Bloch MB.81
The MB.81 was a French military aircraft built by Société des Avions Marcel Bloch as a flying ambulance since it was designed to carry one passenger, in or out of a stretcher. Developed in response to a government-sponsored competition in support of the new doctrine of "aerial first aid", it was employed exclusively in the overseas colonies, specifically Morocco and Syria. Unlike the MB.80 prototype, the MB.81 had a closed cockpit and a somewhat larger cargo space. This was the company's first design to reach production.
History
Based on experience of using modified Breguet XIV as ambulance aircraft during the Rif War in Morocco and in French administered Mandate for [Syria and the Lebanon|Syria and the Lebanon], in 1929, the French Ministry of War launched a programme to acquire a new ambulance aircraft. The recently established Société des Avions Marcel Bloch proposed a design to meet this requirement, but as the company was busy with the MB.60 mailplane, submitted its proposal too late to gain an official order for a prototype. Marcel Bloch, the founder of the company, decided to design and build an aircraft to meet the requirement as a private venture, using his own money.The Bloch design, the MB.80, was an all-metal monoplane with low wings. A casualty could be carried, lying prone on a stretcher, in an enclosed compartment behind the engine, which was accessed via a full length door on the port side of the compartment, allowing the patient to be easily loaded and unloaded, while the pilot was provided with an open cockpit behind the stretcher compartment on the starboard side of the fuselage. The stretcher compartment was fitted with padding to help soundproof it, while the stretcher was mounted on rubber shock absorbers to minimise vibration. Oxygen and an electrically-heated suit could be provided for the patient, who could communicate with the pilot using a speaking tube arrangement. The aircraft had a wide-track fixed conventional landing gear, with low pressure tyres and a tailwheel, with brakes fitted to the mainwheels to ease operations out of unprepared airstrips.
The prototype MB.80, which had been built for Bloch at the Letord factory at Meudon near Paris, made its first flight in July 1932 at Villacoublay Air Base|Villacoublay], piloted by Zacharie Heu. It was powered by a five cylinder Lorraine 5Pc radial engine of which allowed it to reach a speed of, and an altitude of. It was able to take off in and to land in. In a 1932 test, the MB.80 carried out 209 landings in thirty-six hours without any problems.
Based on the largely successful trials, an order was placed by the Ground French Forces with Bloch for 20 aircraft. As the MB.80 had proven to be underpowered for its intended use in hot climates, a Salmson 9Nd 9-cylinder radial engine, with the modified type becoming the MB.81, and was the first production order placed with the Bloch company. The modified prototype, designated the MB.81.01, flew in October 1932. Deliveries of the 19 production aircraft, built at Bloch's new factory at Courbevoie, a suburb of Paris, began in 1933, continuing to 1936.
The production model, called the MB.81, was fitted with a French Salmson 9Nd of 128.68 kW. It took part in military operations in Morocco and in Syria at the beginning of the 1930s.
The MB.81 entered service in 1935, and was used extensively throughout North Africa and the Middle East. A few were used in 1939–1940, before the French surrender, and in July 1941 in the battle for Syria between the Vichy French and the British/Free French.
Variants
;MB.80;MB.81