I spent part of the day yesterday at the Association of the US Army’s Aviation Symposium here in the DC area and among other interesting things, got my first exposure to an experimental Sikorsky helicopter that could change the paradigm of rotor wing aviation.
I remember way back in the day when Sikorsky purchased Schweitzer helicopter company (the forebears of the MQ-8B Firescout helo-drone) and planned to turn that shop into the rotor wing equivalent of Lockheed’s Skunk Works.
Well, it looks like they’ve turned out a very interesting product in the new X2 Technology Demonstrator.
According to Doug Shidler, VP for Sikorsky’s Army Programs office, it was only recently — and with the help of new technology flight tested on the Army’s Rascal (rotorcraft aircrew systems concept airborne laboratory) UH-60 tech demonstrator — was the company able to incorporate mature systems that didn’t make the X2 so unstable it couldn’t fly for very long.
“There’s a lot of technology that we’re applying that we learned on the Comanche program and that we’re learning on the [Blackhawk] upgrade program that we’re applying right now,” Shidler said. “It will demonstrate a lot of different things that we had difficulties with in the ‘70s and ‘80s. … What we’ve done is apply a lot of the technologies that we’ve learned developing and embodied in our platforms today and to go ahead and develop this new platform.”
[Photo and Slides from Sikorsky]
1559_X2-007_Trifold
The X2 features a set of two counter-rotating blades and a rear-mounted propulsion blade. The goal is to get the aircraft to speeds in the 250 kt range — which puts it in close competition with the Osprey’s specs, but of course the V-22 is operational and can carry a load of troops.
Sikorsky claims this technology can be applied for light attack, light transport, SAR and intermediate commercial applications, and Shidler hinted that it could be used for heavy lift.
Their literature on the X2 claims the configuration will allow for increased payload, improved range, low downwash and cheaper price.
Shidler showed a slide that said Sikorsky had conducted a successful test flight in August.
– Christian
{ 17 comments… read them below or add one }
Christian,
Were there any stands/models/info on a Quad tilt rotor or other contenders for the JHL? Or even any discussion in the panels on what would provide lift to the FCS in a vertical assault mode?
Has Boeing indeed given up on concepts like the X-50 Dragonfly Canard Rotor Wing or the LAMV that they looked at a few years ago? Are these programs too hi-tech for the Army?
Finally any new missile tech for rotary wings such as a renewed look at the DAGR or other contenders for the APKWS program?
Will this sucker end up like the Cheyenne, dropped for a cheaper product?
atacms, any links for those programs you mention? That would be good for discussion, to standardize our sources.
I remember seeing concept art for a quad tilt…looked like a C-130 but this may be old news (especially how things change in the procurement world)
This doesn’t look particularly revolutionary (which can be a good thing): Russians already use contra-rotating rotors, and Piasecki “pusher” rotor has been around, but I don’t recall if it’s been used anywhere.
I suppose the additional advantage is that there are no large wings that get in the way of say, carrier ops; and if I recall correctly, the wings and the pylons for the props get in the way of door-mounted guns in the Osprey.
Engineering-wise, how much more complexity is added when you use counter-rotating blades? Will it add significantly to maint and kill reliability?
would you please publish upcoming articles with a *direct link* for the described media?
are you in any way affialiated with scribd, as it seems?
well if they keep cost down looks like the marines may get a escort for the osprey.
looks awsome if they can make it work well enough cheap enough and dependable enough for military work
From what I have read, this tech from sikorsky is different from the traditional contra-rotating rotors. The program was started in the 60-70s in the Advancing Blade Concept (ABC) program. The rotors do not have flapping hinges of the traditional rotor, resulting in greater lift and smaller vertical spacing when compared to the traditional contra-rotating rotors, but this results in a choppier ride which is one of the reasons why the ABC program was not developed further. The X2 concept seems to have built in active control damping of this vibration.
Ive actually done work on the X2 program. So far the first two test flights have looked extremely promising. Currently sitting in WPB awaiting further incremental testing to increase the flight envelope and begin high speed testing with the propulsor. All of us engineering staff are excited for this AC’s potential; level acceleration/deceleration, excellent hover dynamics, and and 250+ knots make this a truly amazing machine.
The substantial differences between the X2 and the XH-59A ABC involve Moog AVD from the S92 in addition to a full FBW control system and a weather-vaning hub fairing. The combination of these systems and some significant efficiency advancements in our blades and transmissions allow for this to be a viable concept. Before the ABC program was concluded due to lost funding, the XH-59B was actually slated to have a ducted fan on the rear for propulsion similar to the X2.
The V-22 has three primary advantages speed, altitude and range. This combo rotor sounds like it may match speed, increase helicopter but not match V-22 range, and have minor altitude increase.
You don’t want 20-30 ton heavy lifters having to fly nap of the earth to avoid your insurgent AAA. Heavy lifters don’t need to be at the point of the spear but they need to be able to come up the shank with some security.
Bottom line sounds like a highly competitive attack helicopter. High potential for the hide in the trees then pop up dash to next hide to ambush X tank column, then dash out.
@ C-Roy
The V-22 also has some major disadvantages, including the lack of autorotation (landing in airplane mode results in major damage and possible loss of the AC), high disc loading, and quite poor hover/loiter performance.
In late 2007 the Army had stated they were only considering tilt-rotor solutions for JHL, but early in 2008 reversed their position and provided funding to Sikorsky to continue research in pursuit of a scaled X2 concept in addition to our VDTR.
Im glad they scale the X2, need more Heft for heavy lifting & the V22 can use some competition.
We need the jobs, so produce this baby.
How about a 2 deck commercial X2 type carrying 100 passengers?
Ideal for HI, Caribbean area & Helo tours.
& to replace the Hueycobra gunship?
I thought ABC coax rotor was dead…I wonder how many engineers with relevant experience from the 80′s program are still in the company.
The rotors do not have flapping hinges of the traditional rotor, resulting in greater lift and smaller vertical spacing when compared to the traditional contra-rotating rotors, but this results in a choppier ride
I am fascinated by the Sikorsky X2 but know little about helicopters. Worse thing if the counter-rotating blades hit one-another. I recall that the gyro-plane was the necessary step to the helicopter and that the blades have to be hinged or they snap off?
I wonder if there is a technology that measures how close the counter-rotating blades come such as magnetic resonance which could be an input into the fly-by-wire stuff?
Here’s hoping Sikorsky can pull it off. It’s important to keep in mind, though, that the X2′s first flight was waaay late, and based on what C. Foskey wrote, they’ve only gotten it in the air twice so far, which is slower progress than they estimated. So while we should be cautiously optimistic, we should realize there’s along way to go to meet the promises of those marketing illustrations. Still, if it advances the technology, the US rotorcraft industry needs it.
Regarding a couple of V-22 notes: The V-22 can’t autorotate to a full stop, but it was never required to, just to make a survivable landing either by autorotation OR by gliding and a slow speed run-on It does the latter. Keep in mind its size. How many conventional helicopters of its size can autorotate to a full landing? Regarding the gun issue, the V-2 was originally intended to have a turret in the front mounting a cannon, but this was cut for funding reasons. Now, it looks like it is being restored.
The funding got cut on the XH-59 because, due to hub drag and the control technology wasn’t advanced enough then, it was totally outperformed by the kludged-together XV-15. Wags used to point out that when a flight demonstration was scheduled out of the local area, they’d just fly the XV-15 there, but they’d load the XH-59 on a rail car and ship it. With the our improved technology today, hopefully those issues have been overcome.
Congratulations to Sikorsky for having the guts to try!
@ Sven Ortmann
More than you’d probably expect.
@ 45north
The X2 blade system is rigid, and designed so that blade contact is nearly impossible throughout the entire flight envelope.
@ Watcher
You are correct, the X2 was slated to fly in 2006. However, the strike at Sikorsky during that timeframe affected its development, plus its mostly an “out of pocket” endeavor for the company.
Autorotation on the V22 was actually an original requirement in the 80s, until it was removed for technological and cost reasons. Same for the gun (which is being re-added by BAE systems in the belly).
Regarding performance of the XV-15 being “better” than the XH-59, it all depends on your criteria. If range was your goal, then yes, it had much better performance. But regarding hover dynamics and typical rotorcraft maunverability the XH-59 was much more viable. Test pilots claimed the thing handled like a fighter plane, and broke several helo speed records during its time. The real issues were the vibration, transmission tech and control systems, which we’ve mostly solved.
>The V-22 has three primary advantages speed,
altitude and range. This combo rotor sounds like it
>may match speed, increase helicopter but not match V-22 range, and have minor altitude increase.
Osprey has more speed at flight, but less speed for hover downward due to the vortex ring issue, lacks freedom for weapon attachments, maintenance difficulties, and comes with an expensive price tag. X-2 has less speed, rather between tilt rotors and conventional helicopters, but less likely to suffer vortex ring problems resulting in better hover performance, more freedom of weapon atachments, likely could be easier for maintenance, and with a lower price tag. Osprey and X-2 have different weakness and strengths. X-2 would likely be a low solution to the hi-low with Osprey. I’m not sure about combat radius, but it sounds like cross Atlantic capabilities gives Osprey an advantage over X-2. In other words, when speed and range is needed, the solution is Osprey, when speed could be compromised and hovering is more improtant, X-2. Speed for hovering downward is sometimes critical in hostile areas, which the VTOL may be targeted from ground fire. Osprey sounds like more quality approach versus quantity.
pedestrian,
Not THAT myth again.
The V-22 is actually LESS seseptable to vortex ring problems than traditional helicopters. It was only an issue when NON HELICOPTER pilots flew the V-22 & had no experience with vortex ring. Simply being AWARE of vortex ring & how to avoid it, along with some flight software changes have all-but resolved such problems. And even when the V-22 experiences vortex ring, the pilot simply rotates the engines forward (IIR like 10-15 degrees) & no more vortex ring…
The TRUTH is that the V-22 can get in, offload & vacate the landing zone FASTER than any transport helicopter (and I do not mean getting to & from the landing zone, I mean actual time spent IN the landing zone). Quit thinking of the V-22 as a helicopter, it DOES NOT operate like one other than being capable of vertical flight.
@C. Foskey: Thanks for the reply.
from the wikipedia article:
http://en.wikipedia.org/wiki/V-22_Osprey
as a drive shaft connects the nacelles through the wing; one engine can power both proprotors.[22]
would this be useful in a conventional twin-engine airplane? you could put the engines further out and have improved single engine operation – I’m guessing that cost of engines would double, extra transmission, extra weight, reduced reliablity – after all twin engine airplanes fly pretty well on just one engine?