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dangermouse
16th Sep 2010, 12:03
a 250 kts compound rotorcraft

DM



widgeon
16th Sep 2010, 13:03
Does anyone have any fuel burn figures ?

heli1
17th Sep 2010, 05:37
Was the latest speed maintained over any great distance and in continuing level flight or after pulling out of the 260kt dive ?
Did the aircraft have the full hub drag reducing kit fitted?

Ascend Charlie
17th Sep 2010, 10:03
It was in level flight.
He got to 260kt in a shallow dive.

When the fairing goes on, it is expected to get another 15kt.

riff_raff
19th Sep 2010, 02:51
According to this article (http://www.flightglobal.com/articles/2010/09/17/347444/sikorsky-expects-265kt-from-x2.html), maintaining 250kts required 1300hp from the T800, leaving 300hp in reserve.

Sikorsky (http://www.sikorsky.com/Index) engineers say the company's self-funded X2 advanced technology helicopter could reach 265kt (490km/h) or more in the next few months after a central sail fairing is installed on the rotor mast.
The twin coaxial contra-rotating rotor demonstrator reached its project goal speed of 250kt in level flight during a morning test flight on 15 September in West Palm Beach, Florida.
At that speed, test pilot Kevin Bredenbeck says the T800-powered pusher had a reserve of around 300hp (225kW), although test limits held the speed to 250kt, a programme target speed achieved about midway through the 1.1h flight. Total power required to maintain 250kt was 1,300hp, 80% of the T800's capability.
In slightly over two years of testing, the X2 has flown for 16.2h on 17 flights, far exceeding the maximum level cruise speed for a helicopter to date - officially 217kt by a Westland Lynx (http://www.flightglobal.com/landingpage/westland%20lynx.html), and unofficially 236kt by the company's XH-59A demonstrator in the early 1970s.
Sikorsky is investigating whether to attempt an official speed record during the final flight-testing on the vehicle, which is likely to involve two flights for acoustic testing and two flights for sail fairing and higher speed testing.
Steve Weiner, chief engineer for the X2 programme, says the stationary sail fairing, sandwiched between the two main rotors, could add 15kt to the cruise speed, once engineers perfect the installation.
Ground tests of the fairing are to start in the next few weeks.
Weiner says Sikorsky is investigating whether to attempt an official speed record during the remaining testing on the vehicle, which is likely to involve two flights for acoustic testing and two flights for sail fairing and higher speed testing.


The CTS800-5 used in the X2 is rated at 1681hp for take-off. And there is always the hot rod modifications of water or nitrous injection sometimes used for temporary power boosts. So the X2 might be capable of substantially more than that 250kts. At least if Sikorsky is willing to trash an engine to get there......

To answer widgeon's question on fuel burn, the published SFC of the CTS800-5 is about 0.49 lb/shp-hr at MRP. Which means the X2 was burning about 637 lbs/hr at 250kts.

riff_raff

turboshaft
19th Sep 2010, 14:57
T800-LHT-801 rated at 1,563 shp. No laughing gas.

prehar
21st Sep 2010, 17:12
If the horizontal stabiliser is giving a download in forward flight and its a fly-by-wire machine with a lot of control law tweeking still going on during flight tests ,will Jeff or Chris tell us if any thought to extract more from the X-2 with a Canard foreplane is on the cards either now or in the future ...before design freeze ??

IFMU
22nd Sep 2010, 00:37
Are they Ppruners? I can't place their names with Pprune ID's.

Another 15 kts would be cool. Thanks riff_raff for the link.

It seems we are missing some of the thread regulars. Loss of interest, I suppose.

-- IFMU

JohnDixson
22nd Sep 2010, 11:36
IFMU sent:

"It seems we are missing some of the thread regulars. Loss of interest, I suppose."

It does make it tougher when a team sets a goal and then methodically and safely achieves it.

Thanks,
John Dixson

The Sultan
22nd Sep 2010, 21:29
John

Been looking at more impressive feats such as:
Highland Park racer sets land speed record | News for Dallas, Texas | Dallas Morning News | Dallas Business News (http://www.dallasnews.com/sharedcontent/dws/bus/stories/092210dnbusNearburg.11705dcf8.html)

360 knots on a V8 engine. Now that is impressive, probably has much better fuel efficiency.

The Sultan

Dave_Jackson
22nd Sep 2010, 22:02
What is there left to discuss, if 'the goal' was 4 years of marketing by 'Sikorsky Innovation'?

http://www.unicopter.com/Closed.gif


_______________________

If 'the goal' is technical improvements, which might lead to a marketable product, can anyone mention a single improvement on the X2-ABC that was not proposed 30 years ago at the conclusion of the XH-59-ABC. This, of course, excludes improvements over the past 30 years that are available to any new aircraft?


Enough of the 'sizzle'. Where's the 'steak'.

JohnDixson
23rd Sep 2010, 11:00
Sultan, I can imagine that the " Spirit of Rett" racing team operates with the same enthusiasm and technical energy as the X2 team, and while I might not be able to agree that it is a more impressive achievement than the X2 due to my inescapable bias, it is a terrific feat. And all the more so when I read that their Chevy engine doesn't have a blower; it is naturally aspirated!

Dave Jackson, it appears that the X2 can do nothing to impress you, and that's too bad, because the only thing it shares with the XH-59 is that it has a contra-rotating main rotor. It couldn't have been built at the conclusion of the preceding ABC as "the stuff" that goes into it wasn't available.

Thanks,
John Dixson

heli1
23rd Sep 2010, 11:43
Come on Nick Lappos....time to back Bell and the Model 533......the real world's fastest !

Dave_Jackson
23rd Sep 2010, 18:27
John, you are correct. The continuum of hyperbole from the marketing department and the frivolous patents from the legal department do not impress me. They appear to be little more than attempts to maintain image and stock value. Any serious buyer will want to 'look under the hood and kick the tires'.

What does impress me are those manufacturing companies that have innovative engineering departments, which are given the opportunity and the ability to provide new and improved products.

I asked for anyone to provide just one single improvement on the X2-ABC that the engineering personnel did not recommend at the conclusion of the XH-59-ABC. Unfortunately, your response was "the only thing it shares with the XH-59 is that it has a contra-rotating main rotor". Excuse me, but the essence of what the two craft share is the Advancing Blade Concept ~ both its strengths and its warts.


Sikorsky elected to not pursue the ABC concept after the XH-59 lost in competition. However it did acquire a considerable amount of data and the engineering department itemized many specific recommendations for improvement. Therefore I again ask, what is specific and unique to the Advancing Blade Concept, that makes the coaxial version of the ABC so viable today, when it wasn't 30 years ago?


Dave

Dan Reno
23rd Sep 2010, 20:11
Dave,

Perhaps you can name some of "those manufacturing companies that have innovative engineering departments" and their latest innovations?

All that's been heard from abroad has been crickets.

Best.

Dave_Jackson
23rd Sep 2010, 21:52
Dan.
Perhaps you can name some of "those manufacturing companies that have innovative engineering departments" and their latest innovations?

Internet related companies.

Dave

Dan Reno
23rd Sep 2010, 22:26
Dave,

I guess I'm just confused (nothing new). Sikorsky on their own dime developes over the years a fine machine that does what no one else in the helicopter business can do and we applauded that.

You weren't impressed so I'll ask again: What other helicopter company accross the pond has done ANYTHING comparable?

You say: "Internet related companies." What does that mean? That's why I'm confused. Perhaps you can unconfuse me please?

Thanks.

IFMU
24th Sep 2010, 00:44
Dave,

You talk about marketing hyperbole. Sikorsky claimed 5 years ago they would get the X2 to go 250 kts. Now they have gone 250 kts. Where is the hyperbole? On that article that riff_raff linked to, they talk about another 15 kts with some fairing. If they can actually squeak 265 kts out of the aircraft, then what you have is not hyperbole. Actually, it says they were holding back with what they thought it could really do.

-- IFMU

Dave_Jackson
24th Sep 2010, 01:32
Dan.

Sorry for my lack of clarity. The reference to "those manufacturing companies that have innovative engineering departments" was in reference to all manufacturing companies and not the rotorcraft industry specifically.


IFMU,

With their previous knowledge and 1500+ HP engine, who thought that the craft would not achieve 250 kts?

Who's to say that with a few modification they could not have achieved 250+ kts thirty years ago? And why didn't they????


Dave

JohnDixson
24th Sep 2010, 01:50
Dave, you posted:

"John, you are correct. The continuum of hyperbole from the marketing department and the frivolous patents from the legal department do not impress me. They appear to be little more than attempts to maintain image and stock value. Any serious buyer will want to 'look under the hood and kick the tires'."

Your construction implies that my assessment of the SA marketing and legal departments matches yours. I worked with both groups for 39 years and my opinion of both groups is 180 degrees from yours.

Secondly, although I have far from perfect recall, I think that we decided not to continue with the XH-59 after a decision by the supporting US Gov't agencies in 1980-81 not to continue with financial support of that program. A few years later the Army decided that the LHX was to be a conventional helicopter. That was around 84-85. Remember, at the time Sikorsky had a new production program with the UH-60, a new production program with the CH-53E, a new production program with the S-76A, (the 76B was on the boards) the development/qualification testing program on the SH-60B Seahawk, and I am certain we did not have enough people to try an ABC development toward a production model.

By the way all of those concurrent models were the product of that non-innovative engineering department to which you referred. Nowadays, they are working on some other "non-innovative" new models in addition to the X2, so as to be sure to keep the marketing guys and girls awash in hyperbole.

Thanks,
John Dixson

Matari
24th Sep 2010, 02:00
Bravo to the guys and gals wherever they are who actually design stuff, manage people, sell things, bend metal, and fly dangerous tests, versus those who sit in a chair, punching an archaic keyboard, and claiming superior knowledge over those actually doing something.

Jack Carson
24th Sep 2010, 22:45
I believe that another element that stymied the X-59 in the 1980s was the lack of a Sugar Daddy. The X-59 was a DARPA sponsored program that had no home in DOD. By contrast the XV-15 had DOD support resulting in continued development, ultimately growing into the V-22. Examples of other programs that similarly went by the wayside are Northrop’s F-20, Sikorsky’s S-67 and until recently the Lockheed C-130J. Privately funded programs with little or no government backing have limited chance for success.

IFMU
26th Sep 2010, 01:57
A neat article. Sort of humanizes the people behind the effort, so content may not be suitable for all.

IEEE Spectrum: The Fastest Helicopter on Earth (http://spectrum.ieee.org/aerospace/aviation/the-fastest-helicopter-on-earth/0)

Also they link to a "back story" article:

IEEE Spectrum: A Fast Helicopter's Slow Revival (http://spectrum.ieee.org/aerospace/aviation/a-fast-helicopters-slow-revival)


-- IFMU

Dave_Jackson
26th Sep 2010, 06:14
Thanks IFMU,

The effort and the people behind the helicopter with extremely-rigid coaxial rotors is neat.

However, for a full appreciation of the effort one must include the earlier work, before Sikorsky called it the 'Advancing Blade Concept'.

"Stanley Hiller flew the first successful American co-axial helicopter, the XH-44, in July 1944, when he was only 19 years old. It also featured the world's first successful all-metal rigid-rotor blades." Hiller X-2-235 (http://www.aviastar.org/helicopters_eng/hiller_x-2-235.php)


Dave

TXSIK
27th Sep 2010, 17:52
It seems we are missing some of the thread regulars. Loss of interest, I suppose.




I suspect it results from a distaste for crow.

Lonewolf_50
27th Sep 2010, 18:03
I don't understand, Dave_Jackson, how you consider lacking in innovation the company who (in partnership with Boeing) put together Comanche -- a helicopter that did a number of new and innovative things in the helicopter biz. (Sadly, it was cancelled for what were IMO internal program reasons driven by the Army choice not to go single pilot ... risk averse strikes again ... but I digress, and I am sure others much closer to that program may not agree with my opinion on that).

Dave, what what floored me was your choosing to compare internet companies with helicopter companies in the realm of innovation. The orders of magnitude in complexity don't compare.

Sir, may I ask, please: huh?

Mister Jackson, do you actually take the MBA's approach to business, actual product being irrelevant to the bottom line's being red or black?

Given your enthusiasm for things rotary wing, I sincerely hope not.

Graviman
28th Sep 2010, 11:47
Wow! 250kts - what an amazing machine: developed by a dedicated team and flown by a talented TP. I never had any doubt. :ok:

Other priorities have kept me away from Rotorheads for a while, but i can assure you there is no loss of interest.

I can't wait to see how the high speed (compound) helicopter story unfolds. Sikorsky has opened another pioneering door.

http://images.gizmag.com/gallery_lrg/sikorskyx2250knots.JPG

http://images.gizmag.com/gallery_lrg/sikorskyx2250knots-0.JPG

Sikorsky’s X2 demonstrator sets unofficial world record speed of 250 knots (http://www.gizmag.com/sikorsky-x2-demonstrator-250-knot-milestone/16424/)

Sikorsky Aircraft’s coaxial X2 Technology demonstrator has achieved the 250-knot (287.69 mph) milestone that was established as the goal of the craft from its inception. The speed, which was achieved in level flight during a 1.1-hour flight on Wednesday, September 15, is an unofficial speed record for a helicopter, easily beating the current official world record that stands at 216.46 knots (249.1 mph) set by the British built Westland Lynx ZB-500 in 1986.
Earlier this year (http://www.gizmag.com/sikorsky-x2-demonstrator-181-knots/15277/), the X2 demonstrator achieved a speed of 181 knots in a test flight – faster than the 160-170 knot (184-195 mph) speeds generally possible with conventional helicopters – but achieving a speed of 250 knots was always the ultimate aim for the X2 Technology program since its beginnings in 2005 (http://www.gizmag.com/go/4117/). The 250-knot milestone was reached at the Sikorsky Development Flight Center where the demonstrator also reached 260 knots (299.2 mph) in a very shallow dive during the flight.
“The aerospace industry today has a new horizon,” said Sikorsky President Jeffrey P. Pino. “The X2 Technology demonstrator continues to prove its potential as a game-changer, and Sikorsky Aircraft is proud to be advancing this innovative technology and to continue our company’s pioneering legacy.”
The X2 Technology demonstrator combines an integrated suite of technologies intended to advance the state-of-the-art, counter-rotating coaxial rotor helicopter. It is designed to demonstrate that a helicopter can cruise comfortably at 250 knots while retaining such desirable attributes as excellent low-speed handling, efficient hovering, and a seamless and simple transition to high speed.
Kevin Bredenbeck, Sikorsky’s Director of Flight Operations and Chief Pilot for the company and for its X2 Technology program, manned the milestone flight. Bredenbeck said the demonstrator has been performing well, meeting expectations of performance predictions and progressing with every test flight.
“Our primary key performance parameter has been met,” said Jim Kagdis, Program Manager for Sikorsky (http://www.sikorsky.com/Index) Advanced Programs. “The 250-knot milestone was established as the goal of the demonstrator from its inception. It’s exciting to imagine how our customers will use this capability.”

Lonewolf_50
28th Sep 2010, 13:50
Mulling over a few thoughts:

From XV-15 to V-22 took about 15 years, then another seven or eight for IOC.

How long from X2 to a cargo, pax, or "mission" sized aircraft that people/companies/nations can use to fulfill various needs that helicopters fill now?

That fixed wing aircraft fill now, but without the need for as much runway?

Dave_Jackson
28th Sep 2010, 21:56
Lonewolf 50

Nope. I do not support today's capitalism that serves the short term 'need for greed'. Its flaws are becoming very obvious.

Time will tell whether the X2 becomes a viable product or another Comanche.

Dave

Graviman
29th Sep 2010, 11:55
Dave,

The other way to see this is that despite the disappointment in not being able to develop XH-59 further a new generation of engineers picked up the concept, dusted it off, realised the potential, then had the gumption to take that potential to full realisation. All we have to do is give them a pat on the back for being so bold. ;)

Will X2 spawn a new generation of high speed helicopters? That depends on us.

We could nit pick and criticise those dedicated engineers or we could congratulate them. The purse holders will be looking to us "experts" to see whether this idea is worth further investment - i for one whole heartedly support the X2.

Mart

davh12
7th Oct 2010, 17:30
I have not yet flipped through all of the thread pages for the X2..........A pilot associate from rotor space suggested this web site to me.........so I'm a Newby. Anyway, I have seen several pictures of the X2 and my question is does the X2 have adjusable mast incidence....+/- tilt forward or aft?????? Reason I ask is some pics seem to show the bottom rotor blades closer to the forward fuselage than in others? Anyone know? Thanx,

Regards,

D. Hickman:hmm:

riff_raff
8th Oct 2010, 23:22
It looks like the X2 and other high-speed rotorcraft concepts now will have a DOD program of record. According to this Aviation Week article (http://www.aviationweek.com/aw/generic/story_generic.jsp?channel=awst&id=news/awst/2010/10/11/AW_10_11_2010_p24-259969.xml&headline=U.S.%20Army%20Rotorcraft%20Initiative%20Draws%20Praise), an Army AMRDEC spokesman stated that the JMR rotorcraft program is funded to produce two different prototype aircraft (likely a tilt rotor and a compound helo) for a fly-off in FY'17. The program will kick-off with concept studies in mid FY'11.

Since the X2 is already flying, Sikorsky has an excellent shot at one of the two TD contracts.

riff_raff

Graviman
12th Oct 2010, 11:51
davh12,

The advantage of X2 is that it seperates out lift and thrust. The main rotor is a fixed incidence design, which means that for emergency autorotation all you need to do is drop collective pitch. This means that despite its speed capability it can still perform all of the tasks a conventional helicopter can - only faster. You pay for the performance benefit with the increased weight of a coaxial rotor system, which means a slight reduction in payload for a given mission. On the other hand, for your line of work, it means the bad guy has less time to react...

davh12
12th Oct 2010, 11:55
....thanx for the insight.

Regards,

Dave

heli1
12th Oct 2010, 15:01
Perhaps some of that insight could be directed at the editor of Rotor and Wing who seems to think in her editorial that the X2 has a "tandem" rotor...Gawd 'elp us !!

davh12
12th Oct 2010, 18:03
yeah..."tandem double stack"...it is tandem right..........two sets of propeller thingys...lol:ugh:.........:}. That's about as insightful as hoping that God will put a "post it" sticker on your bird when it's time for preventive maintenance

davh12
19th Oct 2010, 11:50
I've heard the X2 dubbed an "absolute rigid rotor system"........it may have been discussed in this thread since 2006........been going on a while, but I'm not patient enough to read through every post in the past 3 or 4 years. That being said, if it is an absolute rigigd rotor system, how does it over come dissmmetry of lift? :}

Shawn Coyle
19th Oct 2010, 16:34
Rigid refers to the hub design - implying that there are no flap or lead-lag hinges, only feathering hinges. Flap and lead-lag forces are absorbed by the material in the rotor head.
Good question- I'm in West Palm Beach for a special press thingy on the X-2 tomorrow, and have a ton of questions - it's for an article in Vertical in the very near future!

TwinHueyMan
19th Oct 2010, 19:09
Just out of curiosity... with all the fanfare of the X2 breaking the Heli speed record, how does anyone figure the X2, a compound helicopter, can be compared to the current (or previous) record holding Lynx, which achieved the speed record without any thrusting appendages?

And if it did indeed steal the record and non rotor system thrust is allowed, would it not still be trying to catch up the Bell 533, which hit almost 275 knots back in 1969?

Mike

Dave_Jackson
19th Oct 2010, 20:01
Shawn,

You may wish to ask Sikorsky about the mast fairing, which is yet to be installed.

Two patents;
7,607,607 ~ De-rotation system suitable for use with a shaft fairing system (http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7,607,607.PN.&OS=PN/7,607,607&RS=PN/7,607,607), and
7,621,480 ~ De-rotation system for a counter-rotating, coaxial rotor hub shaft fairing (http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=7,621,480.PN.&OS=PN/7,621,480&RS=PN/7,621,480)
show many potential mechanical and electrical means of limiting its rotation.

Apparently, the uncontrolled rotation of the mast faring is due to the fact that it is located between a clockwise rotating rotorhub and a counter-clockwise rotating rotorhub. It appears that there is nothing stationary to attach mast fairing to.

Dave


P.S. If you want to be mischievous, you can ask them if the Intermeshing-ABC (http://www.unicopter.com/UniCopter.html) has a mast. http://www.unicopter.com/Devil.gif

widgeon
19th Oct 2010, 20:16
Chop Chop (http://www.aviationweek.com/aw/blogs/defense/index.jsp?plckController=Blog&plckBlogPage=BlogViewPost&newspaperUserId=27ec4a53-dcc8-42d0-bd3a-01329aef79a7&plckPostId=Blog%3A27ec4a53-dcc8-42d0-bd3a-01329aef79a7Post%3Aa088db22-7333-4077-8e81-8b5d6b346748&plckScript=blogScript&plckElementId=blogDest)

the next step ??

"Expect something from Sikorsky inside a couple of months", company manager for advanced programs Jim Kagdis said at the International Powered Lift Conference in Philadelphia on Tuesday. As the X2 program winds down - the demonstrator is designed for a limited life, and Sikorsky plans to place it with the Smithsonian after a couple more sorties - the company is pitching the idea of replacing the Army's Kiowa Warriors and Special Forces AH-6 and MH-6 Little Birds with an X2-technology aircraft.

That is also the goal of the Army's Armed Aerial Scout program, currently in the analysis of alternatives stage with a report due next year.

Sikorsky showed a full-scale mockup of its Light Tactical Helicopter (LTH) design at last year's Association of the US Army convention in Washington DC, but Kagdis would not be drawn on whether the company plans to announce a new initiative at the 2011 event later this month.


http://sitelife.aviationweek.com/ver1.0/Content/images/store/11/1/5bdcea65-d603-4e3b-b147-713c47b5ca02.Large.jpg (http://sitelife.aviationweek.com/ver1.0/Content/images/store/11/1/5bdcea65-d603-4e3b-b147-713c47b5ca02.Full.jpg)

Kagdis said that the company sees the LTH as having the most potential for an early transition of the X2 to production. He also stressed that the X2 concept is not just about speed: the program started with four key performance parameters (speed, low workload, low vibration and low noise) and that as the project progressed, the company recognized also that the high power required for speed woulkd translate into much improved hot-and-high performance.

The X2 just completed some acoustic tests with the pusher propeller shut down and the speed of the main rotors reduced. Its remaining tasks include testing a "sail" fairing on the rotor mast - not to increase speed but to reduce drag at speed, critical to achieving long range with a coaxial design.

Kagdis did not hand out copies of his IPLC presentation, but outlined an LTH with a normal takeoff weight of 8950 pounds and a max of 10500 pounds (about the size of a classic AH-1G Cobra), powered by a single 3,000 hp engine. Despite its size, the relatively small rotor diameter (33 feet) and lack of a tail rotor give it an "operating length" between that of the Kiowa Warrior and the Little Bird, while the high installed power allows it to hover at 14,000 feet - today's helicopters, Kagdis says, cannot hover over 40 per cent of Afghanistan, but the LTH can cover 97 per cent of the country.

Small size would make it easier to operate in mountains or urban canyons, the ability to pull 2.9 g turns would cut turn radius, and the X2 layout can (unlike a conventional helicopter) accelerate and decelerate in a flat attitude.

It's an interesting prospect, An early LTH program would depend on the Army's ability to find the money and the politics of a competition - as in the early days of the V-22 program, the problem is that no US company other than Sikorsky has a comparable aircraft at the same maturity level.

But the Connecticut company is clearly preparing to take a shot at jump-starting rotorcraft development. If I was doing it, I'd think about a teaming arrangement, and I'd go with Boeing and its tool-kit of Apache and AH-6 pieces.

Dave_Jackson
20th Oct 2010, 01:57
A triple sleeve mast with the centre sleeve stationary and providing support for the other sleeves could serve as an adequate mount point for the mast fairing.This is a quotation from US 7,621,480.

"During forward flight, airflow stabilizes the shaft fairing on the bearing arrangement relative the rotating interconnecting main rotor shaft. During hover and low speed maneuvers, however, frictional forces acting on the bearing arrangement may tend to cause the shaft fairing to undesirably rotate in unison with the main rotor system. Rotation of the shaft fairing may increase drag and reduce the low-observability benefits of the contoured shaft fairing."


This is one of the proposed solutions on US 7,607,607.

http://www.unicopter.com/Temporary/CoaxialFairing2.gif

Other ideas cover various means of getting the electrical power, plus the sensory and control instructions into this fairing.

Dave

Graviman
20th Oct 2010, 11:56
I had wondered about the fairing rotating with the mast. The solution is obvious: fit a gear to the underside of top rotor and topside of lower rotor and have a differential system in the mounting system for the fairing. These needn't be heavy since no actual load is to be carried other than sticktion in fairing bearings. Of course it would require rotor system to be dismantled with whatever procedures are required for an airworthy machine. Probably we won't see it fitted in flight - a real shame in my opinion.

It would be nice if fairing was fitted when machine is presented in the Smithsonian - if only as an aknowledging nod towards the difference between concept and development.

Shawn Coyle
20th Oct 2010, 16:59
Just back from the demonstration at West Palm Beach. Impressive display.
Sikorsky also unveiled the X-49 as a company funded project for two demonstrators to be flown within 4 years. Gutsy!
More in a not-too-distant issue of Vertical!

Dave_Jackson
20th Oct 2010, 18:40
cattletruck,Does that mean the mast fairing would be electrically stabilised in its proper position during low forward speed? Yes, you are basically correct. However, the two patents cover many electric and mechanical means of setting the azimuth of the fairing. Plus, a variety of control methods, since the may want to select different azimuths for different flight conditions.


Dave

IFMU
21st Oct 2010, 00:42
Just back from the demonstration at West Palm Beach. Impressive display.
Sikorsky also unveiled the X-49 as a company funded project for two demonstrators to be flown within 4 years. Gutsy!
More in a not-too-distant issue of Vertical!

The X-49? Isn't that the Piasecki Speedhawk? Surely you jest! That would be quite a turnabout.

-- IFMU

JimL
21st Oct 2010, 06:54
Sikorsky Commits to Build X2 Technology Prototypes to Advance Military Rotary Wing Operations
Wednesday, October 20, 2010 - Sikorsky

WEST PALM BEACH, Fla.,– Sikorsky Aircraft will design, build and fly two prototype light tactical helicopters as the follow-on advancement to the X2 TechnologyTM demonstrator aircraft that unofficially shattered the helicopter world speed record here in September with a flight speed of 250 knots (287 mph). The decision to continue development of the next-generation rotary wing technology will enable Sikorsky and select suppliers to offer the high speed X2 prototype vehicles for flight test and evaluation by U.S. armed forces. Sikorsky Aircraft is a subsidiary of United Technologies Corp. (NYSE: UTX).

“Having proved the X2 Technology design to ourselves, we have full confidence we can now mature the technology for the U.S. Army’s light armed reconnaissance helicopter size,” said Sikorsky President Jeffrey Pino. “Self funding the design of a brand new light tactical helicopter – the Sikorsky S-97 – and manufacturing two prototypes we have designated as the Raider&™ X2 helicopter will help military aviation evaluate the viability of a fast and maneuverable next generation rotorcraft for a variety of combat missions.”

In March 2010, Sikorsky submitted an X2 aircraft design to the Army’s Armed Aerial Scout (AAS) program in response to a request for information. The AAS program is currently conducting an analysis of alternatives for the Army’s next armed reconnaissance helicopter.

Like the X2 Technology demonstrator that unofficially broke the helicopter speed record, the X2 Raider prototypes will feature twin coaxial counter-rotating main rotors (in place of one main rotor and a tail rotor) and a pusher propeller.

For the armed reconnaissance mission, the X2 Raider helicopter will have space aft of the two-pilot cockpit for armament and auxiliary fuel. In an assault configuration, the cabin affords space to accommodate up to six troops.

In addition to flying at nearly twice the speed of a conventional helicopter, the X2 Raider prototype aircraft will incorporate other key performance parameters critical to combat operations — increased maneuverability, greater endurance, and the ability to operate at high altitudes.

Compared to other light military helicopters, the X2 Raider prototypes are expected to significantly reduce turning radius and acoustic noise signature, while significantly increasing the aircraft’s payload, flight endurance and hot and high hover capability.

“These attributes will enable the X2 Raider aircraft to meet or exceed the potential U.S. Army requirements for its next armed reconnaissance helicopter,” said Doug Shidler, Sikorsky’s Light Tactical Helicopter director. “If selected by the Army, the X2 Raider aircraft design will enable high performance flight operations in high altitude regions that currently pose challenges to today’s light military helicopters.”

Sikorsky will conduct its X2 Raider aircraft development program utilizing military standards. The company expects to conduct its first major program milestone — a preliminary design review — in 2011. First flight, projected in four years, could depend in part on the pace of development and customer need.

Graviman
21st Oct 2010, 11:55
Wow - gutsy indeed!

The Advancing Blade Concept is a technology that has come of its time.

I'll be following X2 Raider / S-97 story.

Shawn, i'm looking forward to next issue of Vertical.

Lonewolf_50
21st Oct 2010, 15:28
For the armed reconnaissance mission, the X2 Raider helicopter will have space aft of the two-pilot cockpit for armament and auxiliary fuel. In an assault configuration, the cabin affords space to accommodate up to six troops.

Arggh! Why can't the US Army write a spec for single pilot? Save some weight, allow more payload. It can be done!

Sorry, I'll get off my soap box now ... :ugh:

IFMU
22nd Oct 2010, 02:04
Was reading the register's latest article, some good captions and found there was a youtube video.
gK7ktLXhq88
-- IFMU

Shawn Coyle
22nd Oct 2010, 11:56
Lonewolf:
The X-2 derivative will have options for two, one or no pilots.
One of my FW colleagues many years ago suggested that if you wanted to automate a complex task (such as the scout helicopter mission) to the point where one pilot could do it, why not go all the way and take the pilot out?
In many cases, the second set of eyes makes a huge difference.

Lonewolf_50
22nd Oct 2010, 17:42
Shawn: yes, two sets of eyes never hurt, but if you are making an attack helo, like Cobra or Apache, which has tandem seating (as they did with Comanche) there is enough electronic stuff now to make the single pilot paradigm fit quite nicely, and the side by side field of view problem isn't an obstacle to see and avoid.

The problem is in trusting the pilot work load reducing mission gadgets to actually reduce pilot workload, rather than adding to it ...

squib66
22nd Oct 2010, 21:30
Same weight as a UH-60 but half the troops seems a fairly crude trade for speed.

IFMU
23rd Oct 2010, 16:40
Some cool video on flightglobal. Looks like bootleg video, like a zippercam or something. It's long, 25 mins or so.

Flightglobal Videos (http://link.brightcove.com/services/player/bcpid3138436001?bclid=1481460921&bctid=643105987001)

-- IFMU

IFMU
23rd Oct 2010, 16:42
Same weight as a UH-60 but half the troops seems a fairly crude trade for speed.

The trade off of high speed, I suppose. V22 has the installed power of a CH53E and the lifting power of a blackhawk. Yet the aircraft has its fans.

-- IFMU

cjb60
24th Oct 2010, 01:38
Not the same weight as a UH-60; actually just under half the max gross weight (S-97 ~ 10,500 lbs vs. UH-60 22,000 lbs). This aircraft is meant as a replacement for the OH-58D with a secondary mission to carry a small number of troops. A comparison with the Black Hawk is really apples to oranges.
This is my first post here, although I've been lurking for awhile. I'm a UH-60 pilot in the U.S. Army and am excited about the prospects of X2-type aircraft. Whether you want to call it a compound helicopter or whatever doesn't reallly matter. What matters is good hover performance combined with 200+ knot cruise speed.

Hunt3r
24th Oct 2010, 07:26
Just imagine this thing fitted out with an M230, FLIR/TV optics, and a nicely contoured radar on the mast, and maybe some fold-out weapon pylons that can carry either a full load of Hellfires, FFARs, and anything in between. Make it a side by side cockpit, surrounded with a titanium bathtub of armor, and you basically have a gunship that can lob Hellfires from a distance, or go in fast with guns and rockets, and also be quick on it's feet.

Would really bring on the hurt.

The AH-6/MH-6 and Kiowa replacement configuration would be very nice to see though, both are aging airframes.

Shawn Coyle
24th Oct 2010, 13:43
Hunt3R:
You've got a remarkably similar view of things to Sikorsky... That's exactly what they're thinking. You'll note the prototype S-97 has a streamlined fin between the two rotors - ideal place for a radar...

ShyTorque
24th Oct 2010, 14:37
Good stuff, the way forward.

Interesting that the tailwheel sits lower than the mainwheels to protect the prop tips. Settling the aircraft onto all three results in a nose-down pitch. Can the pusher prop go into reverse pitch?; I'm thinking about the implications on running landings and ground taxying speeds.

P.S. They say there is nothing new in engineering. Anyone else see a certain external likeness to the Cierva Rotorcraft CR-LTH-1, first flown in 1969? Mind you, that was only half as fast but who else would have tried twin piston engines?

And obviously, it also looks a bit like the Lockheed Cheyenne. ;)

riff_raff
26th Oct 2010, 04:37
cjb60,

If you're an Army H-60 pilot and are anxious for something like the X2, then you should follow the JMR program. The JMR concept is intended to eventually replace most or all of the existing Army rotorcraft with either an X2-type compound or a tilt-rotor configuration. Either way, you'll get higher speeds, greater payload/range, and better hot/high performance.

If you believe the AATD press releases (http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=defense&id=news/awst/2010/10/11/AW_10_11_2010_p24-259969.xml), two JMR prototypes are supposed to be flying by FY'17.

riff_raff

cjb60
26th Oct 2010, 23:42
riff raff,

I am familiar with the JMR program. The concept sounds good (but vague at this point), I just have a hard time picturing any program with the word "joint" as part of the program name surviving. Of course, whenever the JSF goes operational it'll blow that theory, but trying to get two or more of the services to agree on specs is difficult to say the least. JMR sounds a lot like the original LHX program; not a good thing seeing how that program turned out.
It's cool to see companies like Sikorsky and Eurocopter investing their own resources to advance the state of the art. Hopefully it will pay off both for the companies and customers.

U.S. Army Rotorcraft Initiative Draws Praise | AVIATION WEEK (http://www.aviationweek.com/aw/generic/story_channel.jsp?channel=defense&id=news/awst/2010/10/11/AW_10_11_2010_p24-259969.xml)

Dave_Jackson
28th Oct 2010, 02:32
The following table is from an article in the the American Helicopter Society's publication Vertiflite - Fall 2010 issue.

The speed records are as at August 17, 2010.

http://www.unicopter.com/Temporary/Helicopter_Speed_Records.gif

__________________________

And more.

A third Patent Application # 20100264258 ~ MAGNETIC DE-ROTATION SYSTEM FOR A SHAFT FAIRING SYSTEM (http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.html&r=1&f=G&l=50&s1=%2220100264258%22.PGNR.&OS=DN/20100264258&RS=DN/20100264258) was issued on Oct. 21 2010 covering an another proposal for controlling the rotation of the rotor mast fairing.


Dave

riff_raff
28th Oct 2010, 03:46
Dave,

Regarding that Sikorsky X2 "unofficial" speed record entry in the Fall 2010 Vertiflite issue, take a look at who bought the glossy full page ad space on the inside back cover. I imagine it's kind of like winning Car and Driver magazine's "Car of the Year" award.

riff_raff

Dave_Jackson
28th Oct 2010, 19:06
riff_raff,

Perhaps if advertising expenses were not 100% tax deductible there would be a greater incentive for companies to shift more of their promotional resources over to improving products and services.

Dave

dangermouse
29th Oct 2010, 12:33
actually the 1986 Lynx record is the absolute speed record for all classes of helicopter, not just the 15-25km one.

BTW I know I am being picky but in the table if the XH59A has flown at 240kts why is the X2 speed (235kts) a record?

Both are classed as rigid coax, aux propulsion platforms
DM

TwinHueyMan
29th Oct 2010, 16:36
When is anyone going to start shedding light on the fact that Sikorsky didn't really break any record? If you want absolute with a plane jane fling wing, the Lynx got it... Absolute with any assistance, the 533. Otherwise I am going to start setting records for absolute groundspeed with a tailwind, fastest speed over a 20cm course, hell the world record speed with autopilot on... and feel legit because the claim the X2 is now the fastest thing with a rotor system has not been called out. Nothing against the program; Sikorsky is very smart perusing the whole ABC/Aux Propulsion thing as it is one of the futures of rotorcraft and it is very admirable that they are doing it all on their own initiative (and dime)... but the fanfare is going a bit too far and they are greedily overshadowing a lot of the other notable advancements in helicopter history for the sake of publicity.

Mike

dangermouse
29th Oct 2010, 18:15
the point of contention is generally what is a 'helicopter' as much as anything. Actually the X2 isnt even the fastest rotorcraft in the world, that will be the V22 wont it?

In any case unless the FAI ratify it, it isn't a record anyway

SAC are very good with the PR and there is no denying the X2 is a valuable experiment that may well lead to significant changes to rotorcraft technology, but until the FAI say otherwise the record still stays in Yeovil

DM

zondaracer
1st Nov 2010, 10:51
The CV-22 is a tilt-rotor, obviously, and the FAA puts it into it´s own category along with the Harrier, being the Powered Lift Category, I think the X-2 would go into rotorcraft.

Graviman
1st Nov 2010, 12:58
Aw, come on guys. :uhoh:

If the mission is just vertcal take-off to maximum cruise speed then to a vertical landing then any of the Saturn V / Lunar module Apollo missions have got everything beat...

The issue here is which technology is going to have the most influence on the market place. The point about X2 ABC is that it is a logical next step in helicopter development. Neither disk loading or machine congiguration has been compromised to push up the cruise speed. There is a slight weight penalty, which is true of all of the high speed VTOL contenders.

riff_raff
3rd Nov 2010, 04:33
Graviman,

Leave it to a bunch of engineers to beat a technical point to death! Regardless, it's lots of fun to discuss.

If the issue is rotorcraft or helicopter, I'd argue that a rotorcraft is any aircraft that can take-off and land with lift provided solely by a rotor system. A helicopter is an aircraft that operates at all times with lift provided solely by the rotor system.

Having said that, the "rotorcraft" with the highest forward speed is the F-35B. It can take-off vertically, hover, and land vertically on lift provided primarily by an engine-driven "rotor" fan. In forward flight it can exceed the speed of sound.

Regards,
riff_raff

Phoinix
3rd Nov 2010, 10:18
F-35B, fan is only the fwd lifting system, a turboan engine on the aft... so it's not "solely rotor".

bat1
5th Nov 2010, 15:17
Here is another video from Sikorsky's website about the furture Raider project

http://www.sikorsky.com/StaticFiles/Sikorsky/Assets/video/LHT_VNR_102010_lowres.wmv

IFMU
6th Nov 2010, 01:33
Interesting article and pic of the sail fairing:

facts-figures-and-sail-fairings.html (http://www.flightglobal.com/blogs/as-the-croft-flies/2010/09/sikorsky-x2-speed-king---facts-figures-and-sail-fairings.html)

-- IFMU

gdbaldw
3rd Dec 2010, 16:48
Are there any authoritative reports of L/De? I calculate L/De = 5.4 from the data at post #787 and the statement at 17:12 minutes into the video of post #768. Wonder if anyone else has these numbers, and expectations of the sail fairing benefit.

Data used in calculation:

Rolls Royce T800 max continuous power = 1231 HP

Post #787:
GW = 6500lbs
At 250kts (422fps) power is (max continuous - 300 HP) = 931 HP

Post #768:
At 200kts (338fps) power is 60% of max continuous = 739 HP

Assumes SAC is using sealevel Max Continuous Power as reference, and that these reported power levels are both at 6500 lbs GW.

Rb98
14th Dec 2010, 20:50
When is anyone going to start shedding light on the fact that Sikorsky didn't really break any record? If you want absolute with a plane jane fling wing, the Lynx got it... Absolute with any assistance, the 533. Otherwise I am going to start setting records for absolute groundspeed with a tailwind, fastest speed over a 20cm course, hell the world record speed with autopilot on... and feel legit because the claim the X2 is now the fastest thing with a rotor system has not been called out. Nothing against the program; Sikorsky is very smart perusing the whole ABC/Aux Propulsion thing as it is one of the futures of rotorcraft and it is very admirable that they are doing it all on their own initiative (and dime)... but the fanfare is going a bit too far and they are greedily overshadowing a lot of the other notable advancements in helicopter history for the sake of publicity.

Mike

Didn't the record setting G-Lynx get a significant (~10%) amount of forward propulsive force from the engine thrust? I've heard this several times but can't find a difinitive source.

dangermouse
14th Dec 2010, 22:54
I went to the RAeS lecture at Yeovil on the record flight, where this was explained. The clever thing that was done was to tune the exhaust pipes to achieve minimum drag and also produce some forward thrust when operating at very high powers as a byproduct of the necessity to get rid of the exhaust gasses . It wasnt compounding as no additional power source was used, just some lateral thinking, I guess it could be applied to any helicopter if necessary, I am sure there must have been some downsides as well...

DM

Ian Corrigible
14th Dec 2010, 22:56
Rb98,

In an earlier post (http://www.pprune.org/rotorheads/245168-sikorsky-x2-coaxial-heli-developments-35.html#post5885261), heli1 quotes "Putting the Record Straight: World Helicopter Speed Record" by David Gibbings as giving the figure as 600 lb. Nick also mentioned previously (http://www.pprune.org/rotorheads/253767-westland-lynx-merged-threads-21.html#post2772332) that "the exhaust was tuned to be sure there was just enough thrust to do this without making the aircraft a compound helicopter."

I/C

dangermouse
15th Dec 2010, 09:12
'well he would have said that wouldn't he?'

Surely getting rid of exhaust from the normal driving engines cannot be construed as compounding.

DM

Hilife
15th Dec 2010, 11:45
Unless of course in one’s attempt to set a world speed record, the exhaust is tweaked to provide a not insignificant level of extra thrust to that provided by the main rotor. ;)

dangermouse
15th Dec 2010, 16:31
agreed

compounding involves use of another powerplant to provide additional propulsion, using existing powerplants and no new moving parts isn't.


DM

Ian Corrigible
15th Dec 2010, 18:16
DM,

The more common description of a compound is the use of an auxiliary propulsion system, not necessarily an additional powerplant - the X2, X-49A and X3 all use the same powerplants to drive both the main rotor(s) and the aux propulsor(s).

I/C

heli1
16th Dec 2010, 11:44
Doesn't propulsion include propellors then ?

dangermouse
16th Dec 2010, 13:04
but to my eyes a necessary exhaust pipe isn't a seperate propulsion system (if it had afterburning etc it would be classed as a new propulsar though)

and the FAI agreed

DM

Dave_Jackson
16th Dec 2010, 18:22
http://www.unicopter.com/Think.gif

http://aviastar.org/foto/gallery/kaman/kaman_huskie_2.jpg

Graviman
23rd Dec 2010, 11:50
Interesting that nobody so far has commented about the benefit of not having a tail rotor on X2. ;)

heli1
23rd Dec 2010, 11:55
The benefit....let's see.Would that be not getting your hands cut off when you walk into the tail rotor as opposed to being shredded by the airscrew?:rolleyes:

Ian Corrigible
23rd Dec 2010, 16:04
That rear mounted prop didn't work out too well for the big German guy in Raiders.

'Course, in the alternate ending it didn't work out too well for Indy, either...

-au9DeVKi8E

:E

I/C

Dave_Jackson
24th Dec 2010, 07:34
Optimally, the propeller should not be turning when the craft is on the ground or hovering.

The propeller's speed should be inversely linked to the speed of the rotors. and these speeds will be related to the forward velocity of the craft. Variable Speed Rotors and Prop (http://www.unicopter.com/Variable_Speed.html)


This was one of the technical subjects that used to be discussed on PPRuNe. Subsequent to this discussion, Sikorsky, in Nick's name, applied for a patent. On October 14, 2008 Sikorsky received US Patent 7,434,764 ~ Variable speed gearbox with an independently variable speed tail rotor system for a rotary wing aircraft.


Dave

Ian Corrigible
24th Dec 2010, 12:28
Dave,

The S-97's prop will indeed be declutchable.

I/C

Dave_Jackson
24th Dec 2010, 15:36
Thanks I/C

The clutch and the variable pitch propeller are steps toward the optimum.

Dave

TwinHueyMan
27th Dec 2010, 03:55
Regarding the world speed record/compound helicopter debate... I'm gonna go grab me a 777 engine and throw it in a tube frame with 1% of its compressor bleed air turning a main and tail from a R22. The rest will be used as thrust. But since its the same engine as is used to power the rotor system, I'll own the record for rotary winged flight at somewhere around Mach 1. Suck my contrails, X2.

Anyone who has stood behind a turboshaft engine knows there is no way that the Gems on G-LYNX were providing thrust on the same level as the X2 or any of the other compound helicopters out there. Compound helicopters in my opinion are a contraption that uses a rotor system to get up and something else to get going - IE compounding vertical lift with horizontal thrust. The X2 is no better than the 533, and neither of them should be compared to the Lynx. Good job Sikorsky, you revived an old idea that deserved a second chance.

Mike

Shawn Coyle
27th Dec 2010, 07:07
TwinHueyMan:
the point is that the Gems on the Lynx were producing enough thrust to make the difference. Westlands has never come right out and stated how much thrust was produced, nor now they did it (at least, I haven't seen it and I think I keep my ear pretty close to the ground on stuff like this).
But you can be assured it was quite a bit of thrust.

Ascend Charlie
27th Dec 2010, 08:02
The whole idea behind a turboshaft is to suck every last ounce of power out of the airflow, power is sent to the gearbox, and the airflow just trickles out the exhaust.

If that Gem was producing thrust, it was because some dude altered it to make it do so, otherwise it must have been a seriously inefficient engine. usually there is only about 10lb of thrust at the exhaust.

Hilife
27th Dec 2010, 15:05
Not so A C.

In a perfect world, yes all the energy in the gas stream would be absorbed by the turbines, but this assumes 100% (or close to) efficiency and in a gas turbine engine (even a modern design), this is simply not the case.

For example, on the Pratt & Whitney Canada PT6A-65AR, the pressure (PSIA) of the gas stream at station P7 (Exhaust Duct Outlet) at take-off power is some 9% to 10% higher than at station P1 (Inlet) and as it’s ejecting around 9lbs in weight of air per second at max power, that an awful lot of gas flow to use for thrust should you wish to point it in a rearwards direction.

In my Chinook days, I was once told that around 5% of the energy in the gas stream was ejected rearwards out of the exhaust as thrust, and that’s without tweaking, so certainly not insignificant.

Those 'Pasty Boyz' ;) played around with the exhaust for a reason and it wasn’t for looks.

TwinHueyMan
27th Dec 2010, 16:48
If they did indeed create such a significant amount of thrust out of the exhaust, why is this not a technology that was explored as a mainstream solution? Bell went to all the trouble to get a couple degrees of aft tilt on the 429s tail rotor to throw in a few pounds of thrust but Westland abandoned their turbojet turboshaft idea when it single handedly produced enough thrust to (according to pprune'rs) push a 160 knot helicopter into the 200+ category?

Mike

helisphere
28th Dec 2010, 19:17
Don't forget that an integral part of the Lynx's ability to set that speed record with out any fixed lifting surfaces were the BERP rotor blades, not just the jet thrust.

Ascend Charlie, yes you are correct. The exhaust nozzles were modified to a smaller area to produce the thrust.

TwinHueyMan, it looks like they were considering using this in production, not sure why they haven't.

Lynx ACH - Proposed Advanced Compound Helicopter technology demonstrator, partly funded by the Ministry of Defence. Announced in May 1998, the ACH was planned to be powered by RTM322 engines with variable area exhaust nozzles and a gearbox from the Westland 30-200, have wings attached at cabin roof level and BERP rotor blades. It was predicted to fly approximately 50% faster than a standard Lynx.

heli1
2nd Jan 2011, 12:55
Sorry Shawn butv the residual thrust from the Lynx has been well publicised,even on this thread if you go back far enough. It certainly didnt contribute much,it was the blade design that made the speed possible and controllable over the distance required.

IFMU
25th Feb 2011, 01:19
Was just sent this video link. I don't think it has been posted here but the thread has been quiet for a while.

gK7ktLXhq88

-- IFMU

Edit: never mind, it looks just like the youtube one I posted. Tough getting old.

Graviman
1st Mar 2011, 11:46
Still an excellent video IFMU.

I suspect X2 will go a little quiet while S-97 goes through design & development. ;)

Actually, I have suggested the Sikorsky/Schweitzer design/analysis/test engineers attend some low key engineering lectures - say I.Mech.E or RAES. The need for commercial secrecy may make this unfeasible though. Pity.

Dave_Jackson
4th Mar 2011, 20:34
Did the X2 do a full touchdown autorotation?

The X2 blade profile (http://www.unicopter.com/Sikorsky_Blade.jpg) and its interaction with the stall, driving and driven regions of the rotor disk (http://www.dynamicflight.com/aerodynamics/autos/fcevectvert.gif) are of technical interest.


Thanks

Dave

IFMU
16th Mar 2011, 02:28
The X2 has won the Collier trophy!

2010 Robert J. Collier Trophy (http://www.sikorsky.com/About+Sikorsky/News/Press+Details?pressvcmid=900187305eabe210VgnVCM1000004f62529fRCRD)

-- IFMU

Graviman
22nd Mar 2011, 12:50
Never a doubt in my mind that this day would come.

Serious congratulations to all involved: managers, designers, analysts, testers, and pilot :D

This about sums it up:

The Collier Trophy is an annual aviation award administered by the U.S. National Aeronautics Association (NAA), presented to those who have made "the greatest achievement in aeronautics or astronautics in America, with respect to improving the performance, efficiency, and safety of air or space vehicles, the value of which has been thoroughly demonstrated by actual use during the preceding year."


Collier Trophy - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Collier_Trophy)

Just goes to show how a carefully scheduled test program can overcome all the criticism of those ne'er sayers. ;)

nimby
22nd Mar 2011, 15:09
... hang on. What do they mean by "... actual use"??

Dave_Jackson
22nd Mar 2011, 19:41
The Collier Trophy is an annual aviation award

Is an annual award a statement about the quality of the choice or a statement about the quantity of available choices?

IFMU
23rd Mar 2011, 01:44
... hang on. What do they mean by "... actual use"??
nimby,
I would take that to mean that they actually flew it, as opposed to generating a large quantity of work of some quality that is contained wholly on the internet. I take it from your post that maybe it means less because the X2 is a one-off machine, not put into production, and focused on a single goal. This is the same category as Rutan and Space Ship One (2004), or the Rutan Voyager team (1986), or Chuck Yeager (1947). I thought about throwing in the crew of Apollo 11 too, but in fairness they did build more than one spaceship.

-- IFMU

Dave_Jackson
27th Apr 2011, 19:27
"The Royal Aeronautical Society Presents “The Future of Rotorcraft – Enabling Capability through the Application of Technology”

The performance and utility of the ubiquitous edge wise rotary wing configured aircraft has reached a natural limit. The enormous strides taken by the fixed wing community in the development of increasingly efficient, mission focused, cost effective, green and quick to market solutions have not been matched by the rotary wing community. The barrier to matching the fixed wing community is not concepts or vision, it is the infrastructure of technology and manufacturing techniques that have contrived to hold our community back. Learning lessons from the fixed wing community and adapting them to meet the needs of the rotary wing vehicle is our challenge and the time is right now to take on this challenge and succeed. This two day conference will take place June 15-16, 2011 at the Royal Aeronautical Society, No. 4 Hamilton Place, London."


Additional information on this subject;

'The Cost of High Speed' by R.W. Prouty in the American Helicopter Society's publication Vertiflite ~ Spring 2011.

Graviman
28th Apr 2011, 17:59
This looks like a great conference: I will attend if possible.

Dave_Jackson
28th Apr 2011, 19:08
Mart,

This appears to be the program for the conference.
The Future Rotorcraft ~ Enabling capability through the application of technology (http://www.raes.org.uk/conference/PDFs/660.pdf)

If you do go, it would be appreciated if you could give a synopsis of any presentations of interest, on this thread or a new separate thread.


Dave

IFMU
8th May 2011, 13:29
oHcd2-2rr6M

Bravo73
10th May 2011, 12:19
Hello everyone,

I've got a question about the possible future variants for the X2 technology:

http://aviationweek.typepad.com/photos/uncategorized/2007/06/01/sikorsky_x2.png

Does anybody know if any of these possible variants (except for the UAV, of course!) are planned to have a pressurised cabin?


Thanks

IFMU
15th Jun 2011, 22:41
Pilot Recounts Taming World’s Fastest Helicopter | Autopia | Wired.com (http://www.wired.com/autopia/2011/06/kevin-bredenbeck-sikorsky-x2/)

Old Rusty
8th Jul 2011, 14:22
First post to a great site.

I've got a question for all you smart folks and I realize that I may not have the proper knowledge to word this question so please ignore my ignorance.

The question is-looking at the Sikorsky X2 aircraft can anybody estimate how much thrust that pusher prop is creating? If so, can anybody tell me the formula of how you figure the thrust of a propeller?

Thanks, MjH

FlyHiGuy
8th Jul 2011, 15:20
Welcome to the forum Rusty - I doubt you're really "Old" ! I'm sure that one of the Sikorsky guys can help you with the rated thrust of the X2's prop. I used to know one of the program pilots Kevin Bredenbeck so maybe you can try his name in the standard Sikorsky email format; kbredenbeck@<hidden>. Most of those guys are quite bright and also like to share their love of rotorcraft knowledge with others so he will probably give you more than you want or even need to know !

As for the formula; I used to have it in my old college aero textbook but its long gone. In simple terms, its just geometry and fluid mechanics with a few other minutae. Google is your friend - don't need to pull out the old textbooks anymore :-)

Dave_Jackson
9th Jul 2011, 07:20
MjH,

The thrust of a propeller is roughly 5 lbs per horsepower for relatively small aircraft.

The following are approximate values for the X2. The gross weight is 6,095 lbs. The power of the engine is 1,450 SHP. The X2's rotors maybe in a low-rpm powered state or in an autorotative state at maximum forward speed. It has been mentioned that the craft was using somewhere around 80% power at this speed.

The high parasitic drag of the X2 is one of it's primary limitations, since drag increases at the square of the forward velocity. Hypothetically, the X2 could just about takeoff and hover on its prop as a Tailsitter (http://en.wikipedia.org/wiki/Tailsitter). 6,095 lbs / (1450 x 0.8) = 5.25 lbs per horsepower.


The following may provide you with a more exact answer.
I think that Aero Composites, Inc. (http://www.aerocomposites.com/) provided the propeller.
The propeller specifications plus this article Theoretical Max Propeller Efficiency (http://www.jefflewis.net/aviation_theory-theo_prop_eff.html) may be of value. The article was written by an engineer at CarterCopters.


If you get some information from Sikorsky, please post it. There is nothing better then the facts.


Dave

Old Rusty
10th Jul 2011, 00:29
Dave and FlyHi, thanks to both of you for great answers. I will do some reading from those articles. I promise to post anything I find that's concrete, though I doubt Sikorsky will openly answer any pointed questions about their new toy (and I don't blame them for that:)

IFMU
16th Jul 2011, 01:27
As reported on the Sikorsky homepage:

Award-Winning X2 Technology Demonstrator Takes its Final Flight - Program paved the way for upcoming S-97 Raider helicopter (http://www.sikorsky.com/About+Sikorsky/News/Press+Details?pressvcmid=1304e5f1c4521310VgnVCM1000004f62529fRCRD)

http://www.sikorsky.com/StaticFiles/Sikorsky/Content/Image Gallery/x2_final_flight-0714_med.jpg

heli1
18th Jul 2011, 09:46
So did it ever fly the sail fairing ?

Ian Corrigible
18th Jul 2011, 12:12
From Flight (http://www.flightglobal.com/articles/2011/07/15/359509/sikorsky-retires-record-breaking-x2-with-one-goal-unmet.html):

A picture released by Sikorsky showed that the sail fairing was absent on the X2's final flight.

Sikorsky later explained that the sail fairing was sacrificed to apply more resources to meeting a "fairly aggressive" schedule for flying the first two S-97 prototypes within three years.

"We had planned to install and test the fairing but have since decided our focus needs to shift 100% to the S-97 Raider," Sikorsky said.

I/C

SansAnhedral
18th Jul 2011, 17:56
aka...they couldnt work the bugs out of its operation. Interesting as the sail fairing was one of the key peices of technology that differentiated the X2 from the XH59A. Had the XH59B been built and taken flight, it would have been largely the same aircraft as the current X2 minus all of the FBW controls.

Remember that something like 40% of drag was from the rotor mast, so flying without the highly developed sail fairing on it is a pretty big deal IMO.

One major concern for the X2 has got to be fuel burn in addition to noise signature. SAC has been mum on these points.

Lonewolf_50
18th Jul 2011, 19:04
Maybe the S-97 prototypes will allow them some time and opportunity to work the fairing issue.

From a late 2010 Sikorsky "Frontlines" release.
S-97 Raider helicopter prototypes will feature twin coaxial counter-rotating main rotors (in place of one main rotor and a tail rotor) and a pusher propeller.

{Describes modular design, to run a small (six person) assault, or more fuel and run a recon/weapons mission}.

In addition to flying at nearly twice the speed of a conventional helicopter, the S-97 Raider prototype aircraft will incorporate other key performance parameters critical to combat operations — increased maneuverability, greater endurance, and the ability to operate at high altitudes.

Compared to other light military helicopters, the Raider prototypes are expected to significantly reduce turning radius and acoustic noise signature, while significantly increasing the aircraft’s payload, flight endurance and hot and high hover capability.

The company expects to conduct its first major program milestone — a preliminary design review — in 2011. First flight, projected in four years, could depend in part on the pace of development and customer need.

Those interested in this program might want to keep an eye on how steep DoD budget cuts are. This program may be at risk in the fight for dollars. (Recalling what happened to Comanche ... )

The Sultan
18th Jul 2011, 22:25
Lone

The fairing could be the issue, but it could also be that the processed the loads data, started getting chips in an xmsn, or found a crack or two in critical components.

Just a few weeks after stating the final goal and suddenly abandoning it for "manpower" indicates a more serious issue than taking a little time to install a fairing.

The Sultan

IFMU
19th Jul 2011, 01:10
I would think that if the sail fairing was a big deal, and they hit their goals without it, it says they had a fair margin of performance. But, this is a rumor network, and a theory like that may not sound as fun as something more sinister. I'm sure none of my fellow Ppruners would just make something up and post it!

-- IFMU

Dave_Jackson
19th Jul 2011, 03:34
I would think that if the sail fairing was a big deal, and they hit their goals without it, .......

IMFU,

And exactly what were these achieved goals??????

IFMU
20th Jul 2011, 01:37
Dave,

From here:
Sikorsky X2 Technology (http://www.sikorsky.com/About+Sikorsky/News/Press+Details?pressvcmid=900187305eabe210VgnVCM1000004f62529fRCRD)

it says:

“The X2 Technology demonstrator program set out to accomplish four key performance objectives: low single pilot work load, low vibration, low acoustic signature, and speed – defined as cruise at 250 knots,” said Jim Kagdis, program manager for Sikorsky’s Advanced Programs. “There was a fifth key objective that remains a driving force to all that we do at Sikorsky: to preserve the legacy and pioneering spirit of our company founder, Igor Sikorsky, and to educate and inspire the next generation of engineers and aviation professionals. The Collier Trophy exemplifies this fifth objective, so it is hugely rewarding for the team to stand recognized for upholding the basic tenets on which Sikorsky Aircraft was founded. I am extremely proud of the team and our accomplishment.”

So to enumerate those goals from the above:
1) Low pilot workload
2) Low vibration
3) Low acoustic signature
4) 250 kts
5) Inspire the next generation

-- IFMU

Dave_Jackson
20th Jul 2011, 03:17
That is a very insipid list of goals. Four of the five could apply to a lawn mower.


The predominant focus of the marketing was the 'targeted' 250-knot speed.

Therefore, where did this 253-knot 'record' come from; the Pitot tube, the local sheriff's radar gun, a desk in the marketing department? It certainly did not come from the Fédération Aéronautique Internationale (http://www.fai.org/), which Sikorsky had previously cited.

NickLappos
20th Jul 2011, 03:21
My David, we are catty tonight! And what goals have you achieved so far, insipid or otherwise?

Dave_Jackson
20th Jul 2011, 03:41
Hi Nick,

As for achieved goals, I build a manufacturing company, got bored, sold it, and retired at 47. But this subject is of little relevance and is off-topic.

Want to have some technical conversations? :)


Dave

Lonewolf_50
20th Jul 2011, 17:25
Dave, are you interested in a technical discussion? :confused:

From above:

IFMU says

1) Low pilot workload
2) Low vibration
3) Low acoustic signature
4) 250 kts
5) Inspire the next generation
Dave says

That is a very insipid list of goals. Four of the five could apply to a lawn mower.
Technical question: was your manufacturing company an enterprise that build 250-knot, low vibration lawn mowers that could boast low pilot work load and low acoustic signature?

If yes, I'd consider Dave Jackson enterprises both successful and inspirational. :8:ok: (Oh, and where does one find these, at Lowes or at Home Depot? :}:E )

My neighbors would be much obliged, what with me cutting the grass in the mornings ...


Back to the fairing:

In program concept and implementation, it seems to me shortsighted to demand that the fairing be a serial, verus parallel, design criterion when you are building a scale prototype. It was proof of concept, was it not? Performance goals included the 250 knots, right? Goal met?

From where I sit, there is time to deal with the fairing as the "closer to production sized prototypes" go through the design and design reviews, don't you think? ;) Scope limitations in a program: a requirement. :ok:

henra
20th Jul 2011, 20:47
From where I sit, there is time to deal with the fairing as the "closer to production sized prototypes" go through the design and design reviews, don't you think? ;) Scope limitations in a program: a requirement. :ok:

Although I generally don't disagree I'm still wondering if the effort for testing it on the prototype would have been really that high ?
If everything else is in place I would have thought this effort shouldn't have been too high and you could learn potentially important things early giving you time to work on it systematically without the ususal rush/stress/time limitations in the 'real' project.
Maybe the budget was simply consumed by then and it was not considered worthwhile...
Coming from an engineering background myself I feel with the engineers/designers who would have surely loved to test it.

IFMU
21st Jul 2011, 01:46
Dave,

You taught me something. I had no idea what insipid meant. I have looked it up and am now one word smarter. Thanks!

In the context of the helicopter industry, I have a hard time understanding these to be insipid goals. In particular, the 250 kt goal. If a 250 kt helicopter doesn't get your fires burning, then your wood is wet!

-- IFMU

PS Nick good to see you back.

IFMU
21st Jul 2011, 02:19
6-u6DZWmgeg

Dave_Jackson
21st Jul 2011, 05:00
IFMU.

Would that wood be knotty pine or was your comment a naughty pine? http://www.unicopter.com/Wink.gif


Seriously;
At 7 hp / knot / occupant it's going to take a hell of a lot of wood to keep the X2's fire burning.

At the projected 220 knot operating speed there may be one hell of a contest between the X2 and the X3.

Dave

Lonewolf_50
21st Jul 2011, 14:31
@<hidden>
Although I generally don't disagree I'm still wondering if the effort for testing it on the prototype would have been really that high ?
Depends on time, schedule, and budget. Also depends on the minimum criterion established to make a "go/no go" decision on the program. No idea, and I am not sure Sikorsky will be telling. :}
If everything else is in place I would have thought this effort shouldn't have been too high and you could learn potentially important things early giving you time to work on it systematically without the ususal rush/stress/time limitations in the 'real' project.

I agree.
Maybe the budget was simply consumed by then and it was not considered worthwhile...

That's my guess.

Coming from an engineering background myself I feel with the engineers/designers who would have surely loved to test it.

Agree yet again. Time and resources are finite, could be they ran out of one of them.

@<hidden> J:

Yes, looks like an interesting competition is shaping up.

Consider the following:

On the X3, where would the weapons stations be located?

Those props look to be an obstruction to conventional weapons mounting points, and weapons release. Can probably be worked out, but it will take some thinking.

SansAnhedral
21st Jul 2011, 17:50
Those props look to be an obstruction to conventional weapons mounting points, and weapons release. Can probably be worked out, but it will take some thinking.

http://www.flightglobal.com/blogs/as-the-croft-flies/Eurocopter_hyrbrid.JPG

With regards to the flight video, looks like a pretty boring demonstration. A bunch of twitchy (still...didnt they dial down the FBW gains?) high speed flyovers (negative ghostrider, the pattern is full), but no display of the much-vaunted pusher-prop-enabled attitude control

SAC bragged how X2 tech could allow the craft to "hang" nose-down on the pusher and maintain a bead on a target without forward flight....a demo which would have been quite appropriate given the audience.

UberFliegeJunge
22nd Jul 2011, 02:45
Actually on the last flight the X2 did some hovering maneuvers. At one time it stood on it's tail in a stable hover with the nose 20 degrees high and turned. And on another to about 15 degrees and then it hung on the tail in a hover with the nose about 10 degrees nose down. The prop on the X2 Demonstrator has only -6 degrees negative prop pitch available where on the S97 Raider it will have about -20 degrees negative prop pitch available for getting the nose down in a hover even further. Pretty cool final approach was made from about 200 kts over the fence using a very agressive level deceleration from 150 kts to hover. Shame this final flight posted video didn't show all it did. Once all the video gets processed i hope Sikorsky will release more from that last flight. Truly amazing and impressive demonstration! Let's hope Sikorsky can capaitalize on what this X2 program accomplished and keep moving rotor wing aviation even further forward into the future!

Lonewolf_50
22nd Jul 2011, 12:54
Sans, is that the same X3 as was discussed in this thread (http://www.pprune.org/rotorheads/409996-eurocopter-x3-hybrid.html)? :confused:

Thanks for the sketch, neat evolution of the idea. :ok:

Graviman
29th Jul 2011, 11:53
At 7 hp / knot / occupant it's going to take a hell of a lot of wood to keep the X2's fire burning.


Dave, you are fogetting that this applies to fixed wing too. As the machine design cruise speed gets faster the drag remains the same because the wings are optimised for the higher speed (wingspan generally). The engine power required is proportional to speed, but flight time is proportionately reduced. Net effect is same fuel consumption for a given payload. This is why pistons gave way to turbines.



Let's hope Sikorsky can capaitalize on what this X2 program accomplished and keep moving rotor wing aviation even further forward into the future!


Absolutely agreed.


Mart

Dan Reno
30th Jul 2011, 12:53
Jul 29, 2011

Comment of the Week: A Defense Contractor Willing to Put Its Money Where Its Mouth Is?

By NICK SCHWELLENBACH

Frequent POGO blog commenter Dfens, citing a recent article in Defense Tech, writes (http://pogoblog.typepad.com/pogo/2011/07/morning-smoke-a-medical-study-isnt-out-but-the-attacks-are-already-in.html#comment-6a00d8341c68bf53ef015390429f34970b):
Check out this interesting video (http://www.youtube.com/watch?feature=player_embedded&v=1lyIkxq-dnI#at=25) Steve Trimble of The DEW Line shot of Sikorsky's presentation at the Oskhosh AirVenture on the future of it's high-speed coaxial rotor helos. Pay particular attention to the part about construction on the prototype S-97 high-speed military bird being set to begin in a "month or so." The first flight of the bird is tentatively scheduled for late 2013 or early 2014. -- Defense Tech (http://defensetech.org/2011/07/28/s-97-construction-to-begin-in-a-month/)
Ok, POGO, here's your chance to get behind something that would really save the US taxpayer some money. Here is a defense contractor that's willing to put their own money where their mouth is and develop a game changing new technology helicopter for the US Army. It took 3 decades to get the V-22 flying, and that crappy thing is still having major issues, not the least of them being a unique ring vortex state that has killed several crews. When the DoD needs real game changing technology it gets it from companies willing to spend their own money to develop it like General Atomics or Sikorsky or Barrett. Here's your chance to take a stand for the US taxpayer, POGO. Are you going to take it?
We agree with "Dfens"—it's encouraging to see traditional defense contractors taking risks to develop new technology with their own money. That's how the commercial marketplace, which generally delivers new technologies faster for less money, works.

Contrast what Sikorsky is doing with how Bell Helicopter charged taxpayers hundreds of millions of dollars (http://www.star-telegram.com/2011/07/15/3225095/bell-helicopters-ba609-development.html) for a helicopter that the military will not even buy. Bob Cox at the Fort Worth Star-Telegram highlights this difference of approach (http://www.star-telegram.com/2011/07/15/3225094/bell-helicopters-sale-of-program.html):
Sikorsky Aircraft Co., one of Bell's major competitors, has said publicly that it is not charging the government for any expenses incurred on development of its new X2 high-speed helicopter. Sikorsky has also said it will build two prototype military aircraft entirely with its own funds.
The way the military-industrial complex tends to work now is taxpayers pay billions for the development of new weapon systems—and the technology upon which they are predicated—but after billions have already been spent, taxpayers then discover it will take far longer and cost far more money to develop the weapon than expected. Often the weapon system gets canceled after billions have been spent (http://defensetech.org/2011/07/19/46-billion-worth-of-cancelled-programs/) on development, leaving our troops with little to nothing.
The contractors, however, still get paid. (This Star-Telegram article (http://www.star-telegram.com/2011/07/15/3225094/bell-helicopters-sale-of-program.html) looks at a special kind of government-funded research and development program, called Independent Research and Development, or IR&D (http://www.cq.com/graphics/crsreports/93-1051_1993-12-17.pdf), which is somewhat different from what I am talking about.)
One way the Defense Department has been tackling this problem is by trying to rely more on mature technologies and less on immature technology. That way there's less risk in the development phase of programs (it's "risky" to taxpayers because, with immature technology, you don't know how long it will take to bring technology to maturity, or how much money it will cost or if it's entirely doable).
It's better to actually have something for troops who need it now that might be less advanced than a highly advanced weapon that is never delivered or is decades away. But the Pentagon still craves advanced technology to gain an advantage on the battlefield, be it on land, sea, sky, space, or cyberspace. Dfens' approach is part of the solution.
Nick Schwellenbach is POGO's Director of Investigations.


Posted at 12:14 PM in Contract Oversight (http://pogoblog.typepad.com/pogo/contract_oversight/), Defense (http://pogoblog.typepad.com/pogo/defense/) | Permalink (http://pogoblog.typepad.com/pogo/2011/07/comment-of-the-week-a-defense-contractor-willing-to-put-its-money-where-its-mouth-is.html)



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Ian Corrigible
31st Jul 2011, 00:03
Somewhat hard on Bell. Just because Sikorsky has decided - for PR reasons - not to apply any Govt [re]funded IRAD to Raider does not necessarily mean that it is less exploitative of the IRAD process than Bell. You can be assured that the smart folk at Sikorsky will make full use of any funding source available.

The Defense Tech piece also fails to recognize that Kevin misspoke when he gave the S-97's first flight as being "two and a half years" away at OSH. The stated FF goal is actually late 2014, i.e. 3½ years hence.

I/C

riff_raff
31st Jul 2011, 03:22
Just because Sikorsky has decided - for PR reasons - not to apply any Govt [re]funded IRAD to Raider.....

IC,

It's probably not just for PR reasons. The minute you spend DOD money on something, the technology can get ITAR restrictions and the gov't gets certain rights to it. Thus Sikorsky could be limited in what applications it may pursue with the X2 concept.

riff_raff

Graviman
8th Aug 2011, 17:51
Don't forget, Riff, the Sikorsky philosophy of designing the product to suit civilian market requirements while meeting DOD specifications. The ability to hop point-to-point at reasonable cruise speed opens up all sorts of new markets. This is definately the case with advancing blade technology since the machine does not compromise at all on the ability to hover. There is a weight penalty, but with so many innovative new hingeless rotor designs out there I would challenge whether this is really an issue. Once the market realises it does not need expensive runway land to meet medium range transport requirements it will demand a cost effective machine to fill the gap...

IFMU
25th Sep 2011, 01:41
AOPA Online: Swamp Pirates (http://www.aopa.org/members/files/pilot/2011/october/feature_swamp_pirates.html)

Also, the X2 is to be displayed at the New England Air Museum 10/1 and 10/2.

New England Air Museum Home Page (http://www.neam.org)

-- IFMU

riff_raff
28th Sep 2011, 03:33
...but with so many innovative new hingeless rotor designs out there I would challenge whether this is really an issue.Graviman,

Those "innovative new hingeless rotor designs" present a whole new set of potential issues. One has to wonder why the X2 spent relatively little time flying (around 22 hours total?) before it was consigned to the museum. One possible reason may have been the "innovative new hingeless" coaxial rotor design. In some of the videos of the X2's high speed runs, I can recall seeing the downward deflecting retreating side blade tip of the upper rotor passing very close to the upward deflecting advancing side blade tip of the lower rotor. While the X2 blades are fairly short, this problem will get more difficult as the blades get longer.

riff_raff

SansAnhedral
28th Sep 2011, 15:22
I can recall seeing the downward deflecting retreating side blade tip of the upper rotor passing very close to the upward deflecting advancing side blade tip of the lower rotor. While the X2 blades are fairly short, this problem will get more difficult as the blades get longer.


Precisely. Take note, sikorsky has almost completely abandoned the marketing of a HGW X2 configuration, especially compared to about 4-5 years back.

There is always talk from them about the X2's "scalability". Thats true...aerodynamically speaking the coaxial rigid rotor system is quite scalable. Building an ultra-stiff blade set that maintains the efficient spacing and doesnt not incur tip-path-divergence issues? Thats an entirely seperate can 'o worms.

IMO the 11-12000 GW range is probably the upper end of the envelope without some radical blade material innovation. And I do mean radical.

Dave_Jackson
29th Sep 2011, 08:04
The removal of the airfoil at the root 'reverse velocity region' results in the location of the lift on the advancing blade being further out on the span. This makes for a greater moment, which wants to bend the blade upward.


A story of coincidence?

Many years ago, while evaluating potentially rotorcraft concepts, it began to appear that the Advancing Blade Concept, which Sikorsky pursued 27 years earlier (http://www.unicopter.com/0891.html), had potential merit. After a few years of research and development I offered to present a paper at an America Helicopter Society conference on an Intermeshing craft that utilized the ABC. This offer was, in turn, forwarded to the heads of two seminars.

The eventual responses were that they both had received a large selection of submissions and for that reason mine could not be incorporated in either seminar. Subsequently, a general e-mail was received that was soliciting papers for one, or perhaps it was both, of those seminars.

I was disappointed that the presentation was declined, and, that later a request had gone out for additional papers. However, this was mitigated by a continuation of the R & D on the ABC that started showing some insurmountable limitations in the concept. The most serious was my inability to develop a satisfying means of converting the reverse velocity region from a downward thrust into a lift (http://www.synchrolite.com/B473.html). Another was the inability to discover a reliable way of providing a Variable Speed Transmission between the rotors and the propeller (http://www.unicopter.com/Variable_Speed.html).

Approximately, a year later Sikorsky announced its intention to remake a Coaxial-ABC under the name X2. Unfortunately, they elected to build a craft which does not overcome these vary same problems. IMO, the X2 may have been a marketing program to keep the stock up, plus a legal program to inhibit others from working on the ABC's limitations. The X2 certainly was not a quiet undercover program to develop a future rotorcraft.

Was the X2 promoted because Sikorsky has nothing else to offer toward the Next Generation Rotorcraft? Should I apologies to Sikorsky on the possibility that I may have unintentionally enticed them into taking a


Road To Nowhere - YouTube (http://www.youtube.com/watch?v=Zlpo8cKdmtk):)


Dave

nimby
3rd Oct 2011, 14:30
As I recall, launching a missile or rocket currently results in everything downwind being damaged by blast, hot exhaust and often chunks of burning propellant. On both X2 and X3 there are propellors "downwind" of potential weapons ... and I remember well what an out of balance prop feels like.

JohnDixson
6th Oct 2011, 12:52
Dave, Rev 1 to "Road to Nowhere":

Sikorsky Chief Test Pilot Awarded SETP Honor for Achievement with X2 Technology™ Demonstrator

October 03, 2011

http://www.sikorsky.com/vgn-ext-templating-SIK/v/images/flags/U.S.A..gif STRATFORD, Connecticut - Kevin Bredenbeck, the pilot who flew the revolutionary X2 Technology™ demonstrator last year to an unofficial speed record for conventional helicopters, has been recognized by the Society of Experimental Test Pilots (SETP) with the Iven C. Kincheloe Award for the year’s outstanding professional accomplishment in the conduct of flight testing, Sikorsky Aircraft announced today. Sikorsky is a subsidiary of United Technologies Corp. (NYSE:UTX).
Bredenbeck, who also is Sikorsky’s Director of Flight Operations, accepted the award at a ceremony in California on Sept. 24.
“It’s hard to believe what has transpired over the last few years, focusing on the task at hand, holding a team together and pushing the envelope of an ‘X’ plane,” Bredenbeck said in collecting the award. “I got to lead a great team and would never have been able to demonstrate the capabilities of this X2 technology without them. I’m even prouder that this team delivered to the doorstep of the future the next generation potential for rotor winged flight.”

The Iven C. Kincheloe Award was established in 1958 in memory of Air Force Test Pilot and SETP member Iven C.Kincheloe to honor exceptional contributions to an aerospace program as a test pilot. The award is sponsored by the Lockheed Martin Corp. The history of previous award winners includes some of the aerospace and aviation industry’s most accomplished and recognized figures in experimental and exploration flight including NASA astronauts from the Space Shuttle and Apollo space program.
The X2 Technology demonstrator has been recognized with a number of aviation, innovation and technology accolades over the past two years including winning the Robert J. Collier Trophy for greatest achievement in aerospace in 2010. In addition, it was chosen by the American Helicopter Society as the winner of the 2011 Hughes Award, given in recognition of an outstanding improvement in fundamental helicopter technology brought to fruition during the preceding calendar year. In April 2011, Professional Pilot magazine named X2 as the “Innovation of the Year.”
The X2 also was previously named one of the Top 10 Technologies to Watch by Aviation Week (January 2010), was awarded a 2009 Breakthrough Award in Innovation from Popular Mechanics magazine, was named One of 2009’s Best Inventions by Time magazine, was identified among the “Best of What’s New” by Popular Science in 2009, and was a finalist for Aviation Week’s Laureate Award in Aerospace and Propulsion.
Mark Miller, Sikorsky Vice President of Research & Engineering, said: “The SETP award is appreciated by the entire Sikorsky workforce as recognition of the great things that can be accomplished with innovative thinking, dedication to the task at hand, and a vision that believes the tough challenges of vertical flight are attainable.”
The X2 Technology program began in 2005 when Sikorsky first committed resources and full funding for the program’s development. The X2 Technology demonstrator combines an integrated suite of technologies intended to advance the state-of-the-art, counter-rotating coaxial rotor helicopter. It is designed to demonstrate a helicopter can cruise comfortably at 250 knots while retaining such desirable attributes as excellent low speed handling, efficient hovering, and a seamless and simple transition to high speed.
Among the innovative technologies the X2 Technology demonstrator employs are:
· Fly-by-wire flight controls
· Counter-rotating rigid rotor blades
· Hub drag reduction
· Active vibration control
· Integrated auxiliary propulsion system
As a “follow-on” to the successful X2 program, Sikorsky Aircraft is continuing development of the next-generation rotary wing technology by launching the S-97™ RAIDER™ program. Sikorsky and select suppliers will design, build, and fly two prototype light tactical helicopters. These prototype vehicles will enable the U.S. armed forces to experience, first hand, the advanced performance capabilities X2 Technology can provide.
Like the X2 Technology demonstrator, the S-97 RAIDER helicopter will feature twin coaxial counter-rotating main rotors and a pusher propeller. In addition to flying at nearly twice the speed of a conventional helicopter, the S-97 RAIDER prototype aircraft will incorporate other key performance parameters critical to combat operations — increased maneuverability, greater endurance, and the ability to operate at high altitudes.
Sikorsky Aircraft Corp., based in Stratford, Conn., is a world leader in helicopter design, manufacture, and service. United Technologies Corp., based in Hartford, Conn., provides a broad range of high technology products and support services to the aerospace and building systems industries.
View related photo: Kevin Bredenbeck (http://www.sikorsky.com/StaticFiles/Sikorsky/Assets/images/news/SETP_2011_092411.jpg)

Thanks,
John Dixson



(http://www.sikorsky.com/Index/Feedback)

Ian Corrigible
6th Oct 2011, 13:24
IMO, the X2 may have been a marketing program to keep the stock up

Sikorsky X2 TD flights (thru 7/14/11): 23
Sikorsky X2 press releases (http://www.sikorsky.com/About+Sikorsky/News/Press+Search?text=x2&keywordMatch=any&fromNews=true&page=1) (to date): 24

I/C

Graviman
6th Oct 2011, 17:59
Kevin Bredenbeck, the pilot who flew the revolutionary X2 Technology™ demonstrator last year to an unofficial speed record for conventional helicopters, has been recognized by the Society of Experimental Test Pilots (SETP) with the Iven C. Kincheloe Award for the year’s outstanding professional accomplishment in the conduct of flight testing.

Much deserved! Thanks for posting John. :D


Was X2 just a publicity stunt? Not really, since it took ABC ideas already demonstrated in XH59 flights and developed them to the point that a helicopter can efficiently operate from hover up to a significant increase in cruising speed. The technology has now caught up with the physical requirements.

Why was X2 consigned to museum after achieving its objective? Because that way it has an umblemished record. This then paves the way for the S97 Raider to be based on flight proven technology.

The data collected from the X2 flights will no doubt be used to improve the design of the S97. This may very well include increased rotor spacing and improved blade aerodynamic optimisation: improved concept design analysis techniques for example. The point is that high cruise speed helicopters that don't compromise the hover are a reality, and the rest is just good engineering.

SansAnhedral
6th Oct 2011, 19:16
The point is that small high cruise speed helicopters that don't compromise the hover are a reality, and the rest is just good engineering

QFT, though one can argue that a sucessful one-off prototype doesnt make for a successful entire class of aircraft. :)

What did the X2 accomplish, performance wise, the XH59A did not also show the world? The devil is in the details.

Hilife
7th Oct 2011, 03:53
Yes the XH59A had performance, but it also had many problems that technology back then could not overcome.

I’ve no doubt Sikorsky learnt a great deal from the XH59A, but I would suggest that without fly-by-wire control technology and material advancements allowing for a reduction in high vibrations for one, further investment at the time would have achieved little reward.

Igor Sikorsky did not invent the helicopter, but he was the first to build a safe and practical platform that could be put into production.

Clearly Sikorsky feels confident enough that the data gleaned from the X2 flight test program justifies a continuation of ABC funding to the next phase, this being the X-97 Raider.

As it’s UTC’s money (and not that of the US taxpayer) they are spending, clearly they feel they could be on to a winner.

Dave_Jackson
7th Oct 2011, 05:29
Igor Sikorsky did not invent the helicopter, but he was the first to build a safe and practical platform that could be put into production.
Hilife,

Some interesting weekend reading that might clear up a few misconceptions. The Luftwaffe Profile 06 - Flettner FL-282.pdf (http://www.unicopter.com/Temporary/Luftwaffe_Profile_Flettner_FL282.pdf)

It may also be interesting to know that Flettner's twin rotor FL282 [on page 5] preceded Sikorsky's, and that Flettner's twin propeller FL185 [on page 4] preceded Eurocopter's Xcubed.

Flettner ~ the unacknowledged genius.


Dave

Graviman
12th Oct 2011, 18:17
Dave, at the risk of going off topic:

Surely the Kolibri was not ABC because the retreating blades were not actually unloaded? The rotor shafts just were not designed with the intention of supporting fully asymmetrically loaded rotors. From memory of the assembly I saw in Coventry (I sent you photos) the hub was more or less articulated: with the direction of rotation chosen for optimal sideslip-yaw coupling would lead to unloaded retreating blades flapping down to considerable extent, along with flap back if ABC was attempted.

I'm not trying to diminish Flettner's genius, but just saying that high speed was not his design intent (at that stage).

Dave_Jackson
12th Oct 2011, 20:48
Mart,

My posting was a response to an error in the preceding post. Igor Sikorsky was NOT "the first to build a safe and practical platform that could be put into production."


The second sentence was anecdotal information on Flettner. It relates to the fact that he preceded both Sikorsky and Eurocopter in building a configuration with twin rotors and building a configuration with single rotor with twin propellers. A subject that happens to be topical today.

If super-rigid rotors (ABC), is the subject, then anecdotally, Hiller preceded Sikorsky. Hiller X-2-235 (http://www.aviastar.org/helicopters_eng/hiller_x-2-235.php)

We should give credit where credit is due.


Dave

IFMU
16th Nov 2011, 01:26
Kevin Bredenbeck won the Flightglobal Aviator of the Year Award for flying the X2:

Aviator of the year (http://www.flightglobal.com/page/Flightglobal-Achievement-Awards-2011/Aviator-2011/)

turboeddie
16th Nov 2011, 02:38
http://img195.imageshack.us/img195/2571/img0264ty.jpg

got this pic at the stuart air show last weekend. talked to one of the guys on the project. lots of potential there. just crank up that prop.:ok:

Graviman
30th Nov 2011, 11:54
Great photo, TurboEddie. Really shows and contrasts the different aerodynamic systems required for this technology.

http://postmediaottawacitizen.files.wordpress.com/2012/01/id40441_600.jpg



Sikorsky Aircraft Corp., a subsidiary of United Technologies Corp. (NYSE: UTX), has selected 35 companies to join its team assembling two prototype S-97 RAIDER™ helicopters for evaluation by the U.S. military. Self-funded by Sikorsky and its team members, the RAIDER program will demonstrate the military applications of Sikorsky’s break-through X2™ rotorcraft design, which proved its capability in 2010 to double the cruise speed of conventional helicopters.

Sikorsky announced its supplier team during the Association of the United States Army’s ILW Aviation Symposium and Exposition, National Harbor, Md.
“As designer and integrator of a next-generation light tactical helicopter capable of outperforming conventional helicopters in almost every performance parameter, it was imperative we chose our suppliers for the maturity of their advanced aerospace products and technologies,” said Doug Shidler, Sikorsky’s RAIDER program manager. “Product maturity will enable Sikorsky to demonstrate the RAIDER helicopter’s flight and aerodynamic performance in a simulated military environment starting in 2014, and ultimately bring X2-designed helicopters to future customers quickly and at a very affordable price.”

The majority of the RAIDER team members are U.S.-based companies from 20 states.

Structures: Aurora (Va., Miss.); Cytec (Calif., N.Y.); East/West Industries
(N.Y.); Fischer (Germany); Hexcel (Conn., Utah); PPG (Calif.); Triumph Group
(Wash.).

Avionics: Avionics Instruments (N.J.); BAE Systems (N.Y.); Eaton (Miss.);
Esterline Control Systems (Calif., Ill., Wash.); Garmin (Kan.); Goodrich (Fla.,
Minn.); Hamilton Sundstrand (Conn.); Honeywell (Ariz.); Lockheed Martin (N.Y.); Northrop Grumman (Calif.).

Propulsion: Ametek (N.Y.); Ducommun (N.Y.); Eaton (Mich.); General Electric
(Mass.); Honeywell (Ariz.); Liquid Measurement Systems (Vt.); Meggitt-USA (Ga., Calif.); Spectrum (Conn.); TIGHITCO (Conn.).

Rotors and transmission: Emerson-McGill (Ind.); Fatigue Technology (Wash.); FAG Canada; Goodrich (N.Y.); Hamilton Sundstrand (Conn., Ill.); Kamatics (Conn.); LORD Corp. (Pa.); Pankl Aerospace (Calif.); Parker Aerospace (Calif., Ga.); Schultz (Calif.); SIFCO (Ohio); Triumph Group (Utah, Mich.).

Blades: Cytec (Calif., N.Y.); Eagle Aviation Technologies (Va.); Hexcel (Conn., Utah); Rotating Composites (Conn.).

The RAIDER aircraft program follows Sikorsky’s successful X2 TECHNOLOGY™
demonstrator helicopter, which in September 2010 achieved more than 250 knots (287 mph) flight speed, or twice the average cruise speed of a conventional helicopter. The National Aeronautic Association awarded Sikorsky the 2010 Robert J. Collier Trophy for the achievement, and for its potential as a future rotorcraft technology.

Sikorsky will invest about 75 percent of the RAIDER program’s expected cost,
with suppliers investing about 25 percent. Like the X2 demonstrator aircraft, the single engine S-97 RAIDER helicopter will feature coaxial counter-rotating main rotors and a pusher propeller to provide cruise speeds up to 220 knots (253 mph) with dash speeds up to 240 knots (276 mph) or higher.

“We anticipate these S-97 RAIDER prototypes will provide dramatic improvements over conventional helicopters in maneuverability, range, endurance, altitude and hover efficiency — in addition to speed,” said Chris Van Buiten, Vice President of Sikorsky Innovations, the advanced engineering and development division of Sikorsky Aircraft that has pioneered the X2 design. “These attributes of the RAIDER aircraft could very well change the way the U.S. military fights with helicopters.”

While the RAIDER aircraft will showcase the X2 design’s considerable airframe
and flight characteristics, its configuration as a light tactical helicopter
will enable Sikorsky to offer the aircraft as a candidate for the U.S. Army’s
Armed Aerial Scout helicopter competition. The U.S. Army is seeking a new
aircraft to replace the OH-58D Kiowa Warrior helicopter.

With a maximum gross weight of approximately 11,000 lbs, the RAIDER helicopter will offer full operational performance at speeds and altitudes more than twice the capability of today’s light tactical helicopters.

The Raider cockpit will feature side-by-side seating for two pilots. For armed
reconnaissance and light attack missions, the aircraft can host a variety of
sensors and externally-mounted weapons, with the flexibility to carry additional fuel and ammunition for extended missions. In a light utility or special operations configuration, the helicopter cabin will carry up to six troops.

Sikorsky Aircraft Corp., based in Stratford, Conn., is a world leader in
aircraft design, manufacture and service. United Technologies Corp., based in
Hartford, Conn., provides a broad range of high-technology products and support services to the aerospace and building systems industries.



Sikorsky Lines Up Suppliers For Its Prototype RAIDER Helicopter | Ottawa Citizen (http://blogs.ottawacitizen.com/2012/01/13/sikorsky-lines-up-suppliers-for-its-new-raider-helicopter/)


Looks like Nick Lappos is being kept busy. ;)

ShyTorque
21st Jan 2013, 13:30
Any recent news of this project? Not heard anything for almost a couple of years.

BossEyed
21st Jan 2013, 13:43
This from Flight last October:

Sikorsky starts construction of S-97 Raider prototypes (http://www.flightglobal.com/news/articles/sikorsky-starts-construction-of-s-97-raider-prototypes-377868/)

Sikorsky has started building two prototype S-97 Raider high-speed compound helicopters for the US Army's prospective Armed Aerial Scout programme.

The coaxial-rotor, pusher-prop machine is based on the company's revolutionary X-2 design which won the Collier Trophy in 2010. The S-97 is currently in its detailed design phase, but because Sikorsky is developing the aircraft as a prototype, the company has already started fabricating the new rotor-craft.

"We're in detailed design right now," says Doug Shidler, Sikorsky's S-97 programme manager. "And because we're a rapid prototype programme, as we're going through detailed design, we're also building parts."

Parts of the aircraft's fuselage are already being built as are other components throughout the airframe. In fact, some components have already been completed, Shidler says. The objective for the year is to complete the design.

The aircraft should move into final assembly by the middle of next year, Shidler says. The aircraft should enter ground and flight testing in 2014. "Things are moving along as projected," he adds.

http://www.flightglobal.com/Assets/GetAsset.aspx?ItemID=48082


Fascinating programme.

Edit: Also, this video from Nov/Dec 2012:

_aop2ePwcYg

SansAnhedral
21st Jan 2013, 14:11
Curious to see if they can figure out how to install their own sail fairing this time :ouch:

ShyTorque
21st Jan 2013, 16:14
Thanks for posting the clips. Interesting that they seem to be concentrating on a military version, bearing in mind what happened to the Commanche.

Anyway, I want a civvy one! ;)

Dave_Jackson
21st Jan 2013, 18:56
Was it shown on the Military Channel in December, as mentioned in the video?

IFMU
11th Mar 2013, 13:21
Looks like the building where X2 was created is available for lease.

Cushman & Wakefield - Schweizer Aircraft Former, Manufacturing, 1250 Schweizer Road, Horseheads, NY (http://looplink.cushwake.com/ll/17919190/1250-Schweizer-Road/)

IFMU

jpphoopha
30th Jun 2013, 15:53
The gyrodyne main rotor was powered at all times during flight. During cruise, about one-third of available power was directed to the rotor and the remainder to the propeller. This arrangement permitted to the rotor tip-path plane to fly parallel to the flight path in autorotative pitch, providing high cruise speed capability with low vibration.