Amusingly, the single-engine complaint leveled against Cheyenne was never made against Cobra, and it didn't get its second turbine until 1972 - well after the cancellation.
I love combination design helicopters, I love the pusherprop system and what it could do to control the aircraft, and the sheer amount of firepower and speed that Cheyenne had (as well as the Gunstar's own actual gunner's station, watch it spin around someday) really made it an effective program. It was stealthy to the guys on the ground too - not radar, but sound envelope; during observation tests the AH-56 was able to zoom up on the post at extreme low altitude at high speed. She wasn't noticed until it was virtually overhead and well after it'd have fired on its target.
It was probably the perfect CAS bird, able to respond fast to a situation, carry a LOT of firepower, and get in those early shots. Once the strategic plan and needs changed, pull-type CAS became less of a thing and tank-hunting from cover was the new way to go about it. So Cheyenne was pushed off the board, and something new was done.
Still, it's a shame gyrodynes never took off, even in the civilian market. Much higher speeds, more fuel, more capacity...well maybe now they'll get their chance.
Or maybe we'll fly this.
