Tag Archives: Messerschmitt-Bölkow-Blohm

7 April 1967

SA 340 F-WOFH (Airbus Helicopters)
Jean Boulet hovers the prototype Sud-Aviation SA 340 Gazelle, 340.001, F-WOFH, at Marignane, France, 7 April 1967. (Airbus Helicopters)

7 April 1967: The prototype Sud-Aviation SA 340 Gazelle, c/n 340.001, F-WOFH, made its first flight at Marseille–Marignane Airport on the south coast of France with test pilot Jean Boulet. The SA 340 was a five-place, light turboshaft-powered helicopter, flown by a single pilot. It was intended as a replacement for the SA 313B/318C Alouette II and SA 316/319 Alouette III.

The prototype used the engine, drive train, tail rotor and landing skids of an Alouette II, and a new three-bladed, composite, semi-rigid main rotor, based on the four-bladed rigid rotor of the Messerschmitt-Bölkow-Blohm (MBB) Bo-105.

Sud-Aviation test pilot Jean Boulet in the cockpit of the SA 349, an experimental variant of the SA 340 Gazelle.
Sud-Aviation test pilot Jean Boulet in the cockpit of the SA 349, an experimental modification of the prototype SA 340 Gazelle, 340.001. (Airbus Helicopters)

d0b7f1c4dd16bf5b51c015e78fb3ebdfSociété nationale des constructions aéronautiques du sud-ouest (Sud-Aviation) was a French government-owned aircraft manufacturer, resulting from the merger of Société nationale des constructions aéronautiques du sud-est (SNCASE) and Société nationale des constructions aéronautiques du sud-ouest (SNCASO) in 1957. In 1970, following another merger, the company would become Société nationale industrielle aérospatiale, or SNIAS, better known as Aérospatiale. This company combined several other manufacturers such as Matra and Messerschmitt-Bölkow-Blohm to become Eurocopter, then EADS. It is now Airbus Helicopters.

The SA 340 was powered by a Turboméca Astazou IIN turboshaft which turns 42,500 r.p.m. (± 200 r.p.m.). The output shaft speed is reduced through a 7.34728:1 gear reduction.  The engine rated at 353 kW (473 shaft horsepower) continuous, or 390 kW (523 shaft horsepower) for takeoff. It is temperature-limited to 500 °C. for continuous operation, or 525 °C. for takeoff.

The main rotor assembly, mast, transmission and Turbomeca Astazou engine of the prototype SA 340 Gazelle. (Airbus Helicopters)
The main rotor assembly, mast, swash plate and pitch control links, transmission, main driveshaft and Turboméca Astazou turboshaft engine of the prototype Sud-Aviation SA 340 Gazelle, F-WOFH. (Airbus Helicopters)

F-WOFH was used to test the new fenestron anti-torque system. The conventional tail rotor was replaced with a smaller 13-bladed ducted fan contained within a large vertical fin. The fenestron had several advantages: It was safer, as it was protected from ground strikes or from ground personnel walking into it. It was more effective in producing thrust for anti-torque, though it required more engine power at a hover. It reduced the aerodynamic drag of the helicopter in forward flight, and was not subject to large displacements resulting from dissymmetry of lift. The large fin was cambered and relieved the anti-torque system during forward flight. This meant that the  helicopter could be flown following an anti-torque failure, rather than requiring an immediate emergency autorotation.

Sud-Aviation fenestron on an early production SA 341 Gazelle, c/n 1006, F-WTNV
Sud-Aviation fenestron on an early production SA 341 Gazelle, c/n 1006, F-WTNV. (Airbus Helicopters)

The Aérospatiale SA 341 Gazelle entered production in 1971, as both a military and civil helicopter. The aircraft was also produced by Westland. It was the fastest light helicopter, with a maximum speed of 310 kilometers per hour (193 miles per hour). It was also the first helicopter to be certified for instrument flight with a single pilot.

Approximately 1,775 Gazelles were built between 1967 and 1996, when production ended.

Sud-Aviation SA 340.001, F-WOFH. (Airbus Helicopters)
Sud-Aviation SA 340.001, F-WOFH. (Airbus Helicopters)

© 2016, Bryan R. Swopes

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16 February 1967

Wilfried von Englehardt tests the Bölkow-Entwicklungen KG Bo-105 V-2, D-HECA in an out-of-ground effect hover, with engine cowlings removed, 16 February 1967. (Eurocopter)
Wilfried von Englehardt tests the prototype Bölkow-Entwicklungen KG Bo-105 V-2, D-HECA, in an out-of-ground effect hover with engine cowlings removed, 16 February 1967. (Eurocopter)
Wilfried von Englehardt (Académie de l’Air et de l’Espace)
Wilfried von Englehardt (Académie de l’Air et de l’Espace)

16 February 1967: At Ottobrun, Germany, test pilot Wilfried von Engelhardt made the first flight of the Bölkow-Entwicklungen KG Bo-105 prototype V-2, D-HECA, a twin-engine, rigid rotor helicopter. This was the second prototype. The first one was destroyed by ground resonance during pre-flight testing.

Messerschmitt AG merged with Bölkow-Entwicklungen KG in June 1968, becoming  Messerschmitt-Bölkow. The following year, the new company merged with Blohm & Voss to become Messerschmitt-Bölkow-Blohm, or MBB. The Bo-105 entered production in 1970.

The Bo-105 is a 5-place light helicopter powered by two turboshaft engines. It has a four-bladed rigid (or hingeless) main rotor. This gives it a high degree of maneuverability, and it is capable of performing aerobatic maneuvers. The two-bladed tail rotor is mounted high on a pylon and gives exceptional ground clearance for a helicopter of this size. There are two “clam shell” doors located at the rear of the cabin section, giving access to a large flat floor. The helicopter has been widely used by military, law enforcement and as an air ambulance.

Messerschmitt-Bölkow-Blohm Bo-105 V-2, D-HECA. (Eurocopter)
Bölkow-Entwicklungen KG prototype Bo-105 V-2, D-HECA, during flight testing. (Eurocopter)

The Bo-105 is 38 feet, 11 inches (11.86 meters) long. The diameter of the main rotor is 32 feet, 3.5 inches (9.84 meters). Overall height is 9 feet, 10 inches (3.00 meters). The helicopter has an empty weight of 2,813 pounds (1,276 kilograms) and maximum takeoff weight of 5,511 pounds (2,500 kilograms).

The prototype was powered by two Allison 250-C18 turboshaft engines, with increasingly more powerful 250-C20, -C20B and C-28C engines being added through the production run. The Allison 250-C18 is a 2-spool, reverse-flow, gas turbine engine with a 6-stage axial-flow, 1-stage centrifugal-flow, compressor section, and a 4-stage axial-flow turbine (2-stage gas producer, and 2-stage power turbine). The 250-C18 is rated at 317 shaft horsepower at 6,000 r.p.m. (100% N2). These were very light weight engines, ranging from just 141 to 173 pounds (64.0 to 78.5 kilograms).

The helicopter’s cruise speed is 127 miles per hour (204 kilometers per hour) and maximum speed is 167 miles per hour (242 kilometers per hour). The range is 691 miles (1,112 kilometers. Service ceiling is 17,000 feet (5,180 meters).

The Bo-105 was produced in Germany, Canada, Spain, Indonesia and the Philippines from 1967 to 2001. More than 1,500 have been built.

Wilfried von Englehart tests the Bölkow-Entwicklungen KG Bo-105 V-2, D-HECA, at Ottobrun, Germany, 16 February 1967. (Eurocopter)
Wilfried von Englehart tests the Bölkow-Entwicklungen KG Bo-105 V-2, D-HECA, at Ottobrun, Germany, 16 February 1967. (Eurocopter)

Wilfried  Baron von Englehardt died 24 January 2015 at the age of 86 years.

Wilfried Baron von Englehardt 1928-2015)
Wilfried Baron von Englehardt (11 September1928–24 January 2015)

© 2017, Bryan R. Swopes

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