Originally Posted by
noneofyourbusiness
Fuel burn - Let's say a fully loaded V-280 cruises at 280 knots. A fully loaded Defiant maybe 220? knots. Because the Defiant is slower, that makes its fuel burn look better than it really is. A fixed wing provides 15? lbs of lift per lb of thrust - a clear advantage for the V-280 Valor. Does Defiant have to carry more fuel to meet the Army range requirements? That would be a significant penalty, both in terms of weight, and in fuel cost.
A twin main rotor design has more drag than a single main rotor design. The close spacing of the rotors is intended to minimize this extra drag. This extra drag can be overcome with brute force, but this means burning more fuel. The same applies to the FARA program. Does DOD want to procure high fuel burn aircraft for the next 30 years?
The question remains: how important is all this “cruise” stuff.... you can take a Hercules for that part. For a tactical helicopter you need surviveability, agility, low costs, small footprint, good OGE power margins, low, easy maintenance... that kind of stuff and yes maybe a bit quicker than the one it is replacing....