yasotay said:
V-280 flew with gear up last week. Bell only has one of them and they are being very methodical with the test program. While I have to admit that F-14D has a valid concern regarding the Army ineptitude at aircraft acquistion, the USMC has benefitted from the Army's problems. Marines have made no bones that they want a Tilt Rotor to replace the H-1 aircraft.
I would also remind you that this aircraft, nor the SB>1 or the S-97 Raider are built to a specific military requirement. They are demonstrator aircraft, built as such. True they are built to a specification defined by the Army, but these parameters have yet to be promulgated into a requirements document.
I did not know about the lack of requirement. If there's no well thought out requirement, this should stay a prototype.
High speed helicopters make fundamental trades against hover performance, and you buy a helicopter because you want to hover. I'm also skeptical about the need for speed - does it actually make you more survivable? If you can't do close terrain following flight because of the speed how much do you lose? Also the navy, while not the lead service, doesn't need speed - it needs hoverin' for resupply and ASW.
The second aspect of FVL is the boost in range requirements. If the army does not have the range requirements of the marines (and should they?) then its not needed. If so, then half the program's justification isn't there and that alone should kill the program.
If you replace the blackhawk with a clean-sheet traditional design with modern engines and a composite airframe, you can probably get enough of a range and payload boost to make the expense of something fancy not really worth it. When these things get past demonstrator, they need to make an honest comparison against a traditional design, or else there's a good chance of wasting a ton of money for not much. Then, if it's not worth it, you take the money you saved and buy a scout helicopter - an actual sensible need. It's not unreasonable to claim that transport helis are glorified trucks, and program requirements should be written as such.
And from what my heli-informed friends have told me, Bell's design is extremely sound, while Sikorsky has major technical challenges ahead in scaling up their design. Their rigid co-ax lift-offset rotor design requires accurate vibratory load prediction and clever vibration damping, and if that stuff doesn't work as well as expected, their design will be in deep trouble.
I honestly hope these aircraft fly and do cool stuff, but my personal doubts combined with the Army's lukewarm commitment, means that I'll take the betting odds that these designs never make it past being demonstrators.