In Tables IV. and V. the angle is given both in circular measure and in degrees; in the case of the gliding angle Table VI. the equivalent is given in the inverse form, i.e., as a gradient. In all cases the assumption is that of the small angle as already stated.
In actual aerodrome models, owing to the necessity for organs of equilibrium the resistance is greater than that due to the considerations taken into account in the foregoing Table; there is additional resistance due to the added surface, or body resistance.
Table VII. (Aeroplane).
Least Resistance. Values of
From Equation—
Values of assumed from Table II. (Plausible Values).
| for values of as follows:— | ||||||
| .030 | .025 | .020 | .015 | .0125 | .010 | |
| 3 4 5 6 7 8 — 10 — 12 |
6.76° 6.60° 6.43° 6.30° 6.22° 6.13° — 6.00° — 5.93° |
6.16° 6.02° 5.87° 5.76° 5.67° 5.59° — 5.48° — 5.41° |
5.51° 5.38° 5.25° 5.15° 5.07° 5.00° — 4.90° — 4.34° |
4.77° 4.66° 4.55° 4.45° 4.39° 4.33° — 4.24° — 4.19° |
4.35° 4.25° 4.15° 4.07° 4.00° 3.95° — 3.87° — 3.83° |
3.90° 3.80° 3.71° 3.64° 3.58° 3.54° — 3.46° — 3.42° |
Owing to this and other causes which will be explained later, the gliding angle is never found to be as low as the theoretical value, and in the most carefully made model is usually at least 50% greater than theory would indicate.
Reverting to the simple case of the plane aerofoil, or aeroplane (§§ 162 and 172), we have seen that the value of for least
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