Alpha (K-25)-style Fin Unit BT50 for 18mm

This is a reproduction of the fin plan introduced in the Estes kit K-25. Note this is the full classic swept tapered fin plan first described in pattern sheet SP-25 and definitively dimensioned in Estes Tech. pub. TR-11. I thought it would be fun to make a fin unit out of it, to get folks of the sanding business which is becoming less tolerable these days. What I maintain as charm is not having the 'fin tip-to-root taper' that I commonly use, but describe the fins as per the original kit instructions. They subsequently have the sheet stock thickness look, and having a perfect symmetrical airfoil profile as instructed to shape according to those plans. I have even left out fillets, as the plans pre-date the technique. You can compare this fin unit to my other offering in the PFS-50 ( Alpha 3 )-style fin can that I also reproduce maintaining those classic, though slightly different swept delta lines as well. I hope the purists could appreciate these as much as I do. Enjoy!