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Aviation History
1946
1946 - 0553.PDF
JOURNEY TIME FOR 6.60O MILE TRIPWITH I STOPS OF ONE HOUR EACH -HRS. 26 , zk , 22 I » , I 18 ,1 16 FLIGHT Fig. s. Direct opera-ting cost per ton- mile of pay loadplotted against effec- tive cruising speed. 283- Fig. 6. Earningcapacity, or the ton- miles of pay loadthat can be shifted per annum per air-craft. 300 350 400 EFFECTIVE CRUISINC SPEED M.P.H. 3OO 35O 4OO 45O 5OO EFFECTIVE CRUISING SPEED M. P. H. 550 25,000 2O.OOO Along the bottom of the graph of Fig. 5 has been put a scale of total time for a journey of 6,600 miles in three hops, allowing one hour on the ground per stop. This is about the distance to South Africa or South America, and half the distance to Australia. This scale has been included because it is really time saved rather than cruising 'speed for which the passenger is paying. In connection with Fig. 6, operating costs have been calculated as in the feeder-line type, but maintenance cost per unit of airframe weight and engine power has been increased by 33 per cent due to greater complexity. Crew cost has been raised appropriately; insurance raised to 12 per cent; first cost of airframe per unit weight in- creased by 20 per cent, and spares allowance increased to 30 per cent. A utilization of 3,000 hours per annum has been assumed. . The characteristics of trans-oceati and long-range aircraft are plotted in Fig. 7. For operating from trans-ocean air- ports, wing loadings can be allowed to go up to 80 lb/sq. ft. and take-offs to about 2,000 yards to clear 50ft. Fig. 7 shows curves of pay load against still-air range for several aircraft of fixed weight and size. The fuselage capacities have been adjusted to their pay loads along the curves, so that any point on a curve is an aircraft designed to carry that particular pay load over that particular range. Mr. Clarkson said he could not see that still-air ranges of much more than 5,000 miles were of much practical value, but it seemed quite possible to do 8,000 miles with 35.OOO 3O.OOO - 5,000 15,000 pisTON ENGlk? IO.OOO Au.W-LB. 124,000 W/B.HP 4-85 PL/Au.W. 180% INITIAL CRUISING,-___ ALTITUDE-FT. M.OOO A.U.WI W/B.H. RLA 100,000975 RLAaW. JZ-SSfc MTTIALCRUISNC ALTITUDE-FT. &3S- 25.000 20,000 315,000 Au-W-LB. 125.00O W/B.H.R 2-75 RL/A.UW. ISIS, INITIAL CRUISINC ALTITUDE-FT. > , f PHOPELUR-DRIVINC AXIAL GASTUR8INES 510,000 600 AJJ.W-LB. 100,000 W/B.H.P. 11-5 P.L/A4I.W. 13S% INITIAL CRUiSINC ALTITUDE-FT. Au.W-LB. IZJ.OOO W/B.H.P. 80SRL/AJI.W. 8-i% IMITIAL CRUISING „„,„ALTITUM - FT. 35.000 Fig. 4. Effect of cruising speed on pay load with various engines in aircraft of a given size. 25OO 35OO 45OO 55OO 6SOO 75OO 85OO 30O0 4.OOO 5OOO 6OOO 7OOO 8OOO STILL:AIR RWGE— MILES Fig. 7. Curves of pay load against stili-air range for severallong-range aircraft of fixed weight and size. reasonable economy, as indicated by the figures of payload /a.u.w. per cent marked along the curves. If the 5,000 miles was the practical commercial maximum the straight- forward turbine-airscrew combination could make a very good showing, and it might be asked whether commercial aviation could profitably use the more advanced forms of heat engines giving specific consumptions of 0.3 lb/b.h.p./hr. MINISTERIAL CREED WE believe in flying boats," said Mr. Ivor Thomas at acivil aviation dinner given by the Knights of the Round Table Club in London on March nth. He added thatsuch a belief was natural in a maritime nation. Viscount Bennett, the former Canadian Prime Minister, presided at thedinner, which was attended by a large number of prominent people in the civil aviation world. So far as civil aircraftwere concerned, Mr. Thomas estimated that in three or four years' time this country would be able to hold its own withany other country in the world, in spite of the fact that the designs for the majority of aircraft nowadays were out of datewhen they left the drawing board. On the subject of airfields, he suggested that the outlook forHeathrow was not so black as was often painted, and that an announcement could be expected shortly regarding the generalairfield pattern for the U.K. Other speeches were made by Sir Frederick Handley Page, Sir Bertram Jones, Mr. A. C. R.Carter, and Wing Cdr. Geoffrey Cooper. LOSS OF SHETLAND I THE chief inspector of accidents, Air Ministry, has nowissued the results of his enquiry into the loss by fire, on January 28th, of the Short Shetland flying boat at its mooringsoff Felixstowe. He has reached the conclusion that the fire was caused by the overheating of the auxiliary engine in thehull. This appears to have been caused by the omission of the leading aircraftsman to open the cooling shutters when start-ing the engine on the morning of January 28th. The two leading aircraftmen who were on board were unable to preventthe fire from spreading, and the Shetland sank. It will be recalled that the Shetland was undergoing tests atFelixstowe at the time, many of which had been made while others were to follow. The loss, although serious, is not irre-mediable as a second boat is fairly far advanced at the Roches- ter works of Shorts.
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