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Aviation History
1911
1911 - 0910.PDF
(TEjggg Partly owing to the pressure of the air on the feathers, perhaps partly also to the wing having been slightly rotated, the area of the wing now forms an inclined plane, inclined in the opposite direc tion. As in the former case, there is a resultant force tending to lift the bird. Because the bird remains in the same place, the lift on the down stroke must equal the lift on the up stroke. If, owing to its shape, the area of the wing is less efficient in lifting on the up stroke, then this lack of efficiency must be compensated by greater speed. Whether or not this is the case in the pied kingfisher it is not OCTOBER 21, 1911. fisher resembles a horizontally-placed propeller whose blades reverse every half-revolution. Fig. 43 represents a pied kingfisher poising, not in calm air, but in a wind. Under these conditions the direction of the strokes of the wing is no longer horizontal, but slightly inclined to the horizon. The arrow W represents the wind direction. The arrow R represents the direction of the propelling effect of the wings. As in the first case, it must be obvious that propelling work is being done on the up stroke besides on the down stroke. I was once watching a pied kingfisher poising in a calm. It Fig. 39.—Position of wing of poising kingfisher during down stroke. Fig. 40.—Position 01 wing of poising kingfisher during up stroke. Fig. 41.—Front view of poising kingfisher near end of down stroke. Fig. 42.—Front view of poising kingfisher at beginning of up stroke. Fig. 43.—Side view of kingfisher poising in a wind. The arrows, A B, show direction of beat of wings, C G centre of gravity, W direction of wind, R direction of propelling force of wings. possible to see, owing to the extreme rapidity of the beats when poising. But in the case of some larger birds, and in the case of the flying fox, I have been able definitely to observe that the move ment of the wings when in horizontal flight is faster on the up stroke. In the poising pied kingfisher the strokes are of much greater amplitude than they are in ordinary horizontal flapping flight. At the end of the down stroke the wings nearly meet in front of the body. At the end of the up stroke the wings nearly meet behind the back. Fig. 41 shows the bird as seen from in front when the wings are coming together near the end of the down stroke. It must be obvious that the two wings, when approaching, tend to squeeze out air from between them in a downward direction, thereby, in a small degree, aiding the lifting effect. Fig. 42 shows the bird, again as seen from in front, when the wings are receding from one another at the commencement of the up stroke. Owing to their movement there must be a tendency for the air to be sucked in from above. That is to say, there is again a slight addition to the lifting effect. It must be obvious from this description that the poising king- ® ® was struck by a puff of wind, as shown by ripples that appeared on the water below it. The consequent change in the direction of the beats of the wings could be clearly seen. Owing, no doubt, to this change, the bird was not blown to leeward, but retained its position. When the pied kingfisher is flying from place to place its mode of flight is quite different from that seen in poising. The long axis of the body is horizontal (or nearly so), instead of being strongly inclined as in poising. The direction of the beat of the wings appears to be vertically up and down. The rate and also the amplitude of the beat is lessened. So far as we have gone in considering flapping flight, everything appears to be explained with one important exception, namely, what is the adjustment by means of which the kingfisher can change from poising to cross-country flight ? Obviously, to do so, the bird has to rotate round its transverse axis. The method of rotating round this axis that is used in gliding flight is clearly not applicable. The discovery of the method used in flapping flight will be described in the next chapter. (To be co7itinued). ® ® AIRSHIP NEWS. The Naval Airship Disaster. THE fact that Mr. McKenna, First Lord of the Admiralty, and Lord Ilaldane, Minister of War, were present at the opening of the inquiry on board H.M.S. "Hermione," on Wednesday of last week, into the disaster to the Naval dirigible points to the importance which is attached to the event at headquarters. The Commission consists of Rear-Admiral Sturdee, chairman, Capt. Nicholson, and Mr. Whiting. Before the proceedings opened, a visit was made to the wreck of the airship. Some 200 Marines were examined by the Commission as to their knowledge of the accident, and among others present at the inquiry were several aeronautical experts from the Admiralty and three of the Army airship officers. The " Schwaben's " Record* DURING the 54 days she has been in service the Zeppelin liner "Schwaben" has made 81 ascents, and this includes nine long voyages ranging from 200 to 400 kilom. She has been in the air for 187 hours altogether, has covered IO,8II kilom., and carried 1,675 persons. It is proposed in a few days to make an excursion from Dusseldorf into Holland, and then in November the vessel will return to Frankfort, where she will be permanently stationed. " Schwaben " goes to Dusseldorf. ON the 13th the Zeppelin liner " Schwaben " left Baden Baden with five passengers on board, and passing by Heidelberg and Darnstadt reached Frankfort after a trip of 3 hours. A Stop was made there for just an hour and then via Mayence, Coblence and Bonn, the dirigible went on to Dusseldorf, which was reached after 3j hours. During this time the misty conditions made steering a The difficult task, and several times the vessel got off her course, full distance covered was about 300 kiloms. "Parseval VI" Returns to Bitterfeld. AT haif-past ten on the morning of the 13th, "Parseval VI " was brought out from her shed at Johannisthal and sailed over to Bitterfeld, the journey taking about three hours. The *'Schutte-Lanz" Makes its Debut. AT last the " Schutte-Lanz" dirigible, which it will be. re membered is of the rigid type with a wooden framework, has made its appearance in the open, it having made a short cruise on Tuesday last. The wooden framework is 430 ft. and 60 ft. diameter at its biggest section. Extensive experiments in wireless telegraphy are to be carried out with this airship. A Long Voyage by " Adjudant Vincenot." ON the 6th inst., the Clement Bayard dirigible "Adjudant Vincenot" was brought out of its shed at Lamotte Breuil and was sailing for just on three hours over Soissons, Courcy-le-Chateau and Compiegne. She carried a crew of eight persons. The New Transatlantic Dirigible. SOME particulars are to hand of the new dirigible "Akron" with which Mr. Melvin Vaniman proposes to attempt a transatlantic trip this month. The envelope has been made by the Goodyear Tyre Co., of Akron, and is 26S ft. long and 45 ft. diameter at the largest section. It is made up of 2,200 pieces of fabric ixyin. thick, consisting of three layers of cotton cloth interleaved between four layers of rubber. 912
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