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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 76: Data Sheets
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 SHEETS.

DATA SHEET No. 1. Weight of Aerodrome No. 5, as photographed on May 11, 1896. Certified to by R. L. Reed, May 6, 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. 2443
2 Engine, gears, shafts, etc. 1110
3 Pump, pump shaft 231
4 Hull covering 350
5 Gasoline tanks, valves 178
6 Smokestack 342
7 Float 275
8 Reel 77
9 Wing clamps, 235; clamp for guy-posts, 29 264
10 Other things, counter 75
11 Burners 360
12 Boilers 651
13 Separators, steam gauge, pipe to engine 540
14 Exhaust pipe 143
15
16
17 Wings (without clamp) 1950
18 Tail (without clamp)
19 Rudder 350
20 Guy sticks, each, 57 114
21 Propellers 800
22 Extra length of midrod, 308; drop piece for rudder, 40 348
23 Wood Bowsprit 74
24 Other things
25
26
27 Fuel (at starting flight) 200
28 Water (at starting flight) 900
29
30
31 Sundries unknown
32
33
34 Total flying weight 11,775 26
35
36
37
38 Total area of support (not including tail) . . . sq. ft. 68
39 Total area of support in feet, divided by total flying weight in lbs. 2.6
40 Total area of horizontal tail . . . sq. ft.
41 Total area of rudder (vertical) . . . sq. ft. 6
42 Horse-power at brake. Horse-power by formula* .72 7
43 Minimum pressure during 40 secs. lift, 150 lbs.
44 Lift at pendulum (during 40 secs. absolute) 5772
45 Lift at pendulum (during 40 secs. in terms of wt.) 49%
46 Minimum pressure with which wheels turn, 10 lbs.
47 Position of center of pressure of wings† F. W., 1575; R. W., 1383.5
48 Time of getting up full steam, 1 minute
49
50 Curvature of wings, 1/11
51 Root angle of wings, 9°
52 Tip angle of wings, 9°
53 Position of wings, Front rib on F. W., 1607; R. W., 1415.5
54 How guyed
55
56
57
58 Position of tail
59 Angle of tail
60 Co-efficient elasticity of tail
61 Position of rudder, center, 1288.3; rear end, 1229.8
62 Line of thrust, 2500
63 Line of thrust, 1500 which is 9 cm. below the center of midrod
64 Center of gravity1 of whole, 1497
65 Center of gravity2 2501, i. e., 1 cm. above line of thrust
66 Center of pressure1 of whole estimate, 1498
67 Center of pressure2, 2536
68
69
70
71
72

Parts. Remarks.

  • 1 Front end of bowsprit, 1686.3.
  • 2 Front end of midrod, 1611.6.
  • 5 Front edge of F. W., 1607.
  • 8 C. of P. on F. W., 1575.
  • 11 Back edge of F. W., 1527.
  • 14 Back edge of cross frame, 1509.
  • 17 Line through center of propellers, 1500.
  • 21 C. of G., 1497.
  • 24 Front edge of R. W., 1415.5.
  • 27 C. of P. on R. W., 1383.5.
  • 30 End of mid-rod, 1360.5.
  • 33 Front end of rudder, 1343.8.
  • 36 Back edge of R. W., 1335.5.
  • 39 Center of rudder, 1288.3.
  • 41 Back end of rudder, 1229.8.

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.