Originally Posted by
SplineDrive
When Sikorsky teamed with Boeing on SB>1, the Sikorsky troops were told that Boeing examined Bell's proposed tilt rotor and decided it wasn't a good aircraft, Boeing didn't have technology inside the firm to meet FLRAA goals, and that left Sikorsky with the technology Boeing wanted to partner with. Of course, that line was a bunch of BS. Some years later, when V-280 first flew, there were some public congratulations on social media by various Sikorsky engineers. The SB>1 CE called an all-hands meeting and told staff not to give congratulations because Bell's success was a serious threat to Sikorsky. Defiant was badly behind schedule with lots of critical paths holding first flight far into the future.
So I don't know that Sikorsky's leadership really bet on Bell failing badly, but their schedule and flight successes were a shock.
Sikorsky has actually studied tilt rotors quite a bit, though mostly in the context of their variable diameter technology, but the VDTR bits aren't necessary. There must have been some critical meetings in the early 2000's where the future IRAD efforts of the company were aimed. The V-22 was still struggling towards initial operating capability and the 609 was entering flight testing. So tilt rotors were moving from a future threat to a present threat, but one with observable challenges even for the industry leader in the field. Instead of being a second tier OEM for tilt rotor technology, they reached to the XH-59A and decided to be the first tier OEM for a different approach to higher performance. All the problems of the XH-59A were known but only some got solved or improved sufficiently by todays technology (in the end). Would love to have been a fly on the wall during those discussions. The XH-59A had the same general level of technology as the XV-15 but only few a few hundred hours before being retired as opposed to the thousands of hours and decades of flight history of the XV-15. Given the same level of technology, the tilt rotor appears to be a more practical aircraft. Even if today's technology made an X-2 practical, did Sikorsky not imagine that the same level of technology applied to a tilt rotor would make it even more practical? Or did they imagine that Bell would use the 1980's technology of the V-22 and Defiant could leap past it?
From what I've been able to determine, when Bell and Boeing talked, the latter wanted too much control, espeecially in the Fkight Control System, and Bell wouldn't agree so Boeing walked (much to Bell's relief).
Regarding the XH-59A, after the initial tests, the Government proposed a shared cost continued program with the craft being converted to an "XH-59B" configuration that involved new advanced rotors, two GE T700s) and a ducted pusher propeller at the tail. Sikorsky refused to share any of the costs and so the plane was grounded. Not a great show of confidence.
Contrast that with the XV-15 where Bell shared the cost of the initial NASA testing and then with supplemental NASA/Army testing. After that phase, NASA was going to ground one of the two XV-15s because it wasn't needed for what further research was planned. Bell stepped forward and leased their XV-15 back from the government and continued flying it at 100% their cost. That's where you saw all those demonstrations, air shows and guest pilot flights. It even went to the Paris Air Show. . That one flew until August of 1992 when while being flown by a guest pilot a bolt slipped out of the collective control system on one pylon and caused a rollover while in hover. The aircraft suffered major damage but the crew only had minor injuries. The other XV-15 flew until September of 2003 when after using up all its rotor life it was flown to the Smithsonian.
Probably more than anyone wanted to know, but it shows there was an advantage even then.