I have been reading old posts by some of you knowledgeable fellows about fast flight string and decided to give it a try.  I made an endless loop string with D-97 , ten strands and double served.  It shoots great on my 62" recurve and I have to say that I should have tried it sooner...  I am hard headed and slow to change.  It seemed a little faster, a little quieter, and less aggravating to break in.  B-50 always has a break in period where I have to adjust brace height a few times as the string is stretched out.  This string was a breeze.  I set the brace height one time - done.    All this is well and good, but I ran into trouble on my next ff string...  
  On my longbows, I have come to appreciate my flemish strings with the loop at one end and the bowyer's knot on the bottom.  It doesn't fall off when the bow is unbraced and I like that.  I couldn't get a bowyer's knot to work with my fast flight material.  The knot kept slipping and I need some advice on how to proceed.  I am sure one of you guys has figured this one out.  What do I need to do?