So I have one of these I'm getting ready to start working on the fin can for, made a few mods when I ordered the kit. I upped the MMT to 75mm, the fins came stock (roots for 54mm MMT), so far I'm NOT planning to trim the roots, the extra bit of 'flat' fin at the top & bottom of each fin should be covered by my fillets so I don't think I need to take any action here (and for other reasons pulling the Cp back a bit seems like a fine idea). I also had the MMT lengthened and have a TA7539PA tailcone adapter (not as pronounced of a cone since it's only 98->75, not 98->54 like pictured earlier in this thread, but will still look nice I think). This will be my first split-fin, first tailcone and first 75mm MMT (I'm still a L2 and only have 38/54mm cases so far, so it will do a lot of flying with an A5475 adapter at least to start).
But as my first split-fin, I'd really like to get this to whistle. I saw the mention on this thread about the earlier kits having the fins closer together, and have observed that the newer kits don't appear to whistle. I need to widen Madcow's slots so that the fins can actually fit in them anyway, so I'd be happy to shift the upper slots downward a bit in the process. When MC lengthened the MMT for the tailcone it probably wasn't quite enough, there's barely any MMT past the top of the upper slots, so shifting those fins back will leave a bit more room for the top CR which I'd prefer.
Made a few other mods while ordering, I prefer to go for the 'chute cannon' approach rather than separating right above/below the avbay, so I skipped the vent band and just sized the upper tube to include the vent band length (also means I can use a shorter avbay coupler since it'll be epoxied into the upper airframe, I don't need a 9" bay for my redundant electronics). I also ordered an extra coupler, and plan to cut some off the upper airframe (don't need that much space for my chute) and add that length to the lower airframe to accommodate longer motors for when I am an L3 and can stuff bigger motors in this tube.
So I'm wondering, does anyone have an X-celerator that whistles, and if so could they measure the fin gap they have? If not an X-celerator, any other examples of a 4" airframe (Frenzy or the like) with a good whistle and it's fin gap?
