Is the prototype still @ Langley? Or did they once again destroy a piece of aviation history? Anyone have a lead on its whereabouts?

Don't know if Don's still interested, but there IS now a resin kit of this aircraft. I'd advise reading this review and thinking carefully about it though:

http://modelingmadness.com/scotts/viet/us/xfv12.htm

And if XFV-12 had been successful, the USN would have trouble beating Argentina. Thanks for the explanation, Captain. Know anything about the Avenger?

Should have added the '1591 mph' obviously didn't come from Navy as we measure speed in knots (and/or Mach). I dont recall that value -- probably a projection for an operational jet -- but truth is, I continue to tussle with those who add hyperbole to system description.

...and Don -- the only model I ever saw was a few 1:48 desktop display models. Good luck of you plan to build one.
CAPT Ern Lewis, USN ret

Perhaps I can shed a bit more light on the XFV-12 Project for those who are interested. After 15 years as a jet carrier pilot -- including a combat tour in VietNAM -- I earned an MSAE and was accepted into the Aeronautical Engineering Duty Officer corps. In my first PM assignment I was assigned to head the XFV-12 Project during the Test & Evaluation Phase -- after the prototype was built -- and headed it for about 18 months from late 1977 through early 1979.

Mr Rudnicki's comments seem a bit simplistic -- and are not strictly speaking true. The research objective was to explore the concept of THRUST AUGMENTATION using momentation exchange. Basically the design concept was a 'jet pump'. Of course we have used jet pumps for many years to move fluid -- but the notion of augmenting thrust through momentation exchange had not been tried in an experimental aircraft.
The "...tin-bangers" were dealing with titanium ducting -- and the "...plumbers" and "...guys that drive the train" were struggling to package high thrust ducted flow and modulated flow mixing to exchange the momentum and entrain more mass [F=MV] to achien=ve augmented thrust and vector it down to achieve veriical lift -- while controlling the roll,pitch,yaw,lift, surge and slip by modulating differentially the wing and canard augmenters.
Within a week after I assumed the job, I was thoroughly briefed on the problems. Both the Navy and Rockwell well understood the duct losses -- and were trying to reduce duct losses, mixing losses and reduce weight -- as we were all acutely sensitive to the risk that the prototype would not generate enough thrust to lift off vertically.
The project had several other research objectives but ALL knew the vertical lift tests -- which were conducted at NASA Langley in 1978-79 -- were a one-shot deal.

The technical challenge was being exercerbated both by political issues -- by legitimate concerns that this project had been pushed too fast and was being used as a rationalization to reduce the funding for upgrading the big-deck aircraft carriers.
So the problems were not simply technical.
If you were there during the test program, I must appologise as I don't recall your name. I should say the then Commander of the Naval Air Systems Command, VADM FC Peterson (who was the first Navy pilot to fly the X-15 as a young test pilot) understood R,D, T &E very well. He convened a panel of top scientists and engineers (including the late Dr Hans von Ohain & Dr. Bill Sears) to work with our engineers --and ALL agreed we were at one of the more murky edges of aero science at that time -- given the complexity of the control surfaces, ducting and system desgned to integrate flight controls from VTOL through STOVL transition to CTOL were NOT trivial. Even the JSF today is still struggling to optimize the control balance.

Actually the XFV-12 did get off the ground -- and was tested in a tethered mode. 'Twas an interesting and educational FIRST PM & I co-authored a paper on the PM aspects. We must recall this was a technology research and development prototype -- and many experimental aircraft prototypes in the past that have not flown have still taught us lessons -- hence the designator "X" FV-12.

The comprehensive tech report added to the technology base that has led us to the Joint Strike Fighter.
Ern Lewis

Somebody made a model of this thing. They didn't have any good tin-bangers or plumbers or those guys that drive the train, engineers, to explain ducting losses. It never got off the ground. 1591 mph? It didn't even move.

oh i just like this aircraft to me it has special design features. i'm trying to find out if anyone ever made a model of this.