Forum: X-planes

Even though the X-44 project was cancelled, I'm wondering about the proposed nozzle design that it was to have. I've seen two designs: a round, more conventional nozzle, and a flattened, square nozzle.

The square nozzle intrigues me.

When I look at it, I have trouble understanding how the designers planned on making it actually work. From the images that I've seen, the nozzle looks like a single-piece structure. How would it have vectored thrust like that? How would it have altered its cross section in response to speed and thrust conditions like other nozzles do? Perhaps it was to be made of some elastic material that could deform without the needed for multiple plates or "turkey feathers"?

On a similar note, do any jet nozzles incorporate elastic or flexible materials into their design? Flexible plastics that I'm aware of would melt at jet nozzle temperatures.

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Elite 1K Joined: May 26, 2005 - 08:39 PM Posts: 1496

Kriptid wrote:

When I look at it, I have trouble understanding how the designers planned on making it actually work. From the images that I've seen, the nozzle looks like a single-piece structure.

That's concept art. It's like asking in G.I. Joe cartoons, how does the Cobra Rattler's wing pivot when there's no apparent actuator mechanism.

To your second question, no there aren't any plastic polymers that could withstand the heat from an afterburning turbofan. Even exotics like carbon-fiber reinforced polyetherketones melt at around 700 degrees F.

Was there any discussion about possible nozzle designs for it within the circle where it was envisioned?

I think squire one is the real one. I still don't why it is cancelled? Any reason?

Too public maybe?

I wonder what's really in those wings that such a massive wetted area and essentially unsaveable area rule design is even necessary.

In _The Five Billion Dollar Misunderstanding_, Ben Rich mentioned that Lockheed had materials that 'worked at afterburner temperatures' much higher than 1,400`.

If you want to divert exhaust stream flow, why not use bypass or perhaps fuel base fluidics as ejectors which shape it as a function of thermal response, upstream?

Square nozzles allow much greater diffusion of plume as waste heat (at some cost in thrust efficiencies) so once you create an instream Coanda effect, all's you really need to do, whether it's a conventional condi or some kind of squared off expansion nozzle, is keep the nozzle perimeter evenly thermal as pressure loaded so as to function as an expansion throat leaving the 'insulated' exhaust stream to function as it's own (non mechanical = much lower weight) vectoring agent.

Forum: X-planes

X-44 MANTA TVC Nozzles