The French Diesel Challenge
In 1934, the French Ministry of Aviation announced a competition for the creation of an aviation diesel engine. The goal of this contest was to eliminate France’s backwardness in this area of engine manufacturing. However, the development of an indigenous aviation diesel engine progressed with great difficulty. Only two manufacturers undertook the task.
Rexovice and Gaston Botali created an eight-cylinder radial diesel with 350 hp, but they never managed to put it into production. Pierre Clerget’s company (Clerget) had more luck; the Clerget 14 F2 engine developed there was tested on the Wibault 368 aircraft, but a transatlantic flight could not be carried out due to lack of necessary funding.
The Bernard 86: A Flying Laboratory
The Compagnie Lilloise de Moteurs (CLM) took a different path – it purchased a license from Junkers for their 535 hp Jumo 205 diesel aircraft engine. To research the engine’s operation in flight, CLM needed an aircraft to use as a flying laboratory during the testing of new diesel engines.
In 1935, CLM acquired a Bernard 82 from the already bankrupt Société des Avions Bernard, and equipped it with a licensed copy of the Jumo 205 – the CLM 6AS engine. Re-designated as the Bernard 86, the aircraft made its first flight on September 9, 1936. There were also plans to build a Bernard 88 aircraft with three CLM 6AS engines, but these could not be realized.
Testing and the Final Incident
In December 1936, the Bernard 86 (with number Z-019) and its CLM 6AS engine was transferred to CEMA, where numerous tests were conducted. However, in June, during one of the flights, the main landing gear failed to deploy, and test pilot Konstantin Rozanov was forced to belly-land the machine.
With this incident, the last hopes of the developers were shattered; they had hoped to use this fuel-efficient engine to set a world record for straight-line flight distance – over 12,000 kilometers.
Technical Specifications
| Modification | Bernard 8 6 |
| Wingspan, m | 27.10 |
| Length, m | 18.10 |
| Height, m | 3.68 |
| Wing area, m2 | 90.00 |
| Empty weight | 2140 |
| Normal takeoff weight | 7800 |
| Engine type | 1 Piston engine CLM 6AS |
| Power, hp | 1 x 560 |
| Maximum speed, km/h | 300 |
| Cruising speed, km/h | 250 |
| Practical range, km | 13700 |
| Practical ceiling, m | 9000 |
| Crew, crew members | 2 |
Image and diagram gallery of the Bernard 86
 Bernard 86 |
 Bernard 86 |
 Bernard 86 |