Only in the 1970s helicopter manufacturers started to see a role of the helicopter as a luxury private transport, for example from the airport to a downtown heliport. Speed was important, so these helicopters needed a streamlined fuselage and a retractable gear. Agusta and Sikorsky were the first to develop such a helicopter.
The Sikorsky contribution was the S-76. As explained above it has a streamlined fuselage, that gradually transitions into the tail boom. Only the width of the fuselage becomes narrower more quickly. At the rear of the fuselage is a single wheel main gear, that retracts rearward in the fuselage. The The heli has a four blade main rotor and a four blade tail rotor on the top left side of the vertical stabiliser. There are low mounted horizontal stabilisers on both sides of the end of the tail boom. The S-76 has two turboshaft engines on top of the fuselage, of which the shape depends on the (engine) model. Finally, there is a single nose wheel that retracts rearward in the fuselage, behind long narrow nose gear doors.
To distinguish the different versions of the S-76 you'll have to look at
- the shape of the gear box/engine housing
- the type of cabin doors
Details will be added later.
Confusion possible with
Being used for a similar role, the Leonardo AW109 (originally Agusta A109) looks similar to the S-76 as well. The tail boom is narrower though and has a pointed end. Moreover, the tail rotor is attached to the tail boom instead of the vertical fin. The main gear is retracted in small stubs or up in the side of the fuselage.
Bell was later on the market with an executive helicopter, but it still looks alike. The tail boom is even more narrow than on the A109 and the gear retracts in sponsons (unless it has skids). The tail rotor is placed low. The main rotor has two or four blades.
Although shorter than the S-76, the AW139 and AW169 have a wide tail boom as well. The Leonardo helicopters have a high placed tail rotor on the right though and horizontal stabilises with bent-up tips. Like the Bell helicopter above the main gear of the AW139/AW169 retracts in sponsons. Finally, it has twin wheel nose gear.