Thursday, October 1, 2009

The Messerschmitt Me 262 Schwalbe

The Messerschmitt Me 262 Schwalbe ("Swallow") was the world's first operational jet-powered fighter aircraft. It was produced in World War II and saw action starting in 1944 as a multi-role fighter/bomber/reconnaissance/interceptor warplane for the Luftwaffe. It has been considered the most advanced German aviation design in service [5] and according to some Allied historians it was a plane that might have won the war by giving air supremacy back to the Luftwaffe, being much faster and more heavily armed than Allied fighters in service at that time such as the Gloster Meteor I.  But it had a negligible impact on the course of the war due to its late introduction and the small numbers in service. It claimed a total of 509 Allied kills (although higher claims are sometimes made[Notes 1]) against the loss of about 100 Me 262s. The Me 262 influenced the designs of post-war aircraft such as the North American F-86 and Boeing B-47.
Me 262 Schwalbe


Messerschmitt Me 262A
Role
Fighter
Manufacturer
Messerschmitt
First flight
18 April 1941 with piston engines

18 July 1942 with jet engines [1]
Introduction
April 1944[2][3]
Retired
1945, Luftwaffe

1957, Czechoslovakia
Primary users
Luftwaffe

Czechoslovak Air Force
Number built
1,430
The Me 262 was already being developed as Projekt P.1065 before the start of World War II. Plans were first drawn up in April 1939, and the original design was very similar to the plane that eventually entered service. The progression of the original design into service was delayed greatly by technical issues involving the new jet engines. Funding for the jet program was also initially lacking as many high-ranking officials thought the war could easily be won with conventional aircraft. Among those was Hermann Göring, head of the Luftwaffe, who cut back the engine development program to just 35 engineers in February 1940, Willy Messerschmitt, who desired to maintain mass production of the Bf 109 and the projected Me 209, and Major General Adolf Galland, who supported Messerschmitt through the early development years, flying the Me 262 himself on 22 April 1943. By that time problems with engine development had slowed production of the aircraft considerably.

In mid-1943 Adolf Hitler envisioned the Me 262 as an offensive ground-attack/bomber rather than a defensive interceptor, as a high speed, light payload Schnellbomber ("Fast Bomber"), to penetrate Allied air superiority during the expected invasion of France. His edict resulted in the development of (and concentration on) the Sturmvogel variant. It is debatable to what extent Hitler's interference extended the delay in bringing the Schwalbe into operation.  Albert Speer, then Minister of Armaments and War Production, claimed in his memoirs that Hitler originally blocked mass-production of the Me 262 before agreeing to production in early 1944. He rejected arguments that the plane would be more effective as a fighter against Allied bombers then destroying large parts of Germany and wanted it as a bomber for revenge attacks. According to Speer Hitler had felt that its superior speed compared to other fighters of the era meant that it couldn't be attacked and so had preferred it for high altitude straight flying.

Although it is often stated the Me 262 is a "swept wing" design, the production Me 262 had a leading edge sweep of only 18.5°. This was done after the initial design of the aircraft, when the engines proved to be heavier than originally expected, primarily to position the center of lift properly relative to the centre of mass, not for the aerodynamic benefit of increasing the critical Mach number of the wing, where the sweep was too slight to achieve any significant advantage. On 1 March 1940, instead of moving the wing forward on its mount, the outer wing was repositioned slightly aft. The trailing edge of the mid-section of the wing remained unswept.. Based on data from the AVA Göttingen and windtunnel results, the middle section's leading edge was later swept to the same angle as the outer panels

The first test flights began on 18 April 1941, with the Me 262 V1 example, bearing its Stammkennzeichen radio code letters of PC+UA, but since its intended BMW 003 turbojets were not ready for fitting, a conventional Junkers Jumo 210 engine was mounted in the V1 prototype's nose, driving a propeller, to test the Me 262 V1 airframe. When the BMW 003 engines were finally installed, the Jumo was retained for safety, which proved wise as both 003s failed during the first flight and the pilot had to land using the nose mounted engine alone.

The V3 third prototype airframe, with the code PC+UC, became a true "jet" when it flew on 18 July 1942 in Leipheim near Günzburg, Germany, piloted by Fritz Wendel. This was almost nine months ahead of the British Gloster Meteor's first flight on 5 March 1943. The conventional gear, forcing a tail-down attitude on the ground, of the Me 262 V3 caused its jet exhaust to deflect off the runway, with the wing's turbulence negating the effects of the elevators in the tail-down attitude, and the first attempt was cut short. On the second attempt, Wendel solved the problem by tapping the aircraft's brakes at takeoff speed, lifting the horizontal tail above and out of the wing's turbulence.[

The aircraft was originally designed with a tailwheel undercarriage and the first four prototypes (Me 262 V1-V4) were built with this configuration, but it was discovered on an early test run that the engines and wings "blanked" the stabilizers, giving almost no control on the ground, as well as serious runway surface damage from the hot jet exhaust. Changing to a tricycle undercarriage arrangement, initially a fixed undercarriage on the "V5" fifth prototype, then fully retractable on the sixth (V6, with Stammkennzeichen code VI+AA) and succeeding aircraft, corrected this problem.

The BMW 003 jet engines, which were proving unreliable, were replaced by the newly available Junkers Jumo 004. Test flights continued over the next year, but the engines continued to be unreliable. Airframe modifications were complete by 1942, but hampered by the lack of engines, serial production did not begin until 1944, but deliveries were low with 28 Me 262s in June, 59 in July, but only 20 in August.  This delay in engine availability was in part due to the shortage of strategic materials, especially metals and alloys able to handle the extreme temperatures produced by the jet engine. Even when the engines were completed, they had an expected operational lifetime of approximately 50 continuous flight hours; in fact, most 004s lasted just 12 hours, even with adequate maintenance. A pilot familiar with the Me 262 and its engines could expect approximately 20–25 hours of life from the 004s. Changing a 004 engine was intended to require three hours, but this typically took eight to nine due to poorly made parts and inadequate training of ground crews.

Turbojet engines have less thrust at low speed than propellers, and as a result, low-speed acceleration is relatively poor. It was more noticeable for the Me 262 as early jet engines (before the invention of afterburners) responded slowly to throttle changes. The introduction of a primitive autothrottle late in the war only helped slightly. Conversely, the higher power of jet engines at higher speeds meant the Me 262 enjoyed a much higher rate of climb. Used tactically, this gave the jet fighter an even greater speed advantage in climb rate than level flight at top speed.

With one engine out, the Me 262 still flew well, with speeds of 450-500 km/h (280-310 mph), but pilots were warned never to fly slower than 300 km/h (190 mph) on one engine, as the asymmetrical thrust would cause serious problems.

Operationally, the Me 262 had an endurance of 60 to 90 minutes.

General characteristics
  • Crew: 1
  • Length: 10.60 m (34 ft 9 in)
  • Wingspan: 12.60 m (41 ft 6 in)
  • Height: 3.50 m (11 ft 6 in)
  • Wing area: 21.7 m² (234 ft²)
  • Empty weight: 4,404 kg (9,709 lb)
  • Loaded weight: 7,130 kg (15,720 lb)
  • Max takeoff weight: 6977 kg (15,381 lb)
  • Powerplant: 2× Junkers Jumo 004 B-1 turbojets, 8.8 kN (1,980 lbf) each
  • Aspect ratio: 7.32
Performance
  • Maximum speed: 900 km/h (559 mph)
  • Range: 1,050 km (652 mi)
  • Service ceiling: 11,450 m (37,565 ft)
  • Rate of climb: 1,200 m/min (3,900 ft/min)
  • Thrust/weight: 0.28
Armament
  • Guns: 4 × 30 mm MK 108 cannons (A-2a: two cannons)
  • Rockets: 24 × 55 mm (2.2 in) R4M rockets
  • Bombs: 2 × 250 kg (551 lb) bombs or 2 × 500 kg (1,102 lb) bombs (A-2a only)

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