Page:Aerial Flight - Volume 1 - Aerodynamics - Frederick Lanchester - 1906.djvu/396

Sept., 1905. Trial of model, with added surface.

	Distance. Ft.	Time. Secs.	Velocity. Ft./Secs.
1 2 3 4 5 6 7 8	29 29 32 28 34 33 31 36	2.6 2.6 2.8 2.8 ? 2.8 2.6 2.8	11.15 11.15 11.44 10.00 11.80 11.80 12.84
Total	8) 252	7) 19.0	80.18
Mean	31.5	2.71	11.45

Fig. 154. Whence, $\gamma ={\tfrac {7}{31.5}}$ = .222 or resistance in line of flight = .222 $\times$ .60 = .1332 grams.

∴ Resistance due to added surface = .1332 – .1172 = .016 grams.

∴ resistance per sq. ft. added surface = ${\tfrac {.016\times 144}{1.06}}$ = 2.175 grams.

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