Focke-Wulf 1-TL Jäger Projekt I
Flying trials with the Messerschmitt Me 262 V2 prototype were conducted at the end of 1942. The test programme included high-altitude combat revealing unexpected compressibility effects during high-speed dives between 7,600 and 5,500 m. The Me 262 had been designed in 1940, before the aerodynamicists discovered the destructive effects associated with the transonic flux. The turbulent airflow generated in the junction between the engine nacelles and the wing under surface generated some tail plane buffeting and elevator flutter.
Like its predecessors, Bf 110 and Me 210, the Me 262 proved to be an easy prey in dogfight against the single-engine Allied fighters, demonstrating the correctness of the Latin sentence
errare humanum est, sed perseverare diabolicum. It was also expensive, requiring a lot of strategic materials during its construction and thrice man-hours that a standard Bf 109 G required. What the Luftwaffe needed in 1943 was a single-engine air-superiority jet fighter to replace the old ‘0-nine’, the only successful fighter built by the firm, whose basic design dated back to 1934.
Early in 1943, the
Technisches Amt (RLM Technical Office) asked Messerschmitt if the Bf 109 G could be adapted to take one Jumo 004 turbojet. The answer was negative.
In fact, the firm had all the necessary resources to comply with the RLM requirement: using the wing of the Me 209 and the nose wheel of the Me 309, it would only have been necessary to design a new central wing section so that the attachment points of the undercarriage would not interfere with the jet exhaust. But the
Sofortprogramm (interim solution) proposed by the RLM was contrary to the plans of Messerschmitt who at that time had already decided to continue the development of the Me 262. This situation gave the firm Focke-Wulf the opportunity to participate in the supplies of turbojets that until then had only been available for the Me 262 and the Arado Ar 234.
In February1943, the Bad Eilsen design team envisaged the study of several possible fuselage-turbojet-air intake configurations and their integration with different types of wings, tail surfaces and landing gears for the construction of a future single jet fighter. The simplest solution was to replace the BMW 801 radial engine of an Fw 190 by a Jumo turbojet, mounted under the nose to not altering the position of the centre of gravity of the aircraft. Unfortunately for the firm, the new engine turned out to be too long, so the jet nozzle would interfere with the retraction of the main wheels of the Fw 190. It was necessary to design a new type of wings capable of housing the mainwheels of 660 x 160 mm. The greater consumption of J2 heavy kerosene of the turbojet required the installation of two fuel tanks of 390 litres each in the fuselage, making necessary to advance the location of the cockpit 170 cm.
It was planned to mount two Mauser MG 151/20 cannons in the wing roots and two Rheinmetall-Borsig MK 108/30 cannons under the cockpit floor. The
Projekt I was introduced to the OKL in March 1943 as a realistic solution that would have allowed the
Jagdwaffe to have an interceptor that would be faster than the
Mustang, better armed than the
Tempest and the
Meteor and able to overcome the
Thunderbolt in dive. It could have been mas manufactured by late 1944, but the
Technisches Amt rejected the project claiming that the position of the turbojet (whose axis was located 86 cm lower than that of the BMW 801) would substantially decrease the rolling properties, and it was feared that the Jumo 004 would suffer serious damage at belly landing. Also taken into consideration was the risk that jet exhaust gases would cause damage to the tailwheel or burn the airfield surface.
In April 1946, the Soviets demonstrated with their Yak-15 that these precautions were unfounded. The new Yakovlev fighter was based on the same formula as the
Projekt I and was powered by the same turbojet, being mass-produced and entering into service smoothly in May 1947.
The integration of the turbojet in the airframe of a Yak-3 piston fighter was relatively simple. It was only necessary to modify the wing spar central section, replace the tailwheel with another metal shield, protected by a blast deflector, and to cover the lower part of the fuselage with steel plates. The Soviets successfully used the same formula on the experimental prototypes Lavochkin La-152 (October 1946), La-156 (March 1947) and La-160 (June 1947), all propelled by copies of the Jumo 004. The Italians also used this aerodynamic solution in their prototypes Ambrosini
Saggitario I (January 1953) and their first supersonic aircraft Aerfer
Saggitario II (May 1956).
Technical data
Airframe: light alloy
Wing span: 10.33 m. Length: 9.8 m. Height: 2.6 m. Wing area: 16 sq. m.
Engine: one Jumo 109-004 B turbojet rated at 890 kp static thrust
Estimated maximum weight: 3,400 kg. Maximum speed: 780 kph. Ceiling: 12,000 m.
Estimated endurance: 35 minutes.
Armament: two MG 151/20 cannons with 175 rounds per gun (rpg) and two Mk 108/30 cannons with electro-pneumatic cocking, electrical firing and 70 rpg.
