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History Brief, by Alfred Damen, edited by Johan Visschedijk

August 12, 2006

Leduc 0.10 to 0.22


Since 1929 aeronautical engineer René Leduc concentrated on development of ramjet power for aircraft. He patented his idea in 1933 and produced a small unit of 1.18 inch (30 mm) in diameter, which developed 8.8 lb (4 kg) thrust in 1935. Leduc demonstrated the practical application of the ramjet engine in June 1936, and the next year the French government contract number 407/7 ordered the construction of the Leduc 0.10 ramjet-powered aircraft. Design and construction began immediately at the Breguet workshops at Villacoublay (near Paris) and the aircraft was nearly finished early 1940.

Due to the German invasion, Breguet evacuated the Paris area, the aircraft being transferred to Montaudran in Toulouse, later being destroyed in a bombardment of the factory. In 1945 work began again and by November 1946 the aircraft was ready. As the ramjet has no static thrust (the combustible mixture being compressed by forward speed only) the 0.10 was fitted on top of a modified Sud-Est SE-161 Languedoc four-engined transport. At least four Languedoc's were used in the program, including F-BATF (c/n 6) and F-BCUT (c/n 31).

The first composite flight was from Blagnac on November 19, 1946, but it was not until October 21, 1947 before the 0.10 was released and made its first unpowered flight. Only two more unpowered flights were made before the first powered flight. On April 21, 1949, with test pilot Jean Gonord in the Leduc 0.10-01 and Colonel Jean Perrin piloting the Languedoc, the 0.10-01 was released over Blagnac, the burners were lit and thus became the first aircraft solely propelled by ramjet power. The aircraft was released in a shallow dive flying at 13,123 ft (4,000 m) at 267 mph (430 kmh) and in the following 9 minutes the 0.10-01 reached 423 mph (680 kmh).

The 0.10 proved the extraordinary capabilities of the athodyd engine (a simple, essentially tubular jet engine), in particular its incredible rate of climb. During the test flights, producing 4,409 lb (2,000 kg) thrust, the aircraft was able to climb 7,792 ft (2,375 m)/min, and reached 500 mph (805 kmh) at 36,089 ft (11,000 m). A second aircraft (0.10-02) was built and flown in the Paris area, but from 1951 testing continued at Istres, near Marseille. On February 8, 1951 a third and similar aircraft was flown, the Leduc 0.16. Initially fitted with a 661 lb (300 kg) thrust Turboméca Marboré I turbojet at each wing tip for standby power during landings, these soon were replaced by mass balances.

The CEV (Centre d'Essais en Vol = Flight Test Center, part of the French ministry of defense) at Istres also conducted test flying. In 1951, a technical failure caused the destruction of one of the 0.10s seriously injuring the CEV test pilot, Jean Sarrail. The following year the second 0.10 was written off following another accident in which Leduc test pilot Yvan Littolff was seriously injured.

Next type to join the test program was the Leduc 0.21. Of new design, it was 30% larger than the 0.16, and two of these were built. Like the Leduc 0.10 and 0.16 it was a subsonic test vehicle for ramjet power, but also provided data for a proposed Mach 2 interceptor. The Leduc 0.21-01 commenced air tests on top of the Languedoc transport in May 1953, making its first powered flight on August 7, 1953, followed by the 0.21-02 on March 1, 1954.

The proposed Mach 2 interceptor prototype, the Leduc 0.22-01 was fitted with a Turboméca Atar D.3 turbojet. This made it possible to take off on its own power, and it did so for the first time in the hands of Jean Sarrail on December 26, 1956. Not before the 34th flight the ramjet was fired on May 18, 1957, a further 80 flights were conducted till December 21, 1957 when the program came to a halt due to cutbacks in military contracts.

René Leduc left the aircraft manufacturing scene; the surviving 0.10 and sole 0.22-01 were stored and are now on display in the Musée de l'Air at Le Bourget.

0.10 Alfred Damen collection
0.22 Walter van Tilborg collection

Specifications (0.21)

Type:

Experimental ramjet monoplane

Engine:

14,330 lb (6,500 kg) static thrust at 556 mph (1,029 kmh) Leduc fuselage duct ramjet

Span:

38 ft 0.71 in (11.60 m)

Length:

41 ft 0.11 in (12.50 m)

Height:

9 ft 0.28 in (2.75 m)

Empty Wt:

8,345 lb (3,785 kg)

Max T/O Wt:

13,228 lb (6,000 kg)

Max speed:

576 mph (1,066 kmh)

Ceiling:

65,617 ft (20,000 m)

Climb:

initial 39,370 ft (12,000 m)/min, falling to 2,887 ft (880 m)/min at 49,213 ft (15,000 m)

Fuel:

757 gal (2865 l)

Endurance:

15 minutes to one hour

Models

0.10:

2 built

0.16:

1 built

0.21:

2 built

0.22:

1 built