convertible t/r
As a new" kid" on this I`ll add my 10 penn`th.As already mentioned ,in 1964 two proposals were submitted to the US Army for the Advanced Aerial Fire Support System(AAFSS),which was to be a Chinook support a/c,all-weather,top speed of 220kts and a ferry range of 2400nm.Not asking much really,plus ability to hover at 6000ft at 95*f.Sikorsky and Lockheed both submitted proposals,the Sik. S-66,and the Lockheed CL-840. Both designs were similar with a narrow fuselage,tandem cockpits,sponson and stub wings for stores,The S-66 had a swivelling t/r to provide thrust as speed increased to 100kts or so,up to 200kts,and had a large"T" tail with rudders/elevators/trimmers.A modified S-61 (N-318Y) as a system test vehicle,but in practice the swivelling bits were not found to be very flexible(no pun!) in operation.Sikorsky later built the S-67 Blackhawk(original),which was very sleek,sadly it crashed at F`boro whilst doing aeros-very sad for all. So,Lockheed actually won the competition in 1965 ,their vehicle was to become the AH-56A Cheyenne,with rigid rotor,T-64 of (4200hp),conventional t/r and a fully reversible pusher propeller as well at the end of the fuselage.Eventually it could reach 215kts in level flight,245 in a dive,sustain +2g,demo`ed+2.6G and -0.2G.