suttonr,

There were two different articles in RCJI magazine 2-3 years ago about pipes and in particular the Wren augmented pipe. It would be worthwhile reading for you. My take-away was that a properly sized straight pipe with the right gap can yield zero thrust loss. A Wren pipe done right can give a 5% thrust improvement.

I just completed some preliminary balancing on my F-16 and it looks like I will need about 24 oz. of batteries in the nose to balance it. I plan on putting redundant receiver packs and a nicad ECU battery up there. The plane will come out a little over 20 lbs.

If I had put the engine in the tail I'd need a lot more nose weight. It would really help if FEJ could make some changes to reduce the weight in the back of the plane. As jetmodeller pointed out earlier in this thread the supplied tailpipe is rather heavy (13 oz.). They could have used substantially thinner stainless for the outer wall and saved a few ounces. I'm not sure it is worth the extra cost of buying another pipe though.

Joe