Stargazer2006 said:
Well, the Asian-made display models scarcely depict little-known projects or alternate configurations.

Not exactly true. I've seen a lot of oddball stuff offered by such manufacturers on ebay. I suppose they can make a profit off of *one* model sold, so it's in their interest to offer as many types of models as possible.

I went to ebay to find a few such listings to prove my point... but there are *too* *many*. Go to ebay and do a search for VTOL and MODEL. My search produced 47 hits, about half (eyeballing) are the Asian slavemade type, and about two thirds of those are of the "unbuilt projects" variety. A lot of *those* are actually unbuilt *models,* you win the auction, you pays your money, and *then* they go to the bother of building the model. Stuff like the CL-379, the Ryan "VTOL F-104," the Bell "XF-109," c an all be yours if you pay up and wait.
 
Hi,


here is two X-wing concepts,first x-wing single rotor helicopter
and the second is X-wing tandem rotor helicopter.
 

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Regarding the above X-wing model - it, like coca cola, is the real thing. A few tells: the fineness of the horizontal and vertical stabs - tails on the majority of mohogany junkers are obviously out of scale thick and rounded on the leading edge. 2) the decal carrier film is yellowed pointing to age - making this a pre-web era model, after which junk mass production went into high gear. Plus you have to have an "eye" for it - the form on this model is finely proportioned - the lines ring true - this is never the case with the mahogany equivalent to a black velvet painting.
 
Not trying to being a n00b with what are the dimensions of the ''PV5N6B.jpg''' not the file, but the helicopter on it.
 
boxkite said:
Paul, are you sure this one is a Sikorsky proposal? I know this from Interavia 7/1983, described as a Boeing-Vertol concept (however using the Sikorsky X-wing!).

I have found a source calling it "This Boeing Vertol "X"-wing convertiplane..."

I'll soon post this image in color - unless my continued search finds it in another thread.
 
I found this in Airplanes of the Future by Don Berliner, Learner Publications, 1987.

Posting this here because the black and white version is here and I didn't find a dedicated Boeing X-wing thread.
 

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Orionblamblam said:
It looks good, but I can't tell if that's a factory model or a "hand-made with Asian slave labor from gen-u-wine Philipine mahogany" wonder. It's surrounded by a whole lot of the latter:
http://lloydralstontoys.com/jan10/jan10lots3.html


This model belongs to me, it is in my collection. It is 100% a real factory model. I believe it to be from the Sikorsky model shop, which makes it very rare. Made out of heavy resin material, and the antennas are made from brass. It came from the estate of someone who worked in marketing for Sikorsky. There were also a wide range of other sikorsky helicopter models for sale. This was the only in-house model, the rest were made by Microwest.
 
Hi,


a good report about Sikorsky X-wing project.


http://www.dtic.mil/dtic/tr/fulltext/u2/a128959.pdf
 

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Hi,

please see its estimated speed,about 0.89 Mach.

https://apps.dtic.mil/dtic/tr/fulltext/u2/a029168.pdf
 

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hesham said:
Hi,

please see its estimated speed,about 0.89 Mach.

https://apps.dtic.mil/dtic/tr/fulltext/u2/a029168.pdf

That's not necessarily the estimated speed. Mach 0.89 is stated to be the drag-divergence Mach number, which is the speed at which drag begins to increase much more rapidly with increasing speed. The aircraft's speed would depend on the installed thrust. It could therefore be more or less than Mach 0.89 (the F-4 Phantom's drag divergence Mach number is also on the order of Mach 0.9).
 
hesham said:
a good report about Sikorsky X-wing project.

http://www.dtic.mil/dtic/tr/fulltext/u2/a128959.pdf

thank you my dear Tailspin.
 

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Есть точные характеристики этой машины?
 
Via google, По английски пожалуйста.
 

At the time of termination the X-Wing technology was still in the development stage. The true potential of the concept was not yet demonstrated in flight. Perhaps some day it will be demonstrated and a mission capable X-Wing will enter service.

Ship 2 then completed ground checkout testing at the Boeing facility in Mesa, Ariz., where it was configured for flight. After a flight readiness review, the vehicle was shipped to Yuma where it completed a preparatory "pop up" flight Nov. 4. The flight lasted only about 30 seconds during which the aircraft stabilized briefly at 16 feet above the ground and then landed. Success with the initial flight led to the hover flight Dec. 2.

Mitchell said that flight tests are expected to continue into early next year. The flight-test schedule calls for 11 flights. Under the remote control of a pilot in a ground station cockpit, the X-50A Dragonfly will gradually perform more extensive hover flights, then forward-moving rotary wing flights.

The test program will culminate with the first ever "conversion" from rotary wing flight to fixed-wing flight and back again to rotary wing flight for landing. The conversion requires the main rotor to stop turning in flight, and lock in place to become a fixed wing for high speed flight.


whatever happened?
 
whatever happened?

Both vehicles crashed, dramatically.
Thank you for the answer, did not know about the second crash.
however, unsatisfying it is not to know why the technology was not furthered. Such a radical technology/capability is going to have many hiccups but the payoff may have been worth it.
 
I'm quite sceptical about the "true potential" of this technology. Apparently x-wing rotors can produce the envisaged thrust/lift. However, controllability and maneuverability may be the real issue. And what about emergency situations? In case of engine failure x-wing aircraft most likely would have a glide ratio like a brick. And autorotation doesn't work as well.
X-Wing-15.jpg
 
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In case of engine failure x-wing aircraft most likely would have a glide ratio like a brick. And autorotation doesn't work as well.
Which is less of a issue then most think.

Especially since it looks like you do something normal helicopters cannot.

Install ejecto seato.

Which goes far for safety. Especially since it be easiler to have the rotor to lock up or explosivily shatter.

Most modern fighters jets are SOL without power. Enough so that the SOP is that if you loss all power punch out.

Cause you are in an unstable design that needs its computers to stay in the air. Those go down? Just pull the level and hope you high enough for the chute to make the landing softish.

Most military helicopters don't even have that and need to have the rotor system intact enough to auto rotate.

Which is often not possible cause the transmission froze up.
 
Fair enough, so this technology is only applicable for combat and not transport aircraft. However, controllability and maneuverability remain a concern.
 
Fair enough, so this technology is only applicable for combat and not transport aircraft. However, controllability and maneuverability remain a concern.
Extremely rapid response sensor based actuation is readily and easily available and a very small scale. IMHO, 2 crashes is a cultural/business/program killer and cancellation of a promising technology i n the West has nothing to do w/ the viability of the technology.
 
Imho, if this technology is viable, we would have already seen a Chinese version orbiting Taiwan ;)

Jokes aside, it's a very tempting technology and I wish someone would have developed a tech demonstrator in the meantime. However, I havn't seen anyone interested in x-wing tech in past decades. Neither private nor governmental.

Btw, it took tilt rotor technology about 50 years to become operational (XV-3 to V-22) and another 10 years to be considered mature.
 
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Imho, if this technology is viable, we would have already seen a Chinese version orbiting Taiwan ;)

..will agree but the above paper was accepted as late as July of last year. There once was an artist rendition of a counter rotating CRW on a Chinese website.

CRW is considered all risk in the Western business model of the aircraft industry and that model is so predominant now that folks have forgotten any other alternative. This has been true since creative risk in aircraft design largely died back in the 90s.
 
It seems unfortunate that they never got to fly the X-Wing prototype in 1987, that Sikorsky program history seems to suggest that they had resolved most of the problems and were ready to go but I'd imagine the actual situation wasn't quite so rosy.

Ultimately the whole concept still looks like a dead-end to me. Seems like compound helicopters and tilt-rotors are better suited to provide an increase in speed over conventional helicopters without having the one of the world's most complicated flight control systems.

Those LHX-related X-Wing designs are sure cool looking though. Looks like they belong in some sort of (good) sci-fi movie.
 
It seems unfortunate that they never got to fly the X-Wing prototype in 1987, that Sikorsky program history seems to suggest that they had resolved most of the problems and were ready to go but I'd imagine the actual situation wasn't quite so rosy.

Ultimately the whole concept still looks like a dead-end to me. Seems like compound helicopters and tilt-rotors are better suited to provide an increase in speed over conventional helicopters without having the one of the world's most complicated flight control systems.

Those LHX-related X-Wing designs are sure cool looking though. Looks like they belong in some sort of (good) sci-fi movie.
What terminates very promising advances.

The lone S-67 prototype crashed while conducting a low-level aerobatic demonstration at the Farnborough Airshow on 1 September 1974. The crew misjudged their pitch in a low-level roll maneuver causing the nose to drop below the horizon: they attempted to recover from their inverted position by performing a Split S maneuver, but they were too close to the ground. The aircraft struck the ground in a level attitude and immediately burst into flames. .... Development work on the S-67 ceased after the accident.[9]
 
From Aviation Week, 02/06/96

DARPA SOUGHT STEALTHY ROTORCRAFT

The former Defense Advanced Research Projects Agency funded at least two secret rotorcraft programs during the 1980s, and at least one of them is still operating. They were low radar cross section technology demonstrators and did not have an operational mission.

The larger of the two was a secret version of the NASA/DARPA/Sikorsky X-Wing Rotor Systems Research Aircraft (RSRA), and it is not clear if a prototype ever flew. The unclassified RSRA X-Wing program was canceled in 1988 after several flights in only its fixed-wing mode (AW&ST Mar. 14, 1988, p. 15; Aug. 31, 1987, p. 23). However, DARPA's secret version of the X-Wing also run by Sikorsky-was a larger program than its unclassified cousin, according to sources familiar with both programs.

THE SMALL ROTORCRAFT is a McDonnell Douglas Helicopters project conducted with the renamed Advanced Research Projects Agency. Configuration details are sketchy, and it is not known if it uses the McDonnell Douglas no-tail-rotor (Notar) technology. More than one of the McDonnell Douglas craft may have been built, and flights are conducted in the restricted airspace of the Nellis AFB range. Tests include flying against radar sites to measure the rotorcraft's signature. The program is considered "extremely black," and the aircraft fly at night or out of sight of uncleared personnel during the day. Flights are scheduled to avoid spy satellite coverage.

It is not clear whether Bell participated in a DARPA stealth helicopter project. One expert noted that the teetering two-bladed rotor used on many Bell helicopters does not adapt itself to stealth. The clearance needed for teetering makes it difficult to closely nest the hub to a fuselage fairing, and the high blade loading is noisier and gives a larger, more visible, rotor diameter. However, Bell has developed helicopters aimed at the special operations market.

The secret X-wing was to use three enabling technologies for low radar signature. One was the X-wing itself. When the rotor was stopped for cruise flight in the "X" position, the 45-deg. angle of the blades reduced radar reflections in the forward aspect, though care had to be taken to prevent the 90-deg. blade intersection from acting as a retroreflector. Also, the stopped blades eliminated the telltale Doppler signature of a helicopter. Equally important, the fixed X-wing allowed for high speed, as retreating blade stall and high tip Mach numbers were eliminated. High speed was the goal of the "white-world" RSRA X-Wing program. Notar-like technology was the second key feature of the stealth X-wing. Eliminating the tail rotor reduces radar signature. However, the Sikorsky design did not use circulation control blowing on the boom itself for anti-torque boom lift, as McDonnell Douglas does with its Notar technology. Instead the stealth X-wing just had thrusters at the tail boom's tip. The RSRA X-wing had a conventional tail rotor.

THE THIRD TECHNOLOGY was an engine that could convert between turboshaft mode for helicopter operation and turbofan for cruise thrust. The convertible engine was a General Electric TF34 turbofan that was tested by the NASA Lewis Research Center (AW&ST Oct. 27, 1986, p. 21). For turboshaft operation, the fan's inlet and exit guide vanes were shut, closing air to the engine's bypass duct and increasing airflow directed through core. The secret aircraft was to use twin convertible TF34s, while the RSRA X-wing used two standard TF34s for thrust and two General Electric T58s for shaft power. The RSRA X-wing program provided an open method to develop the crucial X-wing technology, and provided cover for the broad nature of the classified effort. The white program could order parts for the black program, and vendors would be none the wiser.
 
From: Sharon Weinberger. “The Imagineers of War.”

As DARPA’s black aircraft programs boomed in the 1980s, the agency would often announce a research program in aeronautics as a cover for building a secret military prototype aircraft. This enabled DARPA to award contracts and buy needed equipment without raising suspicion. Atkins described one example of what he called a “White World” program, meaning unclassified, that was run jointly with NASA. Yet the technology was also being looked at for secret military applications. “We built some full-scale models to see how we would militarize it,” said Atkins. The “black” project was a stealth rotorcraft.

The cover project was called the Rotor Systems Research Aircraft/ X-Wing, or RSRA, a joint DARPA-NASA program that funded Sikorsky to design a hybrid of a helicopter and a fixed-wing aircraft. RSRA was a real program, but it was also a cover for one of DARPA’s more significant attempts to develop stealth helicopters. The “black” program involved taking “the rotor head off of the RSRA and putting it onto a stealth vehicle,” Atkins said. A helicopter’s rotor blades typically produce a Doppler shift. Those shifts are difficult to mask from radar, but it could be done, as DARPA learned with the X-Wing.
 
sikorsky_x-wing_01.jpg
spooky x-wing artistic rendering..
 
While it's entirely possible a black program for an X-Wing type design existed at some point I'd have to presume it never went very far considering both the LHX/RAH-66 which was unfortunately cancelled and the existence of some stealthy developments of the MH-60 Black Hawk. If the stealthy X-Wing type design was successful I doubt either program would have been necessary.
 
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