Design and First Flights
The Caudron C.690 was designed as a training aircraft for single-seat fighter pilots. It differed little from the earlier C.720 model, featuring an enlarged rounded vertical tail and non-retractable main landing gear struts without braces, but with wheel fairings.
The aircraft was heavier than the C.720. Instead of a 140 hp Bengali Sport engine, it was fitted with a 220 hp Renault 6Q-03 engine. The first prototype took to the air in early 1936, followed by the second on February 18, 1936.
International Interest and Setbacks
Soon after, the first C.690 prototype was demonstrated to air force missions from Japan, the USSR, and the USA. As a result, one single-seat Caudron aircraft was purchased by the Soviet Union and one by Japan, although the exact models are unknown. It is possible these were C.690 aircraft, but apparently with non-rounded tail stabilizers, similar to the preceding experimental C.580 model.
During subsequent official trials at Villacoublay, the first prototype crashed on May 10, 1937, killing Caudron’s chief test pilot, René Paulhan. Despite the catastrophe, interest in the aircraft continued to grow, and an order for production aircraft for the French Air Force soon followed.
Production and Limited Service
Production machines differed from the prototypes with a triangular shape for the stabilizer and rudder, extended landing gear struts, and non-adjustable slots in the wing’s leading edge.
Series production was slow, and flight tests of the first C.690M aircraft only began in April 1939. These military aircraft were unarmed but featured an OPL photo-machine gun.
By the end of May that year, 15 aircraft were delivered to fighter pilot training centers in Salon, Dijon, and Étampes. However, after the capitulation of France in June 1940, none of them were fit for operation. One aircraft was restored after the war and flew again on April 12, 1945, though its traces were subsequently lost.
Technical Specifications
| Modification | C.690 |
| Wingspan, m | 7.70 |
| Length, m | 7.82 |
| Height, m | 2.60 |
| Wing area, m2 | 9.00 |
| Empty weight | 670 |
| Maximum takeoff weight | 1050 |
| Engine type | 1 Piston engine Renault 6Q.05 |
| Power, hp | 1 x 220 |
| Maximum speed, km/h | 370 |
| Cruising speed, km/h | 340 |
| Practical range, km | 1100 |
| Service ceiling, m | 7000 |
| Crew | 1 |
Image and diagram gallery of the Caudron C.690
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |
 C.690 |