I was just curious what you'd been doing in the ABC? I'd read that they had tested a lot of the X2 concepts using standard helos as a test bed & I wondered how you could test something so radical on a conventional machine?
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Originally Posted by 22clipper
I was just curious what you'd been doing in the ABC? I'd read that they had tested a lot of the X2 concepts using standard helos as a test bed & I wondered how you could test something so radical on a conventional machine?
I have followed the X2 in the media. If you go back through the old press releases, they flew X2 FBW on a 333, and lately they show pictures of ground test of a brand new airframe. Don't get confused with that other thread where they talk about that swing tail thing, that was old news. I saw a clip from aintv, with an interview from Jeffrey Pino. He said that they had all the parts collected & the fuselage built or something like that. http://www.aintv.com/home.asp?CATEGO...&ID=112&FMT=WM There is a little X2 animation, apparently from their HAI booth, but that was the only X2 picture. -- IFMU |
22clipper,
The old ABC demonstrator flew in the 1970's and early 80's and was the predecessor of the X2. Here is Dave's excellent site: http://www.unicopter.com/0891.html The X2 plan is to develop the airframe, the FBW controls and then the X2 rotor, so it is being flown that way. The first two steps have been accomplished, the third is approaching (the blades are going thru qualification, I think, and flight test is being planned). |
@ IFMU
... lately they show pictures of ground test of a brand new airframe ... |
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Thank you :ok:
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The following patent was issued today;
US 7,229,251 ~ Rotor hub fairing system for a counter-rotating, coaxial rotor system |
Sikorsky Cypher?
This may be off base on this thread but the Sikorsky Cypher slowly faded and it was a counter-rotating vehicle, though unmanned. What ever became of it and besides not having a pusher and the noise issue, was it of any help with this new aircraft? Nick? Jack?
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Dan,
The Cypher fell to company decisions on where the UAV future was, back in 2001. The Cypher was small and inexpensive (so that many units had to be built and sold to make any appreciable profit) but engineering labor intensive, so it was put on the back burner. |
Thank you Nick.
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This posting is placed here in the Sikorsky SX Coaxial thread since the following US Patent Application is including the SX coaxial configuration.
____________________ Nick, As you probably know, I have an interest in the concept of 'Variable Speed Rotors and Propellers', having posted this publicly displayed thread in PPRuNe five months before the filing date of the following Patent Application. Therefore, it was interesting to read your US patent application 20070125907 ~ Variable speed gearbox with an independently variable speed tail rotor system for a rotary wing aircraft. A question comes up, which I am sure you can answer. The patent's tittle includes "...with an independently variable speed tail rotor system for a rotary wing aircraft.". In addition, Claim 2 says "... said tail rotor system at an independently variable speed relative said engine speed.", and Claim 14 says " ... and an independently speed-variable tail rotor system ...". However, there are no details on this variable-speed tail-rotor ("transitional thrust system 18 and 18' "). In addition, the associated drawings only show a blank box. I understand that the US Patent Office does not review the Claims in a Patent Application, but my question is why is there an 'all-encompassing' claim in the patent application? Dave |
Dan,
There was another Cypher, it had a pusher: http://avia.russian.ee/foto/sik_cypher2.jpg And according to this page: http://en.wikipedia.org/wiki/Sikorsky_S-69 There is this: ... the Cypher UAV which expanded company knowledge of the unique aspects of flight control laws in a fly by wire aircraft that employed coaxial rotors ... |
Dave,
The prior art in that field is vast. The work that was documented to support that and previous patent applications dates back years before your thread (it was while I was at Sikorsky, and I left months before your thread, for example.) Not being a patent expert, I can't comment on how claims are worded or handled. Like the Michael Keaton character in "NIght Shift" I'm the idea man.... "What if you mix the mayonnaise in the can, WITH the tunafish? Or... hold it! Chuck! I got it! Take LIVE tuna fish, and FEED 'em mayonnaise! Oh this is great. [speaks into tape recorder] Call Starkist!" |
Not sure how many patents do get through - especially the overunity energy claims etc. It is difficult to really invent something new, since most ideas are a new application for an old concept. Must make patenting process more difficult to control.
With the headache that patenting presents to the private inventor, the thing that seperates a good company from a bad company is finantial reward for a patent which is incorperated. This encourages thought outside the box. |
Nick,
Thanks for the reply. Perhaps your departure from Sikorsky resulted in the legal objectives overriding your technical objectives, when the lawyer was writing the Patent Application. Incidentally, your Patent Application includes a coaxial configuration drawing. This drawing was used six months earlier in three coaxial-ABC Patent Applications. In your Patent Application, the lawyer, perhaps in a rush to pump out coaxial-ABC patents, didn't even reference the text to this drawing correctly. Mart, Times have changed. Recently, much has been written about the growing abuse of US patent system and its inability to now serve its basic objectives. Yesterday's article in the highly respected Globe & Mail 'Tech Crusaders Are No Match For Mighty U.S. Patent Lobby' is just one more example. The year-by-year increase in number of US patents is phenomenal. Most of these patents are insignificant drivel. However, one of the things they do is allow large corporations to use their vast wealth as the hammer, and their irrelevant patent as the excuse, to 'squash' the under-funded legitimate invention. You may find the last line in this quote from the above article of specific interest. "The U.S. drug industry has no interest in anything remotely approaching an overhaul. It is lobbying furiously behind the scenes to make sure this legislation dies or is seriously diluted. Joining the drug companies are a broad group of blue-chip manufacturers, including United Technologies and 3M Co." Dave |
http://www.unicopter.com/Temporary/KamovPoutine.jpg
Stolen from quadrirotor off of another forum with out any permission whatsoever. :uhoh: |
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Interesting article. Good luck X2 development team. :ok:
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IFMU said
The hardcopy has a picture in it. Is this the picture? :O http://www.unicopter.com/Temporary/Rieseler_R_II.jpg You've got to admit that those are darn close rotors for a mid-1930's helicopter. Dave |
Dave, i'm impressed with that Rieseler RII - 250KIAS back in the '30s! ;)
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Is this the picture? -- IFMU |
Mart,
Walter Rieseler is referred to, in Germany at least, as the 'forgotten pioneer'. I think that you will find his unique control system very interesting. Here is information on it;
IFMU, The grass is always greener on the other side. ;) Dave |
In searching for the picture, I found this:
http://www.aviationtoday.com/Assets/...-Left-Quad.jpg But this looks like an old picture compared to the december issue of AIN. |
Unable to download NASA pdf of control system analysis, but yes it was ahead of it's time. It certainly demonstrates that a cost effective hingeless gyro is practical. Maybe even manouvreable.
I think part of the difficulty with modern hingeless rotors is that the rotor frequency is so much higher now, due to the higher speeds and lower rotor mass. This means that any rotor eigenmode is comparable to the rotor frequency, so there is inevitably lead angle required in the pitch link. Although the tip radius was quite small, those tip heavy blades would likely have all sorts of interesting modes. Actually, there are days when i catch myself wondering whether you are right about laterally seperated rotors. It would push roll reaction times way down, since heli does not have to pendulate to new equilibrium. I have even pondered about smaller control only rotors, like Sikorsky's early VS-300! But these days a good SCAS control system can response shape the cyclic input to get a reasonable response. I think keeping the cost and weight of the machine down is more important. It will be interesting to see how the X2 development engineers overcome the difficulties if the envelope is pushed above 250KIAS. Clearly active tip control will become critical to avoid blade divergence. I would be curious how much higher the blade 1st bending frequency is pushed too. So roll response may approach that of fixed wing... |
Mart,
In IFMU's article it says; Grant emphasized that the X2 is a demonstrator for a “suite of technologies” that might have applications for future-design civilian and military rotorcraft, but it was unlikely that the twin coaxial main rotor system could be applied to smaller aircraft with smaller rotors due to its rigidity and resultant weight. “You’re probably not going to see these applications in the 3,000-pound weight class,” he said. “This [6,500 pounds] is around the size we would want to be the book end for the low end of the weight class. It is a lot easier to go big.” I think keeping the cost and weight of the machine down is more important. _____________ Rieseler's means of producing 'Absolutely' Rigid Rotors by using aerodynamically balanced pitch instead of aerodynamically balanced flap is ingenious. I'm going to look into it further, since it might be a logical step toward the UniCopter's and the Nemesis' Advancing Blade Concept. It will be posted as a separate topic on a new thread from this X2 thread if it continues to look good. Dave |
Here's another similar picture I found on some German site:
http://img505.imageshack.us/img505/861/x2wj0.jpg and this one was from last year: http://www.vtol.org/news/X2GroundTestStartnightime.jpg -- IFMU |
Rieseler, helico or tail-sitter???
What difference with a tail-sitter? http://www.rotaryforum.com/forum/att...5&d=1189528965 |
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International Internet Theft Ring.
quadrirotor,
The Austrian (OOPS make that German) pilot of the little coaxial must have gone on a diet. This time he was able to keep the craft off the ground. :) Are you here to steal back the picture I stole from you? Or, are you the one who just stole IFMU's X2 picture. :eek: Dave |
IFMU,
It's nice to see the X2 in the flesh at last (or was this a mockup?). Somehow it looks all innocent there, despite what it is going to achieve. I'm always amazed how a pile of parts can slowly, but magically, become a machine in the hands of talented test fitters. I bet it's starting to look the business at Schweizer now... |
Wikipedia entry..
http://en.wikipedia.org/wiki/Sikorsky_X2
http://upload.wikimedia.org/wikipedi.../X2_attack.JPG Artist conception of a potential armed high-speed escort/attack variant of an X2 aircraft. X2 technology is envisioned to be applied to a wide range of typical rotorcraft roles. |
I think this one has a better handling, as she could have a vectorizing tail...
http://www.rotaryforum.com/forum/att...0&d=1194272226 |
I think this one has a better handling, as she could have a vectorizing tail... -- IFMU |
At an all-hands meeting, Jeff Pino claimed first flight target date is 1/15.
A bare rotorhead run was performed late last month. |
Looking at those pix reminds me of the ill fated Cheyenne......too complex for what you achieve.
P.S. Jeff Pino seems to be slipping the date again...first flight was supposed to be before Christmas. |
Originally Posted by LupinIII
At an all-hands meeting, Jeff Pino claimed first flight target date is 1/15.
A bare rotorhead run was performed late last month. Take your time guys, and make it the success it deserves to be. Us X2 fans have waited patiently this long... |
At an all-hands meeting, Jeff Pino claimed first flight target date is 1/15. A bare rotorhead run was performed late last month. I guess we'll find out, in another month! -- IFMU |
IFMU, i can only speak from the perspective of having been involved in the design, analysis, testing & development of many ground vehicles for various industries (it still ain't helicopters :sad:). Any particular objective date will be more a target for the engineer's to aim towards. A well run project will adjust to the development activities, but will not dictate them.
Let's face it this is a complex helicopter program, not a train timetable! |
Mart;
The originally promised date was late 2006. You say;- "Any particular objective date will be more a target for the engineer's to aim towards." Perhaps you recall; "They’re calling their cocktail of integrated digital, aerolelastic and compound technology the X2 and say that its unique co-axial/pusher prop design will do 250 KTAS knots by the end of 2006. .............. ......... Jeff Pino, now in charge of Sikorsky’s strategic programs put his people in special shirts, had a mock-up ready, and pulsed people’s cell phones to get them to come to a briefing. There were some interesting sidelights: the legendary Marat Tischenko, head of Mil under the communist USSR rose to his feet to challenge Finger on making ‘a mistake’ by selecting the co-axial design. Finger paused, then turned away, body language suggesting this was no time - no time at all - to engage in a debate on the esoterics. ................." David S. Harvey |
Dave,
The original date communicated to subs when the program started was actually mid 2006. |
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