The WWII German Dornier Do-335 Pfeil (Do-335 Pfeil)
Hitler, from the time he came to power to the end of World War II, used to pin the hopes of the Third Reich on all kinds of "secret weapons", but most of them were just fleeting, adding to the archaeological interest of future generations. However, most of these weapons were only fleeting, adding to the archaeological interest of future generations, such as the one that missed its target - the Dornier Do 335.
< p>Since the Wright Brothers realized the dream of human flight, every aircraft designer has been racking their brains in pursuit of higher speeds, a natural approach is to increase the number of engines to provide more powerful power, however, according to the conventional will be more than one engine installed in a horizontal arrangement, there will undoubtedly also be an expansion of the overall area of the aircraft windward area, the increase in the resistance is not to be underestimated. In addition, if one side of the engine fails, the balance of the flight will be adversely affected. Then consider another point of view, if the longitudinal front and rear configuration of the engine, along the fuselage axis of the power transmission, so that the aircraft can be single-engine aerodynamic shape to utilize the power of the twin-engine, will not be able to overcome these shortcomings?Before and after World War I, Germany's Claude Dornier designed a series of seaplanes along these lines, with the two engines back-to-back in a pull-forward, push-back drive format, the Do 15 seaplane of 1922 being a successful example, and the even better Do 18 in 1935. But the high, protruding engine compartment was obviously not enough to meet the drag reduction requirements of high-altitude aircraft, so Dornier thought of integrating the power assembly with the fuselage to achieve truly high speeds, and in August 1937 he filed patent No. 7,280,044 specifically for this idea.
When World War II broke out, Dornier was busy developing a new bomber, and one of the projects, P.231, was to set up an engine in the nose to drive the pulling propeller in the conventional way, and a second engine in the rear fuselage to drive the propeller at the rear, with the key to the technology lying in the way the rear engine was driven to the propeller. For feasibility testing, a G.ppingen G.9 was built in 1940, with a slender fuselage equivalent to a 1/2.5 Do 17, a 60 kW Hirth HM 60R engine in the center of gravity, and a specially designed extended propeller shaft in the rear fuselage, which drove the propeller through the tail. The successful test flights of the G? 9 proved the effectiveness and reliability of this rear-mounted propulsion system and drive train assembly.
In 1942, when the German Air Ministry (RLM) requested a single-seat, high-speed bomber, Dornier submitted a revised P.231/3 proposal for bidding in May, and won the contract for the RLM Do 335, beating out two strong rivals, Arado and Junkers. However, it was a mixed bag, and just as the design was getting underway, the growing Allied air threat made the bomber an anachronism, and the Air Ministry directed that the development be directed towards a multi-purpose aircraft capable of adapting to a wide range of operational requirements, with the flexibility to be converted into a fighter-bomber, high-speed reconnaissance, two-seat night-type, and a heavily armored interceptor. Although the Do 335 was quickly developed, the technical department of the Air Ministry, which had long been skeptical of this unconventional design, was reluctant to renew the contract, and Dornier turned directly to Air Marshal Erhard Milch, the director general of the Air Force, to push the design through to final completion.
In early 1943 Dornier received a contract to build three prototypes, but at this time jets were more desirable, and Messerschmitt's Me 262 was given a higher priority under Hitler's personal intervention, and although the Do 335 was in many ways no slouch, Milch's support for more prototypes was pushed back. The first prototype, Do 335 V1 (CP+UA serial number W.Nr 230001), was completed at the Friedrichhafen factory in Dornier, and first flew off the ground from Mengen, Wurttemburg, on October 26, breaking the high speed limit of 600 km/h on its fourth flight. v1 was built using two 1,305-power engines. The V1 was powered by two 1,305 kW Daimler-Benz DB603A-2 12-cylinder, liquid-cooled engines driving three-bladed, counter-pitch propellers at the front and rear. The rear engine in the center of the fuselage drove the rear propeller via an extended driveshaft, and was equipped with a radiator and an exhaust pipe in the appropriate positions. Like the G-9, the Do 335 had a front three-point landing gear and a cross-shaped tail consisting of an upper and lower drogue and left and right flat tails, with a wingspan almost as long as the fuselage, giving it a rather stout profile. Another unusual feature was the then-rare use of ejection seats in the cockpit, powered by compressed air but requiring manual opening of the cockpit cover before use. To avoid possible injury to the pilot, these dangerous parts could be thrown away by detonating explosive bolts in the upper pitot tube and rear propeller, and the lower pitot tube could be thrown away in the event of an emergency belly-landing.
After passing initial tests, the V1 was shipped to the Luftwaffe's Rechlin Erprobungstelle for more extensive official evaluation. Although some longitudinal instability was noted at high speeds, the pilots involved in the tests gave positive reviews of the handling, maneuverability, and especially the acceleration and slewing characteristics, finding no major structural problems with the aircraft, and that such a twin-engine layout wasn't too difficult to master, it was only the poor rearward visibility and the lack of landing gear strength that became the focus of criticism. The Do 335 was named the "Pfeil" (Arrow) for its high speed performance, but the long nose and thick body made the pilots prefer to call it the "Ameisenbaer" (Ameisenbaer).
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Ameisenbaer
Ameisenbaer was the most popular of all the Anteaters.)
In the winter and spring of 1943-44, a number of prototypes were shipped for further testing at Oberpfaffenhofen. Minor improvements were made to V2 (CP+UB) and V3 (CP+UC), including repositioning of the fuel cooler vents, optimizing the shape of the cockpit cowling and adding mirrors, and redesigning the main landing gear hatch, while V4 (CP+UD) was planned as a prototype for the two-seat, all-weather, night-fighting Do 435, with the Junkers Jumo 222 engine at 1,865 kW and a longer wingspan. V5 (CP+UE) was the first prototype to be armed, with a 30mm MK103 cannon in the nose with 70 rounds of ammunition, the barrel of which passed through the rotor hub of the front propeller on the center axis, and two 15mm MG151 machine guns on the nose, each with 200 rounds of ammunition. V6 (CP+UF) and V7 (CP+UG) were mainly used for installation tests of various equipment, V7 was later shipped to Dessau for modification of the Jumo 213 engine, and V8 (CP+UH) became a test bed for the DB603E-1 engine in Stuttgart.
In view of the positive results of the test flights, in December 1943 the Ministry of Aviation drew up a production program for 310 Do 335s by the end of 1945, with the main production line based at Manzel, but Allied air raids in March-April the following year destroyed most of the equipment, forcing the Daunier to move back to the Oberpfaffenhofen to set up a new production line. By May, production of the Do 335 was accelerated by signs that the Allies might land in France at any time to launch a counter-offensive, and the V9 (CP+UI), a pre-production prototype of the A-0, still using the DB603A-2 engine, with a further reinforced landing gear and a complete weapons system, was also undergoing official testing at Rechlin. However, constant Allied bombing affected the availability of major components such as engines and the assembly of the Do 335 was complicated, so only 10 A-0 combat bombers rolled off the production line from July to October, partly equipped in the test flight unit EK335 (Erprobungskommando 335) for intensive testing and operational evaluation before official service.
In November 1944, the initial production Do 335A-1 entered production, with the engine upgraded to the 1,342-kilowatt DB603E-1, and in addition to internal belly bays for 500 kilograms of bombs, the wings were fitted with two additional hard mounting points, both of which could carry 250 kilograms of bombs or sub-tanks, and deliveries began in January 1945.
The Do 335A-1 was designed to fly at speeds of up to 1,000 kilograms with boost. The A-1 could fly at a speed of 763km/h with power and 685km/h without power, with a maximum climb rate of 1,400m/min and a combat radius of nearly 1,500km, which was good enough for the A-2 and A-3 to compete with the rest of the fleet at the time. The later A-2 and A-3 models were supposed to be improved to increase firepower, but this was not done. The Do 335A-0 was converted into the A-4 long-range reconnaissance prototype with an aerial camera and external fuel tanks, and the engine was replaced by the 1,417 kW DB603G. 10 A-4s were ordered, but none were ever built, and the A-6 two-seat night-fighter was based on the V10 (CP+UK) with the FuG 220, the "Bright Diamond" and the "Bright Diamond". "The A-6 two-seat night fighter, based on the V10 (CP+UK), was equipped with the FuG 220 Lichtenstein SN-2 radar in a vertical cockpit arrangement, with the radar operator positioned higher in the rear compartment. With the addition of the cockpit, crew and corresponding electronics, the internal fuel capacity was reduced, and overall performance was down about 10% from the single-seaters, while the armament remained the same as the single-seaters, with a flame arrestor on the exhaust to increase stealth in night combat. 218 Neptune radar did not materialize, and the final versions of the A-series, including the A-10 and A-12 two-seat trainers, were completed in very limited numbers.
By the winter of 1944-45, the sound of approaching artillery was already crashing relentlessly against the German gates, leaving the once-unbeatable Luftwaffe in a state of exhaustion. The deterioration of the war situation prompted Dornier to develop the Do 335 from an A-series fighter-bomber to a more powerful B-series heavy interceptor, the "destroyer", of which the V13 (RP+UA) was a prototype, with modified landing gear and DB603E-1/QE-1 engines front and rear. The V13 (RP+UA) was the prototype of the B-1, with a modified landing gear, DB603E-1/QE-1 engines in the front and rear, 1,566 kilowatts of power in a short period of time with a booster unit, two 15-mm machine guns converted to 20-mm cannons, and two 30-mm cannons on the wings of the B-2 (five guns in a row)! From the B-3 to the B-8, some were fitted with more powerful engines, and some were converted to two-seat night-fighter models, but most of them were just half-finished products on the production line up to the time of the defeat.
Lack of manpower and fuel prevented the Do 335 from being ready for combat, even though it had been partially deployed to combat-converted units as early as 10 months before the Armistice. The only "war stories" were a claim by an Allied pilot that he had encountered one of these "monster birds" on patrol and fired at it, but was able to get away at high speed, and a few Do 335s that were parked on the ground when the Allies took over an airfield and were shot at. By the time the U.S. Army took over the Dornier factory in late April 1945, fewer than 40 Do 335s of all types had been finalized, and the total number of unassembled units*** was only about 90 (exact numbers vary from source to source). There were also a number of derivatives that remained on the drawing board, including the Do 535 with mixed piston/jet engines, the twin-fuselage Do 635 long-range reconnaissance model, and the P.256 twin-engine jet model.
The destruction of the Nazis was followed by the division of the spoils by the victors, with two surviving Do 335A-0s and other Fw 190s, Me 262s, He 219s, and other "hardened" fighters flying in July 1945 as part of the U.S. Army's Operation Sea Horse. The two surviving Do 335A-0s and other Fw 190s, Me 262s, He 219s, and other "hardened" aircraft were loaded onto the escort carrier HMS Reaper for shipment back to the United States. Two other A-12s in good condition were flown directly to Farnborough, England, for research at the Royal Aeronautical Establishment (RAE), and the French also found two B-series prototypes for restoration and test flights (see "Testing the Enemy's Arrow"), but within a few years the remaining Do 335s in Europe were all destroyed and scrapped.
The two Do 335s that made it across the ocean to the United States had better luck, as they were assigned to the US Navy's Patuxent River Naval Air Station in Maryland, where they were subjected to detailed evaluations until 1948.
The two Do 335s that made it across the ocean to the United States had better luck, as they were assigned to the US Navy's Patuxent River Naval Air Station in Maryland, where they were subjected to detailed evaluations until 1961. In 1961, one of the aircraft (originally numbered 240102, the second of the A-0 pre-production models) was transferred to the collection of the National Air and Space Museum (NASM), where it has since fallen into disrepair due to prolonged open-air storage. In October 1974, after much effort, the only remaining Arrow was returned to its home base at Dornier Aircraft in Munich to undergo a complete restoration, with many of the same engineers and craftsmen again working on the aircraft. Many of the engineers and mechanics of the day were able to touch the former product (and were surprised to find that the explosive device on the fuselage was still in working order). The restored Do 335 made its debut at the Hannover Air Show in May 1976, and was then loaned to the Deutsches Museum in Munich for display, but it was never returned to its original home, and in 1986 was returned to NASM in the United States to be dismantled and preserved for the present day.
The Do 335 was a more conventional design than the "new" XP-55 and Go 229, but it still had many innovations. The Do 335 was the fastest piston-propeller fighter of its time, with the exception of a few special models, and with its range and firepower, it would have been a nightmare for the Allied bomber fleet, with the potential for further development. Due to various unfavorable factors, it was difficult for the Do 335 to get a chance to show off its strengths. In fact, the reliability of the mechanical parts and the safety of the ejection seat had not been perfected yet, and even though it was built in larger numbers than the other "alternatives", it never got a chance to prove itself, and the "sharp arrow" only flew in the air. The "arrow" is just a dazzling trajectory in the sky, disappeared in the end of no target.