Hans Guido Mutke

Hans Guido Mutke's Me 262A on display at the Deutsches Museum

Dr Hans Guido Mutke (25 March 1921 – 8 April 2004) was a fighter pilot for the German Luftwaffe during World War II. He was born in Neisse, Upper Silesia (now Nysa, Poland).

It is claimed that Mutke made the very first flight breaking the sound barrier in 1945, in a Me 262, though this claim is subject of controversy. Mainstream opinion continues to regard Chuck Yeager in his Bell X-1 as the first person achieving this milestone in 1947.

The flight

On April 9, 1945, Fähnrich Mutke, part of the EJG2 conversion squadron, 3rd flight, took off from Lagerlechfeld in his Messerschmitt Me 262, marked Weiße 9, for a planned high-altitude flight. He was climbing through at an altitude of 12,000 m (36,000 ft) in near perfect weather with a visibility of over 100 km, listening to the radio conversations, when his chief instructor Oberstleutnant Heinz Bär detected a P-51 Mustang approaching the plane of another comrade, Unteroffizier Achammer, from behind.

Mutke went into a steep 40° dive with full engine power to assist. While passing through the altitude of 12,000 m, the Me 262 started to vibrate, combined with the plane swinging from side to side. The speedometer was stuck against its limit of 1,100 km/h (682 mph) (the maximum speed of the Me 262 is 870 km/h. The speed of sound is 1,062 km/h (670 mph) at an altitude of 12,000 m, depending on the environmental variables). The shaking increased, and rivets started popping out of their holes. Mutke temporarily lost control of his plane. He reported that with the speedometer still off the scale he attempted to recover from the uncontrollable dive by adjusting the main tailplane incidence of the Me262. Rather than just having an elevator flap, the Me262 could change the incidence of the whole tailplane, a design feature that was later added to the Bell X1. Most significantly, Mutke claimed that without decelerating, the buffeting suddenly stopped and control resumed for a few seconds but he had throttled back and his engines flamed out and after the short period of smooth flight, the buffeting resumed and craft began shaking violently again. He fought to regain control and re-light the engines eventually reducing the speed below 500 km/h. After a difficult landing, it was found that his plane was missing many rivets and also had distorted wings.

Claims

At the time, Mutke did not understand the reasons for this strange behavior. Only after learning about the supersonic flights of Chuck Yeager in 1947 did he attribute these phenomena to the effects of supersonic flight and claim to be the first person to break the sound barrier. This claim is disputed, and there are a number of other pilots and countries that claim the first supersonic flight.

In a series of carefully controlled flight tests conducted in World War II by Messerschmitt, it was established that the Me 262 went out of control in a dive at Mach 0.86, and that higher Mach numbers would lead to a nose-down trim that could not be counter-acted by the pilot by use of the joystick. The resulting steepening of the dive would lead to even higher speeds and self-destruction of the airframe due to excessive negative G loads. Postwar testing by the British government corroborated Messerschmitt's results, though neither actually exceeded Mach 0.86.

Mutke claimed to have overcome the ever steepening dive by adjustment of the 262's whole tailplane incidence. Rather than just pulling back on the elevator, he reset the incidence angle of the all flying tailplane. This is the same technique employed by Chuck Yeager in the Bell X-1 to avoid what is known as Mach tuck. However what is most significant about Mutke's claims are not his reference to buffeting. Buffeting was a phenomenon known to high speed aircraft test pilots and was the reason pilots were warned not to exceed critical speeds. Heini Dittmar encountered severe buffeting in his Me163a in 1941 at 1000 km/h and his observations were well noted by the Luftwaffe. What is most significant was Mutke's observation that the buffeting stopped and control resumed without the aircraft slowing, with the speedometer stuck off the scale. It is the cessation of buffeting and resumption of control at extreme speed that is significant, not that he experienced buffeting. Mutke experienced engine flame-out and his craft decelerated, and as it slowed he suddenly encountered buffeting again and loss of control. It is the sequence of acceleration, buffeting, loss of control authority, sudden cessation of buffeting and resumption of normal control whilst speed increases and then later, deceleration and resumption of buffeting and control difficulty which is characteristic of a supersonic flight profile. Mutke did not claim supersonic flight because he experienced a shaking, buffeting plane. He claimed to have flown supersonic flight because the plane stopped shaking and became controllable again as speed increased. It started shaking again only as he decelerated. To misunderstand this point is to misunderstand the significance of the claim and his observations.

After the war, American test pilots filed reports about the Me 262, including the possibility of a speed of Mach 1. A detailed discussion of the high speed capability of the Me 262 can also be found at Messerschmitt Me 262. Compressibility in pitot tubes of the time often resulted in exaggerated speed readings near the speed of sound, particularly in German equipment, which was adversely affected by supply shortages as the war progressed. American Sabrejets and other high-speed aircraft (including the Bell X-1) also experienced anomalous airspeed readings in the high-subsonic flight regime (between 0.8 Mach and Mach 1). The Me 262's pre-area rule fuselage would have additionally resulted in very high transonic drag, and its engines were already underpowered and temperamental to begin with. However, aircraft such as the Bell X-1, F-86 Sabre and Convair F2Y Sea Dart similarly did not have area ruled fuselages yet are acknowledged to have flown at supersonic speeds—here the engine thrust, either alone or in combination with the pull of gravity during a dive, supplies enough force to accelerate the airplane to supersonic speed. Thus, having an area-ruled fuselage is in no way a prerequisite for supersonic flight. The Mach-20 Space shuttle does not need to have an area ruled fuselage, either, as it generally only dissipates energy (brakes aerodynamically) and slows down when returning from the orbit.

Due to the nature of Mutke's combat flight, it is impossible to determine the exact speed of his plane, and it is also difficult to estimate the exact speed of sound at that time and altitude. Therefore, it is not possible to either prove or disprove his claims, and there is much discussion among experts as to whether the Me 262 was able to break the sound barrier. It is believed that the damaging effects experienced by Mutke were a side effect of supersonic airstream and shock waves over different parts of the airframe called buffeting. This effect occurs at speeds approaching Mach 1 but ceases above Mach 1. A number of other Me 262 experienced similar strange accidents, or breaking apart in the sky because of buffeting and the different aerodynamics at the sound barrier. Transonic buffeting effects had also been widely reported by pilots of propeller-driven Allied fighters including the Supermarine Spitfire, P-38 Lightning and P-51 Mustang, aircraft that were known to have top diving speeds of less than 0.85 Mach. Allied fighter pilots reported seeing supersonic shock waves and popped rivets during dives as the high-speed air rushing over the wing exceeded Mach 1 even though the forward airspeed of the overall aircraft was well below that speed.

Proponents of the claim also often believe that after the end of the war the allied powers had no interest in emphasizing any German achievements during the war. Mutke's claim, however, is unique and without controlled, experimental confirmation. A computer based performance analysis of the Me 262, carried out in 1999 at the Munich Technical University, has shown that the Me 262 could exceed Mach 1.

After World War II and death

After the war he worked as an airline pilot and as a doctor for aviation medicine. He died in Munich in 2004, during a heart valve operation. He donated his body remains to the anatomist Gunther von Hagens.

References

aerospaceweb.org

Persondata
Name	Hans Guido Mutke
Alternative names
Short description	German WW2 fighter pilot
Date of birth	March 25, 1921
Place of birth	Neisse, Upper Silesia
Date of death	April 8, 2004
Place of death	Munich, Germany