I had the Bob Fiorenze variable outlets on my YA F-18 single (which was orginally Bob's plane). They worked really cool, although it either required a mix in my radio to use or else just manual actuation for show. I'm not sure if they made much of a difference in real world performance on the plane. They definitely looked cool, and I don't see why a similar setup wouldn't work for a turbine jet if the material was changed to something that could withstand the heat. I've attached some pics.