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Brian Abraham
28th Aug 2009, 00:28
From Aviation International News

Sikorsky Aircraft yesterday said it has begun whirl testing a demonstration rotor system with active flaps as part of the company’s “commitment to design, develop, test and ultimately field next-generation technologies that will advance the current state of rotorcraft.” Development partners on the project are United Technologies Research Center for the blades and Hamilton Sundstrand Claverham for the flap actuators. According to Sikorsky advanced programs manager Jim Kagdis, “We have reached full speed of 450 rpm and commenced testing flap integrity and functionality. Now we will investigate rotor reconfiguration capabilities to demonstrate the potential to reduce rotor vibration and noise, and increase blade loading, which enables higher maneuverability and speed.” Testing will continue throughout this month and wind-tunnel testing is scheduled for next year. “We are on a path to prove the concept of configuring a helicopter’s dynamic system to maximize aircraft performance, reduce noise and lower vibration while enhancing overall mission effectiveness,” said Sikorsky vice president of research and engineering Mark Miller. “It is another step toward meeting future needs and customer expectations.”

Agaricus bisporus
28th Aug 2009, 07:44
"Whirl Testing!!!"

What are they going to do? Tie a rope to it and swing it around their heads?

What's with the baby-talk? Ga-ga Ooooh!

MightyGem
28th Aug 2009, 08:09
What's up AB? get out of the wrong side of the bed this morning?
"whirl testing" - Google Search (http://www.google.co.uk/search?hl=en&q=%22whirl+testing%22&start=0&sa=N)

Graviman
28th Aug 2009, 11:35
Interesting that this technology is having significant R&D budget poured in now. That means that there must be an intended introduction date for production Sikorsky machines. :cool:

The benefits to the helicopter industry will be significant. If nothing else then it means that vibration will be removed at source (by correctly terminating/damping the free end of the blades). If the system can be signed off as sufficiently reliable to perform all of the fatigue assesment against then TBOs may well go up. At the extreme payloads for a given rotor/machine size may well go up too.

So ultimately a little investment for a big return...

heli1
28th Aug 2009, 12:33
Eurocopter are well ahead,already flying active flap technology on an EC135.

skadi
28th Aug 2009, 14:18
@heli1

Eurocopter tested this system on a BK117 ( S/N 7045 Reg. D-HMBD ) in the first days of September 2005:

Helionline.de (http://www.helionline.net/536-657831-867721/photogallery/6/40////7045.html)


skadi

nimby
28th Aug 2009, 15:01
Should the presser have read "Sikorsky plays catch-up"?

Graviman
28th Aug 2009, 17:34
Eurocopter are well ahead,already flying active flap technology on an EC135.

Heli1, are there any links / publications on that work? Not that that i doubt your word, i am genuinely interested. I know that ONERA were doing a lot of work on this system recently (using an EC135 rotor system i imagine). The difficulty with the trailing edge only servos, as i recall, is that for the desired lift modification you also get an undesired pitch modification. I had wondered about leading and trailing edge devices to counter this, and maybe also allow twist resonance damping (blades resonate in flap and twist - ideally at well seperated frequencies to avoid flutter).

Mart

Dave_Jackson
28th Aug 2009, 18:30
Nimbi wrote;
Should the presser have read "Sikorsky plays catch-up"?

Sikorsky's Patent Application 20080145220 ~ On-blade actuator for helicopter rotor blade control flaps (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=%2220080145220%22.PGNR.&OS=DN/20080145220&RS=DN/20080145220) was filed on December 14, 2006.

This is 15 months after Eurocopter's testing.
_________________________

Sikorsky's Patent Application 20070125907 ~ Variable speed gearbox with an independently variable speed tail rotor system for a rotary wing aircraft (http://appft1.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=%2220070125907%22.PGNR.&OS=DN/20070125907&RS=DN/20070125907) was filed on December 02, 2005.

This is 5 months after the thread Variable Speed Rotors and Prop(s) (http://www.pprune.org/rotorheads/181575-variable-speed-rotors-prop-s.html) on PPRuNe.

Sikorsky's patent lawyer listed Nick L. as the primary inventor. A subject that was politely discussed here. (http://www.pprune.org/rotorheads/245168-sikorsky-x2-coaxial-heli-developments-3.html#post3344991) :)
________________________

Perhaps Sikorsky needs more conceptualization engineers and fewer lawyers. :rolleyes:

BV234driver
30th Aug 2009, 01:03
Nimby- check previous stuff online. Big S has been partnered with NASA for over a decade, running a hydraulic PCL setup, full scale in the NASA wind tunnel. The latest trend tends towards the active flap/trim tab portion.

But seriously, being on the pilot and maintenance side, run a search on video of a blade in-flight. They've taken a camera mounted to the root of a UH-60 system in flight, and it might as well be a spaghetti noodle. So, for those that expect a dramatic change, I'd reevaluate expectations. Not that we wouldn't all like to get rid of M/R dynamic vibe, but it's a bit at a time, I'm afraid. And as much science as it is now, some is still an art. Just not the chalk and flag art that it was of years ago.

Too true on engineers and fewer lawyers, Dave. Maybe why we're seeing products like the S-92 show up.

nimby
10th Sep 2009, 13:24
... I was suggesting (a) prior art elsewhere and (b) other technologies

MrDrumpy
10th Sep 2009, 17:38
Here (http://videoportal.sf.tv/video?id=eb84e33c-352a-4110-8cb4-ef4c53e34c71&referrer=http%3A%2F%2Fwww.sf.tv%2Fsendungen%2Feinstein%2Fsen dung.php%3Fdocid%3D20071129) is a short Swiss tv documentary about the Eurocopter system, tested on a MBB BK117B2 at the Eurocopter Heliport at Donauwoerth in Germany. The video is only in german, but it shows some nice details of the system.:ok:

Dave_Jackson
10th Sep 2009, 18:53
http://www.unicopter.com/Temporary/Early Kaman Servo-flap.gif
Picture from Chapter #3 'Room for Only One Inventor', in the book 'KAMAN ~ Our Early Years'.

Where would rotorcraft be today if United Technologies had kept Charles and let Igor go? http://www.unicopter.com/Think.gif

Dave

JohnDixson
12th Sep 2009, 12:17
Dave, since this is entitled as a Pilots Forum, perhaps this one parameter may answer the question:

At present ( I checked this yesterday with a SA pilot who we hired out of Kaman ),
Kaman has one test pilot.
Sikorsky has 52, working at up to five locations and on 9-11 development projects in addition to the production and customer support activities.Thanks,
John Dixson

widgeon
12th Sep 2009, 14:51
I think he is saying maybe if Kaman had UT's resources and political clout they might have gone further. Although the seaspite is not a good advert for them.

The Westland whirl tower used to be very close to the Rugby pitches at the Garrett end of the factory , I used to wonder how much damage would have been caused if one of the blades let go during test.

NonSAC
12th Sep 2009, 15:16
Perhaps this is explained by the fact that these SAC test pilots spend their time testing Kaman products once SAC has snapped them together with GE engines other sundries in Sratford prior to shipment to the various chop shops for customization?

http://www.kamanaero.com/images/PDFs/9-12-07-HeliworX-Kaman-Sikorsky-Sign-MOA.pdf

Though I believe that some blades, aside from those built by a certain Chinese-owned outsourcing house, are still made in Stratford.

victor papa
12th Sep 2009, 17:01
Graviman, go onto the eurocopter.com website and select the Rotor Magazine option there somewhere. Funnily enough they have an article on the 135, Bk and 145 having been tested with photos and reports in the magazine. Very interesting. You should also be able to track the history and info via the Rotor Magazine link.

Graviman
18th Sep 2009, 11:54
VP,

Do you remember which issue? Search seems to be limited:

issue 82 - Eurocopter, an EADS company (http://www.eurocopter.com/site/en/ref/issue-82-(2009-07-08)_1019.html)

MrDrumpy,

Interesting article but i'm not sure the presenter fully understood the benefits of active vibration flaps. Spreading out the tip vortices (like the owl) will help to reduce speeds near the tip of a fixed wing, but the sound from this is already minimal, but the only way i can see it impacting a helicopter is blade-vortex interaction. The main benefit of active servo flaps is to reduce blade vibration, hence structural loads into the fuselage. But having better controlled blade tips may inturn reduce the peak vorticity strength to nearer the mean vorticity strength around the azimuth. More controlled tip vortices and reduced fuselage vibration may both explain the significant 6dB(A-weighted) which was mentioned.

Dave,

How did that servo flap system work? It looks to me as if designed to damp out vibration by having it's CG ahead of the blade, so that the return to TPP restoring force is reduced by the servo Rel_AOA. At about 2/3rds radius i imagine it worked best at 3P blade vibration, but probably also handled 1P and 5P vibrations.

victor papa
18th Sep 2009, 15:12
It's the latest issue. It is not a main article so look under all the listed catagories on the top of the rotor website-it is under one of them.

Graviman
18th Sep 2009, 16:47
VP, thanks:

Green helicopter: Almost a Reality (http://www.eurocopter.com/w1/jrotor/82/FA2.html)

Shows the tip servos nicely. You can also see the reflex aerofoil section to keep the control forces down. Not sure exactly what is in the hub mounted cylinder. If it is just power electronics then that is some serious cooling!

http://www.eurocopter.com/w1/jrotor/82/iso_album/rotor82_uk_cb3_hd_page_20_image_0003_280x0.jpg http://www.eurocopter.com/w1/jrotor/82/iso_album/rotor82_uk_cb3_hd_page_20_image_0002_185x0.jpg

Dave_Jackson
18th Sep 2009, 17:16
Graviman,
How did that servo flap system work? Was it designed to damp out vibration by having it's CG behind the blade? It looks about 2/3rds radius (ie tuned for 3P blade vibration).

It is a picture of Kaman's initial arraignment for flight control.

Here are a lot of pictures and a drawing on the Kaman K-max rotorhead. (http://oh1ninja.la.coocan.jp/details/KMAX/kmax_e.htm)

Dave