" BERP Plate "
Peter, you made me " burp " with that one! The S-67 swept tip first flew in 1970, long before the BERP blade flew. The UTTAS tip was pretty much a copy of that idea, and applied to the UTTAS design for generally the same considerations, and also in consideration of a bit higher tip speed as well.
Sans, cannot concur with the assumption that had they flown much longer the tip assembly would have departed. That assembly stands on its own structurally and has been flight tested to 3.53 G and a free stream mach number of 1.0. Auto Nr to 125%. The structure was initially designed to be field replaceable ( rather than run a spar all the way to the tip as in the UH-1 ) as it was accepted that the Army tactical environment would inevitably lead to tree strikes. ( Subject of an intense internal trade-off during UTTAS design phase in-house ). Never say never in aviation discussions, but the background indicates the tip cap wasn't going anywhere in the immediate future.
Last edited by JohnDixson; 12th Dec 2014 at 15:15.
Reason: Added info, words.