Lioré et Olivier LeO H-190. The Lioré et Olivier H-190 was a biplane flying boat aircraft designed and produced by the French aircraft manufacturer Lioré et Olivier.

Developed as a passenger transport, various versions of the H-190 were also developed, including catapult-ready mail planes intended to be launched from transatlantic ocean liners and coastal patrol aircraft.

The sole LeO H-194 was flown by Marc Bernard together with a CAMS 37 flown by René Guilbaud in a long-distance expeditionary flight across Africa in late 1926. They covered  in three months, covering Morocco, Mali, Nigeria, Belgian Congo, Mozambique and Madagascar.

Design
The Lioré et Olivier H-190 was a single-bay biplane flying boat with un-staggered wings and powered by a single engine that was mounted tractor-fashion underneath the upper wing and supported on struts in the interplane gap. While early-built aircraft had the pilot's open cockpit located aft of the wing, later-built aircraft had the pilot's cockpit relocated forward of the wing. The lines of the hull were designed around the desired marine qualities of the flying boat; it proved itself to handle well when subjected to five-foot waves. To maintain the hull's condition, regular applications of ordinary boat paint were required. While the flying boat's duralumin elements proved fairly durable, its steel fittings were not so long-living, despite the application of a protective baked enamel. 

Its construction was conventional for the era and harnessed techniques previously used by the company on earlier seaplanes. The fuselage was composed entirely of wood, a large proportion of the framework, including the keel, chines, upper longerons and the majority of the transverse frames, were made from ash, while the deck beams consisted of four thicknesses of ash and spruce that were glued together. The submerged portion of the fuselage was entire1y covered with either a double or triple boarding of Cuban mahogany, upon which a protective layer of bituminous dope was applied. The portion above the waterline was covered with birch plywood instead, which had a special filler applied to it to absorb ultraviolet light and thus better preserve the condition of the wood. Underneath the propeller, the hull was reinforced by sheet metal as well as by a series of compact longitudinal strips, which assisted the crew in not slipping on the hull's rounded edge. 

The box spars were composed of spruce and plywood while the ribs had plywood webs and spruce flanges. The drag wires were piano wires that terminated in fastenings, the design of which was both patented and officially approved. The ties and wing bracing consisted of duralumin tubes while the flying wires consisted of a pair of piano wires held together by a fairing. The landing wires were streamlined and used Chobert fastenings. The floats were attached to the wing via four compact duralumin struts and consisted of a framework of ash that was covered by birch plywood. The wing covering was doped fabric. Washers were typically used in conjunction with rivets.  The tail unit consisted of a primary fin accompanied by two auxiliary fins, one above and one below the stabilizer, which was secured by a pair of duralumin struts and bracing wires. The ailerons, elevator, and rudder all had welded steel frames and fabric coverings.

The flying boat was typically powered by a Gnome et Rhône 9Ad Jupiter air-cooled radial engine, capable of generating up to 420 HP. The engine nacelle contained a supporting frame that was attached via four bolts to the spars of the upper wing and to the struts of the cabane; the nacelle itself was positioned between the two spars and consists of a steel-tubing framework enclosed in an aluminium cowling. Various elements were contained within this cowling, including a pair of fuel pumps, a fire extinguisher, oil radiator, oil sump and tank, as well as several sizable ports to ease inspection and servicing alike. A relatively robust propeller, composed of treated beechwood and partially covered by copper, was typically fitted; a spare propeller was also often carried.

A cartridge ignition arrangement was used to start the engine; engine-related instrumentation included an oil-pressure indicator, a revolution counter, aero-thermometer, multiple fuel gauges, and a fuel regulator. General instrumentation included a drift meter, altimeter, inclinometer, and a pair of compasses; some aircraft were outfitted with 12-volt generators to power apparatus such as cameras. Fuel was housed within the fuselage across a total of six tanks composed of duralumin tanks, each having a capacity of 235 liters (7.36 gallons) and weighing only nine kg (roughly 20 lb.), while the fuel pipes were made of aluminium. Oil was stored in two locations, a 20-liter (21-gallon) tank in the hull and a 35-liter (9.2-gallon) gravity tank in the engine nacelle; a hand pump was used to transfer oil from the former to the latter. Anchoring was aided by the presence of a two-part hatch in the upper surface of the forward deck; baggage was held within a separate compartment just aft of the rear-most pair of fuel tanks.

Variants
H-190T("Transport") - airliner powered by a  Gnome-Rhône 9Ab Jupiter engine; (five built).
H-191trainer powered by a  Lorraine 12Eb; (one built).
H-192airliner similar to H-190T, but with cockpit in new position, powered by a  Gnome-Rhône 9Ab Jupiter; (2 built).
H-193similar to H-192, but with reinforced wing, powered by a  Gnome & Rhône 9Ady; (five built).
H-193S(S - "Surveillance") - maritime patrol version of H-193, powered by a  Gnome-Rhône 9Ad Jupiter; (15 built).
H-193HSH-193S with a  Hispano-Suiza 12Mb engine; (one converted).
H-194version for long-distance flight, powered by a  Gnome-Rhône 9Ab Jupiter; (one built).
H-195
H-196similar to H-193, powered by a  Gnome-Rhône 9Ab Jupiter; (one built).
H-197S(Sanitaire) - air ambulance version of H-193, powered by a  Gnome-Rhône 9Adz Jupiter; (one built).
H-198catapult-capable mailplane, powered by a  Gnome-Rhône 9Af Jupiter;  (nine built).
H-198/2catapult-capable airliner with a  Renault 12Ja engine; (three built).
H-199/1twin-engine version, with second engine mounted in pusher-fashion in tandem with the first: examples with 2x  Hispano-Suiza 6Mbr; (one built).
H-199/2twin-engine version, with second engine mounted in pusher-fashion in tandem with the first: 2x   Gnome-Rhône 7Kb engines; (one built).

Operators

 French Navy

Specifications (H-193S)

References

Citations

Bibliography
 "Liore-Olivier LeO 194 seaplane" National Advisory Committee for Aeronautics, 1 April 1917. NACA-AC-39, 93R19905.

Further reading

 
 Hartmann, Gérard. Les Avions Lioré Et Olivier. Boulogne-Billancourt, France: ETAI. 2002.  (in French)

1920s French airliners
Flying boats
H-190
Single-engined tractor aircraft
Biplanes