A series of design variants for securing the nozzle and end closures were discussed at an ad-hoc Chimera meeting between the two project leaders, Howard Smith and Mark Field, on July 7th at PARS HQ. The design variants are available to see in the Chimera Notebook - Closure page.
At this meeting, Design Option #6 was viewed as promising, avoiding large size (38mm) inside or outside threading or the use of circlips. At the same meeting, it was decided that the two core challenges from now on were the Nozzle Design and Injector Design. The focus of work in Chimera will now be upon these two design challenges, as well as experiements in machining plastic rod for reloads. (The idea of using home made reloads with a commercial rocket motor was mooted)