An inner coating layer for solid-propellant rocket engines, constituted by a material comprising from 45% to 55% wt. of a a cross-linkable, unsaturated-chain polymer base, from 11% to 13% wt. of silica, from 15% to 25% wt. of vulcanizing agents and plasticizers, from 5% to 7% wt. of aramid fiber and from 10% to 15% wt. of microspheres made of a material selected among glass, quartz and nano clay, having diameter lower than 200 μm, density comprised between 0.30 and 0.34 g/cc and resistance to hydrostatic pressure greater than, or equal to, 4500 psi.

The invention relates to a method for assembling a first metal part with a second part made of an organic matrix composite material, the first part having a first connecting portion and the second part having a second connecting portion, the method comprising the steps of: causing the first connecting portion and the second connecting portion to overlap, a through-hole of the second connecting portion opening onto the first connecting portion, forming a protective layer on the side wall of the through-hole, forming a seal between the protective layer and the first connecting portion, and forming, by additive manufacturing using cold gas spray deposition of metal powder, a fastening element which extends into the through-hole, is fastened to the first connecting portion and encloses the second connecting portion.

Piece comprising a first metal part and a second part in organic matrix composite material, wherein the first part has a first connecting portion and the second part has a second connecting portion, the second connecting portion having at least one through-hole, the second connecting portion being totally or partially sandwiched between the first connecting portion and a metal fastening element, the fastening element being fastened on the first part both onto the first connecting portion via the through-hole of the second connecting portion and onto a portion other than the first connecting portion, whereby the first part and the second part are fastened to each other.

A solid propellant propulsion motor may comprise: a forward propellant grain extending along a longitudinal axis of a motor case between a forward end of the motor case and a first burn inhibitor layer in the motor case; the first burn inhibitor layer disposed axially adjacent to the forward propellant grain; an aft propellant grain disposed axially adjacent to the first burn inhibitor layer; a second burn inhibitor layer disposed axially adjacent to an aft end of the aft propellant grain; and an ablative material layer disposed on a radially inner surface of the aft propellant grain.

A rocket motor has an energetic material between solid fuel (propellent) and a casing that surrounds the solid fuel. The energetic material is configured to be burned along with the solid fuel during normal operation of the rocket motor to produce thrust. The energetic material can also be detonated to cause rupture of the casing. The detonation may be initiated as part of a flight termination process. The detonation may also be initiated as a part of process to prevent as a higher-order reaction, such as in reaction to heating from a fire or other cause. The energetic material may be arranged to function as part of a shaped charge, able to split the casing when detonated. By being located inside the casing, the energetic material does not adversely affect aerodynamics of the flight vehicle of which the rocket motor is a part, such as a missile.

A precursor composition comprising, before curing, ethylene propylene diene monomer (EPDM), zinc oxide, silica, polymerized 1,2-dihydro-2,2,4-trimethylquinoline, a solid chlorinated paraffin, stearic acid, a five carbon petroleum hydrocarbon, trimethylolpropane trimethacrylate, and a peroxide. A rocket motor including a reaction product of the precursor composition and a method of insulating a rocket motor.

A precursor composition comprising, before curing, ethylene propylene diene monomer (EPDM), an aramid, and a carbon material comprising carbon nanotubes, graphite, or a combination thereof. A rocket motor including a reaction product of the precursor composition and a method of insulating a rocket motor are also disclosed.

A preceramic resin formulation comprising a polycarbosilane preceramic polymer, an organically modified silicon dioxide preceramic polymer, and, optionally, at least one filler. The preceramic resin formulation is formulated to exhibit a viscosity of from about 1,000 cP at about 25° C. to about 5,000 cP at a temperature of about 25° C. The at least one filler comprises first particles having an average mean diameter of less than about 1.0 μm and second particles having an average mean diameter of from about 1.5 μm to about 5 μm. Impregnated fibers comprising the preceramic resin formulation are also disclosed, as is a composite material comprising a reaction product of the polycarbosilane preceramic polymer, organically modified silicon dioxide preceramic polymer, and the at least one filler. Methods of forming a ceramic matrix composite are also disclosed.

A precursor formulation of a liner comprising a polymer and at least two curatives is disclosed. One of the at least two curatives comprises a curative formulated to preferentially react with the polymer and the other of the at least two curatives comprises a blocked curative formulated to be substantially unreactive with the polymer. A method of lining a rocket motor is also disclosed, as is a rocket motor including the liner.

A multi-component structure includes a first hybrid metal composite structure, a second hybrid metal composite structure, and a joint structure. The first and second hybrid metal composite structures include layers, each layer comprising a fiber composite material structure including a fiber material dispersed within a matrix material and at least one metal ply located between layers of the layers. The joint structure extends between and connects the first hybrid metal composite structure and the second hybrid metal composite structure. Additionally, the joint structure exerts a clamping force on the first and second hybrid metal composite structures and to reduce gaps between the layers, between the layers and the at least one metal ply, and between the joint structure and the first and second hybrid metal composite structures to less than half a thickness of the at least one metal ply.