Abstract: A cooling system for an aircraft comprises a gas turbine engine, an ancillary apparatus, and a heat exchanger. The gas turbine engine comprises, in axial flow sequence, a compressor module, a combustor module, and a turbine module, with a first electric machine being rotationally connected to the turbine module. The first electrical machine is configured to generate an electrical power PEM1 (W). The heat exchanger is configured to transfer a total waste heat energy Q (W) generated by the gas turbine engine and the ancillary apparatus, to an airflow passing through the heat exchanger, and a ratio S of: S = ( Total ? Electrical ? Power ? Generated = P EM ? 1 ) ( Total ? Heat ? Energy ? Rejected ? to ? Airflow = Q ) is in a range of between 0.50 and 5.00.

Abstract: An aircraft gas turbine engine includes a heat exchanger module, and a core engine including an intermediate-pressure compressor, a high-pressure compressor, a high pressure turbine, and a low-pressure turbine. The high-pressure compressor is connected to the high-pressure turbine by a first shaft, and the intermediate-pressure compressor is connected to the low-pressure turbine by a second shaft. The heat exchanger module includes a central hub and heat transfer elements extending radially from the central hub and spaced in a circumferential array, for transferring heat energy from a fluid within the heat transfer elements to an inlet airflow passing over the heat transfer elements prior to entry of the airflow into an inlet to the core engine. The gas turbine engine further includes a first electric machine connected to the first shaft and positioned downstream of the heat exchanger module, and a second electric machines connected to the second shaft.

Abstract: A set of anti-scuff boots for a tile cutter comprises a pair of loops made from a soft, durable material such as leather for demountably mounting on the breaking wings of the tile cutter. The loops are connected to one another and prevented from sliding off the breaking wings by means of a strap or cord which extends over the handle of the device, preferably resting against a thumb screw in the handle which prevents the cord from slipping.