From Wikipedia"
The Dornier Do 335 Pfeil ("Arrow") was a World War II heavy fighter built by the Dornier company. The two-seater trainer version was called Ameisenbär ("anteater"). The Pfeil's performance was much better than other twin-engine designs due to its unique push-pull configuration and the lower aerodynamic drag of the in-line alignment of the two engines. It was Nazi Germany's fastest piston-engined aircraft of World War II. The Luftwaffe was desperate to get the design into operational use, but delays in engine deliveries meant that only a handful were delivered before the war ended.
The origins of the Do 335 trace back to World War I when Claude Dornier designed a number of flying boats featuring remotely driven propellers and later, due to problems with the drive shafts, tandem engines. Tandem engines were used on most of the multi-engine Dornier flying boats that followed, including the highly successful Do J Wal and the gigantic Do X. The remote propeller drive, intended to eliminate parasitic drag from the engine entirely, was tried in the innovative but unsuccessful Do 14, and elongated, tubular drive shafts as later used in the Do 335 saw use in the rear engines of the four-engined, twinned tandem-layout Do 26 flying boat.
There are many advantages to this design over the more traditional system of placing one engine on each wing, the most important being power from two engines with the frontal area (and thus drag) of a single-engine design, allowing for higher performance. It also keeps the weight of the twin powerplants near, or on, the aircraft centerline, increasing the roll rate compared to a traditional twin. In addition, a single engine failure does not lead to asymmetric thrust, and in normal flight there is no net torque, so the plane is easy to handle. The choice of a full "four-surface" set of cruciform tail surfaces in the Do 335's rear fuselage design, included a ventral vertical fin–rudder assembly to project downwards from the extreme rear of the fuselage, in order to protect the rear propeller from an accidental ground strike on takeoff. The presence of the rear pusher propeller also mandated the provision for an ejection seat for safe escape from a damaged aircraft, and designing the rear propeller and dorsal fin mounts to use explosive bolts to jettison them before an ejection was attempted — as well as twin canopy jettison levers, one per side located to either side of the forward cockpit interior just below the sills of the five-panel windscreen's sides, to jettison the canopy from atop the cockpit before ejection.
In 1939, Dornier was busy working on the P.59 high-speed bomber project, which featured the tandem engine layout. In 1940, he commissioned a test aircraft, closely modeled on the airframe of the early versions of the Dornier Do 17 bomber but only 40% of the size of the larger bomber, with no aerodynamic bodies of any sort on the wing panels (the original Do 17 had twin engine nacelles on its wings) and fitted with a retractable tricycle landing gear to validate his concept for turning the rear pusher propeller with an engine located far away from it and using a long tubular driveshaft. This aircraft, the Göppingen Gö 9, showed no unforeseen difficulties with this arrangement, but work on the P.59 was stopped in early 1940 when Hermann Göring[citation needed] ordered the cancellation of all projects that would not be completed within a year or so.
In May 1942, Dornier submitted an updated version with a 1,000 kg (2,200 lb) bombload as the P.231, in response to a requirement for a single seat, Schnellbomber-like high-speed bomber/intruder. P.231 was selected as the winner after beating rival designs from Arado, Junkers, and Blohm & Voss development contract was awarded as the Do 335. In autumn 1942, Dornier was told that the Do 335 was no longer required, and instead a multi-role fighter based on the same general layout would be accepted. This delayed the prototype delivery as it was modified for the new role.
On 23 May 1944, Hitler, as part of the developing Jägernotprogramm directive, which took effect on 3 July, ordered maximum priority to be given to Do 335 production. The main production line was intended to be at Manzell, but a bombing raid in March destroyed the tooling and forced Dornier to set up a new line at Oberpfaffenhofen. The decision was made, along with the rapid shut-down of many other military aircraft development programs, to cancel the Heinkel He 219 night fighter, which also used the DB 603 engines, and use its production facilities for the Do 335 as well. However, Ernst Heinkel managed to delay, and eventually ignore, its implementation, continuing to produce examples of the He 219A.
At least 16 prototype Do 335s were known to have flown (V1–V12, W.Nr 230001-230012 and Muster-series prototypes M13–M17, W.Nr 230013-230017) on a number of DB603 engine subtypes including the DB 603A, A-2, G-0, E and E-1. The first preproduction Do 335 (A-0s) starting with W.Nr 240101, Stammkennzeichen VG+PG, were delivered in July 1944. Approximately 22 preproduction aircraft were thought to have been completed and flown before the end of the war, including approximately 11 A-0s converted to A-11s for training purposes. One such aircraft was transferred to the Royal Aircraft Establishment in Farnborough, and later, after a rear-engine fire burnt through the elevator controls during a flight, crashed onto a local school.
The first 10 Do 335 A-0s were delivered for testing in May. By late 1944, the Do 335 A-1 was on the production line. It was similar to the A-0 but with the uprated DB 603 E-1 engines and two underwing hardpoints for additional bombs, drop tanks or guns. It had a maximum speed of 763 km/h (474 mph) at 6 500 m (21 300 ft) with MW 50 boost, or 686 km/h (426 mph) without boost, and climbed to 8 000 m (26 250 ft) in under 15 minutes. Even with one engine out, it reached about 563 km/h (350 mph).
Delivery commenced in January 1945. When the United States Army overran the Oberpfaffenhofen factory in late April 1945, only 11 Do 335 A-1 single-seat fighter-bombers and two Do 335 A-12 trainers had been completed.
French ace Pierre Clostermann claimed the first Allied combat encounter with a Pfeil in April 1945. He describes leading a flight of four Hawker Tempests from No. 3 Squadron RAF over northern Germany, when he intercepted a lone Do 335 flying at maximum speed at treetop level. Detecting the British aircraft, the German pilot reversed course to evade. Despite the Tempests' considerable low altitude speed, the Royal Air Force fighters were not able to catch up or even get into firing position.
Only one Do 335 survives, the second preproduction Do 335 A-0, designated A-02, with construction number (Werknummer) 240 102, and factory radio code registration, or Stammkennzeichen, of VG+PH. The aircraft was assembled at the Dornier plant in Oberpfaffenhofen, Bavaria on 16 April 1945. It was captured by Allied forces at the plant on 22 April 1945. VG+PH was one of two Do 335s to be shipped to the United States aboard the Royal Navy escort carrier HMS Reaper, along with other captured German aircraft, to be used for testing and evaluation under a USAAF program called "Operation Lusty". One Do 335 (registration FE-1012) went to the USAAF and was tested in early 1946 at Freeman Field, Indiana, USA. Its fate is not recorded.
VG+PH went to the Navy for evaluation and was sent to the Test and Evaluation Center, Patuxent River Naval Air Station, Maryland, USA. Following testing from 1945 to 1948, the aircraft languished in outside storage at Naval Air Station Norfolk. In 1961, it was donated to the Smithsonian's National Air Museum, though it remained in deteriorating condition at Norfolk for several more years before being moved to the National Air and Space Museum's storage facility in Suitland, Maryland. In October 1974, VG+PH was returned to the Dornier plant in Oberpfaffenhofen, Germany (then building the Alpha Jet) for a complete restoration. In 1975, the aircraft was restored by Dornier employees, many of whom had worked on the airplane originally. They were surprised that the explosive charges built into the aircraft to blow off the dorsal fin and rear propeller prior to pilot ejection were still installed and active 30 years later.[citation needed]
Following restoration the completed Do 335 was displayed at the Hannover, Germany Airshow from 1 May to 9 May 1976. After the air show, the aircraft was loaned to the Deutsches Museum in Munich, where it was on display until 1988, when it was shipped back to Silver Hill, Maryland. VG+PH can be seen today in the Steven F. Udvar-Hazy Center of the National Air and Space Museum alongside other unique late-war German aircraft, such as the only known example of the Arado Ar 234 B-2 Blitz jet reconnaissance-bomber, and the fully restored fuselage and tail surfaces of the only complete surviving Heinkel He 219A Uhu (Eagle-Owl) night fighter (the wings and engines/nacelles are still undergoing restoration).
Looks great and yet again another lesson for me. Possibly lucky this was delayed because of the engines it may have changed history?
ReplyDeleteIndeed - If this aircraft and the Me 262 had gone into full scale production who knows what would have happened.
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