With its three 120hp Salmson 9 Ac engines, the MB 60 could carry a crew of three, and made its first flight on 12 September 1930, with René Delmotte.
Origins and prototypes: the first Bloch aircraft
At the beginning of 1930, the Marcel Bloch design bureau, which had been created at the end of 1929, received an order for a light high-wing three-engine mail aircraft, suitable for conversion for commercial transport and medical service. Like Henry Potez, after the First World War, Marcel Bloch adopted the official SEA serial numbers, which they had jointly developed. The aircraft was therefore given the designation Type VI, subsequently becoming the MB 60.
Initially designed by an engineer called Pineau, the project was pursued by Marcel Riffard. The aircraft was built with great care and featured several innovations:
- all-metal construction;
- stressed-skin wing without ribs, stiffened simply with extrusions riveted externally before assembly to the longerons;
- empennages designed for easy disassembly;
- tail fin and stabiliser adjustable by the pilot in flight;
- steerable light-metal tail wheel in place of the traditional skid;
- fuselage covered with flat sheets riveted to closed structure of frames and U-section stringers.
All of these features were retained on subsequent Bloch designs, particularly the metallic construction with external stiffeners.
Considerable attention was paid to flight safety:
- comfortable power margin;
- oil and fuel tanks located away from the engines, fitted with circuit breaker in case of fire;
- sliding cockpit roof panels, allowing the pilot to jump from the aircraft if need be;
- cockpit layout (engine control levers and switches) rationalized, within easy reach of pilot or flight engineer.
With its three 120hp Salmson 9 Ac engines, the MB 60 could carry a crew of three. The prototype was built rapidly. Construction started on 15 January 1930 and, with no factory to work in, Marcel Bloch had the aircraft built by an aircraft tank manufacturer, under his personal supervision or that of his engineers. After assembly in the Blériot hangars, the aircraft made its first flight at Buc on 12 September 1930, with René Delmotte at the controls. It was then tested by the pilots of the Villacoublay flight test centre.
The aircraft performed well, even with one engine shut down, and was ranked first in its category.
MB 61 (F-ALLO) flew in February 1931. Identical to the MB 60, it was powered by three 120hp Lorraine 5 Pc engines. It was highly ranked, like is predecessor, but was not ordered due to a lack of immediate users. At the end of April 1931, following a control inversion error during a modification stoppage, the aircraft skidded on takeoff and was seriously damaged. After repairs, it flew again on 1 May 1931.
A military version, ET 4, with the same engines as the MB 61, was envisaged in 1932. Designated MB 62, it did not advance beyond the project stage.
|Wing span||17,204 m|
|Wing area||40,56 m²|
|Empty weight||1610 kg|
|Max gross weight||2600 kg|
|Cabin||1,25 m x 1,30 m x 2,22 m = 3,650 m3|
|Type||3 Salmson Ac 9 de 120 ch|
MB 60 Datasheet
|Wing span||18,744 m|
|Wing area||42,48 m²|
|Empty weight||1660 kg|
|Max gross weight||2650 kg|
|Cabin||1,25 m x 1,30 m x 3,82 m = 6,2 m3|
|Type||3 Lorraine 5 Pc de 120 ch|
MB 61 Datasheet
|Wing span||18,500 m|
|Wing area||42 m²|
|Max gross weight||2600 kg|
|Maximum speed||200 km/h|
|Engine||3 Lorraine 5 Pc de 120 ch|