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    Liore-et-Olivier LeO 25 Maritime Patrol Bomber / Floatplane Aircraft

    The rugged LeO 25 series of French bombers served during the interwar years and proved completely outmoded by the time of World War 2.

     Updated: 5/11/2016; Authored By Staff Writer; Content ¬©www.MilitaryFactory.com

    The Liore-et-Olivier was a bomber platform developed by the French for its Air Force and also went on to see service with its navy. Some were exported and the type was seen in both land-based and floatplane forms throughout its career. Introduced during the decade prior to World War 2 (1939-1945), the aircraft managed an existence leading up to the first shots fired. It was pressed into service during the early campaigns but its technology and performance lagged far behind its modern counterparts to warrant the aircraft series a symbol of a previous age of flight. Less than one hundred were ever produced and remaining stocks fell to the Vichy government of France that emerged after the fall of the country to the invading Germans in 1940.

    Liore-et-Olivier ("LeO") was a French-based aviation firm that had formed prior to the fighting of World War 1 in 1912. It was founded by Fernand Liore and Henri Olivier and produced various aircraft and types into the interwar period - from the LeO H.13 of 1922 to the LeO 45 of 1938. The company was nationalized in 1936, joining CAMS, Potez, Romano, and SPCA to form SNCASE - the "Societe Nationale des Constructions Aeronautiques de Sud-Est". This company soldiered on into post-World War 2 1957.

    In 1927, Liore-et-Olivier test-flew its LeO 20 model night-bomber intended to compete for a new French Air Ministry contract and a total of 311 were eventually secured for operational service. A year later, LeO engineers furthered development of this airframe and delivered a prototype outfitted with 2 x Hispano-Suiza 12Hb engines for evaluation to the French Air Force. This aircraft, too, was accepted for service and serial production begat 96 examples (including prototypes).

    The aircraft's arrangement was a mix of aviation eras, still retaining open-air cockpits for its pilot and gunners, a biplane wing structure, and a fixed undercarriage. The nose was glazed for observation of the terrain below with a defensive machine gun tub fitted just above. The cockpit was seated ahead of the upper wing assembly with the pilot behind a simple windscreen. The position offered commanding views all about the aircraft. Aft of the wing assemblies was a second dorsal gun tub for protecting the vulnerable sections of the aircraft. The fuselage was deep with slab sides and the tail sported a rectangular vertical fin with low-mounted horizontal planes. The undercarriage retained the same tail-dragger form as seen in the earlier LeO 20 and showcased large, spatted wheels at the main legs and a simple tail skid under the tail. The biplane wing arrangement made use of parallel struts with three bays. Within one of these bays were the engine nacelles seated over the lower wing unit and outboard of the fuselage sides (one engine to a wing). The aircraft's crew numbered four to five personnel and defensive armament was between two to four 7.5mm machine guns. The offensive payload reached up to 1,320lbs of conventional drop ordnance and there proved support for the carrying and releasing of torpedoes for the maritime strike role. First flight of the LeO 25 prototype was in 1928.

    To exact better performance from their LeO 25 prototype, there was a switch in 1929 to Hispano-Suiza 12Mbr engines of 575 horsepower each which, through the sole converted LeO 25 airframe, became the "LeO 252". The Romanian Air Force purchased this form in one example. The line then evolved into the "LeO 253" which was largely based on the LeO 252 model and three were produced in all, these seeing service with the Brazilian Air Force. In 1931, the aircraft was modified, yet again, this time with underwing floats instead of wheels for the French Navy to become the "LeO H-254". Two were completed and operated in the reconnaissance-bomber floatplane role. A single airframe was modified for record-setting as the "LeO H-255", outfitted with Hispano-Suiza 12Xbrs supercharged engines intended to claim several altitude/payload records during its tenure aloft. The "LeO H-256" was based on the H-254 model but featured a larger wingspan. Only one was built. The final limited-production variant of note became the sole "LeO 259" that was completed with Hispano-Suiza 12Ydrs engines.

    Liore-et-Olivier LeO H-257bis Technical Specifications

    Service Year: 1928
    Type: Maritime Patrol Bomber / Floatplane Aircraft
    National Origin: France
    Manufacturer(s): Liore-et-Olivier - France
    Production Total: 96

    Structural (Crew Space, Dimensions and Weights)

    Operating Crew: 5
    Length: 57.55 feet (17.54 meters)
    Width: 83.66 feet (25.50 meters)
    Height: 22.31 feet (6.80 meters)

    Weight (Empty): 11,684 lb (5,300 kg)
    Weight (MTOW): 21,076 lb (9,560 kg)

    Installed Power and Standard Day Performance

    Engine(s): 2 x Gnome-Rhone 14Knrs/Kors engines developing 870 horsepower each.

    Maximum Speed: 143 mph (230 kph; 124 knots)
    Maximum Range: 932 miles (1,500 km)
    Service Ceiling: 26,247 feet (8,000 meters; 4.97 miles)

    Armament / Mission Payload

    2 OR 4 x 7.5mm Darne machine guns

    Up to 1,323lbs of bombs OR 1 x Torpedo

    Global Operators / Customers

    Brazil; France; Romania

    Model Variants (Including Prototypes)

    LeO 25 - Night Bomber Prototype; fitted with Hispano-Suiza 12Hb engines; single example.

    LeO 252 - Bomber; fitted with Hispano-Suiza 12Mbr engines; single example.

    LeO 253 - Bomber similar to LeO 252; 3 examples produced.

    LeO H-254 - Seaplane based on the LeO 252; 2 examples produced.

    LeO H-255 - Speed Racer Conversion Model based on the LeO H-254; fitted with supercharged Hispano-Suiza 12Xbrs engines; single example.

    LeO H-256 - Based on the LeO H-254 with wider wing span; single example.

    LeO H-257 - Fitted with Gnome-Rhone 14Kbrs engines; enclosed cockpit; single example for French Navy.

    LeO H-257bis - Definitive Production Model; based on the LeO H-257; enclosed nose-gunners position; fitted with Gnome-Rhone 14Kirs/Kjrs engines; reinforced airframe; 60 examples produced.

    LeO H-258 - Similar to H-257bis production model; fitted with Hispano-Suiza 12Nbr engines; French Navy usage; 26 examples produced.

    LeO H-259 - Fitted with Hispano-Suiza 12Ydrs/Yfrs engines; single example.

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