Graham-nice work on both-though I can't help thinking that you've replaced one minimalist AP 15 muffler with an equally minimalist OS one!

As for the V7 I am working on a similar project-but for F/F rather than R/C so I will be trying to see how big a bore venturi I can get away with, and simply use a smaller spinner on the 4mm prop shaft a la Cox. I'll make up something similar to a Cox Conquest venturi for it ultimately-after I've tried a few different diameters out. I have a turbo 074 head from Ronald Valentine plus a std plug adapter from Mecoa, so a lot of plug experimentation is on the cards. The V7 seems to be fitted quite well, and not as tight as some of the Revlite AMEs-and sports a bushed main bearing as well. I was a bit chary of the clutch plate housing but it seems to hold OK and with the front face knurled should make an acceptable- if not very elegant- prop driver. I think it will be quite potent on a Master 7x3 or APC 6.6x2.9!

'ffkiwi'