Yes, you'll be pleased to know, I know what the pintle is, I have had to extract it from the motor several times :-) Not straight after testing you'll understand :-)

Compared to a bell nozzle, yes, since it is operating at optimum efficiency throughout the thrust regime.

Absolutely, you're spot on :-) And in fact, the ED nozzle does have a very large area ratio. Even with the large area ratio, the performance gains compared to a bell nozzle should be greater than any mass hits you take by having a large area ratio nozzle in the ED. In terms of how great, that's what the ED rocket test programme that Reaction Engines is carrying out is designed to find out.

1) The graphics were produced a fair while ago. I daresay they could be improved nowadays. Much of the design work is in Solid Works, so I imagine that could be skinned and modeled accordingly.

2) Reaction Engines is focused on trying to develop an SSTO spaceplane, not a Hollywood movie. If the money was available, yes, I'm sure the graphics could be souped up, but when the budget choice is graphics or components for a rocket engine say, guess what wins in a rocket related company that is focused on developing the hardware?

Personally, I would rather trust a company that bring real hardware that has been tested to the table than a company that just has a bunch of gorgeous CG images and PowerPoint slides.

Actually not. Venturestar was a pure rocket SSTO, as opposed to an air breathing rocket SSTO. Big difference. Because it was reliant solely on pure rocket propulsion, the structural mass required materials that were very light, and one of the reasons it wasn't continued was problems with the composite non cylindrical liquid hydrogen tank, which was a major show stopper.

Skylon gains significantly by being able to use an engine that air breaths to Mach 5.5 before transitioning to pure rocket propulsion.

My pleasure. I'm sat here working on calculations connected with the ED nozzle this afternoon (the rocket side of the engine is the part I am lucky enough to work on), and thought it made sense to reply to some of the comments where I could.

As you can imagine, there is a lot more going on behind the scenes than is indicated on the website. The problem is, we are rocket people, not PR people, so getting the word out doesn't come naturally, and we spend the vast majority of our time working on the technical aspects :-)

That's why we are developing the ED nozzle :-)

The ED nozzle is a very efficient nozzle design and provides altitude compensation across the thrust operation range. Part of the engine development at the moment is concerned with development of the ED nozzle for this purpose.

Your understanding is spot on.

Then you may need to work on your reading :-)

The precooler tests were run separate to the thrust tests. The thrust tests were related to the ED nozzle work.

As for the reliability, well when I wrote the test plan for the ED nozzle test engine, I can assure you, that reliability was very much part of the plan.

As for you not seeing any prototype being tested, note the photograph of a rocket shaped object with hot flame coming out of it in the News section?

I'm sorry the photograph isn't any better, but none of us were prepared to step outside the bunker during the hot firings. I'm working on improving the photos taken during test runs.