Marcel Bloch's first steps
in industry

Marcel Bloch was 22 years’ old when the First World War broke out in August 1914. Because of his training as an aeronautical engineer, which was uncommon at the time, he was not sent to the front but was assigned to the Chalais-Meudon aeronautical research Laboratory and thus made his debut within an industry evolving from craftsmanship to series production.

With Henry Potez, also a graduate of the Ecole supérieure d’aéronautique et de construction mécanique, he was responsible for coordinating and preparing the drawings for the Caudron G 3 aircraft the manufacture of which was distributed between four factories belonging to different aircraft manufacturers.

With the Eclair propeller, Marcel Bloch became part of the legend of aviation

Having seen that existing propellers provided only mediocre performance, he decided to design one himself in 1916.

This propeller, known as the “Eclair”, passed the official tests. The Armed forces ordered an initial series of 50 units which were built on the premises of a furniture manufacturer in the faubourg Saint-Antoine in Paris.

Marcel Bloch convinced Henry Potez to join him. They then set up the Société des Hélices Eclair company which they became the engineering directors of.

The Eclair propeller was fitted to many French aircraft and, in particular, the Spad VII of the ace Georges Guynemer. In 1917, the equipment Inspection department classified it among the best three propellers out of 253. Marcel Bloch became a legendary name in the aviation world.

Creation of the Société d’Etudes Aéronautiques (SEA)

However, just manufacturing propellers was not enough to occupy the two engineers. They undertook the building of an aircraft and, in 1917, they and another friend set up the Société d’Etudes Aéronautiques (SEA) company.

With the help of one of Marcel Bloch’s classmates, Louis Coroller, they designed the SEA 1 single-engined observation aircraft powered by a 120 hp engine that quickly proved to be unsuitable for the use for which it was intended. While the engine was not powerful enough, the airframe proved to be suitable.

The three friends then designed the SEA 2 (single-engine, two-seater reconnaissance and fighter aircraft) and the SEA 3 (three-engine, three-seater reconnaissance aircraft) but, due to the lack of engines providing sufficient power, these aircraft were not manufactured.

The emergence of the Lorraine 370 hp engine finally allowed the SEA 4 (two-seater combat aircraft) to be produced which probably made its maiden flight at the end of 1917.

The Armistice put an end to Marcel Bloch’s initial industrial career

1,000 aircraft were ordered by the ministry of Armament and War Manufacturing. To honor the contract, a new company, Anjou Aéronautique, was set up in Angers in August 1918.

The first series model was rolled out on November 11, 1918. Since dawn, the guns on the battlefield had fallen silent and the war was over. Military aviation resumed its peacetime format and the contract for 1,000 aircraft was cancelled. Only a hundred or so aircraft in the process of being manufactured were delivered.

In view of the stocks to be disposed of, the aircraft manufacturing department did not encourage manufacturers to stay in the aviation business. Marcel Bloch withdrew and went into the real estate business.

Zoom: The aviation industry in France 1920 – 1940

Main manufacturers

  • before 1936: Amiot, Bloch, Breguet, Caudron, Dewoitine, Latécoère, Lioré, Morane-Saulnier, Potez, Renault
  • after 1936: SNCAC, SNCAN, SNCAO, SNCAM, SNCASE, SNCASO (state-owned companies) and Amiot, Breguet, Latécoère, Caudron, Morane-Saulnier, Renault (privately-owned companies).

Number of staff and Rearmament-related production

Year  Staff Rearmament-related production
1920 5 000
1937 35 000 743
1938 1 382
1939 3 163
June 1940 250 000 2 113

One of the main French
aviation companies

The setting up of the Air ministry in 1928, drew Marcel Bloch back into the aviation business. The engineering and industrial managing director, Albert Caquot, placed an order with him for a prototype for a postal three-engined aircraft program.

To manufacturer his aircraft, Marcel Bloch set up the Société des Avions Marcel Bloch company and hired several young engineers.

First State orders

Success came at the end of 1931: the authorities ordered the MB 80, a single-engined “medevac” aircraft, and the MB 120 a three-engined 10-passenger colonial transport aircraft.

Marcel Bloch regrouped his design and manufacturing departments and set them up in Boulogne in a disused garage. To build his aircraft and new prototypes, he rented larger premises in Courbevoie, quai Paul Doumer in September 1932.

Prototypes for civil aircraft (MB 220) and military aircraft then followed on at a faster pace.

Restructuring of French aviation

In 1934, Marcel Bloch understood that the French aviation industry was about to enter a crisis. Anticipating shortcomings in production facilities, he entered into an agreement with Henry Potez, the largest aviation company at the time.

In January 1935, they bought the Société Aérienne Bordelaise (SAB) company which then became the Société Aéronautique du Sud-Ouest (SASO) company which produced the MB 200 and MB 210 bombers. They also agreed to buy most of the shares of the Société des Moteurs et Automobiles Lorraine (SMAL) company.

While the social climate grew tenser in France, Marcel Bloch negotiated with trade-unions and granted a week’s paid leave in 1935. When the Popular Front government decided to grant two weeks’ paid holidays a year later, Marcel Bloch gave his staff three weeks.


In October 1930, Henri Déplante (the future engineering managing director) joined the design office of the Société des Avions Marcel Bloch company:

Those of us who still remember those tiny dusty workshops in which our first duraluminium, or even magnesium “crates” began their days are now few and far between.

Our “half riddle, half puzzle” drawings delighted a workshop which always showed itself full of indulgence for the three poor old guys in the design office. They shared drawings and calculations for two aircraft developed in parallel: a colonial three-engined aircraft and a “medevac” single-engined aircraft“.

and rearmament

In accordance with its electoral program, the Popular Front government passed a law nationalizing the armament industry, in the Chamber of Deputies on July 17, 1936. The aviation industry was directly concerned. The nationalization of a major part of the airframe sector led to the setting up of six state-owned aircraft manufacturing companies.

Nationalized aviation industry

On January 16, 1937, the Société des Avions Marcel Bloch was fully nationalized, and its factories (Courbevoie, Châteauroux-Déols, Villacoublay, Bordeaux) formed the essential part of the Société nationale de constructions aéronautiques du Sud-Ouest (SNCASO).

As the minister for Air, Pierre Cot, had no executives qualified enough to manage it, he asked Marcel Bloch to be its delegated administrator.

Creation of the Société Anonyme des Avions Marcel Bloch (SAAMB)

Although his factories had been expropriated, Marcel Bloch was left a free hand in running his office and development workshop. He merged his facilities in setting up the Société Anonyme des Avions Marcel Bloch (SAAMB) in Courbevoie in 1936. This company was able to design and develop prototypes that were mass produced by the state-owned companies alone. This independence did not last long, however, and the minister for Air merged the SAAMB’s design office with the SNCASO on February 17, 1937, through an amendment to the convention of January 16.

Rearmament of France

In view of the deteriorating European context, the State embarked on a rearmament policy in 1937. It became urgent to manufacture new aircraft to counter the powerful Luftwaffe being established by Adolf Hitler. SNCASO took up the rearmament challenge and produced the MB 150 series of single-engined fighter aircraft and then a twin-engined bomber, the MB 170 and its offshoots, as well as a four-engined civil transport aircraft, the MB 161.

Marcel Bloch and Henry Potez bought a building in avenue Kléber in Paris where they set up their offices. Marcel Bloch then bought land in Saint-Cloud on which he began to build a new factory, in 1938. Instead of aircraft, he built Chauvière propellers that were fitted to combat aircraft manufactured by state-owned companies, as well as small engines for private planes.

In September 1939, to meet increasing production demands, SAAMB bought industrial buildings in Talence, near Bordeaux, that it sold back to the Bordeaux-Aéronautique company, set up in October 1939. Of all the future belligerents of 1940, France was the one that made the greatest efforts to rearm.

During the war

On September 3, 1939, Great Britain and France declared war on Germany. The industrial aeronautics effort became a priority and a large number of airplanes were finally ordered, but too late. During the “Phoney War,” Marcel Bloch accelerated production and improved the performance of his prototypes. But on February 15, 1940, after a dispute with the French Air Ministry, he left French aircraft manufacturer SNCASO.

Marcel Bloch refuses to work for the Third Reich

After the Armistice of June 1940, the victorious Reich did not spare French aviation. Equipment, stocks and industrial establishments had to be delivered intact to Germany. The French aviation industry was virtually completely disbanded and manufacturing ceased.

Victim of a violent campaign of defamation, Marcel Bloch was arrested by the Vichy government on October 5, 1940, being considered as a “dangerous individual for national defense and public security”. In spite of his internment, he kept abreast of aeronautical developments. From prison, he noticed the considerable interest taken by Germans in his aircraft, in particular the two-engined MB 175, 200 of which they wanted built by SNCASO and the MB 161 four-engined civil transport aircraft, the largest French commercial aircraft, for Lufthansa.

The occupying force sought to obtain his collaboration, but he refused systematically using his poor health as an argument. To deprive the Germans of as many industrial resources as possible, he delegated all his powers, by letter, on December 20, 1940, to Henri Carol (the director of the Saint-Cloud factory) who had to act as the managing director of the Company in the occupied area.

In his absence, Marcel Bloch’s staff took steps to preserve the interests of the Société anonyme des Avions Marcel Bloch. An extraordinary general assembly was held on December 31, 1940 to appoint a new manager. In accordance with its articles of association, a board of directors was appointed. Marcel Bloch was appointed as chairman, and Auguste Le Révérend and Georges Hennequin as directors. The extraordinary general assembly also decided to transfer the Saint-Cloud head office to Thiers.

The Bloch Design Office was set up in Cannes

The Germans requisitioned the potential of the Saint-Cloud factory to their advantage and placed manufacturing under the control of the Junkers company. To save the factory, the Société anonyme de constructions aéronautiques et mécaniques (SACAM), which had run the Saint-Cloud factory under lease since May 1, 1941, was set up in April 1941 by Marcel Bloch’s staff and with his approval. In Talence, where Bordeaux-Aéronautique had to work for the occupying power, André Curvale (chief pilot) and Paul Déplante (engineering director) attempted to keep manpower and equipment intact.

In March 1941, the Service technique aéronautique decided to bring together the various design offices of state-owned companies and incorporate them within SNCASO in Cannes, then in the Italian occupied zone, where Marcel Bloch’s engineers could work on aircraft projects.

On August 16, 1941, the occupation authorities appointed a temporary manager of Marcel Bloch’s companies for the occupied zone while the Commissariat for Jewish Questions appointed a manager for the French zone. In 1942, with Marcel Bloch’s approval, Auguste Le Révérend and Henri Carol then attempted to preserve as much property as possible in buying a former bodywork workshop in Boulogne to produce propeller blades.

Some engineers joined the Free French Forces

In Cannes, the technical Group became increasingly concerned with development of the situation. Henri Déplante managed to visit his former boss who, ever an optimist, kept the hope of a better world. He advised him to bring together as many aeronautical engineers as possible and send them to Britain or the United States to form the core in the rebuilding of the post-war French aviation industry.

But the future was looking gloomier. After the French zone was invaded November 1942, Henri Déplante and Bention Grebelsky decided to leave France via Spain. After many difficulties, they reached Britain and joined a fighting unit of parachutists of the Special Air Service (SAS). In October 1943, Xavier d’Iribarne reached Algiers and then the 1st armored Division.

Marcel Bloch is deported to Buchenwald

In 1944, Marcel Bloch was deported to Buchenwald as a political hostage. During his detention, the Germans asked him, in exchange for his freedom, to work for them as director of a Focke-Wulf factory in Hanover. Once again, in spite of his fragile health, he refused and was almost hanged. During this period, he kept abreast of developments in the aviation industry and sent messages to his family and staff. He managed to send a letter to the Sup’Aéro former pupils’ Association he was president of:

“Dear comrades, times may be difficult, but don’t loose hope in the future”.

“At the end of this war, during which ships, rolling stock and commercial aircraft will have been destroyed, commercial aviation will expand as never before and will replace most means of transport”.

“There is no doubt that the government of France will, in a rebuilt Europe, be able to preserve the share of aeronautical production in keeping with our technical expertise and our geographic position in the world”.

The Buchenwald camp was liberated on April 11, 1945, and Marcel Bloch and his deported comrades were set free.

By the end of the Second World War, French aeronautical industrial facilities had been considerably depleted, the base of machine tools had aged or had been destroyed, and design offices teams dispersed. Only factory staff were available in any numbers. State-owned companies continued to exist while the private sector attempted to re-emerge.


During the armistice convention on July 17, 1940, a German commission, led by Kurt Tank, Focke-Wulf’s technical director, came to Mérignac. During its assessment visit, it tested the MB 175 and appreciated its qualities. Henri Déplante was surprised:

It’s the first time that we’ve been congratulated! The Germans appreciated the considerable efforts that our staff had made!