After trimming the rails a little bit I got on with making the bell mounts. I set the bell centrally to the rails (note that the rails are not central to the turbine as it sits on mounting plates but it's a good start). My approach to finding the centre is set the string out reasonably taught then position the bell mouth until you have the widest width of string covered. Then you have the centre
I'm using the Grumania pipe fitting kit here, which includes aluminium straps that are in a handy size and also pop rivets. After marking the centre point, I create a rivit mark for the bracket.
One rivet would hold the bracket but I'm playing safe and going with two per side. The aluminium strips are easy to work with pliers, but be careful if you bend them too many times in different directions they snap in two - which turns out to be a handy way to adjust to the length you need
After some fiddling around due to the precise fit, the bell mouth is mounted to the pipe and the brackets ready to find a final resting place.
Before I screw the pipe down, I'll make up turbine mounting plates, matching plates for the pipe to get it nice and central to the turbine and also CG the whole plane to the in case I need to locate the turbine forward or aft in the model.
More fun to come...