Ornicopter Project

A single rotor helicopter without reaction torque

The tail rotor of helicopters has always been considered a necessary evil. Tail rotors are indispensable since they counteract the reaction torque on the fuselage and provide yaw control. They are however expensive, consume 5 to 10 percent of the total power, have only marginal control authority under unfavorable wind conditions, and are on top of that noisy, vulnerable and dangerous. No wonder that numerous attempts have been made to find alternative solutions.

Such attempts include e.g. mounting small engines at the tip of the blades, multiple contra-rotating main rotors or the pneumatic NOTAR-system. Even though some of these solutions have been relatively successful, all of these alternative systems solve only a part of the problem. The ideal solution would be to have a main rotor without a reaction torque at all... but would this be asking for a system that violates Newton's law?

The Ornicopter wind tunnel model We dare to claim that it is possible to design such a system: the Ornicopter. The mechanism of the Ornicopter is derived from bird flight. When birds flap their wings they are able to derive both a lifting force and a propelling force out of it. Instead of propelling a helicopter blade by spinning it around and deriving lift from this rotating movement, as is done in conventional helicopter configurations; the Ornicopter flaps its blades like a bird and derives both lift and a propulsive force from this movement. In this case the blades propel (i.e. rotate) themselves and there is no longer a need for a direct torque supplied by the engine to rotate the blades. The fact that the engine torque is no longer directly transferred from the fuselage to the rotor is the key feature of the Ornicopter, and it is this feature that makes the anti torque device redundant.

 

A nice video about the Ornicopter can be found here. (WMV, 33.0Mb)

 

To learn more about the Ornicopter follow one of the following links:

If you would like to contribute to the Ornicopter project, would like some more information or if you would like to remain informed about the ongoing developments please send an e-mail to prof. dr. ir. Theo van Holten.
Also have a look at the research on conventional helicopters that is performed by the DAR group.

 

Naam auteur: d.j.vangerwen
© 2014 TU Delft

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