Birds
Birds for use in aircraft
Birds were occasionally imagined as a means of propulsion for airships. (Not to be confused with ornithopter, an aircraft which itself resembles a bird.)
Mac Sweeny, 1844, Essay on Aerial Navigation, pp. 33, 35:
Trained falcons may be taught to fly with a balloon, and to alight on a car at command. If all were to rest on the car, their weight would cause a descent, lower than would sometimes be desirable. The rope to which the birds are tied, may be in parts, joined by hooks and eyes, so that part of the rope with a bird may be separated. Some of the birds may be placed in bags, in the car, the rest may be allowed to fly with the rope. By the aid of falcons, men may thus ascend, or descend, into a favourable current.
[...]
If we reject them for propulsion, by them we can cause a balloon to ascend and descend. We can haul in and throw the weight of the birds on the car.
| Enclosing categories | Propulsion |
|---|---|
| Subcategories | |
| Keywords | Ballast |
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- Patents in category Birds
- Patent GB-1869-1769
- Patent FR-1894-237416 (Applicant person: Von Szenimklôsy)
- Patent US-1887-363037 (Applicant person: Charles Richard Édouard Wulff, Filing date: 1886-05-24)
As models
Naturally birds were also investigated as models for successful flight.
Hiram Stevens Maxim makes a point about the computing the energy required for bird flight:
The amount of power which a land animal has to exert is always a fixed and definite quantity. If an animal weighing 100 lbs. has to ascend a hill 100 feet high, it always means the development of 10,000 foot-libs. With a bird, however, there is no such thing as a fixed quantity. If a bird weighing 100 lbs. should raise itself into the air 100 feet during a perfect calm, the amount of energy developed would be 10,000 foot-lbs. plus the slip of the wings. But, as a matter of fact, the air in which a bird flies is never stationary, as I propose to show; it is always moving either up or down, and soaring birds, by a very delicate sense of feeling, always take advantage of a rising column. If a bird finds itself in a column of air which is descending, it is necessary for it to work its wings very rapidly in order to prevent a descent to the earth.[2]
