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THE PRIME MINISTER enquired what evidence there was that the airship which flew over Sheerness was German?
SIR JOHN JELLICOE said that it was known that an airship had left Germany on the day previous.
MR. CHURCHILL said that they had information from other sources which confirmed their belief.
SIR JOHN JELLICOE, continuing, said that at night an aeroplane was as yet inefficient. Its radius of action was four hours only, and landing at night was very dangerous. Putting aside that serious limitation, Sir Arthur Wilson underrated the rapidity with which a modern airship could rise. One of the Zeppelin type could rise 2,500 feet by use of engine and rudders, and without expending the ton of spare ballast. In any design we built we should provide for the propellers being so arranged as to be able to be used to drive the vessel vertically upwards. He thought that the aeroplane would find it by no means easy to get above the airship. The aeroplane had an advantage in speed-70 miles an hour to 50. An airship rose when stationary, and its buoyancy increased as its fuel was consumed.
COLONEL SEELY said that the fundamental error lay in applying to modern airships the considerations which applied to spherical balloous. There was no loss of hydrogen from a modern airship; consequently the buoyancy increased as the fuel was consumed, and the greatest buoyancy was attained when the fuel was exhausted.
THE PRIME MINISTER enquired what the present greatest height attainable by an airship was ?
COLONEL SEELY said that the Superintendent of the Army Aircraft Factory stated it at 6,000 feet.
SIR ARTHUR WILSON said that both Sir John Jellicoe and Colonel Seely missed his point. The airship could of course go up as fast as the engines would drive her, but unless hydrogen was let out with the decrease in atmospheric pressure the gas reservoir would burst. Therefore, to rise to any given height so much less hydrogen must be in the reservoir before starting. The consequence of this was that, for every 80 metres it was desired to rise, 200 kilog. in weight must be sacrificed. This very quickly reduced the carrying capacity. In the case of an airship with a 7 or 5 ton lift at sea-level; to reach a height of 2,900 feet from 2 to 24 tons would have to be sacrificed, and this would have to be left behind at the start. He did not want to criticise the report further, but he would urge that construction should not go beyond experiment. When they had got their airship the Admiralty would see that his arguments were perfectly sound.
MR. CHURCHILL said that all the report asked for was the means of experimenting.
COLONEL SEELY said that it really was not necessary now to sacrifice hydrogen. The hydrogen was absolutely sealed up. Its expansion was compensated by letting air out of the ballonet. His advisers were constantly dealing with airships, and really knew what they were talking about. There was, of course, a limit to the height which an airship could attain.
SIR ARTHUR WILSON said that the lifting power was reduced when the ballonet was full. His recollection was that our naval airship had been designed with a lift of 5 tons, but they had to remove the keel before she could rise off the water, and without her keel she immediately collapsed.
THE PRIME MINISTER said that the discussion showed the advantage of confining our present efforts to experimental work. Sir Arthur Wilson took a pessimistic view of the capacity of these vessels. From our point of view this was an optimistic attitude. As to which view was right, he might vary the Latin quotation and say solvitur volando.
MR. CHURCHILL hoped most sincerely that Sir Arthur Wilson was right. The problem of defence against attack from aircraft caused them very great anxiety at the Admiralty. At present there were no satisfactory defence arrangements
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