Patent GB-941713-A (GB)
Title: Aircraft provided with a vertical lift gas turbine power plant
Inventor: JUBB ALBERT
IPC: B64C29/00
Filed: 1960-11-18
Abstract: 941,713. Gas turbine plant. ROLLS-ROYCE Ltd. Nov. 10, 1961 [Nov. 18, 1960], No. 39813/60. Heading F1G. An aircraft power plant comprises a plurality of gas turbine vertical lift engines, a fuel reservoir, ducting for supplying fuel from the reservoir to the combustion equipments of the vertical lift engines and priming means which is operable before the starting of the vertical lift engines for filling at least part of the ducting with fuel and for removing air therefrom whereby starting of the vertical lift engines can thereafter be swiftly initiated. Three vertical lift engines 16 mounted in an aircraft are shown in Fig. 2, each engine comprising an air inlet 17, compressor 18, combustion equipment 20, turbine 21 and jet pipe 22, also a fuel control unit 24. Fuel is supplied to the engines from a tank 25 through separate fuel lines 27 by way of a shut-off cock 26; the fuel tank may be pressurised at a pressure of say 1-2 p.s.i. gauge, or alternatively, the fuel tank may be disposed several feet above the engines in which case pressurisation would not be necessary. The highest points of the various fuel lines 27 are connected by ducts 28 to a common line 30 which communicates with the space above the fuel in the tank 25. The ducts 28 contain restrictions 31, and the line 30 contains a vacuum pump 33 and a non-return valve 34, the pump 33 being interconnected with the shut-off cock 26 so that when the cock is opened, the pump is started simultaneously. A relief valve 35 is provided in the line 30 and is adapted to open when the pressure in the line 30 falls below a predetermined value. In the arrangement shown in Fig. 2, no booster pumps are required in the ducts 27, but if such pumps are fitted, the vacuum pump 33 and relief valve 35 are not required but the non-return valve 34 should still be fitted. In the embodiment shown in Fig. 3 fuel is supplied from a single tank 37 to both the forward propulsion engines (not shown) and to the vertical lift engines 16, three of which are shown. Fuel is supplied by means of a booster pump 41 and line 38 provided with a non-return valve 40 to the forward propulsion engines. Fuel also passes by way of a line 42 containing a shut-off cock 43 and non- return valve 44 to branch lines 45 leading to fuel control units 46 of the vertical lift engines 16. A bleed line 52 interconnects the line 38 and line 42 dowstream of the non-return valve 44. The highest parts of the branch lines 45 are connected by pipes 47 containing flow-limiting restrictions 50 to a common pipe 48 which contains two non-return valves 51 in series, the line 48 connecting with the space above the fuel in the reservoir 37. At take-off, the pump 41 is started and the shut-off cock 43 is opened, whereby the forward propulsion engines are supplied with fuel through line 38 and fuel flows to the line 42 partly by gravity and partly through the bleed pipe 52, air in the line 42 being vented through pipes 47, 48. The lift engines may now be started, fuel flowing through the line 42 by suction. After take-off the lift engines are shut down and the shut-off cock 43 is closed, but the line 42 remains primed because of the flow through the bleed pipe 52, the fuel line 42, the branches 45 and the pipes 47, 48 to the reservoir.