Major Thomas S. Baldwin, U. S. A. C., considered one of the best authorities in regard to balloons and dirigibles in the United States, said that the Germans had constructed aircraft that could stay in the air for two weeks and could make upward of 75 miles an hour. Major Baldwin stated that the relatively small American Blimps were capable of 60 miles an hour. Only recently one of these flew from Akron, Ohio, to New York without stopping, a distance of more than 300 miles, and the Naval NC-1 flew from New York to Pensacola, Florida, a distance of over 1,000 miles, stopping at Norfolk, Virginia, and Savannah, Georgia.
On December 12 an interesting experiment of launching a plane from a dirigible was conducted at Rockaway Beach, New York. The dirigible rose about one hundred feet above the sand-field near Fort Tilden. An aeroplane was attached to the roof. After discharging ballast and starting the motor the dirigible ascended to three thousand feet and released the aeroplane, which dived about one thousand feet and then flew off to Mineola. Lieutenant George Crompton, Naval Flying Corps, piloted the dirigible, assisted by J. L. Nichols and G. Cooper. The plane was piloted by A. W. Redfield.
In the flight of the British naval dirigible R-23 over the North Sea, in April, 1919, the aeroplane was hung suspended from the keel amidships and launched when near the British coast.
The above experiment is cited only as an indication of what the possibilities are of combining the aeroplane with the dirigible in landing mail or express from dirigibles crossing the Atlantic. Undoubtedly aeroplanes weighing only a thousand pounds, with a flying radius of 600 miles and making 150 miles an hour, will be launched from superdirigibles 500 miles from the journey’s end, especially when airships are to be constructed with 10,000,000 cubic feet of gas, with a 60 per cent gross lift for crew, fuel, freight, and so on, as Mr. Marsh says is quite possible in the immediate future.
Experiments for launching aeroplanes from ocean-liners for a like purpose are already under way. The object is to fly the mail for London or New York from the ocean greyhounds as soon as they get within five hundred miles of either coast. This will, of course, cut the flight time from New York to London considerably. As a matter of fact the dirigible might fly over only the great expanse of water from land’s end to land’s end, while the aeroplanes negotiated the remainder of the distance. It is granted that for short flights over land the aeroplane is twice as fast as the Zeppelin, whereas the latter, because it can stay in the air for weeks, is the best adapted for long cruises over large bodies of water. Moreover, the removal of the weight of an aeroplane from a dirigible six hundred miles from its journey’s end would facilitate the remaining flight of the Zeppelin by just so much; it would be equivalent to throwing out ballast to keep a balloon in the air.
Perhaps of all the revolutionary scientific developments of the Great War—especially in the field of chemistry—the one that may perform the greatest service to mankind is the steps taken by the Bureau of Mines to produce helium, the non-inflammable gas which has 92 per cent of the lifting power of hydrogen, in sufficient quantities to be used in floating airships!
A non-inflammable gas with such a lifting capacity as helium has been the dream of the aeronaut and the dirigible engineer ever since the Robert brothers first conducted their experiments in France in 1784 and found that hydrogen had greater buoyancy than any other gas available in large quantities for balloons; for with it they could jump over the highest peaks of the Himalaya Mountains and the broadest expanses of the Pacific Ocean without danger of the gas igniting from the sun or the engine.
It will be recalled that we pointed out that the greatest danger to people riding in dirigibles was the possibility of heat expanding and exploding the hydrogen gas. One of the first airships to experience this fate simply passed through a cloud into the hot sun, whose rays expanded and exploded the gas, blowing the airship and its crew into smithereens before they could open the gauges and release the pressure. The same thing may have caused the explosion of the German dirigible L-2, which killed its crew of twenty-five; and the American airship Akron, which blew up, destroying Vaniman and his companions. The substitution of helium entirely eliminates that danger and makes it possible to carry heating devices for the comfort of passengers in high altitudes where it is so cold.
Of course, the lifting power of helium was known to students of aerostatics before the war, but the mechanical difficulties and cost involved in producing this gas on an industrial basis were so great that it would hardly pay to produce it for commercial purposes. Indeed, the largest amount of helium in any one container up to the beginning of 1918 was five cubic feet, and it cost between fifteen hundred and six thousand dollars, whereas under the new system it is expected that one thousand cubic feet can be produced for one hundred dollars!
In war, however, cost is nothing—results are everything. As there was a possibility that helium might be one of the chief factors in winning the war, the joint Army and Navy Board on Rigid Airships in August, 1917, provided the Bureau of Mines with the requisite funds to do the necessary experiment work.