Patent GB-546572-A (GB)
Title: Improvements in or relating to aircraft launching apparatus
IPC: B64F1/06
Filed: 1941-04-28
Abstract: 546,572. Electric traction. GILLESPIE CO., T. A. April 28, 1941, No. 5483. Convention date, April 17, 1940. [Classes 104 (ii) and 104 (iii)] [Also in Group XXXIII] Aircraft launching apparatus comprises a runway along which the aircraft is accelerated by an electric induction motor device, the primary and secondary elements of which are arranged one on the aircraft or a trolley connected thereto and the other along the track, a generator being provided to supply three-phase alternating current of gradually increasing frequency and voltage to the primary element. For use on a warship the runway comprises a structure 5 provided with angle members 22 carrying series of upper and lower rollers 20, 21 between which run the flanges 26 of Z-members 13 secured to struts 9 extending between the floats of an aircraft. A primary element 28 consisting of slotted laminations in a series of sections is clamped between angle-irons 32, copper conductors 30 being wound within the slots. The secondary element comprises a single section 15 clamped to the Z-members 13 and has a squirrel cage winding composed of transverse copper bars 17 and longitudinal strips 18. The spacing of the slots in the primary element is slightly greater than the spacing of the bars 17, Current is supplied to the primary windings from a three-phase generator driven by an electro-motor which is speeded up as the aircraft is accelerated. A portable launching way for army use is described comprising a series of track sections on which runs a trolley supporting the aircraft to be launched. The primary elements are rigidly secured to the track sections and their windings are connected by detachable bonding devices. At the end of the run the current through two of the three leads is reversed in order to brake the trolley, and a buffer stop is provided at both end sections of the track. The trolley may have ordinary flanged wheels running on Vignolessection rails or it may be provided with rollers engaging between upper and lower flanges on the track. Fig. 8 shows a rail joint for connecting the rail sections together. It comprises a fish plate 58 with integral bolts 59, passing through the rails and a companion fishplate, to receive wing nuts 60. Current may be supplied to the whole of the primary windings simultaneously or it may be fed to successive sections by switches which are manually controlled or automatically actuated by a timing device or by the passage of the aircraft. For more permanent use on an aerodrome the track, which may be longer than those just described, is sunk underground, and the trolley running thereon has a pillar extending through a slot at ground level where connection is made directly to the aircraft or to a second trolley running on a separate track. In this case the primary element is carried by the underground trolley and current is collected from conductors in the conduit. Reversal of current for braking the trolley is effected by a switch actuated by trip gear towards either end of the track. The launching device may be run in either direction.