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Aviation History
1917
1917 - 0381.PDF
APRIL 19, 1917. A NEW PROPELLER SHAPING MACHINE. WHILE laminated wood propellers are being employed on air-craft the amount of work involved in making a propeller is very considerable, and as the degree of accuracy demanded ishigh it follows that, where made by hand, highly skilled labour is essential. At the present moment the supply of suchlabour is by no means unlimited, as any propeller manufac- turer can testify, and therefore any machine which will per-form a certain amount of the work that would -otherwise have to be done by a skilled workman is entitled to con-sideration. Such a machine is the " Excelsus" propeller shaper illustrated in the accompanying photographs. Fundamentally, the " Excelsus " is constructed on the well-known principle of the copying machine, but the design is so ingenious that it will reproduce either a two-bladed or a four-bladed propeller from a single-bladed metal pattern. The propeller to be shaped is supported by its boss from two pro-jecting wings on the large driving cylinder. This is accom- plished by means of a single bolt, and the operation onlyrequires a couple of minutes. So firmly is the propeller held in tliis central support that it is scarcely necessary to support is of the same length as the horizontal arm that carries thetracer wheel, the propeller will be shaped exactly to the dimen- sions of the pattern. The centre on which the two wheelsoscillate consists of a threaded shaft of large diameter secured at each end to the main framework of the machine. Thisshaft forms the only sliding surface, and is, of course, perfectly true. On the spindle of the shaft of the cutter wheel is aworm which causes a nut carried by the central boss of the rocker bracket to revolve slowly on the threaded shaft, thuscausing the cutter to travel the length of the propeller blade. By moving a lever on the vertical arm the feed speed can bevaried, and an arrangement in the arm itself disengages the nut when it reaches the end of its traverse. A few turns ofthe hand wheel at the right hand end of the machine brings the cutter back to the tip end of the propeller, ready forshaping another blade. The cutter wheel is driven from a pulley on a shaft inside Front view of the " Excelsus " propeller shaping machine, showing cutter wheel and mounting of propellerin driving cylinder; and, on the right, rear view of the machine, showing metal pattern and tracer wheel. the ends, but in order to guard against any ill effects ofvibration of the extreme tips during machining these are firmly held in a thimble-shaped centre which revolves insidea ball thrust bearing. The centre is adjustable longitudinally so as to take propellers of different lengths. The metal pattern to be copied is mounted on the oppositeside of the machine, and is made to revolve at the same speed as the propeller by means of worms on a common drivingshaft, the gearing being such that for every 60 revolutions of the shaft the propeller and pattern each make one revolution. The cutter wheel and roller or tracer wheel are mountedon opposite arms of a rocker, and as both wheels are of the same diameter and the vertical arm carrying the cutter wheel the frame. This pulley travels with the rocker bracket, andany accident to the belt instantly stops the traverse, so that no damage can be done to the blade being shaped. Thewhole operation of shaping a blade can, if desired, be done in one cut, and only takes from 40 to 60 minutes, according tothe length of the blade. As the operation is exactly the same for each blade it follows that all blades are exactly alike inevery respect, a feature difficult to attain by hand labour. The " Excelsus" propeller shaping machine is designedand built by the Kerr Pattern Co., of Lincoln, from whom further particulars can be obtained, and who will be pleasedto show the machine in operation to anyone,,interested. Fatal Accidents.Two aviators, one of whom was Lieut. J. A. Williamson, were killed in Leicestershire on April 10th. A machine wastravelling very fast and high, when it suddenly started spiralling and descended rapidly. Something was observedto fall from the machine, which proved to be a passenger. The machine, with the pilot strapped to the seat, crashedinto a field about 100 yards from where the passenger fell. 2nd Lieut. Hugh Howells, R.F.C., was flying an aero-plane at rather low altitude in an Eastern County on April 10th, when the machine fell, struck a corner of a build-ing, and burst into flames. The officer was so badly burned that he died in a neighbouring military hospital during thenight. At a hospital in th£ Lincoln district on the 12th inst. aninquest was held on Capt. P. A. Kirkup, R.F.C. He was practising attacking at a great height when the machinegot into a spin and crashed to the ground. Capt. Kirkup was an experienced pilot, and had flown in France as anobserver. A verdict of " Accidental Death " was returned. At Marylebone, on April 13th, an enquiry was held concern-ing the death of Capt. S. E. Lukyn, M.C., Royal W. Surrey Regt., who died in the R.F.C. Hospital, Bryanston Square,as the result of injuries received in an aeroplane accident. The mother stated that her son had been learning flying for10 days, and had been up on several occasions. Major Macdonneli O'Malley said the greatest care wastaken with every flying pupil, and only expert flyers were sent up to give instruction. Capt. Harrison, the pilot andinstructor on this occasion, was an expert, with experience in France and in England. The machine in which he andCapt. Lukyn were flying was a brand new one, and had only- been in use for 10 days. The enquiry was adjourned untilJune 4th for the attendance of Capt. Harrison, who is in hospital suffering from severe injuries. Prominent German Pilots Killed. REPORTS from Berlin state that Lieut, von Rendell, whosucceeded Immelmann as the chief pilot of his squadron, was killed recently while attacking a French aeroplane overCambrai. Lieut. Frankl, who was promoted by the Kaiser from the ranks last year w'hen he had brought down fourhostile machines, and was subsequently given the Order Pour le Merite, has been killed on the Western Front. FirstLieut. Hans Berg is also reported to have been killed in a fight with two Allied machines. It was announced onTuesday that Lieuts. Schulte and Baldamus had been killed in air fights over Cambrai. 381
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