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Technical Specifications
Medium Bomber four-seater with low-wings and retractable landing gear
Date first flight
January 16, 1937
22,52 m 
17,20 m 
5,24 m 
Wing Area
68 m2 
Empty Weight
7530 Kg 
Max. Takeoff Weight
11400 Kg 
Cruising Speed
360 km/h. 
Maximum Speed
495 km/h at 4800m 
Climbing Speed
5000m in 14mn  
Service ceilling
2900 kms unladen
4 Men
2 Radial Engine Gnôme Rhône 14 N38/39 of 1030 Hp each at 4800m
1 fixed machine-gun MAC 34 of 7.5mm in the nose with 300 rounds
1 machine-gun MAC 34 de 7.5mm in ventral position with 100 rounds
1 Cannon Hispano Suiza HS404 of 20mm in dorsal position with 120 rounds
1400 kg of bombs among which 1000 in main bomb bay



604 Leo 451 about have been built since the date of the first flight on January 16 1937 . They are divided into :

  • 1 léo 45 No01 with engines Hispano Suiza AA06 and 07 who became Léo 451 N 01 when he was equipped with 2 Gn�me Rh�ne 14N more reliable
  • 602 Leo 451 of serie
  • 1 Prototype Leo 455 (see "Versions")

To date, out of the 604 aircraft manufactured ,133 are listed in the list below :



The LeO-45 is studied in order to respond to the B5 program launched in November1934. The latter corresponds to a twin-engine bomber capable of reaching 400 km / h, and capable of carrying a ton of bombs over a distance of 700 km. Meanwhile, the program evolves to become "B4" with a crew reduced to 4 people. Subsequently, the maximum speed is increased to 470 km / h. The first prototype made its first flight on January 16, 1937 in Villacoublay. Equipped with Hispano-Suiza AA engines of 1080 hp, this metal monoplane with low cantilever wing could reach 465 km / h. The first tests reveal some defects and lead to a series of modifications: the drifts are modified to compensate for lateral instability at take-off, and the radiators integrated in the leading edge, which are not very effective, are moved towards the engine cowls. The weak point however remains the engines.These are little reliable, with a perfectible cooling. This defect is corrected by the adoption of modified cowls, and the Hispano-Suiza engines will eventually be replaced by Gnome-Rhone 14N.

The unit resumed its tests under the name of Leo-451 and a first order of 20 aircraft was placed, followed by an additional request for 100 aircraft to be delivered from the end of 1938. The manufacturing is distributed between subcontractor's significant number and the deliveries know unfortunately frequent delays in the French aircraft industry of this time. The first series aircraft did not fly until March 1939 and an experimental squadron was set up in April 1939.

Two other orders followed with 100 then 480 additional aircraft and the Air Force began to collect its first LeO-451 from August 1939. However, on a total order of 789 aircraft, only 10 units had been delivered in September 1939. The "funny war" will be used to make more LeO-451. Thus, on 10 May 1940, if 222 aircraft were manufactured, only 94 were in units.

The Bombardment Groups planned to receive the new aircraft were withdrawn from the front from the end of 1939 to be transformed. But delays accumulate and some groups will continue to use the old Bloch MB200 alongside the few LeO-451 available.

It is the GB I / 12 and II / 12 which realized the first missions from May 11th, 1940. The Leo-451 are used in particularly dangerous and inadequate missions : without cover of fighter, they are thrown to low height in the assault of the convoys of German troops strongly protected by Flak. From June 16th onwards, some of the groups equipped with LeO 451 are withdrawn to the AFN, the 11 remaining groups continuing the fighting against Italy, recently returned to war. At the Armistice, 130 aircraft were lost in combat on the 452 manufactured, of which only 373 delivered in units.

The aircraft present in AFN or in the free zone, will be reused by the Vichy aviation after the Armistice. The Leo-451s will participate in the Syrian campaign in the summer of 1941, as well as various retaliation missions, particularly to Gibraltar. These models will have an ultimate evolution with the adoption of drift without stall and the addition of a pairing of machine guns of 7.5mm on each side of the cannon of 20mm in rear defense. In April 1941, the German authorities authorized the government of Vichy to resume construction of Leo 451, and 225 aircraft were ordered, of which only 109 would be delivered before the dissolution of the Vichy Air Force in November 1942.

During the invasion of the southern zone by the Germans, more than 150 LeO-451 were seized and delivered by the Germans to Italy or the Luftwaffe. The Leo 451s present in North Africa pass to the service of the allies, but worn out and outdated, they will soon be replaced by more modern bombers, B26 or B25.


Léo 451 T

Transformed version for transport after the invasion of the free zone.

Léo 451 M
Version intended for the Naval Aviation. 68 ordere aircraft, the first copies of which will be delivered at the end of May 1940
Léo 452
Version that was to receive Hispano-Suiza 14 engines, but was eventually equipped with Gnome-Rhone GR14N-38
Léo 453
This version was to be supplied by American engines Pratt & Whitney R-1830 Twin-Wasp. No manufactured copies. After the war, this denomination was taken over for aircraft re-equipped with Pratt & Whitney R-1830-67
Léo 454
Version that was to receive Bristol Hercules II engines. The prototype was never completed.
Léo 455
Version powered by Gnome and Rhone 14R 0/1. He made his first flight on 3 December 1939 and served as a test bed for various weapon configurations. Other aircraft were transformed into LeO 455 and will be used in particular by the IGN.
Léo 457
Pressurized version with specific fuselage designed to be equipped with Hispano-Suiza 89ter engines. The prototype was not completed at the Armistice and was abandoned.
Léo 458
Version that was to receive Wright-Cyclone engines of 1600CV. The completed prototype was destroyed before the Armistice.
Léo 459
Version adapted for the transport of passengers after the Armistice with in particular the addition of additional tank.



1 ) _ Éditions Lariviére :

- Docavia No23 : "LeO45, Amiot 350"


2) _ French Wings No 4

- Lioré & Olivier LeO45



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