Robert Esnault-Pelterie

Robert Esnault-Pelterie
Robert Esnault-Pelterie
Born	8 November 1881 (age 145); Paris, France
Died	6 December 1957 (aged 76); Nice, France
Occupation(s)	Aerospace engineer, inventor, rocketry pioneer
Known for	Early rocketry, astronautics, invention of the joystick flight control
Notable work	L'Astronautique (1930)

Robert Albert Charles Esnault-Pelterie (8 November 1881 – 6 December 1957) was a pioneering French engineer and theorist in aerospace, acknowledged as one of the originators of contemporary rocketry and astronautics alongside Konstantin Tsiolkovsky, Hermann Oberth, Wernher von Braun, and Robert H. Goddard.

Biography

Esnault-Pelterie was born in Paris into a family involved in the textile industry. He pursued engineering studies at the Faculté des Sciences of the Sorbonne. During World War I, he served with distinction and attained the rank of Officier de la Légion d'Honneur.

In November 1928, while traveling aboard the Ile de France to New York City, he wed Carmen Bernaldo de Quirós, who was the granddaughter of the Marquis of Santiago and had ties to Spanish aristocracy.

He passed away on 6 December 1957 in Nice, France.

REP

Esnault-Pelterie established REP, a firm dedicated to the design and production of aircraft and aero engines, playing a vital role in advancing early aviation technology.

Aeroplanes

His initial aeronautical experiments were inspired by the Wright brothers' 1902 glider. The first glider he tested near Calais failed due to an incomplete grasp of the Wrights' design principles. Although initially employing wing-warping for control, he rejected this method because of its hazards and instead innovated the aileron concept by installing control surfaces mid-gap ahead of the wings—one of the earliest practical implementations preceding other inventors.

In 1906, he commenced experiments with towed flights, achieving his first such flight on 19 September. His inaugural powered flight took place on 10 October 1907 with the REP 1, covering a distance powered by a self-developed seven-cylinder, 30 hp air-cooled engine.

Testing of the monoplane REP 2 began on 8 June 1908; it set a record with a flight lasting and reaching an altitude of . After piloting an updated variant for the final time in 1909 at Rheims, Esnault-Pelterie retired from flying to concentrate on aircraft design and production.

The Vickers R.E.P. Type Monoplane was derived from his innovations and marked the beginning of aircraft manufacturing at what would become Vickers Limited. In 1912, he introduced the REP Type N, followed by the REP Parasol monoplane in 1914.

Although his family faced near financial collapse due to heavy investments, his invention of the "joystick" flight control—patented in 1908 and incorporated into Louis Blériot's aircraft—became a foundational element in flight control systems. Legal actions after World War I secured him royalties from numerous manufacturers who utilized his design during the conflict. These settlements and ongoing payments restored his family's wealth and brought him considerable fortune.

Aero engines

Esnault-Pelterie also engineered and produced his own line of aero engines under the R.E.P. brand. These powerplants featured an uncommon multiple-banked fan or half-radial configuration. The original model included seven cylinders arranged in two banks (four cylinders in one bank and three in another), delivering . A subsequent development expanded this to a 14-cylinder quadruple-bank engine producing .

Rocketry

Esnault-Pelterie made significant strides in early rocketry, independently formulating the rocket equation in 1913 and estimating the energy demands for journeys to the Moon and other planets. He envisioned propulsion powered by atomic energy, suggesting the use of 400 kilograms of radium, and authored L'Astronautique in 1930. A subsequent 1934 edition expanded on interplanetary travel concepts and the potential application of nuclear power.

In 1927, he delivered a symposium focused on rocket exploration of the upper atmosphere and interplanetary voyages, which led to a partnership with Jean-Jacques Barré. By 1929, Esnault-Pelterie had proposed ballistic missiles for military deployment. In 1931, he and Barré secured funding from the French War Department to investigate liquid-fueled rocket technology. Although they developed a gasoline-liquid oxygen engine and experimented with tetra-nitromethane rockets—an endeavor that resulted in Esnault-Pelterie losing four fingers in an accident—their efforts did not succeed in maintaining long-term French enthusiasm for rocketry.

Prix REP-Hirsch

The Prix REP-Hirsch was an international accolade established by the Société astronomique de France to honor groundbreaking achievements in interplanetary travel and astronautics. Created through the initiative of Esnault-Pelterie and banker André-Louis Hirsch, it was the first prize worldwide dedicated to astronautics, recognizing original scientific work that advanced space exploration or related sciences.

The award originated from discussions at a 1927 Paris dinner centered on “astronautics” and was financed with an annual grant of 5,000 francs from 1928 through 1930. Oversight was provided by a Comité d'Astronautique comprising prominent members such as Esnault-Pelterie, Hirsch, J.H. Rosny the elder, General Gustave-Auguste Ferrié (President), Jean Perrin, and Eugène Fichot (Vice-Presidents). The prize was bestowed for a decade before being renamed the Prix International d'Astronautique in 1936.

Distinguished recipients included:

1929 — Hermann Oberth, honored for his foundational work.
1931 — Pierre Montagne, recognized for his research on combustion chamber gas temperatures.
1934 — Pierre Montagne (for studies on chemical equilibria in rocket propulsion) and Ary Sternfeld (received an encouragement award for Initiation à la Cosmonautique).
1935 — Louis Damblanc, awarded for advances in solid rocket propellant technology.
1936 — The American Rocket Society and Alfred Africano, acknowledged for liquid-fueled rocket experiments.
1938 — Giovanni Serragli, noted for investigations into slow-burning powders suitable for high-altitude exploration.
1939 — Frank J. Malina (awarded the Médaille de vermeil) and Nathan Carver (awarded the Médaille d'argent).

Although its duration was limited, this prize played a vital role in promoting early astronautical research and celebrating pioneering contributors.

2019 — Jacques Blamont*

Legacy

Esnault-Pelterie held nearly 120 patents spanning diverse domains such as metallurgy and automotive suspension systems. He is credited with inventing the "center stick" control mechanism for aircraft and developing an innovative fuel pump. Additionally, he was a trailblazer in controlling rockets through vectored thrust techniques.

Honors

Recipient of the Prix Jules Janssen in 1930, the highest distinction awarded by the Société astronomique de France.
Elected member of the French Academy.
The lunar crater Esnault-Pelterie is named in his honor.
A street in Paris, Rue Robert Esnault-Pelterie, bears his name.
Inducted into the inaugural cohort of the International Space Hall of Fame.

Publications by Esnault-Pelterie

L'Astronautique, Paris, A. Lahure, 1930.
L'Astronautique-Complément, Paris, Société des Ingénieurs Civils de France, 1935.

External resources