Page:Aerial Flight - Volume 1 - Aerodynamics - Frederick Lanchester - 1906.djvu/364

Velocity of Wind.” Many of these results have been already referred to in a previous chapter.

Table XVII.

Showing the pressure upon various plates at a velocity of 20.86 miles per hour. The values are reduced to the standard temperature and pressure. The flat plates were cut out of hard wood $\scriptstyle {\frac {3}{8}}$ inch thick. Allowance has been made for the arm which carried them.

Plates.	Actual Pressure in pounds.	Pressure in pounds per square foot.	No. of Experi- ments.
A square, each side 4 in. A circle, 4.51 in. diameter, same area A rectangle, 16 in. by 1 in. A circle, 6 in. diameter A square, each side 8 in. A circle, 9.03 in. diameter, same area. A rectangle, 16 in. by 4 in. A square, each side 12 in. A circle, 13.54 in. diameter, same area A rectangle, 24 in. by 6 in. A square, each side 16 in. A plate, 6 in. diameter, 4$\scriptstyle {\frac {3}{4}}$ in. thick A cylinder, 6 in. diameter, and 4$\scriptstyle {\frac {3}{4}}$ in. long A sphere, 6 in. diameter A plate. 6 in. diameter, with 90 degrees  cone at back The same, with cone in front A plate, 6 in. diameter, with sharp cone  30 degrees angle at back The same with cone in front A 5 in. Robinson cup, mounted on 8$\scriptstyle {\frac {1}{2}}$ in.  of $\scriptstyle {\frac {1}{2}}$ in. rod The same with its back to the wind A 9 in. cup, mounted on 6$\scriptstyle {\frac {1}{2}}$ in. of $\scriptstyle {\frac {5}{8}}$ in. rod The same with its back to the wind A 2$\scriptstyle {\frac {1}{2}}$ in. cup, mounted on 9$\scriptstyle {\frac {3}{4}}$ in. of $\scriptstyle {\frac {1}{4}}$ in rod The same with its back to the wind One foot of $\scriptstyle {\frac {5}{8}}$ in. circular rod	0.17 0.17 0.19 0.29 0.66 0.67 0.70 1.57 1.55 1.56 2.70 0.28 0.18 0.13 0.29 0.19 0.30 0.12 0.28 0.12 0.82 0.28 0.13 0.05 0.09	1.51 1.51 1.70 1.47 1.48 1.50 1.58 1.57 1.55 1.59 1.52 1.45 0.92 0.67 1.49 0.98 1.54 0.60 1.68 0.73 1.75 0.60 2.60 1.04 1.71	4 9 7 7 8 12 4 7 14 6 6 5 4 8 4 4 4 4 8 4 3 3 3 3 9

In addition to the experiments tabulated, other resistance experiments are recorded, notably those on perforated plates dealt with in § 143, also the effect of a projecting lip on the edge of the normal plane, § 141.

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