Leduc
René Leduc built aircraft that were mostly engine: hollow ramjet tubes with a pilot inside, launched from airliners in mid-air, until the money ran out and he switched to hydraulic pumps.
Leduc: the company and the aircraft that made its name
An apprentice with a patent
René Leduc left school at 14 to become an apprentice mechanic, fought in the artillery in the First World War, then studied engineering. Working at Breguet he filed, in 1933, a patent on the thermo-propulsive nozzle, the basis of the ramjet. By 1937 he had started building an aircraft around it, and construction continued semi-secretly at Breguet during the German occupation. The idea caught the attention of Louis Breguet and the Ministry of Aviation, which funded tests of small-scale prototypes.
Launched from a mothership
The result, the Leduc 0.10, was a fuselage that was essentially the engine: the pilot sat in an inner shell while air rushed through the gap around him into the ramjet. Because a ramjet gives no thrust at a standstill, the 0.10 was carried aloft on top of a Languedoc airliner and released. Its first powered flight, over Toulouse on 21 April 1949, was one of the first flights anywhere powered solely by a ramjet. The larger 0.21 made 284 free flights and reached Mach 0.95.
From ramjets to pumps
The final step was the swept-wing 0.22 interceptor, which added a turbojet so it could take off by itself and first flew on 26 December 1956. In 1958 the French Air Force cancelled it for budget reasons. Leduc turned his company to hydraulics as Hydro Leduc, which made pumps for excavators, and ran it until his death in 1968. The 0.22 had been ordered to a 1953 requirement for an interceptor able to take off from a 940-metre grass runway, armed with two air-to-air missiles, in competition with the Nord Gerfaut and Griffon.
Leduc in numbers
The company
- In short
- Ramjet pioneer
- Founded by engineer René Leduc
- Ramjet patent filed 1933
- Aircraft work ended 1958
Production
- Best known for
- Leduc 0.10
- 0.10: among the first ramjet-only aircraft
- 0.21: 284 free flights
- 0.22 supersonic interceptor prototype
Today
- Now
- Hydro Leduc
- Company converted to hydraulic pumps in 1958
The numbers
- Leduc 0.21 free flights
- 284
- Leduc 0.10 top speed
- Mach 0.85
- Hydro Leduc workforce
- over 200
Every notable Leduc aircraft
| Aircraft | Role | First flight | Built | Status | Note |
|---|---|---|---|---|---|
| Leduc 0.10 | Ramjet research aircraft | 1947 | 3 | Retired | Glide tests from October 1947, first powered flight 21 April 1949; built at Breguet |
| Leduc 0.16 | Ramjet research aircraft | 1951 | Retired | Third 0.10 airframe with wingtip turbojets, later converted back | |
| Leduc 0.21 | Ramjet research aircraft | 1953 | 2 | Retired | About 30 per cent larger than the 0.10; reached Mach 0.95 |
| Leduc 0.22 | Mixed-power interceptor prototype | 1956 | one flown | Retired | Ramjet plus turbojet; cancelled 1958 before the second was finished |
Where Leduc built, who led it, what it achieved
People
- René Leduc · founder, engineer — Born 1898 at Saint-Germain-lès-Corbeil, died 1968 at Istres; ramjet pioneer
Records and firsts
- Leduc 0.10 made one of the first flights powered solely by a ramjet, 21 April 1949
- Leduc 0.10 climbed at 40 m/s, better than the best jet fighters of the time
Leduc, year by year
René Leduc born
Patent on the thermo-propulsive nozzle, the basis of the ramjet
Construction of the Leduc 0.10 begins
Unpowered glide tests of the 0.10 begin
First powered flight of the 0.10 over Toulouse
Leduc 0.21 flies
Leduc 0.21 shown at the Paris Air Show
Leduc 0.22 interceptor first flies
Programme cancelled; company converts to hydraulics as Hydro Leduc
René Leduc dies at Istres
Everything people ask about Leduc
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Around Leduc
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Verified 2026-10-03.