Lioré et Olivier LeO 45
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Lioré-et-Olivier LeO 45 was a French
medium bomber A medium bomber is a military bomber aircraft designed to operate with medium-sized bombloads over medium range distances; the name serves to distinguish this type from larger heavy bombers and smaller light bombers. Mediums generally carrie ...
that was used during and after the
Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposi ...
. It had been designed for the new ''
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 Arm ...
'' as a modern medium bomber capable of performing independent strategic operations, unlike the majority of previous French bombers. The LeO 45 was a low-wing monoplane, all-metal in construction, equipped with a retractable undercarriage and powered by two 1,060 hp Gnome-Rhône 14N engines. The prototype, which made its
maiden flight The maiden flight, also known as first flight, of an aircraft is the first occasion on which it leaves the ground under its own power. The same term is also used for the first launch of rockets. The maiden flight of a new aircraft type is alw ...
on 15 January 1937, had been fitted two 1,100 hp Hispano-Suiza engines.Angelucci and Matricardi 1978, p. 254. The LeO 45 had been developed as a modern and advanced bomber for the new ''Armée de l'air'', which had gained its independence on 1 April 1933. Introduced to operational service in 1938, it was a very effective and capable bomber. As only a handful of aircraft had been introduced into the French Air Force by the outbreak of the Second World War, the LeO 45 was too late to provide a substantial contribution during the Battle of France in the face of an invasion by
Nazi Germany Nazi Germany (lit. "National Socialist State"), ' (lit. "Nazi State") for short; also ' (lit. "National Socialist Germany") (officially known as the German Reich from 1933 until 1943, and the Greater German Reich from 1943 to 1945) was ...
. As a result of the
Armistice of 22 June 1940 The Armistice of 22 June 1940 was signed at 18:36 near Compiègne, France, by officials of Nazi Germany and the Third French Republic. It did not come into effect until after midnight on 25 June. Signatories for Germany included Wilhelm Keitel ...
, the type continued to be manufactured and operated by occupied
Vichy France Vichy France (french: Régime de Vichy; 10 July 1940 – 9 August 1944), officially the French State ('), was the fascist French state headed by Marshal Philippe Pétain during World War II. Officially independent, but with half of its te ...
as
Free France Free France (french: France Libre) was a political entity that claimed to be the legitimate government of France following the dissolution of the Third Republic. Led by French general , Free France was established as a government-in-exile ...
forces operated the aircraft. The LeO 45 participated in combat missions throughout the remainder of the war and continued to be used for some time after its end by the post-war French Air Force. The last examples in active service were retired in September 1957.


Development


Background

On 1 April 1933, the French Air Force was officially recognised as an independent military service.Danel 1967, p. 3. In accordance with this new position, in addition to cooperating with land and naval operations, there was a newfound emphasis on the ability to execute independent strategic-level operations. It was quickly determined that existing aircraft would be incapable of performing the latter role to a sufficient degree, thus a modernisation programme, known as ''Plan I'', was promptly initiated. This plan called for 1,010 modern combat aircraft suitable for first-line service to be provisioned by late 1936; out of these, 350 of these were to be bombers, further divided into 210
medium bomber A medium bomber is a military bomber aircraft designed to operate with medium-sized bombloads over medium range distances; the name serves to distinguish this type from larger heavy bombers and smaller light bombers. Mediums generally carrie ...
s, 120 twin-engined
heavy bombers Heavy bombers are bomber aircraft capable of delivering the largest payload of air-to-ground weaponry (usually bombs) and longest range (takeoff to landing) of their era. Archetypal heavy bombers have therefore usually been among the larges ...
, and 20 four-engined heavy bombers. While numerous multi-seat aircraft, such as the Bloch MB.200,
Bloch MB.210 The Bloch MB.210 and MB.211 were the successors of the French Bloch MB.200 bomber developed by Société des Avions Marcel Bloch in the 1930s and differed primarily in being low wing monoplanes rather than high wing monoplanes. Development The ...
,
Amiot 143 The Amiot 143 (sometimes written as 143M or 143 M.5) was a late 1930s French 5-seat ''Multiplace de Combat'' (M.5) designed to meet 1928 specifications for a monoplane capable of day and night bombing, long-range reconnaissance and bomber escort ...
, Lioré et Olivier LeO 257,
Potez 540 The Potez 540 was a French multi-role aircraft of the 1930s. Designed and built by Potez, it served with the French Air Force as a reconnaissance bomber, also serving with the Spanish Republican Air Force during the Spanish Civil War. Although ob ...
and Farman F.221, were procured between 1933 and 1935, many of these originated from technical programmes which had predated the recognition of the service's independence and thus had not been developed to meet its new strategic ambitions. In addition, several shortcomings was quickly identified with many of these aircraft, including inadequate defensive armaments, being too slow and relatively unmanoeuvrable, and thus too vulnerable for viable sorties over hostile territory. Accordingly, the need for their replacement was apparent. It was out of the ''Plan I'' modernisation programme that the requirements for an advanced medium bomber were formulated for the new service. On 17 November 1934, the ''Service Technique Aéronautique'' released the ''B5'' heavy bomber programme and made approaches to all of the main French aircraft manufacturers. Various requirements were specifying a five-seat bomber with a top speed of 400 km/h (215 knots, 250 mph) at 4,000 m (13,125 ft) and a combat radius of 700 km (435 mi) carrying an internally carried payload of 1,200 kg (2,650 lb). The new bombers would have to be capable of operating at day and night, while carrying defensive turrets, the forward unit being fixed to the fuselage while the ventral position was to be flexible.Danel 1967, pp. 3–4. In late 1935, Amiot, Latecoere, Romano, Lioré et Olivier and Bloch presented the mock-ups of their submissions. During the latter half of 1935, the Service Technique Aéronautique decided to enact several changes to some of the specified requirements; these included the revision of the rearward and lower turret arrangements and the crew reduced from five to four, as it was thought that the co-pilot could also serve as a navigator and bomb-aimer.Danel 1967, p. 4. To reflect the crew change, the programme was re-designated from B5 to ''B4''. In September 1936, the envisioned bomber's requirements were revised to account for development of 1,000 hp (746 kW)-class engines; accordingly, the cruise speed raised to 470 km/h (255 knots, 290 mph).''Air International'' October 1985, p. 179. It was at this point that ''Plan I'' was cancelled in favour of ''Plan II'', which called for an even larger and more capable bomber force to be provisioned for the French Air Force; under this plan, it was envisioned that a total of 41 units each equipped with 12 B4-type aircraft would be established. Amongst the numerous manufacturers to submit proposals for the B4 programme was Lioré et Olivier, which was to be soon nationalized as part of the
SNCASE SNCASE (abbreviated from ''Société nationale des constructions aéronautiques du Sud-Est'') or Sud-Est was a French aircraft manufacturer. The company was formed on February 1, 1937, by the nationalization and merger of Lioré et Olivier, Pote ...
. Lioré et Olivier was a long-time supplier to the ''Armée de l'air'', providing aircraft such as its LeO 20 and other lesser-known biplane bombers. This had earned the company a reputation for reliability, but were had been relatively traditional and conservative in terms of their design. The 1934 programme was put under Pierre Mercier, a younger engineer who had expertise in
cantilever A cantilever is a rigid structural element that extends horizontally and is supported at only one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a cant ...
airframes. It was out of Mercier's work that a new design emerged, which was soon christened as the ''LeO 45''.


Flight testing

On 16 January 1937, the ''LeO 45-01'' prototype, powered by a pair of Hispano-Suiza 14AA-6 / Hispano-Suiza 14AA-7 radial engines producing 1,120 hp (835 kW) each, flew for the first time.''Air International'' October 1985, p.180. Despite problems experienced with longitudinal instability, engine reliability and overheating, the aircraft demonstrated excellent overall performance. During flight testing, the prototype was capable of reaching 480 km/h (260 knots, 300 mph) at 4000 m and of attaining 624 km/h (337 knots, 388 mph) in a shallow dive. In September 1937, the prototype was delivered to the Centre d'Essais de Matériels Aériens at Villacoublay for the type's official evaluation. On 6 December 1937, it was involved in a forced landing incident as a result of both engines having failed simultaneously in mid-flight; the pilot, Jean Doumerc, was able to land without sustaining any damage. The prototype was promptly returned to the manufacturer for adjustments prior to the resumption of evaluation flights. In July 1938, the prototype, fitted with the new Mercier-designed cowlings, attained 500 km/h (270 knots, 311 mph). The earlier instability issues were partially addressed via the adoption of redesigned twin
fin A fin is a thin component or appendage attached to a larger body or structure. Fins typically function as foils that produce lift or thrust, or provide the ability to steer or stabilize motion while traveling in water, air, or other fluids. Fin ...
s and
rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, aircraft, or other vehicle that moves through a fluid medium (generally air or water). On an aircraft the rudder is used primarily to counter adve ...
s on the tail unit.Danel 1967, p. 5. Various issues with the troublesome Hispano-Suiza engines had been experienced and this resulted in several changes being made to the prototype, such as the adoption of broader, more efficient air intakes for the oil coolers, which in turn reduced instances of engine overheating. On 29 August 1938, it was decided to replace the existing Hispano-Suiza engines by Gnome-Rhône 14N 20/21 engines, which were capable of producing 1,030 hp (768 kW) each; as a result of these changes, the aircraft was re-designated as ''LeO 451-01''.Danel 1967, pp. 4–5. Following the completion of the re-engining, the flight test programme was resumed, running from 21 October 1938 to February 1939.Danel 1967, pp. 5–6. In spite of the new engines being slightly less powerful, the speed and general performance of the prototype remained relatively unchanged.Danel 1967, p. 6.


Production

In May 1937, the Armée de l'Air placed an initial pre-production order for a pair of LeO 450 aircraft, one being fitted with Hispano-Suiza AA 06/07 engines and the other with Hispano-Suiza 14 AA 12/13 engines.Danel 1967, p. 7. On 29 November 1937, an order for 20 production machines was received, the first of which being specified for delivery in May 1938. On 26 March 1938, a further 20 LeO 450 was ordered in line with the French Air Ministry's newly adopted ''Plan V'', which called for the reequipping of 22 bomber units. In order to meet French ambitions, which was viewed as requiring 449 frontline aircraft and 185 reserve aircraft, by April 1940, official contracts were also issued for Bloch 131 and Amiot 350 aircraft as stop gap measures, along with another 100 LeO 45 aircraft being ordered on 15 June 1938. On 21 October 1938, it was specified that all production LeO 45 aircraft were to be equipped with Gnome-Rhône engines in place of the originally envisioned Hispano-Suiza powerplants. However, as a result of this demand, there was considerable delays in the delivery of the first production aircraft. During late November 1938, the first LeO 45 was on static display at the
Paris Air Show The Paris Air Show (french: Salon international de l'aéronautique et de l'espace de Paris-Le Bourget, Salon du Bourget) is a trade fair and air show held in odd years at Paris–Le Bourget Airport in north Paris, France. Organized by the French ...
; it performed its
maiden flight The maiden flight, also known as first flight, of an aircraft is the first occasion on which it leaves the ground under its own power. The same term is also used for the first launch of rockets. The maiden flight of a new aircraft type is alw ...
on 24 March 1939. On 28 April 1939, the second production aircraft conducted its first flight. Further production issues were encountered as a result of supply issues with Gnome-Rhone engines and associated propellers; as a result, it was decided to fit the type with Ratier-built propellers instead, which reduced the maximum speed from 500 km/h to 470 km/h. During early 1939, as it was becoming apparent that the international situation was worsening and that the European powers were increasingly likely to be involved in a major war, the Armée de l'Air explicitly requested of SNCASE that the company would not delay production by enacting any further improvements; the mandate was issued in spite of known teething troubles with the type that were far from cleared. At the same time, the requirements of Plan V were elevated to 1188 B4 bombers, 396 of these being first line aircraft. Accordingly, on 20 February 1939, a tentative order for 100 aircraft was confirmed; on 18 April 1939, a large order for a further 480 LeO 45 bombers was received.Danel 1967, pp. 7, 10. By September 1939, the eve of the outbreak of the Second World War, there were a total of 749 LeO 45 aircraft on order; this included several different variants of the type, such as an envisioned high altitude model, aircraft outfitted with American-built Wright GR-2600-A5B engines, and 12 aircraft which had been ordered for the
Greek Air Force , colours = , colours_label = , march = , mascot = , anniversaries = 8 November , equipment = , equipment_label ...
.Danel 1967, p. 10. At the same point, there were only 10 LeO 451 bombers in French Air Force service, while another 22 were in the process of being delivered. It was at this point that a flurry of additional wartime production orders were issued, calling for hundreds more aircraft to be manufactured, amounting to around 1,549 LeO 45 aircraft of various models. While additional productions lines were established in order to produce more aircraft, much of this extra capacity did not arrive until mere months prior to the catastrophic Battle of France, thus making their contribution to the course of the war minimal.Danel 1967, pp. 10–11.


Design

The Lioré et Olivier LeO 45 was a twin-engined
medium bomber A medium bomber is a military bomber aircraft designed to operate with medium-sized bombloads over medium range distances; the name serves to distinguish this type from larger heavy bombers and smaller light bombers. Mediums generally carrie ...
, which had been conceived with the aim of producing a suitably advanced bomber to equip the French Air Force. In contrast to its predecessors, which had relied on machine guns for self-protection, the emphasis was placed on high-speed high-altitude cruise. The expectation was that high speed would force enemy fighters into tail-chase attacks and to that effect the aircraft was designed with a rear-firing cannon which possessed an unobstructed rear arc of fire thanks to the design of the twin tailfins. The LeO 45 featured an all-metal construction and a
monocoque Monocoque ( ), also called structural skin, is a structural system in which loads are supported by an object's external skin, in a manner similar to an egg shell. The word ''monocoque'' is a French term for "single shell". First used for boats, ...
fuselage; the structure included 60 individual fixed frames attached to longitudinal stringers and was covered by flush-
rivet A rivet is a permanent mechanical fastener. Before being installed, a rivet consists of a smooth cylindrical shaft with a head on one end. The end opposite to the head is called the ''tail''. On installation, the rivet is placed in a punched ...
ted light
alloy An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductilit ...
panels. As a consequence of the specified speed requirements of the programme, a lot of effort was spent in reducing
parasitic drag Parasitic drag, also known as profile drag, is a type of aerodynamic drag that acts on any object when the object is moving through a fluid. Parasitic drag is a combination of form drag and skin friction drag. It affects all objects regardless of ...
. The fuselage cross-section was reduced via the adoption of not a main fuselage bomb bay paired to smaller bomb bays that were located within the wing roots.''Air International'' October 1985 pp. 179–180.''Flight'' 16 May 1940, pp. 452c–d, 453. The low
cantilever A cantilever is a rigid structural element that extends horizontally and is supported at only one end. Typically it extends from a flat vertical surface such as a wall, to which it must be firmly attached. Like other structural elements, a cant ...
wing, which employed a structure designed and patented by Mercier, was constructed in four separate sections. Specifically, the inner section was built around two spars equipped with steel booms which had enough room between them to accommodate a 200 kg-class bomb and large
self-sealing fuel tanks A self-sealing fuel tank is a type of fuel tank, typically used in aircraft fuel tanks or fuel bladders, that prevents them from leaking fuel and igniting after being damaged. Typical self-sealing tanks have multiple layers of rubber and reinfor ...
; the spars did not continue to the wing-tip but made way for a box-type structure. The wings were furnished with large split-type slotted flaps, which were electronically controlled and high aspect-ratio slotted ailerons, the latter of which being depressed during takeoff. The fuselage housed the aircraft's four-man crew; the bombardier, who was also the commander as per French tradition, was positioned within an almost-fully glazed nose at the front of the aircraft, ahead of the pilot, and performed observation and bombing aiming functions from this location. Behind the pilot, the radio operator could man a defensive 7.5 mm M.1934 (500 rounds) machine gun from an underbelly retractable "gondola". A corridor alongside the main bomb bay led to the dorsal gunner's position, which featured a powered mounting for the 20 mm cannon
Hispano-Suiza HS.404 The HS.404 is an autocannon originally designed and produced by Spanish/French company Hispano-Suiza in the mid-1930s. It was widely used as an aircraft, naval and land-based weapon by French, British, American and other military services, par ...
, with 120 rounds; the turret could be retracted. Another 7.5 mm machine-gun M.1934 was installed in the nose (with 300 rounds). The Leo 45 had a central
bomb bay The bomb bay or weapons bay on some military aircraft is a compartment to carry bombs, usually in the aircraft's fuselage, with "bomb bay doors" which open at the bottom. The bomb bay doors are opened and the bombs are dropped when over t ...
, within which the majority of the aircraft's armaments were enclosed. In total, the aircraft's armaments comprised: 120 20 mm rounds, 800 7.5 mm rounds, up to seven 200 kg bombs or other combinations (1–2 500 kg bombs in the belly, plus the two 200 kg in the wings). When flown with the maximum payload, this reduced the corresponding fuel load to only 1,000 liters. The fuel tanks were also housed within the wings, these comprising a pair of 880 lts tanks within the inner wings), along with a further two pairs of 330 and 410 liters contained in the external wings.Sgarlato, Nico: "Leo 451", ''Aerei nella Storia'' magazine, Westward editions, Parma, n.14 (10/2005), pp. 28–29. Mercier also used his patented type of fairing for the LeO 45's radial engines. Unlike typical
NACA cowling The NACA cowling is a type of aerodynamic fairing used to streamline radial engines installed on airplanes. It was developed by Fred Weick of the National Advisory Committee for Aeronautics (NACA) in 1927. It was a major advance in aerodynamic ...
s, flow adjustment was not provided by flaps but by a frontal ring that moved back and forth to respectively reduce or increase flow, without change in drag. Like many other French twin-engine aeroplanes of the era, the propellers rotated in opposite directions to eliminate the undesirable effects of propeller
torque In physics and mechanics, torque is the rotational equivalent of linear force. It is also referred to as the moment of force (also abbreviated to moment). It represents the capability of a force to produce change in the rotational motion of th ...
. The undercarriage was fully retractable; it featured an unusually complicated mechanism for the main wheels in order to reduce the size of the engine nacelles. The two horizontal surfaces of the tail unit were constructed in two separate halves and bolted onto a short center section fixed to the upper fuselage; the twin fins and rudders, which were furnished with
trim tab Trim tabs are small surfaces connected to the trailing edge of a larger control surface on a boat or aircraft, used to control the trim of the controls, i.e. to counteract hydro- or aerodynamic forces and stabilise the boat or aircraft in a pa ...
s, were attached at the extreme edges of the tailplane.


Operational history

At the outbreak of World War II, only ten LeO 45s had been formally accepted by the French Air Force. These aircraft were issued to a front line unit to experiment with the new type in the field and flew a few reconnaissance flights over Germany, which resulted in the type's first combat loss.Danel 1967, p. 11. At the start of the Battle of France on 10 May 1940, only 54 of the 222 LeO 451s that had been delivered were considered ready for combat, the remainder being used for training, spares, undergoing modifications and repairs or having been lost.''Air International'' October 1985, p. 183. The first combat sortie of the campaign was flown by ten aircraft from ''Groupes de bombardement'' (bomber squadrons, abbreviated GB) I/12 and II/12 on 11 May. Flying at low altitude, the bombers suffered from heavy ground fire with one aircraft shot down and eight heavily damaged. Within the next eight days many of them were shot down, such as the one piloted by sergent-chef Hervé Bougault near Floyon, during a bombing mission over German troops. By the
Armistice An armistice is a formal agreement of warring parties to stop fighting. It is not necessarily the end of a war, as it may constitute only a cessation of hostilities while an attempt is made to negotiate a lasting peace. It is derived from the ...
of 25 June 1940, LeO 451 of the ''Groupement de bombardement 6'' (bomber wing) had flown approximately 400 combat missions, dropping 320 tons of bombs at the expense of 31 aircraft shot down by enemy fire, 40 written off due to damage and five lost in accidents. Other statistics state that about 47 bombers were lost: 26 to fighters, 21 to anti-aircraft fire.''Aerei nella Storia'', 10/2005. Although the LeOs were typically faster than many fighters and also faster than almost all other types of bomber, the Luftwaffe was equipped with fighters that were even faster (such as the Bf-109 and Bf-110). The cruise speed, up to 420 km/h (7 km/min), was one of the strengths of the LeOs performance and made them difficult to intercept. The diving and climbing speeds were very good as well (the Italian SM.79 took 17 minutes to reach 5,000 m, compared to 14 for the LeO), even if not that useful for a bomber. LeOs were optimized for medium-altitude operations (5,000 m) but were forced to go far lower to search for and destroy tactical targets, rarely with even a basic fighter escort (H-75, D.520). LeOs were not unarmed and German fighters had to keep a look out for their dorsal turret: on 6 June 1940, gunner sergeant Grandchamp, GB II/11 shot down two Bf 110Cs with the Hispano cannon. German fighters came to avoid this danger by attacking from below, forcing the LeOs to deploy their retractable turret, which slowed them. Another problem had been caused by the Germans' initial strike. ''Groupement 6'' had 50 LeOs but these aircraft had not been dispersed and even lacked capable AA defence on their airfields. When the Luftwaffe attacked, a total of 40 bombers were lost. In spite of this, ''Groupement 6'' continued the fight, since the LeOs were produced at a fast pace (around 4–5/day, over 200 built within 45 days) allowing them to re-equip. Losses remained high and, on missions, 13 LeOs were intercepted and four shot down by Luftwaffe fighters. ''Groupement 6'' totalled around 70 losses both in air and ground but still continued to fight until the end. Upon Italy's entry into the war on the Axis side, LeOs attacked Livorno, Novi Ligure, Vado and Palermo in a four-aircraft morning mission. Against Italian forces, the LeOs were able to operate without much difficulty. Turin (Fiat plants) was near the border and easy to reach, while Italy did not possess a radar system and radios were not commonly used on the Italian fighters. On the other front, however, ground-based flak fire and Luftwaffe fighters alike took a heavy toll upon the type. A total of 452 aircraft had then been built, 373 accepted into service (including 13 for the Aéronautique navale), and around 130 lost in action in Europe.''Air International'' October 1985, p. 184. Following the Armistice, LeO 451s continued to fly, under the
Vichy government Vichy France (french: Régime de Vichy; 10 July 1940 – 9 August 1944), officially the French State ('), was the fascist French state headed by Marshal Philippe Pétain during World War II. Officially independent, but with half of its terr ...
. Modifications in Vichy service included fitting the aircraft with larger rudders and two more 7.5 mm machine guns in the rear turret. The extra weapons were added because of the limited capacity of the cannon magazines and the fact that changing them in flight was extremely difficult.''Air International'' October 1985, pp. 183–184. Aircraft production had stopped with the German occupation but a 1941 agreement authorized Vichy authorities to have a limited number of military aircraft built and orders were placed for 225 newly built Leo 451s. In order to speed production, considerable use was made of components that had been built in 1940 and stored in the German-occupied zone. The first of the newly produced aircraft flew on 30 April 1942, and by the time the German occupation of Southern France following Operation Torch brought production to an end, 102 LeOs had been built for Vichy.''Air International'' October 1985, pp. 185–186. In 1942, LeO 451-359 was fitted with an experimental
degaussing Degaussing is the process of decreasing or eliminating a remnant magnetic field. It is named after the gauss, a unit of magnetism, which in turn was named after Carl Friedrich Gauss. Due to magnetic hysteresis, it is generally not possible to red ...
coil for remotely detonating
naval mine A naval mine is a self-contained explosive device placed in water to damage or destroy surface ships or submarines. Unlike depth charges, mines are deposited and left to wait until they are triggered by the approach of, or contact with, any ...
s''Air International'' October 1985, p. 185. (some British
Vickers Wellington The Vickers Wellington was a British twin-engined, long-range medium bomber. It was designed during the mid-1930s at Brooklands in Weybridge, Surrey. Led by Vickers-Armstrongs' chief designer Rex Pierson; a key feature of the aircraft is its ...
s and German Junkers Ju 52s also carried a similar device). On 24 October 1940, Vichy French LeO 451s carried out an air raid against
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in retaliation for the Free-French attack on Dakar, losing one of their number to British anti-aircraft fire. Two bomber units equipped with LeO 451s, GB I/12 and GB I/31 were based in Syria when Allied forces invaded on 8 June 1941, at the start of the Syria-Lebanon Campaign. These were supplemented by GB I/25, which was dispatched from
Tunisia ) , image_map = Tunisia location (orthographic projection).svg , map_caption = Location of Tunisia in northern Africa , image_map2 = , capital = Tunis , largest_city = capital , ...
. During this campaign, the LeO 451s flew a total of 855 sorties, losing 29 LeO 451s in the process.''Air International'' October 1985, pp. 184–185. After Operation Torch which began on 8 November 1942, surviving French LeO 451 in North Africa were used primarily for freight duties, although they flew a few bombing missions against Axis forces during the
Tunisia Campaign The Tunisian campaign (also known as the Battle of Tunisia) was a series of battles that took place in Tunisia during the North African campaign of the Second World War, between Axis and Allied forces from 17 November 1942 to 13 May 1943. Th ...
. They were replaced by
Handley-Page Halifax The Handley Page Halifax is a British Royal Air Force (RAF) four-engined heavy bomber of the Second World War. It was developed by Handley Page to the same specification as the contemporary twin-engine Avro Manchester. The Halifax has its or ...
and B-26 Marauder bombers. The Germans were not especially interested in the type but on 21 May 1943, the Luftwaffe requested the Regia Aeronautica to hand over 39 LeO 451s captured by Italians troops in the
SNCASE SNCASE (abbreviated from ''Société nationale des constructions aéronautiques du Sud-Est'') or Sud-Est was a French aircraft manufacturer. The company was formed on February 1, 1937, by the nationalization and merger of Lioré et Olivier, Pote ...
factory in
Ambérieu-en-Bugey Ambérieu-en-Bugey (; frp, Ambèriô) is a commune in the department of Ain, region of Auvergne-Rhône-Alpes, France. It is the largest town in the arrondissement of Belley and the capital of the Canton of Ambérieu-en-Bugey which consists ...
(
Lyon Lyon,, ; Occitan language, Occitan: ''Lion'', hist. ''Lionés'' also spelled in English as Lyons, is the List of communes in France with over 20,000 inhabitants, third-largest city and Urban area (France), second-largest metropolitan area of F ...
). The Luftwaffe, claiming to have previously bought the LeOs, gave in exchange a stock of 30
Dewoitine D.520 The Dewoitine D.520 was a French fighter aircraft that entered service in early 1940, shortly after the beginning of the Second World War. The D.520 was designed in response to a 1936 requirement from the French Air Force for a fast, modern fi ...
s.''Dimensione Cielo'', 1972, p. 66. The 451s were converted into transport aircraft for fuel and troops. Other LeOs were delivered to the Regia Aeronautica and 12 were put in service with a ground attack unit, although they saw almost no active service. Angelucci and Matricardi 1978, p. 255. Following the war, the 67 surviving aircraft were mostly used as trainers and transports. The LeO 451 was retired in September 1957, making it the last pre-war French design to leave active duty.


Variants

;LeO 45.01 :First prototype, powered by two Hispano-Suiza 14AA-6 / Hispano-Suiza 14AA-7 radial piston engines. ;LeO 451.01 :The first LeO 45.01 prototype was redesignated, fitted with two Gnome-Rhone 14R engines. ;LeO 451 :Production version variously fitted with Gnome-Rhône 14N-48 / Gnome-Rhône 14N-49 or Gnome-Rhône 14N-38 / Gnome-Rhône 14N-39 or Gnome & Rhône 14N-46 / Gnome-Rhône 14N-47 engines ;LeO 451GS: ;LeO 451C :Twelve LeO 451T aircraft were redesignated, used as mail transport aircraft for
Air France Air France (; formally ''Société Air France, S.A.''), stylised as AIRFRANCE, is the flag carrier of France headquartered in Tremblay-en-France. It is a subsidiary of the Air France–KLM Group and a founding member of the SkyTeam global a ...
. ;LeO 451E2 :Post-war flying laboratory, 11 modified. ;LeO 451M: ;LeO 451T :German-captured bombers modified for freight duty, seating for up to 17 troops. Around about 50 aircraft were modified. ;LeO 452: ;LeO 453 :Post-war conversion to high-speed transports and search-and-rescue aircraft, powered by two 895 kW (1,200 hp) Pratt & Whitney R-1830-67 engines, seating for 6 passengers, range 3,500 km (1,890 nm, 2,175 mi) at 400 km/h (215 knots, 250 mph) cruising speed, 40 modified.''Air International'' October 1985, p.189. ;LeO 454 : Bristol Hercules II engines, one prototype left unfinished. ;LeO 455 :High-altitude version with turbo-supercharged Gnome-Rhône 14R engines producing 1,375 hp (1025 kW) each, 400 ordered, one prototype built. The aircraft flew on 12 March 1939 but was later destroyed on the ground. ;LeO 455Ph :Post-war photo-reconnaissance variant, powered by two 1,600 hp (1195 kW) SNECMA 14R engines. Five LeO 451s were modified and were used by the
Institut Géographique National An institute is an organisational body created for a certain purpose. They are often research organisations (research institutes) created to do research on specific topics, or can also be a professional body. In some countries, institutes can ...
. ;LeO 456 (LeO 451M) :Naval version for the
French Navy The French Navy (french: Marine nationale, lit=National Navy), informally , is the maritime arm of the French Armed Forces and one of the five military service branches of France. It is among the largest and most powerful naval forces in t ...
, 68 ordered. Also known as the LeO 451M. ;LeO 457 ;LeO 458 : Wright GR-2600-A5B engines, ten ordered ;LeO 459:


Operators

; *
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 Arm ...
* Aéronautique navale *
Air France Air France (; formally ''Société Air France, S.A.''), stylised as AIRFRANCE, is the flag carrier of France headquartered in Tremblay-en-France. It is a subsidiary of the Air France–KLM Group and a founding member of the SkyTeam global a ...
;
Vichy France Vichy France (french: Régime de Vichy; 10 July 1940 – 9 August 1944), officially the French State ('), was the fascist French state headed by Marshal Philippe Pétain during World War II. Officially independent, but with half of its te ...
*
Vichy French Air Force The Air Force (french: Armée de l'air), usually referred to as the Air Force of Vichy (''Armée de l'air de Vichy'') or Armistice Air Force (''Armée de l'Air de l'armistice'') for clarity, was the aerial branch of the Armistice Army of Vichy Fran ...
; *
Luftwaffe The ''Luftwaffe'' () was the aerial-warfare branch of the German ''Wehrmacht'' before and during World War II. Germany's military air arms during World War I, the ''Luftstreitkräfte'' of the Imperial Army and the '' Marine-Fliegerabtei ...
operated several captured aircraft. ; * Regia Aeronautica ; *
United States Army Air Forces The United States Army Air Forces (USAAF or AAF) was the major land-based aerial warfare service component of the United States Army and ''de facto'' aerial warfare service branch of the United States during and immediately after World War II ...
operated several captured aircraft as unit hacks.


Specifications (LeO 451)


See also


References


Notes


Bibliography

* Angelucci, Enzo and Paolo Matricardi. ''World Aircraft: World War II, Volume I'' (Sampson Low Guides). Maidenhead, UK: Sampson Low, 1978. * * Danel, Raymond. ''The Lioré et Olivier LeO 45 Series (Aircraft in Profile 173)''. Leatherhead, Surrey, UK: Profile Publications Ltd., 1967. * Danel, Raymond and Cuny, Jean ''LeO 45, Amiot 350 et autre B4 (Docavia n°23)'' (in French). Editions Larivière. * Danel, Raymond and Cuny, Jean ''L'aviation française de bombardement et de renseignement 1918–1940 (Docavia n°12)'' (in French). Editions Larivière. * Dimensione Cielo Aerei italiani nella 2° guerra mondiale ''CACCIA ASSALTO 3'' Roma, Edizioni Bizzarri, 1972 * Ehrengardt, Christian-Jacques "Le bombardement français, tome I: 1939/1940". ''Aéro-Journal Hors-Série N°5'' (in French)
"The LeO 45 Bomber: Pride of France's Bomber Force"
''
Flight Flight or flying is the process by which an object moves through a space without contacting any planetary surface, either within an atmosphere (i.e. air flight or aviation) or through the vacuum of outer space (i.e. spaceflight). This can be a ...
'', 16 May 1940, Vol. XXXVII, No. 1636. pp. 452c–d, 453. * "Liore-et-Olivier 45...''A Study in Elegance''". '' Air International'', October 1985, Vol 29 No 4. pp. 179–189. ISSN 0306-5634. * Marchand, Patrick and Takamori, Junko. ''Loiré et Olivier LeO 45'' (in French). Le Muy, France: Editions d'Along, 2004. . * ''Notice descriptive et d'utilisation de l'avion LeO. 451 à moteurs Gnome et Rhône 14N'', SNCASE, 1939


External links


LeO 451 (French)


* ttp://france1940.free.fr/adla/ada_may.html French airforce OrBat in May 1940
French airforce OrBat in June 1940
{{DEFAULTSORT:Liore Et Olivier Leo 45 1930s French bomber aircraft 45 Low-wing aircraft Aircraft first flown in 1937 Twin piston-engined tractor aircraft