Sikorsky X2 coaxial heli developments.

[JohnDixson]

Sikorsky Funded dDevelopment

Hello David Jackson.

I believe you wrote the following:

"Perhaps the larger question might be; What developmental work has Sikorsky done that was not funded by the government? "

My memory is far from perfect, but here are a few items that were funded with Sikorsky/UTC money:

1. S-61F. High speed reaearch aircraft with twin J-60 tourbojets. Took a basic SH-3 airframe, added a wing, ailerons, an entire new tail ( vertical and horizontal, with a rudder experiment ).
2. SH-3 Pusher tail rotor. Tail rotor/tail rotor gear box was gimbaled to rotate 90 degrees in flight so as to obtain forward propulsive thrust from the tail rotor. Incorporated a rudder.
3. S-67 Blackhawk. Took various S-61 drive components, built a totally new airframe, added a wing and horizontal stabilizer ( was a stabilator for awhile ), Incorporated wing-mounted speed brakes. Had an aerobatic envelope.
4. S-67 Fan-in-fin. Incorporated a Hamilton-Standard fenestron-fan in a new tail structure. Had a rudder but this was never fully developed.
5. S-61R. This was a company funded S-61 derivative that won the competition with the Vertol 107 for the USAF contract that turned it into the original HH-3C. But, the S-61R was a company funded design and flight tested aircraft.
6. The ABC. This one you seem to have been aware of.
7. S-60 Skycrane. A crane designed using S-56 components, but in a totally new conceptual heavy lifter.
8. S-64 Skycrane. The original S-64 was designed and flown on Sikorsky /UTC funds. By the way, that included a UTC investment in having Pratt & Whitney design and test the original JFTD-12 engines ( taking a J-60 turbojet and adding a power turbine assembly to make it a turboshaft engine ). The US Army contract came later.
9. Canted tail rotors. Company funded and originally developed and flown on a company owned S-61R.
10. S-76. All models were company funded and developed.
11. S-92. Ditto as for the S-76.
12. S-76 Fantail. Risk reduction for the Comanche Program

There is another category of development, wherein the company could bail an aircraft from the government, and then do development programs using its own money for that engineering work. I am thinking of the CH-53 IRB ( improved main rotor blade ) work and the S-70 composite blade development.

Lastly, there was some discussion about the X2 being just a version of the XH-59. Possibly so, in the same sense that the Wright Flyer and the B-777 are both airplanes. The similarity ends there, however.

Thanks,
John Dixson