Coaxial Rotor System: the future of helicopter design?
The CoaX 415T 5-seat helicopter is one of the models under development
October 28, 2008 Helicopters featuring coaxial rotor designs are not exactly new. The co-axial design of a pair of rotors mounted on the same mast and with the same axis of rotation, but turning in different directions, has been utilized on a number of military helicopters for around half a century, most notably those produced by the Russian Kamov helicopter design bureau. The coaxial design offers a number of advantages over the traditional helicopter designs, which makes it difficult to understand why we haven’t seen co-axial rotor designs taking to the skies for civilian uses. Now Australian based Wieland Helicopter Technologies (WHT) is hoping to change that by designing and manufacturing a range of new coaxial rotor system small format helicopters for commercial markets.
Coaxial rotor designs allow for a more stable, more maneuverable, quieter and safer helicopter due to inclusion of a coaxial main rotor and exclusion of a tail rotor, which also means a smaller footprint. Coaxial rotor helicopters also provide a better power to weight ratio than traditional helicopters, produce greater lift and are also much more efficient.
We've recently seen the technology appear on the Sikorsky X2 demonstrator and now WHT is not only developing two and four seat models with combustion engines and 5 seat models with turbine engines, they are also working on Unmanned Aerial Vehicles and smaller 1 and 2 seat helicopters with electric motor configurations. On top of all this the coaxial rotor helicopters are much easier to fly and therefore much simpler and cheaper to learn to fly.
WHT has complete, working prototypes on which development will be based and is looking for investors.
To check out a prototype in action click here or for further info visit Wieland Helicopter Technologies.
About the Author
Darren's love of technology started in primary school with a Nintendo Game & Watch Donkey Kong (still functioning) and a Commodore VIC 20 computer (not still functioning). In high school he upgraded to a 286 PC, and he's been following Moore's law ever since. This love of technology continued through a number of university courses and crappy jobs until 2008, when his interests found a home at Gizmag.
All articles by Darren Quick
I do not believe that a coaxial helicopter is more maneuverable. The agility created by distant fulcrum points is better with a tail rotor.
But I agree that there will be better lift and speed. But that does not offset the lift of a twin axle helicopter or the speed of an Osprey.
This a good balance of abilities in a small helicopter with a specialized purpose. But you can get better maneuverability with a tail rotor, better lift with a Chinook, and better speed with an Osprey
Does anyone remember the Kammand Helicopter the K-max? Small,Twin rotor, awesome design for heavy lifting.
The Navy looked at it (to replace the H-47 for ship to ship resupply) but it never happened. Even thought it was a much better design than was being used, taking up much less space than the larger H-47, it just did not happen.
I am unsure why. Politics? Range?
Can you autorotate a helicopter of this design?
Can you autorotate a helicopter of this design? I think the aswer is yes, although there is no need to have contra rotation on an auto gyro, as there is no counter rotation on the fuselage. The whole reason to have contra rotation is to do away with the tail rotor. Another benefit is a smaller rotor diameter.
looks like a good system, I particularily like the electric version
There are times I think the military are stuck in a rut. For example the 'flying flapjack'. It was unique in design but had a short take off and landing and could keep pace with the then jet planes. It did not go anywhere. Currently they had an opportunity for an airship but cancelled even it could stay on post for a long time without using a lot of fuel.
I think the co-axel design is really nice.
People in business lie, they lie a lot (American financial debacle 2008). The best product does not always win, that is a myth. For a manifold of reasons, really good designs can be left on drawing-boards. And yet business people, business schools continue to preach that whole best mousetrap fiffle.
The reason counter rotating helicopters are rare is because the mechanisms for powering two main rotors and working the collective and the cyclic are much more complicated and heavy than just having a small tail rotor to counter torque. Most people don't realize that a rotorblade is constantly changing it's angle of attack every single revolution, the machinery to achieve this gets extremely complex if you have to work all of the pushrods, etc. up thru a hollow mast to get to the rotor turning in the opposite direction. This hollow shaft is also the one that is carrying the entire weight of the helicopter and transmitting all of the power of the engine.
It is important to be able to auto rotate so if the power plant fails you don't have to fall like a rock. Autorotation is achived by angling the blades downward so the blades become "glider wings" and will keep turning. enabling the pilot to glide the aircraft to a controlled soft landing. Counter rotating rotors are common on toy or unmanned drone helicopters because nobody dies if the engine fails.
There is a design of helicopter that has two contra-rotating lift rotors but with each on their own drive shaft together with their own collective mechanisms etc.. These shafts are at an angle of about 15 - 20 degrees as far as I remember. (Obviously they have to be contra-rotating as they are in effect, two toothed gears in mesh.)
I have no idea why it has not been more widely applied.
Mel, that was the Kaman HOK. Dual masts, with counter-rotating intermeshed rotors.
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