At the cruising speed the loads naturally increase but still, in
L 70, and more particularly in R 33, they are too small to be
considered commercially. In R 38, however, the load that can be
carried at cruising speed is sufficient to become a commercial
proposition.
From this short statement it is evident that, by a comparatively
small increase in volume, the lifting capacity of an airship is
enormously increased, and it is in this subject that the airship
possesses such undoubted advantage over the aeroplane. In the
heavier-than-air machine there is no automatic improvement in
efficiency resulting from greater dimensions. In the airship,
however, this automatic improvement takes place in a very marked
degree; for example, an airship of 10,000,000 cubic feet capacity
has five times the lift of the present 2,000,000 cubic feet
capacity rigid, but the length of the former is only 1.7 times
greater, and therefore the weight of the structure only five
times greater (1.7); that is, the weight of the structure is
directly proportional to the total lift. Having seen that the
total lift varies as the cube of the linear dimensions while air
resistance, B.H.P.--other things being equal--vary as the square
of the linear dimensions,it follows that the ratio "weight of
machinery/total lift" decreases automatically.
Pages:
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190