Is there anybody working on a technology update and production? I know investors who are interesting in an investments in co-axial helicopter. Thanks. Joni

Dear Michael,I have featured your late father on my test pilot tribute website, however, i would like to add more information and also pictures of him 'in cockpit' or with the helicopters he tested. If you can help in any way, i would be most greatful.
Hope to hear from you,
All the best from Scotland

My late father was KEN REED,the TEST PILOT on the Grasshopper.I have various photos plus all his reports on flights.

i john k. cartwright,was the prelemanary design engineer on this helicopter in 1965.

Tony Higgins and myself running the bare platform with blades on one of the two co-axial rotors only.

The Sikorsky X2 is a Ridgid system No drag henges,No flap henges only feathering.Doesn't need flyby wire,I like the Grasshopper,looks nice,all but one Coaxle rotor A/C have a problem in autorotation,control reversal in yaw,the QH 50 solved this little thing,just a note:

I also worked on the CR Twin with Dr Opatowski and would love to contact him, but an e-mail to his address comes back as unrecognised.

Do you have any further contact details?

In reply to Pierre Terrail: I left the project soon after the stage shown in the photograph when Mr. Shapiro wanted me to join his office (Servotec) in an unsatisfactory position rather than work as a consultant from my own firm of Technical Investigations Ltd. I should also point out that the MK 2 version had its engines in the rear rather than the previous front location. As far as the rotor system is concerned it was very close coupled and the rotors were (theoretically) held apart by a rigid conta-rotating structure patented by Mr. Shapiro. If thay are far apart, as per the Russians, it is not very efficient. My analysis of the system concluded that it would not work safely unless there was a very sophisticated higher harmonic blade pitch control system though something could be done with an appropriate delta 3 hinge. I think that the Sikorsky high speed helicopter under development, which has close coupled contra-rotating rotors, has individual blade pitch control.

Dear Dr. Opatowski, may we have an evaluation of this coax helo: vibrations? performances? why there is no follow up? Why this is not a success? Why aren't we seeing more coax in the sky???
Thanks.

I carried out some of the early development work on this aircraft at Redhill (on a consultancy basis) and have a photograph of the engineer Mr. Tony Higgins and myself running the bare platform with blades on one of the two co-axial rotors only.