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Sikorsky X2 coaxial heli developments.

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Sikorsky X2 coaxial heli developments.

Old 24th Aug 2010, 11:24
  #741 (permalink)  
 
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Originally Posted by heli1
So that big tail surface doesn't contribute lift at the aft end ??
Since it appears to be an inverted aerofoil giving a downthrust (a normal helicopter design requirement) what do you think?

If it was producing lift, there would be quite an issue with aft cyclic authority to keep the fuselage level!
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Old 24th Aug 2010, 15:04
  #742 (permalink)  
 
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The surfaces at the tail are for stability or trim.
A lifting wing must be attached at or near the aircrafts center of gravity.
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Old 25th Aug 2010, 11:35
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Interesting that non of these definitions state a requirement for level flight...

X2 would be able to sustain high speed flight in descending flight without the pusher prop. Not sure what ROD would be required for 235kias.
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Old 25th Aug 2010, 12:19
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I suspect the definitions are in the small print as it would be obvious that any aircraft can go faster in a dive.... however that assumes it can complete the set distance ! The aircraft also has to complete two runs in opposite directions to get an average.
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Old 26th Aug 2010, 01:10
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If you simply move the tail rotor to the starboard side of the fuselage and face it forward, is it still a helicopter? (ie. the Fairey FB-1)



ps. This should make Dave Jackson smile.
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Old 26th Aug 2010, 02:17
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Smile

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Old 26th Aug 2010, 07:44
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The fairey FB1 was a gyrodyne...as was its big brother the Rotodyne.
The main rotor became unpowered in forward flight.
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Old 15th Sep 2010, 23:48
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Sikorsky X2 Technology Demonstrator Achieves 250-Knot Speed Milestone



September 15, 2010

WEST PALM BEACH, Florida - Sikorsky Aircraft Corp.’s X2 TechnologyTM demonstrator today successfully achieved a speed of 250 knots true air speed in level flight at the Sikorsky Development Flight Center, accomplishing the program’s ultimate speed milestone. Sikorsky is a subsidiary of United Technologies Corp. (NYSE:UTX).

The speed, reached during a 1.1-hour flight, is an unofficial speed record for a helicopter. The demonstrator also reached 260 knots 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.”
“Our primary key performance parameter has been met,” said Jim Kagdis, Program Manager for Sikorsky 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.”

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.
“I’m proud of what the X2 Technology team has accomplished,” Bredenbeck said. “This was truly a collaborative effort that demanded a tremendous sacrifice from the full team. This dedication enabled the demonstrator to hit this historically high mark.”
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.
The X2 Technology program began in 2005 when Sikorsky first committed resources and full funding for the program’s development.
Mark Miller, Sikorsky Vice President of Research & Engineering, said: “The X2 Technology program is an initiative of our Sikorsky Innovations team, and today it offers a clear and exciting validation of our ability to take on the toughest challenges in vertical flight.”
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Old 16th Sep 2010, 01:06
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Outstanding!

-- IFMU
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Old 16th Sep 2010, 01:11
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FANTASTIC JOB SIKORSKY !!

It'll be interesting to see what the competition can do in the future.
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Old 16th Sep 2010, 12:03
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well done

a 250 kts compound rotorcraft

DM
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Old 16th Sep 2010, 13:03
  #752 (permalink)  
 
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Does anyone have any fuel burn figures ?
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Old 17th Sep 2010, 05:37
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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?
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Old 17th Sep 2010, 10:03
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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.
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Old 19th Sep 2010, 02:51
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According to this article, maintaining 250kts required 1300hp from the T800, leaving 300hp in reserve.

Sikorsky 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, 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.

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Old 19th Sep 2010, 14:57
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T800-LHT-801 rated at 1,563 shp. No laughing gas.
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Old 21st Sep 2010, 17:12
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Canard for X-2 ??

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 ??
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Old 22nd Sep 2010, 00:37
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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
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Old 22nd Sep 2010, 11:36
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X2 Attendance

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
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Old 22nd Sep 2010, 21:29
  #760 (permalink)  
 
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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

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

The Sultan
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