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Langley Memoir on Mechanical Flight, Parts I and II / Smithsonian Contributions to Knowledge, Volume 27 Number 3, Publication 1948, 1911 cover

Langley Memoir on Mechanical Flight, Parts I and II / Smithsonian Contributions to Knowledge, Volume 27 Number 3, Publication 1948, 1911

Chapter 78: DATA SHEET No. 2. Weight of Aerodrome No. 6. Certified to by R. L. Reed, November 27 and 28, 1896.
By S. P. Langley
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About This Book

The memoir chronicles systematic experimental work toward powered, heavier-than-air flight, presenting a chronological account of small flying models, aerodynamic tests with a whirling table, development of lightweight steam engines and launch apparatus. It explains why laboratory measurements differ from free-flight conditions, analyzes equilibrium and center-of-pressure issues, and records iterative trial-and-error design of wings, propellers, and supporting structures. Part of the text compiles detailed test data, field trial reports, and engineering challenges encountered during attempts to achieve sustained, controllable mechanical flight, with editorial additions completing later sections of the experimental record.

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DATA SHEET No. 2. Weight of Aerodrome No. 6. Certified to by R. L. Reed, November 27 and 28, 1896.

Parts. Sizes. Weight.
m. ft. gr. lbs.
1 Frame, including everything of metal, permanent and undetachable, such as bed-plate, cross-rods for the support of propellers, bearing points for clutch, etc. 1178
2 Engine, gears, shafts, etc. 1043
3 Pump, pump shaft 190
4 Hull covering 345
5 Gasoline tanks, valves 306
6 Smokestack, 302; burner, 172 474
7 Float 275
8 Reel 77
9 Wing clamps, 238; drop piece for rudder, 40 278
10 Other things 156
11 Boiler, frames, mica cover 694
12 Separator, steam gauge, pipe to engines 535
13 Exhaust pipe 82
14
15
16
17 Wings (without clamp), wet 2154
18 Tail (without clamp)
19 Rudder 375
20 Guy sticks, each 53 106
21 Propellers 644
22 Extra length of midrod 398
23 Wood bowsprit 135
24 Counter 75
25
26
27 Fuel (at starting flight) 250
28 Water (at starting flight) 2350
29
30
31 Sundries unknown
32
33
34 Total flying weight 12,120
35
36
37
38 Total area of support (not including tail) . . . sq. ft. 54
39 Total area of support in feet, divided by total flying weight in lbs. 2
40 Total area of horizontal tail . . . sq. ft. .6
41 Total area of rudder (vertical) . . . sq. ft. .6
42 Horse-power at brake. . .Horse-power by formula*
43 Minimum steam pressure during 40 secs. lift 130
44 Lift at pendulum (during one minute absolute) 7,211
45 Lift at pendulum (during one minute in terms of wt.)
46 Minimum pressure with which wheels turn 10
47 Position of center of pressure of wings†
48 Time of getting up full steam, 75 secs.
49 Angle of midrod with horizon, 2° 17′
50 Curvature of wings, 1 in 18, 1/4 from front
51 Root angle of wings, 10° 30′
52 Tip angle of wings, 10° 30′
53 Position of wings
54 How guyed
55
56
57
58 Position of tail
59 Angle of tail
60 Co-efficient elasticity of tail
61 Position of rudder
62
63 Line of thrust 1500
64 Center of gravity1 of whole, 1483.8
65 Center of gravity2, 2482‡
66 Center of pressure1 of whole estimate, 1487
67 Center of pressure2, 2520
68
69
70
71
72

Parts. Remarks.

  • 1 Front end of bowsprit, 1797.
  • 2 Center of float in first trial, Nov.
  • 6 Front end of midrod, 1613.7. 9 Front edge of F. W., 1595.7.
  • 12 Center of float in flight, Nov. 28, 1896, 1575.8.
  • 16 C. of P. on F. W., 1563.7.
  • 19 Back edge of F. W., 1515.7.
  • 22 Line through center
  • of propellers, 1500.
  • 26 C. of G., 1484.4 (old C. of G., 1486.3).
  • 29 Front edge of R. W., 1406.
  • 32 C. of P. on R. W., 1374.
  • 35 End of midrod, 1351.3
  • 38 Front end of rudder, 1334.5.
  • 41 Back edge of R. W., 1326.
  • 43 Center of rudder, 1279.
  • 46 Back end of rudder, 1220.5.
  • 49 Reed wings, 80 cm. × 185 cm. in rectangle.
  • 53 Weight in shop, 1982 g.
  • 56 On day of flight they weighed 2154 g. because they were damp.
  • 60 Area 54 sq. ft.
  • 63 Spread of wings, 359 cms. or 11′ 938″.
  • 67 Weight of aerodrome in flight, 12,120 grs.

Footnotes.

  • * H. P. = (Rev. × diam. × pitch ratio × thrust)/33000
  • † This is calculated on the assumption that the center of pressure on each wing or on pair of wings at a motion of 2000 feet per minute is in ordinary curved wings 2-5 the way from front to rear, that for wings of usual size the rear wings have 2-3 of the efficiency per surface of the front ones and that the tail proper bears no part of the weight; but if rear wing is smaller or larger this efficiency is smaller or larger per unit of surface.
  • ‡ This is undoubtedly incorrect, as if it were true, the C. G. would be just at the center of the separator, and this would be impossible. Mr. Reed states that the C. G. was 2 cm. below the side frame, and if this is correct, we would have C. G. = 2486.