ACAP was created to demonstrate the benefits of a fully composite airframe structure. The goal of which was the development of an all-composite helicopter fuselage considerably lighter and less costly to build than predominantly metal airframes in support of the Light Helicopter Experimental (LHX) program.
(See Wikipedia)
Below is a page on the Bell ACAP from a 1983/84 Bell Helicopter Textron Reference Guide:
-- Edited by Stingray on Sunday 27th of December 2015 01:33:23 PM
I remember a mention of Boeing-Vertol having "something" to do with the ACAP program, but I had no idea they actually submitted their own proposals and design studies for an ACAP airframe. Though, it does make sense recalling the fact they also had their hands in the LHX studies.
Thanks for posting, and please send my thanks to Mark for the wonderful documentation.