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Aviation History
1922
1922 - 0071.PDF
FEBRUARY 2, 1922 the model, without the Eggleston Air Cells is 6-3 lbs., so that the landing speed is 56 m.p.h. From the point of view of carrying a heavy load for a given wing area, the Eggleston Air Cells give a decided advantage. The designer of the plane, Col. Thomas L. Eggleston, states that a larger number of cells, namely, 12, were originally to be used in this plane. It is not improbable that this would further increase the lift and diminish the landing speed. Maximum Speed.—The following calculations are based on the wind tunnel results for scale effect: -„, , , 6,000 x 0-78 Thrust at 90 m.p.h. = — x 375 = 19,500 lbs., assuming propeller efficiency of 78 per cent. Lift/Drag ratio of aeroplane at 90 m.p.h. is 5-1 x 1-14, taking the scale correction as 14 per cent. Drag of aeroplane at 90 m.p.h. = 113,000 19,400 lbs., 5-1 X 114 which is a trifle less than the thrust, and shows that the full speed will be 90 m.p.h., with full load. Climb.—The best climbing speed is 63 m.p.h. ; at this speed, the Lift/Drag ratio of the aeroplane (with scale correction of 14 per cent.) is 7-84. Therefore, the drag is 14,400, and the expenditure of -^- = 2,420 h.p. is required to overcome this drag. The total power available is 3,900 h.p., and the difference or excess of power of 1,480 h.p., which may be used in causing the aeroplane to climb. The rate of climb will be 1,480 x 33,000 ,. , — — = 430 ft. per minute. At 6,500 ft. elevation, 113,000 t-> t- >J the rate of climb will be 100 ft. per minute. Range.—The maximum range is attained at an average speed of 65 m.p.h. The power required from the motors is 113,000 X 65 — = 3.53° h.p. 7-4 X 375 X 0-75 oo:> * The fuel consumption of the motors will be 1,800 lbs. per hour. With a fuel load of 28,800 lbs., the range will be :— 28,800 —s— X 65 = 1,040 miles. 1,800 Useful Load and Pay Load.—The preliminary weight esti mate—which should be later checked^by stress analysis and weight estimates—indicates a useful load of 47,800 lbs. If a fuel load of 28,000 lbs. is carried, a pay load of 19.000 lbs. will be left over, or the equivalent of 100 passengers, with allowance for their baggage. General Conclusions.—The general conclusions to be drawn from the test and general consideration of the plane are :— 1. Perfect longitudinal stability is secured. 2. The Eggleston Air Cells improve the lift of a biplane. 3. The Eggleston Air Cells improve the efficiency of .a biplane as compared with a Warren truss strut bracing of the usual type. 4. With the employment of the Air Cells the number of interplane struts can be increased. This has the effect of decreasing the structural weight, since short spans thus become possible. With ordinary construction, short unsup ported spans increase the aerodynamic resistance. In the Egglestos Air Cells, the extra aercTdynamic resistance would be compensated for by the extra lift. There is, therefore, a possibility of keeping down wing weight for large spans. 5. If the structural weight estimated above can be met, the machine should have a maximum speed of 90 m.p.h., a climb of 430 ft. per minute, a landing speed of 45 m.p.h., a useful load of 47,800 lbs., and a cruising range of 1,040 miles. The consideration of paragraph 4 would indicate that the structural weight of the wings can be kept down. The stability is good.J <t> <$> Aerial Service for Queensland MANY of the railways of Queensland lead to " dead ends," which are but imperfectly linked-up, if at all, by road traction. But that, according to the North Queensland Register, will soon be altered by the Queensland and Northern Territory Aerial Service, Ltd. The ultimate idea is to establish an aerial service from either Bourke or Mungindi, in New South Wales, to Darwin, in the Northern Territory, linking up with the heads of the Queensland railways at Charleville, Blackhall, Longreach, Win ton, and Cloncurry ; but the immediate object is to get the company floated so as to tender for an aerial mail from Charleville to Cloncurry, which is to be subsidised by the Commonwealth Government. The subsidy will pay for the running cost of the service, provision having to be made for carrying 100 lb. of mail 6. The fuel load allowed for gives the machine a cruising range of over 1,000 miles, which is more than ample for any overland travelling; with a pay load of 19,000 lbs., the machine should be a most practical aeroplane of undoubted possibilities in commercial transportation. Eggleston Model Test with Cells Curtiss 7-ft. Tunnel October 12, 1921 1 —6 —4 —•3 —2 —1 o 1 2 3 4 6 8 10 12 14 16 iS 20 i —6 —4 —2 o 2 4 6 8 10 12 14 16 18 i —6 —4 —2 o 2 4 S 12 16 iS 20 D30 •268 •185 :-i58 •143 •135 •138 •159 •178 : -206 •240 •295 •375 :-488 •593 : -700 •837 •979 Do 0-448 0441 0'439 °-437 o-434 0-431 0-429 0-425 0-422 0-419 0-414 0-408 0-401 o-393 0-387 0-380 o-373 0-367 MM —1 -6o —1-45 —1-33 — I-2I 1 -04 —000 —0-33 o 0 1 1 2 2 D30 •286 •218 •190 •177 •180 1 • 205 I-325 1-490 1 -706 1-855 2-080 DsJ0 0-646 0-636 0-633 0-633 0-633 633 635 635 630 630 625 0-610 0-605 o-595 0590 0-585 0-580 °-575 Mo 32 32 D50 0-384 380 337 376 375 373 37o 367 362 o-358 o-354 0350 0-340 0330 0-324 0317 0-310 0304 L30 0341 1-031 22 69 09 72 12 80 32 Do 0-450 o-445 0-440 o-435 0430 0-423 0-410 0-396 0-382 o-375 0-369 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 • 1 • Ljo 049 1-15 1 2 2 3 4 5 e 6 I • 1 2' 2' 2' 3' 3 3 4 5 5 6 6 7 V 7' M,3o 26 20 20 32 30 30 35 50 52 52 53 5.5 56 34 7° 042 43 72 16 52 90 61 33 81 35 65 10 30 10 Lo o • 490 0-490 0-485. 0-485 0-480' 0-480 0-480 0-480 0-480 o-475 0-470 0-470 0-470 0-480 0-480 0-470 0-470 0-470- M50 32 •32: >-32 69 32 98 7i 85 '77 '4§ •60 6-55 •Lo 0-50 5i 50 50 49 49 48 48 47 47 47 Main Dimensions and Characteristics 255 ft. Span of upper wing Span of lower wing Chord of both wings Gap Length over all Total wing area Gross weight—loaded Total power (8 750 h.p. Wing loading Power loading First Rough Weight Estimate Structural weight—37-4 per cent. ' W" motors) Power plant Useful load 223 ft. 25 ft. 25 ft. 137 ft. 11,200 sq. ft. 113,000 lbs. 6,000 h.p. 10 • 1 lbs. per sq.it. 18.8 lbs. per h.p. 42,200 lbs. 113,000 lbs. 23,000 lbs. 47,800 lbs. <$>• <«> matter.. On this Charleville-Cloncurry service, representing a distance of 570 miles, the estimated revenue from subsidy and passengers' fares is ^20,700 a year, while the expenditure, including depreciation, is estimated at ^12,175, leaving a balance of profit of ^8,500. _ Portuguese Award for Two British Seamen The Portuguese Government Gazette contains a decree, signed by the President of the Republic and the Minister for Marine, awarding a silver medal for courage and humanity to Frank Ellis and Charles St. Clair, master and first mate respectively of the British steamer " Gambia River," for saving the lives of Captain Brito Pais and Lieutenant Jose Beires when their aeroplane fell into the sea near Madeira on October 18, 1920.
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