In search of a more powerful night-bomber, the Liore-et-Olivier design team developed a large four-engined machine, the Liore-et-Olivier LeO 203. This was first flown in May 1930, and was powered by four 224kW Gnome-Rhone 7Kb radials mounted in pairs on the lower wings. Soon afterwards a floatplane version was flown under the designation LeO 204.
A 1931 order for 40 LeO 203s was transferred to the LeO 206, the first of which made it maiden flight in June 1932. This had a redesigned nose, a ventral balcony which housed the bomb-bay and, at the rear, a defensive gun position, and was powered by four 261kW Gnome-Rhone 7Kd radials. The LeO 206 equipped Groupe de Bombardement III/12 at Reims and then GB I/22 at Chartres. Three aircraft of the original order for 40 were completed as LeO 207 machines with a nose section similar to that of the LeO 203 and a smaller ventral balcony than that of the LeO 206. Performance was improved by the installation of Gnome-Rhone Titan Kds supercharged engines.
The ability of the LeO 206 to remain aloft on only three or even two engines gave it an extended life. Nicknamed Caravelle, 29 were still in flying condition in September 1939, the majority of them stationed in Morocco.
Engine: 4 x Gnome-Rhone 7Kd Titan radial, 261kW
Max take-off weight: 8450 kg / 18629 lb
Loaded weight: 4230 kg / 9326 lb
Wingspan: 24.54 m / 80 ft 6 in
Length: 14.77 m / 48 ft 5 in
Height: 6.28 m / 20 ft 7 in
Wing area: 118 sq.m / 1270.14 sq ft
Max. speed: 215 km/h / 134 mph
Ceiling: 7250 m / 23800 ft
Range: 2000 km / 1243 miles
Armament: 6 x 7.7mm machine-guns, 1500kg of bombs