Looks like Model Engineering of Norwalk (M.E.N.) is long gone. The copy right for the instruction manual is probably not an issue, especially since OP is just wanting a copy for personal use. Since this is an antique/golden age design you might have better luck over in the golden age forum on this site. Your best bet is finding a collector with a complete kit.The Bombshell is an old design dating back to around 1940 and there have been several variants and sizes of the basic design. Looking at one of the plans sharing websites shows five different variations, at least one of which has a build article that would at least help with setup and balancing. Apparently there is a manual since it is pictured in several old ads for collectible kits that a google search revealed. I do agree with rgburrill when it applies to current production kits and plans but not such a big deal when it comes to a 35 year old kit that came from somebodies' closet.