The unit on the 255 mph run (by my good friend Larry Jacob) was manufactuered by Paul Ivie (the owner and builder of the fast Ultra Viper).

I have not seen Paul in years so I do not know if he is making them any more or not. They were pretty intircate to build. I had one on my old Viper. It was powered by a big servo, tied to a small computer that sensed airspeed. The faster the model went, the more the computer closed down the nozzle.

In my experience, it did some for the top end, but it did A LOT for the low end, as you could open the nozzle up MUCH more than a standard BVM outlet size, made for very good static thrust.

I have an extra one here somewhere but I would not know where to find it. They were pretty specific to a model, not sure how hard it would be to retrofit to a Cobra.

Speaking of Cobras, I think Russ Talbot still has one in LA, there buys must have put 1000 flights on that one.

Good luck,