Airbus Helicopters H135

History of the Airbus Helicopters H135

Born from the Bo 108 prototype, the Eurocopter (now Airbus Helicopters) "EC135" is a market success in its own right, designed to succeed its successful but aging light twin-engine Bo 105 helicopter family. Originally commanded by Messerschmitt-Bolkow-Blohm (MBB) in West Germany, the Bo 108 was designed as a technology demonstrator and became an evolution of the earlier Bo 105. The first flight was recorded on February 15, 1994, followed by the service's launch in 1996, and more than 1,000 examples have been built since 1995.

The militarized variant becomes the product "EC635", which is described elsewhere on this site.

Bo 108 started out as a thorough beta program. Relying on the mature aspects of the Bo 105, this gave engineers the freedom to incorporate minor modifications into the overall design and led to the adoption of hingeless main rotor assemblies, wider use of composite structures, more streamlined gearing, and digital cockpit avionics and an adaptation of a bearingless conventional tail rotor unit. Power comes from 2 Allison 250-C20R-3 turboshaft engines located above the cabin.

Like the Bo 108, the front of the plane has thick glass, and the fixed landing gear acts as a landing gear.

In early 1991, the Bo 108 program proved its worth and led MBB to bring the design to market. It was also decided to use a different engine fit - either the French Turbomeca "Arrius" series or a turboshaft engine supplied by the American company Pratt & Whitney (PW206).

The second prototype took off on June 5, 1991, powered by two Arrius engines.

The emergence of the Eurocopter brand label led to the merger of MBB and Aerospatiale, giving engineers full access to the Aerospatiale-designed "Fenestron" ducted tail rotor, which may be most important for the new helicopter program. In this arrangement, the multi-blade units are housed in fixed housings buried in the vertical tail, reducing noise levels and optimizing efficiency at the expense of complexity. The Bo 108 was modified with tail technology and received the new Eurocopter designation "EC135". The product's first flight took place on February 15, 1994, followed by certification in June 1996.

Since both of the aforementioned engine modifications have proven themselves in testing, both are offered to market customers in different variants.

Like other helicopters in this weight class, the EC135 later found a career in civil, government and military circles around the world. The military operators are Australia, Brazil, Gabon, Germany, Ireland, Japan, Morocco and Spain.

Police and government security forces have also picked up the type in large numbers, as evidenced by its use in skies from Argentina and Australia to Turkey and the United States.

Implemented several variants of the base EC135 design, led by the original EC135 P1 and its Pratt & Whitney engine, each producing 621 hp. The EC135 T1 fits Arrius engines with 583 hp each, followed by the EC135 P2 and EC135 T2 with upgraded engines from PW and Turbomeca respectively.

Modern production versions have the characteristic "+" in their name (eg "EC135 P2+"), the more powerful models are the EC135 P3 and EC135 T3. The military training model is available as TH-135 (based on the EC135 T2+), the official military model is the advanced EC635/H135M, which was originally developed for the needs of the Portuguese Army.

The Eurocopter name is now a subsidiary of the Airbus Group, which uses Airbus Helicopters as its trademark for the helicopter industry. Therefore, EC135 is now called H135.

Specification

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Performance

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Changes