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Sikorsky X2 coaxial heli developments.

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Sikorsky X2 coaxial heli developments.

Old 4th Sep 2008, 19:15
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CEFOSKEY,

Good pictures.

Here is a test flight that I was at a few years ago. It is also a coaxial, and it got a "bit twitchy" at the end of the flight.
First Test Flight Video (16.5MB)


Dave
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Old 5th Sep 2008, 11:17
  #342 (permalink)  
 
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CEFOSKEY, some great photos!

The best metric of success for X2 flight envelope testing will be Kevin Bredenbeck's grin at the end of each flight.

BTW, when are we going to see your rotor fairing?


Dave, looks more like intermeshing to me...

Last edited by Graviman; 12th Sep 2008 at 11:28.
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Old 6th Sep 2008, 01:54
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If the AF is interested as you implied, hopefully they through some money Sikorsky's way and this develops a bit faster. I can only hope the bureaucratic involvement doesn't push things faster than is reasonable.
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Old 12th Sep 2008, 01:43
  #344 (permalink)  
 
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Star-gazette X2 article
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Old 12th Sep 2008, 05:18
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Smile

Mart,

You asked;
CEFOSKEY,
when are we going to see your bits?
Your request is a little unusual. But if you must, this should satisfied your desires.



IFMU,

Your article says;
"In the new design, the vertical tail rotor is moved to a position similar to a submarine's propellers."
Let's see now.

The gross weight of the X2 is 5,300 pounds.
The engine delivers 1,452 horsepower.
Propellers can deliver a thrust of 5 pounds per horsepower.

No! No! Igor. Don't change the X2 to a Nose Sitter.

_____________

OK. No more jokes. A serious question.

How come Russian-American Igors like tail-fans?
Igor Sikorsky is the father of helicopters that have tail-rotors, and
Igor Bensen is the father of gyrocopters that have pusher-props.



Dave
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Old 12th Sep 2008, 17:55
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That's probably about right CEFOSKEY. At 100% collective this works out at roughly 2.1g, meaning that a turn tighter than about 60 degrees would require height loss.
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Old 13th Sep 2008, 02:07
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Originally Posted by Graviman
That's probably about right CEFOSKEY. At 100% collective this works out at roughly 2.1g, meaning that a turn tighter than about 60 degrees would require height loss.
Graviman,

I think that means it could pull 2.1g's vertically from hover, for a moment, if you yanked the collective to 100%. With translational lift I would expect you could do better. A 60 degree bank turn in hover doesn't make sense.

-- IFMU
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Old 14th Sep 2008, 18:45
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CEFOSKEY, I thought about that point after i had logged off for the day...

Don't forget that for a given thrust there will be a velocity for minimum power due to translational effect. Above this velocity the power requirement goes back up again until at dash speed it is probably about the same as it was at hover. So by designing a rotor which can handle 2.1g in the hover it also means it can do this at all airspeeds. Even so this probably means that X2 could pull ~4g without loosing height at minimum power speed, which is no mean feat.

Conventional helicopters are limited by the retreating blade stall, mostly in terms of ability to pull collective. I suspect that the X2 aerodynamics guys wanted to make sure that the manouvre margin was equally good at all airspeeds, with the FBW limiting g loading if required.

That said, being able to pull 2+g at low speed is still an impressive performance.

Last edited by Graviman; 15th Sep 2008 at 11:22.
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Old 26th Sep 2008, 05:01
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Competition?




More.


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Old 26th Sep 2008, 06:41
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Ok, if they can make that KA-92 a reality it will easily replace the Super Puma at the top of my list of stuff I wanna fly during my career!! Pity it's just an idea and not yet, if ever a reality.
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Old 26th Sep 2008, 11:58
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KA-92 demonstrates the risk in letting something out of the bag. It's a two edge sword - it attracts the money men, but also inspires competitors...

I'm hoping the X2 flight test team are being cautious about expanding the envelope, but not overly cautious. My big worry is that the current financial pinch sees X2 development slow.

The ABC helicopter is a good concept. Expect to see more.
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Old 26th Sep 2008, 17:09
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Wow!
it really is a new Russia! Since when did the Russians start caring about the asthetic value of thier designs? We all know Russia makes the ugliest helis Mother Russia would never let a heli that beautiful leave her soil.
Though it is most likely just propoganda that model is beautiful. Maybe Sikorsky can rip off thier concept style.
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Old 26th Sep 2008, 17:56
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The propulsor is coaxial, also.
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Old 26th Sep 2008, 23:47
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X2 second flight article

Flightglobal:X2 Second Flight
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Old 29th Sep 2008, 08:55
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Pleased to see that development is gently stepping up a gear.

Interesting that the FBW gains have been trimmed for flight 2. This definately shows the benefits of a carefully considered flight test program. Fingers crossed that all of the development stays just fine tuning a good design.



Sikorsky plans to build 3h of flight time before grounding the coaxial rotor high-speed helicopter to integrate the pusher propeller into the power train and control system for faster flights planned in phases two, three and four in West Palm Beach, Florida. Kagdis says the pusher system should be integrated by year's end, after which the remainder of the 15h in phase one will be completed in Elmira.

Phase two will see the aircraft flying as fast as 80kt without the aid of the pusher prop. In phase three, test pilots will engage the rear propeller to attain speeds of 120kt, In stage four, Sikorsky will attempt to reach 250kt or more.
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Old 29th Sep 2008, 10:21
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I fly rc helis and adjusting gains on the first couple of flights is always the primary focus especially when all the other mechanical aspects check out. So I would think that mechanically it is working like a singer sewing machine Hopefully 3 hours will go by fast, and then they can get that prop working.
if we can't get video can we get a sound byte? I love listening to the unique sound mae by each type of heli
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Old 8th Oct 2008, 02:15
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Rotorcraft pro

The new issue has the X2 as the cover story. You can read it online here:

Rotorcraft Professional

They have a nifty 'virtual paper' link that lets you flip through the current edition.

-- IFMU
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Old 15th Oct 2008, 01:17
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From UTC Photo Contest

(week 4, page 23, you can get a higher resolution pic here too)



Also, link to the online version of Rotor & Wing, X2 cover and article inside:

Rotor & Wing - October 2008

-- IFMU
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Old 27th Oct 2008, 12:23
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Cefoskey, I'm actually slightly suprised Kamov haven't thought about ABC technology before. It's a logical next step from coaxial. I guess this just means that the time is right for helicopter cruise/dash speeds to go up. Post credit crunch that is.

Has Kamov done any development into the high effective hinge offset blades? I can imagine this being a greater challenge for such a large machine. The alternative would be to accept advancing blade compressibility limitations or an increase in coning angle. Either way KA-92 will not be competing with S-92 instantly...
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Old 9th Jan 2009, 11:44
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Anyone heard any news on X2?

I've not pinged this thread for a while, since i assume Sikorsky are as hard hit as the rest of us by the credit crunch induced recession...
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