A Project for Flying - In Earnest at Last! by Robert Hardley
page 10 of 33 (30%)
page 10 of 33 (30%)
|
a separate pamphlet. According to these experiments it appears, that
the opposition which an ellipsoid or oval (of the nature of the Balloon, if we may so call it, in the model) is calculated to encounter in proceeding _endways_ through the atmosphere is only _one-sixth_ of what a _plane_ or _flat_ surface of equal area with its largest vertical section, would experience at the same rate; while the resistance to the progress of a globe, such as the usual Balloon, would be one third of that due to a similar circular plane of like diameter: shewing an advantage, in respect of diminished resistance, in favour of the former figure, to the extent we have above described; an advantage it enjoys along with an increased capacity for containing gas--the cubical contents of an ellipsoid of the proportions here observed, being exactly double of those of an ordinary Balloon of equal diameter, and consequently competent to the support of twice the weight. Independent of the advantage of reduced resistance in this form, there is another of nearly, if not quite, equal importance, in the facility it affords of directing its course; an object scarcely, if at all, attainable with a Balloon of the usual description however powerfully invested with the means of motion; as any one will readily perceive who has ever noticed or experienced the difficulty, or rather the impossibility, of guiding a tub afloat in the water, compared with the condition of a boat or other similarly constructed body, in the same element. The efficacy of this provision and its necessity will appear more forcibly when we observe that whenever the Balloon in the machine here described is thrown out of its direct bearing by the shifting of the net-work which connects it with the hoop, or by any other accident whereby its position is altered with respect to the propelling power, its course is immediately affected, and it ceases to progress in a straight line, following the direction of its major axis, unless |
|