned to Oberpfaffenhofen, Germany, where the Dornier company restored it to original condition in 1975. The return trip to Germany required an exemption under U.S. laws concerning the export of munitions. The Dornier craftsmen doing the restoration - many of whom had worked on the original aircraft -- were astonished to find that the explosive charges fitted to blow off the tail fin and rear propeller in an emergency were still in the aircraft and active, 30 years after their original installation! The Do-335 was put on static display at the May 1-9, 1976, Hannover Airshow, and then loaned to the Deutsches Museum in Munich, where it was on prominent display until returned to Silver Hill, MD, for storage in 1986.
http://airandspace.si.edu/collections/artifact.cfm?id=A19610129000man that thing must have been fun to fly
