Aérospatiale (Sud Aviation) Alouette III
While the Alouette II was already quite a success for Sud Aviation, it had a relatively small cabin. Hence, the company designed the Alouette III. This has a larger fuselage with many roundings and a lot of glass at the front. The turboshaft engine remains placed on top of the rear fuselage, like on the Alouette II, and is not enclosed. It powers a three blade main rotor. Unlike the Alouette II, the Alouette III has a covered tail boom with a three blade tail rotor end the end. In front are horizontal stabilisers with rounded rectangular end plates acting as vertical stabilisers. The Alouette III further normally has a fixed wheeled landing landing gear, although some have been fitted with large floats. The nose gear is of a trailing link type. The main gear is attached to the side and underside of the fuselage with long struts. All these characteristics together make the Alouette III quite easy to recognise!
The Alouette III was a popular helicopter, and was built under license in India, Romania and Switzerland.
Like the Alouette II the Alouette III has a fully exposed turboshaft engine. Most versions use the Turbomeca Artouste, distinguished by the rectangular air intake at the side.
The Alouette III has a straight tail boom with a three blade tail rotor at the end. Note the typical rounded rectangular end plates on the horizontal stabilisers.
Different versions
The different versions of the Alouette III can be identified by looking at the shape of the engine.
Sud Aviation SE3160, SA316B & SA316C, HAL Chetak and IAR-316
Nearly all versions of the Alouette III are powered by a Turbomeca Artouste engine. This has the air intake at the side; it has a rectangular shape with rounded corners. The SE3160, SA316B and SA316C only differ in the exact engine version, operating weights and performance.
The Chetak is a version of the SA316B built under license by HAL (Hindustan Aeronautics Ltd). Likewise the IAR-316 is the same helicopter built by IAR of Romania. Externally, they are not different.
This is an SE3160, the original version of the Alouette III. Note the cover on the air intake of the engine, nicely showing the rectangular shape of it.
SA319B
The SA319B version of the Alouette III has a different engine, which is the Astazou, also built by Turbomeca. The air intake is different on this helicopter (it has the shape of a ring), so this is how to distinguish it from the versions described above.
Look closely at the engine of this SA319B, and you'll see that it does not have the rectangular air intake at the side, but a ring shaped one. This is how to recognise it from the SE3160 above. (photo: Fabrizio Berni/WikiMedia)
HAL Chetan
This a a HAL Chetak with a different engine, the Turbomeca TM333. This engine seems to be attached at the front only, so it seems to 'float' more. Moreover, it has a large rectangular filter at the side of the engine.
The HAL Chetan variant of the Alouette III has a slightly different engine shape than the other versions.
Confusion possible with
Sud Aviation SA3164 Alouette-Canon
Just one prototype was made of this attack version of the Alouette III. Compared to the base model, the Alouette-Canon has a different cockpit with less glass and with a canon sticking out of the left front window. The SA3164 also has pylons at the side of the fuselage.
Sikorsky S-52
At first the S-52 and Alouette III may seem similar, and that is true regarding the general appearance, but there are significant differences. The S-51 has a four leg landing gear, the engine is in the fuselage, the tail rotor is placed on top of the vertical fin and the horizontal stabilisers have a significant anhedral.
MBB-Bölkow Bo105
The Bo105 has a rounded fuselage like the Alouette, but two covered engines on top of the fuselage. It also has horizontal stabilisers with rectangular end plates. The Bo105 has a skid undercarriage as standard though, a narrower tail boom and a swept vertical fin with two blade tail rotor on top.