Abstract: An explosive device is provided, containing an explosive formulation or explosive ink, which is capable of being disposed of onto a substrate for the device by well known printing and depositing techniques, such as screen printing, ink jet printing or gravure methods. The formulation contains an ink resin binder, a metal and a non-metal in particulate form where the diameter of the particles is less than 10 ?m, such that when the formulation is heated, a reactive output results. The substrate can be chosen from any inert material or alternatively an energetic material for which the formulation provides a means of initiation. Preferred metals are aluminum iron or titanium and non-metals are carbon, silicon, boron or metal oxides such as copper oxide, nickel oxide or molybedenum oxide. Devices according to the invention may take the form of a; pyrotechnic train, initiators, fuseheads, initiators for gas generators, microthrusters, and may form part of a larger system containing energetic materials.

Abstract: A gas turbine engine for a compound helicopter comprises a core gas generator, an upstream fan, and a power turbine. Bypass air is selectively directable to either augmentor wings, or to a second power turbine which is mechanically coupled to the first power turbine.

Abstract: A nozzle for a gas turbine engine having a first fixed petal 44 and a second movable petal 46 which is pivotally mounted at a point intermediate its leading edge 46(a) and its trailing edge 46(b). Actuation means 48 are provided to move the nozzle between a first and a second position. In the petals first position, its leading edge 46(a) is positioned forward of and slightly radially inward of the trailing edge 50 of the exhaust duct 52, such that a small ejector gap 54 is provided therebetween and the trailing edge 46(b) approaches the trailing edge 44(b) of the fixed petal, such that the gap therebetween defines the exit area of the nozzle 36. In the petals second position (shown dotted), its leading edge 46(a) is moved radially inwards of its trailing edge 46(b) such that the exit area of the nozzle is defined by the area between the trailing edge 50 of the exhaust duct 52 on the second petal side and the trailing edge of the first petal 44(b).