The Lorraine-Hanriot LH.70 or S.A.B. LH.70 was a French trimotor designed to a 1930 government programme for a colonial policing aircraft. Only two were built.

Design

The LH.70 was entirely conceived and directed by the

Société Aérienne Bordelaise The ''Société Aérienne Bordelaise'' (SAB) was an aircraft manufacturing company based in Bordeaux, France. The predecessor company, '' Société de Travaux Dyle et Bacalan'' had been founded in 1879. History The ''Société Aérienne Bordel ...

(S.A.B), one a series of nine prototype colonial policing aircraft from different manufacturers. The programme was led by the Direction Générale Technique and one of its requirements was for all metal construction to withstand the hot and humid climates of French

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

n colonies. Another was to provide a large and flexible load carrying space, so it could be used for variety of tasks. It had a

high wing A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple planes. A monoplane has inherently the highest efficiency and lowest drag of any wing confi ...

of trapezoidal plan, built in three parts: a short central section which joined the

fuselage The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...

and two outer panels occupying the great majority of the span. The wings were constructed around four

spar SPAR, originally DESPAR, styled as DE SPAR, is a Dutch multinational that provides branding, supplies and support services for independently owned and operated food retail stores. It was founded in the Netherlands in 1932, by Adriaan van Well, ...

s and, like the rest of the aircraft were

duralumin Duralumin (also called duraluminum, duraluminium, duralum, dural(l)ium, or dural) is a trade name for one of the earliest types of age-hardenable aluminium alloys. The term is a combination of '' Dürener'' and ''aluminium''. Its use as a tra ...

skinned. There were high aspect ratio

ailerons An aileron (French for "little wing" or "fin") is a hinged flight control surface usually forming part of the trailing edge of each wing of a fixed-wing aircraft. Ailerons are used in pairs to control the aircraft in Flight dynamics, roll (or ...

over more than half the span. The LH.70 was powered by three

Lorraine 9Na Algol The Lorraine 9N Algol was a French 9-cylinder radial aeroengine built and used in the 1930s. It was rated at up to , but more usually in the range. Design and development The Algol was a conventionally laid out radial engine, with nine cylind ...

nine cylinder

radial engine The radial engine is a reciprocating type internal combustion engine configuration in which the cylinders "radiate" outward from a central crankcase like the spokes of a wheel. It resembles a stylized star when viewed from the front, and is ca ...

s with narrow chord ring cowlings. Two were mounted on the undersides of the wings with full-chord

nacelle A nacelle ( ) is a "streamlined body, sized according to what it contains", such as an engine, fuel, or equipment on an aircraft. When attached by a pylon entirely outside the airframe, it is sometimes called a pod, in which case it is attached ...

s behind them. The third engine was on the nose of the fuselage, which was in three rectangular section parts, built around four

longeron In engineering, a longeron and stringer is the load-bearing component of a framework. The term is commonly used in connection with aircraft fuselages and automobile chassis. Longerons are used in conjunction with stringers to form structural ...

s and skinned with longitudinally corrugated duralumin. The forward part included the engine mountings and the enclosed cabin just ahead of the wing, seating the pilots side-by-side with dual controls. Behind that was the main load carrying space, up to high, accessed via a port side, obliquely hinged door just aft of the wing

trailing edge The trailing edge of an aerodynamic surface such as a wing is its rear edge, where the airflow separated by the leading edge meets.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 521. Aviation Supplies & Academics, 1997. ...

and lit by a strip of small rectangular windows under the wing. The final part, which had a sloping underside, provided an open dorsal

cockpit A cockpit or flight deck is the area, usually near the front of an aircraft or spacecraft, from which a Pilot in command, pilot controls the aircraft. The cockpit of an aircraft contains flight instruments on an instrument panel, and the ...

for an observer and reached back to the tail. There were three fuel tanks, one under the pilots' cabin and two in the rear of the wings. The

empennage The empennage ( or ), also known as the tail or tail assembly, is a structure at the rear of an aircraft that provides stability during flight, in a way similar to the feathers on an arrow.Crane, Dale: ''Dictionary of Aeronautical Terms, third ed ...

was conventional apart from one feature. The trapezoidal fixed surfaces were built around pairs of spars and skinned with corrugated dural, with a

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 canti ...

tailplane A tailplane, also known as a horizontal stabiliser, is a small lifting surface located on the tail (empennage) behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed-wing aircraft such as helicopters and gyroplane ...

mounted on top of the fuselage. Its slightly tapered, unbalanced rudder extended down to the keel and worked in a small cut-out between the similarly shaped

elevator An elevator or lift is a wire rope, cable-assisted, hydraulic cylinder-assisted, or roller-track assisted machine that vertically transports people or freight between floors, levels, or deck (building), decks of a building, watercraft, ...

s. The novel feature was the result of the colonial's need for multi-tasking and consequent wide range of centre of gravity. Instead of

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, the LH.70 had a pair of trapezoidal winglets, mounted on the lower longerons about ahead of the elevator hinge and projecting about out of the fuselage. To cope with rough colonial landing fields the LH.70 needed a robust

undercarriage Undercarriage is the part of a moving vehicle that is underneath the main body of the vehicle. The term originally applied to this part of a horse-drawn carriage, and usage has since broadened to include: *The landing gear of an aircraft. *The ch ...

. Its track was determined by the separation of the outer engines, as each vertical, shock absorbing

oleo strut An oleo strut is a pneumatic air–oil hydraulic shock absorber used on the landing gear of most large aircraft and many smaller ones. This design cushions the impacts of landing and damps out vertical oscillations. It is undesirable for an airp ...

was fixed to the second wing spar within the nacelle. Instead of an axle each wheel hub was mounted on a near-horizontal V-strut, hinged on the lower fuselage longeron. The wheels had

hydraulic Hydraulics (from Greek: Υδραυλική) is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counter ...

brakes. At the rear there was an oleo-damped, steerable

tailskid Conventional landing gear, or tailwheel-type landing gear, is an aircraft undercarriage consisting of two main wheels forward of the center of gravity and a small wheel or skid to support the tail.Crane, Dale: ''Dictionary of Aeronautical Terms ...

Development

The exact date of the LH.70's first flight is not known but it was between May 1932, when two examples were reported as under construction at Bordeaux-Merignac and January 1933, when one LH.70 was at Villacoublay where Descamps demonstrated it to S.T.I.Aé officials. At the same time the other LH.70 was at Bordeaux undergoing modifications. At Villacoublay modifications to the LH.70 required a redetermination of the

centre of gravity In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force may ...

. It was back in Bordeaux early in 1934, but soon returned to Villacoubly where, after three months, Deschamps once again demonstrated it to the S.T.I.Aé. It did not succeed in the competition for a production contract, which was won by the Bloch MB.120, and no more were built. Their history after this is not known.

Specifications

References

External links

Aviafrance L.H. 70
{{SAB aircraft Trimotors 1930s French military utility aircraft L.070 Société Aérienne Bordelaise High-wing aircraft Aircraft first flown in 1932