The Lioré et Olivier LeO 25 was a bomber aircraft produced in France in the late 1920s.

Design and development

The LeO 25 was a development of the LeO 20 and retained much of that aircraft's structure, adding a new tail and liquid-cooled engines. The prototype was delivered to the ''

Aéronautique Militaire The French Air and Space Force (AAE) (french: Armée de l'air et de l'espace, ) is the air and space force of the French Armed Forces. It was the first military aviation force in history, formed in 1909 as the , a service arm of the French Arm ...

'' amongst a batch of LeO 20s in 1928 for evaluation. This was redesignated LeO 252 in 1929 after an engine change, and a second, generally similar machine was purchased by Romania. In 1931, the LeO 252 remaining in France was fitted with wooden floats and handed over to the '' Aéronavale'', forming the pattern for the majority of LeO 25s which would be produced as seaplanes. The only other members of the family to be built with wheeled undercarriage were three LeO 253s purchased by Brazil in 1931, and which would see service in the Constitutionalist Revolution the following year, and the sole LeO 255 which would later be fitted with floats. This latter machine was equipped with supercharged engines and was used to set a number of height-with-load records for seaplanes. The only versions produced in quantity were the LeO H-257''bis'' and LeO H-258, which together represented orders for 86 units from the ''Aéronavale''. Entering service in June 1935, they flew neutrality patrols during the

Spanish Civil War The Spanish Civil War ( es, Guerra Civil Española)) or The Revolution ( es, La Revolución, link=no) among Nationalists, the Fourth Carlist War ( es, Cuarta Guerra Carlista, link=no) among Carlists, and The Rebellion ( es, La Rebelión, lin ...

and some remained in service at the outbreak of the Second World War. These surviving aircraft flew convoy escort and anti-submarine patrols in September 1939 before being used as tactical bombers against land targets during the

Blitzkrieg Blitzkrieg ( , ; from 'lightning' + 'war') is a word used to describe a surprise attack using a rapid, overwhelming force concentration that may consist of armored and motorized or mechanized infantry formations, together with close air su ...

, suffering heavy losses. Fifty-three remained on strength with Vichy forces in August 1940, and these were used for secondary roles such as training and target towing until 1944.

Variants

* LeO 25 - landplane night bomber with

Hispano-Suiza 12Hb Hispano-Suiza piston aero-engines were predominantly piston engines produced by Hispano-Suiza in France, Spain, and under licence in the United Kingdom, the United States and Russia from the First World War through to the 1950s. Development of these ...

engines (1 prototype) * LeO 252 - landplane bomber with Hispano-Suiza 12Mbr engines (1 built, one converted from LeO 25) * LeO 253 - landplane bomber similar to LeO 252 (3 built) * LeO H-254 - dedicated seaplane version of LeO 252 (2 built) * LeO H-255 - record-setting version of LeO H-254 with supercharged Hispano-Suiza 12Xbrs engines (1 built) * LeO H-256 - version of H-254 with extended wingspan (1 built) * LeO H-257 - modified version for Aéronavale with Gnome-Rhône 14Kbrs engines and enclosed cockpit for pilot (1 built) ** LeO H-257''bis'' - production version of H-257 with Gnome-Rhône 14Kirs / Gnome-Rhône 14Kjrs engines, strengthened airframe, and enclosed nose gun position (60 built) * LeO H-258 - interim version similar to H-257''bis'' but with Hispano-Suiza 12Nbr engines, supplied to Aéronavale while H-257''bis'' production was being undertaken (26 built) * LeO 259 - version with

Hispano-Suiza 12Ydrs The Hispano-Suiza 12Y was an aircraft engine produced by Hispano-Suiza for the French Air Force before the Second World War. The 12Y became the primary French 1,000 hp (750 kW) class engine and was used in a number of famous aircraft ...

/ Hispano-Suiza 12Yfrs engines (1 built)

Operators

; *

Brazilian Air Force "Wings that protect the country" , colours = , colours_label = , march = Hino dos Aviadores , mascot = , anniversaries = 22 May (anniver ...

- 3 × LeO 253 ; * '' Aéronavale'' **

Escadrille 3B1 A flight is a small military unit within the larger structure of an air force, naval air service, or army air corps; and is usually subservient of a larger squadron. A military aircraft flight is typically composed of four aircraft, though t ...

Escadrille 3B2 A flight is a small military unit within the larger structure of an air force, naval air service, or army air corps; and is usually subservient of a larger squadron. A military aircraft flight is typically composed of four aircraft, though t ...

Escadrille B-1 A flight is a small military unit within the larger structure of an air force, naval air service, or army air corps; and is usually subservient of a larger squadron. A military aircraft flight is typically composed of four aircraft, though t ...

Escadrille B-2 A flight is a small military unit within the larger structure of an air force, naval air service, or army air corps; and is usually subservient of a larger squadron. A military aircraft flight is typically composed of four aircraft, though t ...

Escadrille B-3 A flight is a small military unit within the larger structure of an air force, naval air service, or army air corps; and is usually subservient of a larger squadron. A military aircraft flight is typically composed of four aircraft, though t ...

** Escadrille E.7 **

Escadrille 3S4 A flight is a small military unit within the larger structure of an air force, naval air service, or army air corps; and is usually subservient of a larger squadron. A military aircraft flight is typically composed of four aircraft, though t ...

* ''

Armée de l'Air The French Air and Space Force (AAE) (french: Armée de l'air et de l'espace, ) is the air and space force of the French Armed Forces. It was the first military aviation force in history, formed in 1909 as the , a service arm of the French Army; ...

'' **

Groupe de Bombardement II/25 A group is a military unit or a military formation that is most often associated with military aviation. Air and aviation groups The terms group and wing differ significantly from one country to another, as well as between different branches o ...

; * Royal Romanian Air Force - 1 × LeO 252

Specifications (LeO H-257''bis'')

Notes

References