Lioré-et-Olivier LeO 45 / LeO 451


The LeO 45.01 B4 - designed by Jean Mercier to Armee de l'Air Programme A21 (1934) - first flew on 16 January 1937. It was an all-metal low-wing monoplane powered by two 805-kW (1,080-hp) Hispano-Suiza 14Aa radial radial engines. The wings had considerable dihedral and the streamlined elliptical monocoque fuselage had a pointed and fully glazed nose. The landing gear was fully retractable. Accommodation provided for a pilot in an enclosed cockpit, behind which was the radio operator's panel and below the retractable ventral gun turret.
Trials revealed that the tail needed revision, and development problems with the Hispano-Suiza engine led to the decision in favour of Gnome-Rhone 14 radials in the LeO 451, which was built by SNCASE, the nationalised organisation into which LeO had been absorbed.

Production LeO 451s had two 849.5kW Gnome-Rhone 14N 48/49 or 38/39 radial engines in specially designed Mercier cowlings. Despite excellent performance, construction of the type was slow. The first production aeroplane flew in March 1939, and although 1,783 aircraft were ordered only 452 had been produced by the fall of France. Only five LeO 451s were on first-line strength by 3 September 1939.  Subsequent production amounted to 225 more aircraft.

A number of modifications were incorporated during series production, the principal being a totally redesigned fin and rudder assembly. Armament included a fixed 7.5mm MAC 1934 nose machine-gun, another gun of the same type flexibly mounted in the ventral gondola, and a somewhat troublesome 20mm HS-404 on a special mounting in the dorsal position. Maximum bomb load - carried in fuselage and wing bomb bays - was 2,400kg.
The LeO 451s were used initially for long-range reconnaissance missions, then for daylight bombing during the Battle of France and in night raids on Italian targets during June 1940. A further 225 were ordered by the French Vichy regime, the type serving in French overseas territories, later relegated to transport and liaison duties (a number flown in these roles by the Luftwaffe). Twenty-seven LeO 451s were ceded to Italy in 1941 but saw little service.

Variants with different engines reached prototype form, and some production aircraft were modified as transports, glider tugs, mailplanes and trainers. There were numerous experimental conversions of the basic design. Several examples remained in use in secondary roles for several years following the end of the Second World War.

LeO 451
Engines: 2 x Gnome-Rhone 14N-48/49, 850kW (1,140 hp).
Span: 22.5m (73 ft 9.75in).
Length: 17.17m (56 ft 4in).
Max T/O weight: 11400 kg (25,133 lb).
Max speed: 308 mph at 15,750ft.
Operational range: 1,429 miles.
Armament: 1x20-mm Hispano-Suiza cannon and 2x7.5 mm (0.295-in) MAC machine-guns plus up to 1500 kg (3,307 lb) bombs internal.

LeO 451 B.4
Engine: 2 x Gnome-Rhone 14N 48/49, 850kW
Max take-off weight: 11400 kg / 25133 lb
Loaded weight: 7815 kg / 17229 lb
Wingspan: 22.5 m / 73 ft 10 in
Length: 17.17 m / 56 ft 4 in
Height: 5.24 m / 17 ft 2 in
Wing area: 68.0 sq.m / 731.95 sq ft
Max. speed: 495 km/h / 308 mph
Ceiling: 9000 m / 29550 ft
Range: 2300 km / 1429 miles
Crew: 4
Armament: 2 x 7.5mm machine-guns, 1 x 20mm cannon, 1500kg of bombs