Some months ago I looked at Bell's V-280 Valor entry into the US Army's Future Vertical Lift competition. I noted:
When you consider safe separation distances in a landing zone, combined with the probability of having to perform insertions and extractions in confined terrain (natural or man-made - i.e. urban), I'm not at all sure how well the V-280 design will perform, simply because it's so big. It may be forced to land and take off in more open spaces, further away from the action. That will force troops to march further to where they're needed, or fight their way back to their helicopters for extraction. That'll add time and, probably, casualties to the operation - and that can't be a good thing.
. . .
Sikorsky-Boeing's SB-1 Defiant proposal for the FVL program, on the other hand, has a similar footprint to conventional helicopters, despite being much faster. It's not flying yet, but here's a promotional video from Sikorsky-Boeing, showing what it will look like. Note that they're showing it operating in a confined urban environment - perhaps deliberately, to emphasize that it'll be compact enough to be able to work there.
There's more at the link, including videos and other images.
I was reminded of that earlier article when I came across this video clip at The Aviationist. It shows helicopters from the 160th Special Operations Aviation Regiment, exercising in the streets of Los Angeles. Note the very tight landing zones used by the helicopters. Even the small MH-6 Little Bird helicopters must require very careful handling to get in and out of such spaces, much less the larger Blackhawks (both types are shown in the video).
The video drives home my earlier concerns. Landing on streets like that, with wires, tree branches, etc. obstructing access, is difficult enough even in a small helicopter. The SB-1 Defiant, with its coaxial main rotor system, should be able to get into far more compact landing zones than the V-280 Valor (as described in the earlier article). From my own experience with helicopters as a passenger "up the sharp end", I'd say that's a supremely important consideration; yet the tilt-rotor V-280 is considered a viable contender in the competition.
What say my military and veteran readers? Am I putting too much emphasis on this tactical consideration, rather than other elements of the competition? Are there other factors that make the size and accessibility of the landing zone a less important requirement?
Peter
Peter, I'll leave that discussion to the warriors out there, just want to mention something as a now-retired wizard. We were the ones who made or improved the magic chariots and weapons for the warriors.
ReplyDeleteThe mission elements, constraints, and considerations rarely got to the designers or analysts in time. This is true for tactical use, strategic movement or employment, and operational art. Having an understanding of the set of mission conditions, and how fast they shift, helps with setting design parameters: power, size, lift/weight ratio, GPR, armor, firepower, crew entry/egress and casualty extraction. You can check things and test more efficiently if you have the right information on hand. Your point about landing zone sizes and close hazards is important, but unless explained to the design teams with why it's relevant, it gets overlooked; not in the design handbooks or in the test operating procedures.
A lot of systems I worked on which required two or more design cycles because this got missed. Each time design got altered or requirements drifted, it cost at least a year (many times, longer) and a lot of money. Someones' next promotions or lucrative post-retirement consulting jobs were at stake.
Vulcan forbid that you build an "A" model to outfit a brigade, and learn from the experience before going into full production on B or C. It had to be done faster and smarter, with experiments pushed left on the timeline, and production pushed left. Of course everything stayed right.
End of grumble. Heading back to the tower.
Requirements creep is a factor, as is continual tactical development. Tactics, Techniques, and Procedures (TTP) never stop evolving. They will initially require large by comparison LZs, but will grow smaller as the learning curve flattens out.
ReplyDeleteSmall footprint is a needful thing, especially in Spec Ops. The up-engining and 6-blade rotor for the OH-6 Cayuse/Loach was a huge leap in performance while netting a smaller rotor footprint, an excellent innovation.
ReplyDeleteTo go to a team level tilt-rotor is a step back in the needs department. The double rotor with a pusher prop is the way to go. Smaller footprint both in flight and in storage (a very critical concern on helo carriers and small bases.) Less 'high tech' magic to go wrong.
So, well, of course they'll choose the tilt-rotors...
The worrying thing for me in any tilt rotor system is the height of the rotor tips on the outside swing. Closer to stuff on the ground, obstacles and people, that you really don't want to clip.
ReplyDeleteWhat Bean said.
ReplyDeleteRotor diameter is important, but our recent trip to Greece reinforced how narrow streets in much of the world are, and how built-up many old world cities are.
Landing in the street? Even in something the size of the OH-6 Loach that would be difficult in many areas of, say, Athens.
With 26+ years of helo EMS experience under my belt I WILL say this-
Some of my patients could certainly have benefited from being able to swing the rotors to vertical and increasing our speed to 350 knots.
But complexity is expensive, and increases the likelihood of glitches.
The Soviets were smart in some ways.
What, you are saying that the Airwolf TV helicopter never made it into production? Bummer...
ReplyDeleteIt doesn't matter how fast it is if it can't do the job where it counts.
ReplyDeleteI've only been flown in Hueys, and only a few times. I recall only one ride, and that was because the pilot mentioned he had an assignment to B-52s, and he said there was just NO similarity between them. I said, "They both take off nose down."
ReplyDelete