Abstract: The invention is an improvement in a lightweight carbon-carbon composite piston, the improvement comprehending the use of near-net shape knitted or warp-interlock pre-forms to improve the structural qualitites of the piston. In its preferred embodiment, a one piece, tubular, closed-ended, knitted pre-form (a sock) of carbon fibers (11) embedded within the matrix of the piston structure forms the crown (12), side wall (15), skirt (16) and inner surface (18) of the piston, and wrap-interlock pre-forms strengthen the piston crown and wrist pin bosses.

Abstract: Cryogenic foam insulation 20 is adhesively bonded to the outer wall of the fuel tank structure 10. The cryogenic insulation 20 includes square sheets 12 fabricated from an array of abutting blocks 14. Each block 14 includes a sheet of glass cloth 18 adhesively bonded between two layers of polymethacrylimide foam 16. Each block is wrapped in a vapor impermeable membrane 24, such as a polyimide-aluminum-polyimide composite laminate, to provide a vapor barrier. Very beneficial results are obtained by employing the present invention in conjunction with fibrous insulation 28 and an outer aeroshell 30, which is a hot fuselage structure having an internal thermal protection system.

Abstract: A composite piston structure is disclosed which provides a simple and reliable means for joining a carbon-carbon or ceramic piston cap 11 with a metallic piston body 13. Attachment is achieved by means of a special geometry which compensates for differences in thermal expansion without complicated mechanical fastening devices. The shape employs a flange created by opposed frustoconical shapes 12 and 19 with coincident vertices 15 intersecting on the radial centerline of the piston in order to retain the piston cap. The use of carbon-carbon for the piston cap material allows a close fit between the piston and a cylinder wall, eliminating the need for piston rings. The elimination of extra mechanical parts of previous composite pistons provides a lightweight composite piston capable of extended high temperature operation.

Abstract: A lightweight piston 12 composed of carbon-carbon is disclosed. The use of carbon-carbon over conventional materials, such as aluminum, reduces piston weight and improves thermal efficiency of the internal combustion reciprocating engine. Due to the negligible coefficient of thermal expansion and unique strength at elevated temperatures of carbon-carbon, the piston-to-cylinder wall 10 clearance is so small as to eliminate the necessity of piston rings. Use of the carbon-carbon piston has the effect of reducing the weight of other reciprocating engine components allowing the piston to run at higher speeds and improving specific engine performance.

Abstract: A daze fastener system for connecting two or more structural elements wherein the structural elements and fastener parts have substantially different coefficient of thermal expansion physical property characteristics is employed in this invention. By providing frusto-conical abutting surfaces between the structural elements and fastener parts any differences in thermal expansion/contraction between the parts is translated to sliding motion and avoids deleterious thermal stresses in the connection. An essential feature for isotropic homogeneous material connections is that at least two sets of mating surfaces are required wherein each set of mating surfaces have line element extensions that pass through a common point.

Abstract: A dual structure aerospace vehicle 10 having an aeroshell structure 11 and an internally disposed separable and reusable integral tank/thrust structure 13 is disclosed. Tank/thrust structure 13 is insulated for cryogenic fuels and the cavity 24 within aeroshell 11 is insulated from the tank/thrust structure (FIG. 2). An internal support ring 26 within cavity 24 serves as attachment for lugs 30 on tank/thrust structure 13 via double hinges 50 (FIGS. 3 and 4). The aft end of tank/thrust structure 13 is provided with rocket engines and exit nozzles 33, 34, 35 with trunnion support 37 supporting the tank/thrust structure within aeroshell 11.

Abstract: A daze fastener system for connecting two or more structural elements wherein the structural elements and fastener parts have substantially different coefficient of thermal expansion physical property characteristics is employed in this invention. By providing frusto-conical abutting surfaces between the structural elements and fastener parts any differences in thermal expansion/contraction between the parts is translated to sliding motion and avoids deleterious thermal stresses in the connection. An essential feature for isotropic homogeneous material connections is that at least two sets of mating surfaces are required wherein each set of mating surfaces have line element extensions that pass through a common point.

Abstract: A novel blind rivet is provided wherein the blind head is upset by a pin driven from the exposed side into a core of soft metal contained by a closed tube end which is selectively thinned to result in controlled deformation due to the internal pressure created by compressing the soft core. The closed tube end upon expanding to a predetermined shape is transformed into the blind head.This rivet offers high strength, leak-free joining. Consistant controlled snug fitting assembly is offered. The rivet is suited to installation by a tool that prevents forming loads from being transferred to the members being joined. Moreover, the rivet has lower weight and cost while providing a smoother exposed surface than prior art blind rivets.