Fenestron

• Greater safety for people and other objects, including for the helicopter itself (the screw itself is also less susceptible to destruction due to the protective fence in the form of a hard ring);
• Greater rotational speed , lower vibration level;
• The diameter of the fenestron is substantially less than the diameter of a conventional tail rotor , which eliminates the need for a tail boom to break to create the required landing distance between the ends of the propeller blades and the ground and, as a result, eliminates the installation of an intermediate gearbox.

• Greater weight;
• High frequency noise;
• Greater air resistance when cornering, and as a result, higher cost;
• To create the same thrust, greater power is required (up to 25% on hover) than a conventional tail rotor.

First used in the late 1960s on the second experimental model of the helicopter SA 340 and on the later model Aérospatiale SA 341 Gazel .

In addition to the European corporation Eurocopter , the fenestron was used on the RAH-66 Comanche prototype helicopters of the now closed multi-purpose reconnaissance and attack helicopter project for the US Army and is also used on the Ka-60 Kasatka and its civilian heir Ka-62 .

At the MVL MVZ in 1976, when testing a Mi-24A modification with a fenestron, they came to the conclusion that the fenestron is ineffective on helicopters with such a take-off weight ^[1] . Photo modification of the Mi-24A with fenestron .

• Impeller
• NOTAR

• Shaidakov V.I. Aerodynamic design of the fenestron