Dornier Do 335

Do 335 Pfeil
The only surviving Do 335 (VG+PH) at the Steven F. Udvar-Hazy Center at Washington, D.C.'s Dulles Airport
Role	Fighter-bomber
Manufacturer	Dornier Flugzeugwerke
First flight	26 October 1943
Introduction	1944
Retired	1945
Status	Retired
Primary user	Luftwaffe
Produced	1944–1945
Number built	37

The Dornier Do 335 Pfeil ("Arrow") was a World War II heavy fighter built by the Dornier company. The two-seater trainer version was also called Ameisenbär ("anteater"). The Pfeil's performance was much better than other twin-engine designs due to its unique "push-pull" layout and the much lower aerodynamic drag of the in-line alignment of the two engines. It was 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.

...
Wikipedia