The Americans patented rotor with forked endings

The American company Bell Helicopter has received a patent for a new form of blade for the rotor of a helicopter, which, theoretically, could give a reduction in fuel consumption in flight at 15-17 percent. As writes Flightglobal, the company offered to make the blade rotor with a forked tip, curved upward like an airplane winglet.

From the point of view of aerodynamics of a rotating helicopter rotor and fixed wing aircraft are very similar. This means that some technical solution applicable to the aircraft wing can be used in the design of the rotor blades.

With such decisions in the last couple of decades of experimenting, the developers of helicopters, is trying to significantly improve the performance of the rotor. In particular, some sort of winglets in the design of its main rotor at the beginning of 2000-ies used the European consortium Eurocopter (now Airbus Helicopters).

Rotor developed by Eurocopter, had a curved shape of the blade with a little bend upwards at the tip. In addition, closer to the winglets on the blade were installed controllable aerodynamic surfaces such as ailerons of the aircraft wing. These solutions were supposed to reduce the noise of the screw, to increase its lifting force and to reduce the flutter.

In General, the development of new configurations of the rotor and its blades aimed at overcoming several limitations associated with his work. In particular, with the effect of locking the screw, flutter and partly a vortex ring. The solution of these problems becomes especially important when developing high-speed helicopters, capable of performing cruising flight at speeds exceeding 400 kilometres per hour.

According to the patent, Bell Helicopter, a forked blade tip of the rotor with a bend up have already been tested on the model in the wind tunnel. Tests showed that the new design of the blades allows for other settings to increase the lift by 13.5 percent and to reduce the aerodynamic drag screw 17 percent.

In this case the corresponding increase of aerodynamic quality is 36.91 percent. The company believes that potential new design of the rotor allows to reduce noise and reduce fuel consumption in flight.

Previously, Bell Helicopter introduced the electrical system tail rotors and compensation of reactive torque for helicopters. The system is already being tested on a modified multi-purpose helicopter Bell 429. It was called EDAT (electrically distributed anti-torque electric distributed system anti-rotation).

The system consists of four small electric fenestron installed in the rear instead of the traditional tail rotor. The yaw control is the same pedal as that of a conventional steering screw, but the commands to the new system are not transmitted through the rods, and with wire system.

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