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Eurocopter EC135 & Airbus H135

This popular helicopter has its origins in the MBB Bo-108, that was a technology demonstrator developed in the late 1980s by MBB and Aérospatiale. By 1995 the conventional open tail rotor had been replaced by a shrouded one (or fenestron) and both companies had gone up in Eurocopter. Hence the helicopter was re-designated EC135. Later, when Eurocopter became Airbus Helicopters, the EC135 was given marketing name H135.

The EC135 has a very streamlined fuselage that includes the majority of the engine and gear bix housing. Even the air intakes and exhausts of the two engines are nearly flush with the fuselage. On top is still a small pylon with the four blade, hinge-less main rotor directly above. Up front are curved cockpit windows and the helicopter has three side windows (including one in the cockpit door), that have a smaller height further aft. The rear fuselage sloes up quickly, allowing easy access to the cabin via clamshell doors. Above these doors is the slender tail boom ending in a big tail with large shrouded tail rotor. The horizontal stabilisers are just in front of the tail rotor. The EC135 can be equipped with low of high skids.

The engine and gear box housing of the Eurocopter EC135 is very streamlined and forms one part with the fuselage. Note the small pylon on top of it, one of the recognition points compared to the H145.

Different versions

The different versions of the EC135/H135 family can be recognised by looking at:

  • the number, size and location of air intakes on top of the fuselage
  • the presence of end plates at the horizontal stabilisers
  • the presence of a bump below the fenestron (tail rotor)

EC135P1, EC135P2, EC135P2+, EC135T1, EC135T2, EC135T2+, EC635T1 & EC635T2+

The EC135 has two engine options, one from Pratt & Whitney (models with suffix P) and one from Turbomeca (models with suffix T). However, the engine type does not lead to an external difference, except maybe for a sticker of the manufacturer. P2, P2+, T2 and T2+ have updated engines and/or MTOW increases. The plus-models are marketed as EC135P2i, EC135P2e, EC135T2e or EC135T2i. Some late plus models already seem to have the revised air intakes of the H135, but still have vertical fins at the ends of the horizontal stabilisers.

The Japanese navy uses the EC135T2+ for training purposes. It is designated TH-135 over there.

EC635 is the designation for the dedicated military version of the EC135. It is externally the same as the EC135; the main difference is in the re-inforced structure, especially the floor.

The EC135 is a popular medevac helicopter, just like this EC135T2, thanks to the easy access to the cabin underneath the tail boom..

This military EC135T1 is equipped with taller skids than standard and filters on the air intakes..

Here is another example, but now of an EC135P2. Note the round blue sticker with the Pratt & Whitney logo on the engine cowlings.

Some late EC135P2+ helicopters already have the air intake at the side of the cowling, like the H135 below. It retains the end plates on the horizontal stabilisers though.

H135 (EC135P3/T3) & H135M (EC635P3/T3)

Like all helicopters of Eurocopter the EC135 got an Airbus marketing name. This was done from the EC135P3/T3 on. The H135 can be distinguished from the earlier models by the air intake at the side of the cowlings, smaller (cooler) at the front and an additional intake at the rear of the small pylon directly underneath the main rotor. Furthermore the horizontal stabilisers have no end plates anymore. Finally, on most H135s the bump below the tail rotor is gone, but there may be older versions without it as well.

H135M is the dedicated military version of the H135, but not recognisable from the civil H135.

In British military service the H135 (not H135M) is known as Juno HT1. The Brazilian navy operates H135Ms as UH-17.

H135 is the new marketing name for the EC135. This version has different air intakes, no vertical end plates on the horizontal fins and no bump under the tail rotor.

This detail photo better shows the revived air intakes on the H135: a smaller one at fron, a large one at the side and an additional one at the rear of the pylon.

Confusion possible with

Airbus Helicopters H145

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When the MBB-Kawasaki BK117 was fitted with the cabin of the Eurocopter EC135 and later also a fenestron, it became significantly more quite difficult to distinguish the resulting Airbus H145 from the EC135/H135. However, the H145 has no small pylon at the top of the fuselage, four side windows, an older type of main rotor with hinges and a different shape of air intakes.

Airbus Helicopters H120 (Eurocopter EC120)

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The EC120/H120 is clearly part of the Eurocopter family, but still significantly different. It is smaller, has fewer cabin windows, the engine/gear box housing is sticking out more and the EC120 has just engine. Typical for the EC120 (and similar EC130) is the wide rear attachment of the skids.

MBB Bo-108

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Being the predecessor of the EC135, it is natural that is looks similar. The Bo-108 has an open tail rotor though, on top of the vertical stabiliser. Also it has only two side windows on each side, apart from other differences.