Heliplane rides again?

[Shawn Coyle]

It appears that Groen Bros have been bypassed and Scaled composites are now going to build the re-borne Fairey RotoDyne.
See the article

SpaceShipOne firm to build DARPA's Heliplane | The Register (http://www.theregister.co.uk/2008/07/21/heliplane_rides_again/)

Thoughts?

[Graviman]

The main thought is how are they going to ensure the blade structure at 400ktas? This will require at least active servos at the tips, especially as blade passes over nose at a reduced Nr. Still a compromise as wing will impede hover performance, and rotor will impede cruise/dash performance.

It looks as though they are going for a compressed air nozzle at the tip? With a high tip speed these can work, since nozzle area can be small for a given mass flow rate. I gather the problem is generally intenal drag from the need to duct high velocity air streams.

Good luck to 'em though - they'll need it!

[Pilot DAR]

How badly does the world need this type of aircraft?

I hope that they are able to pass the rather stringent noise certification testing, which is sufficiently restrictive as to make approval of propeller changes on light aircraft hardly worth the effort.

Pilot DAR

[ShyTorque]

How badly does the world need this type of aircraft?

The USA's special forces wanted a vertical takeoff / landing / high speed transport many, many years ago, to replace their relatively slow helicopters. They obviously still do need them, as the first models in service have been introduced only a relatively short time ago, straight into an operational theatre.

Had this concept been developed, rather than far more complicated tilt rotor, it could possibly have been in service for a very long time. Fairey did it first 50 years ago and actually had it ready for service before the plug was pulled, arguably mainly for political reasons.

Also, it could fit onto small helipads more easily and therefore might be more acceptable to corporate owners, if the tip-jet noise issues could be resolved.

It would only need to fly at 250 kts to be a winner in UK (250 kts being the maximum allowed speed outside controlled airspace). I could certainly imagine a 5 or 6 seater replacing many current helicopters, if the price and operating costs were good. With a far less complicated transmission, it ought to be less.

[forget]

Fairey did it first 50 years ago and actually had it ready for service

:ok::ok:
YouTube - Fairey Rotodyne (http://www.youtube.com/watch?v=y9633v6U0wo)