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Lighter-Than-Air Craft

USS Akron The 785-foot long U.S. Navy airship Akron, which - along with her later sister ship Macon - was used to test the idea of the dirigible as a weapons system, flies over New York on a development flight circa late 1931.

Naval aviators were against the dirigible as too slow and too vulnerable, views in which future history was to support them. Rear Adm. Mark L. Bristol, however liked the "Big Bags" and wanted specifications for them issued to manufacturers. Lt. Comdr. F. R. McCrary, as well as Richardson and Herbster, accordingly came out with plans embodying some new ideas, such as "a car . . . to allow for resting on the water or for moving on the surface at slow speed"; twin screws of swivel type; and a "secure means" for making fast to the mooring mast. Bristol likened the proposed ships to "Dreadnaughts," declaring that just as battleships did not move in enemy waters without a destroyer escort, so the airship bombers of the future would cross the sky only under "fighter" protection. Wrong about the dirigible as a bomber, he was certainly right enough about future air tactics.

Counting upon early delivery of at least one training dirigible, Bristol, with Rear Adm. B. A. Fiske's backing, ordered from Pittsburgh a hangar shed to house it. Its arrival at Pensacola was much delayed by winter weather too severe for its builders but, in the end, the hangar was received and erected long before its first inmate put in an appearance. Meantime McCrary had been told to devote himself exclusively to dirigibles, beginning on June 1, as inspector of a nonrigid ordered from Connecticut Aircraft Company, to be delivered in October and to cost $45,636.25. One reason for the award of this contract was the report that the company had just hired an Austrian Zeppelin expert; a poor reason because his knowledge proved to be but slight and his ability too small to cope with novel ideas or prevent exasperating delays in construction. Nevertheless, training of personnel began under McCrary and Lieut. Lewis H. Maxfield, both to be prominent "Lighter-Than-Air" men during the war, and all hands went to Akron, where the Goodyear Company, as the result of Fleet interest in spotting, were building a 19,000-cubic-foot, free balloon. While the men were "growing up with that one," Goodyear began building a kite balloon, thus leaving only the rigid dirigible to await the results of these earlier experiments.

On September 2, 1925, Lt. Comdr. Zachary Lansdowne, veteran of numerous airship flights, took the Shenandoah, "Daughter of the Stars," out of Lakehurst. This flight, like others, was designed to afford training and experience but it had the particular purpose of complying with a request that the Navy test the new mooring mast for dirigibles, erected during that summer at the Ford field in Dearborn, Michigan. The flight was uneventful until about four o'clock the next morning, when the ship was over Byesville, Ohio. At that time, her crew saw heavy clouds accompanied by severe lightning looming in the northwestward sky. Almost at once the head winds became so strong that even her five motors hardly gave the ship headway and presently her drift to leeward became faster. Her navigator, Lieut. (now Vice Adm.) C. E. Rosendahl, afterward spoke of a thin, dark, streaky cloud as Just visible in the pale moonlight, and be had barely noticed this when the vicious squall struck. Caught in violently whirling upcurrents, the ship began to rise so fast that all efforts to check her were unavailing. At 4,000 feet she paused, then rushed higher. In the thinner atmosphere of the upper levels the expanding helium created so much pressure on the gas cells that they were in danger of bursting and the crew, already sent by Lansdowne to emergency stations, began opening hand valves to relieve the gas cells more rapidly than the automatic valves could do it. The upward rush continued until, at about 6,000 feet, the ship met the down-currents of the storm. She was "heavy" now because valving so much helium had cost her buoyancy and, to check her as she began to fall swiftly, tons of ballast water were run overboard. In perhaps two minutes she fell about 3,000 feet, where she was struck again by upcurrents and flung up once more. In the hope that the next downthrust of the higher levels might be checked, Lansdowne gave orders to cut adrift the middle gas tank, designed so it could be "slipped" in such an emergency, and sent Roserrdahl forward to supervise this effort. It was just as he stepped up on the ladder leading from the control car to the keel that Rosendahl felt the ship incline to what he knew was a dangerous angle. In the next instant he heard the struts cracking and the metallic crash that meant structural members were parting and suspension wires snapping. From almost under his feet the control car tore itself loose, carrying Lansdowne, three other officers, and four men. Then, looking down through the grey dawn, he could see the whole after end of the ship falling, splitting into sections as it went. Both engine cars broke away, taking with them all the engineers. Not until long after would he know that the stern section, with Lieutenant Rauch and a few of the crew, by some unexplained miracle would reach the ground unhurt. For the moment he had all he could do to clamber into the forward section, now to all intents and purposes a 200-foot free balloon. Up it shot to 10,000 feet, to be drenched in rain squalls, pounded this way and that, driven down to earth into the top of a tall tree, extricated, and at last, by the most expert "valving," brought to the ground and secured. Rosendahl and his small group of six were 12 miles from the crushed control car when they began searching for their shipmates. Three of those in the midship section and 17 in the afterbody were unhurt while two others were injured but recovered, leaving a total of 14 dead. Most of the survivors continue to be as enthusiastic as Rosendahl in advocating the use of airships. The court of inquiry, such as always follows a disaster, found no grounds for such opinions as the one expressed by General Mitchell, that the tragedy was what was to be expected from the "incompetent, criminally negligent, and almost treasonable administration" of the air services by both the Army and the Navy; an expression, by the way, which led directly to the general's trial by court martial and his ultimate resignation from the Army. On the contrary, the court decided that the ship had been adequately prepared for a duly authorized flight; that there had been no warning of the storm; and that the ship had had no apparent structural weakness. It cited the numerous instances of individual heroism and the gallant efforts of groups to save ship and shipmates. It recognized the important fact that the use of noninflammable helium instead of hydrogen had resulted in saving many lives. As far as possible it established the facts; but it could not soften the heavy blow to aviation or halt the wave of adverse publicity that swept the country. One great good did follow when the Secretaries of War and of the Navy together urged President Coolidge, as Commander in Chief, to call upon a group of highly qualified citizens to study the whole problem of "aircraft in national defense and to supplement the studies already made" by both departments. Hardly more than a week after the Shenandoah tragedy the President complied on September 12. The destruction of the Shenandoah and the emphasis laid by the Eberle Board upon the vulnerability of airships in general had put Moffett on the defensive but with characteristic vigor he refused to stay in that uncomfortable position. Instead he gave the board a vivid account of all that had been learned from the lost ship's many successful flights, and followed this by urging the continued study and development of the rigid airship by building at least one successor. As part of the "steady, farsighted, progressive" program, he asked for the establishment of a new base, on the West coast, for lighter-than-air elements. All this was very much what he had previously said to the General Board when he asked that body, in addition, to approve the immediate building of an airship of 1,125,000-cubic-foot capacity, for training purposes, with two giants of 6,000,000 cubic feet to follow.

In lighter-than-air craft, the Navy Department's first design had called for a rigid dirigible with 20 hours' endurance at a top speed of 60 mph under a full load of fuel, a crew of 20, and four machine guns. With this full load it must be able to climb to 4,000 feet; with fuel reduced to five hours' supply it much reach 10,000 feet. Its radio range was to be 400 miles, and it must be "capable of landing on water." Very shortly, these specifications were-modified to reduce the crew to 12, the endurance to six hours at a maximum speed of 50 mph, and the radio range to 200 miles. The full load ceiling was raised, however, to 5,000 feet.

The training dirigible design, after modification of the original one, prescribed 45 mph with 12 hours' endurance at 35, a crew of three, a 150-mile radio range, and the ability and strength both to land on the water and to be towed through it. The length was to be 160 feet, the diameter 31.5 feet, the gasoline capacity 100 gallons, and, because weight was considered more important than provision for emergency, there was to be but one motor.

In January, 1917, Hunsaher's plans made it clear that this "B" airship for training could more than meet the specifications. These plans were accordingly approved, and in February the Secretary of the Navy unexpectedly ordered 16 ships to be built immediately. Of five firms who wanted to undertake this work, only one, Connecticut Aircraft, had ever built a dirigible and even that firm had had many difficulties. No rubber manufacturer had ever made a hydrogen-resisting fabric. For these reasons a conference held in Rear Admiral Taylor's office, finally decided to pool materials, information, and experience in order to produce craft with speeds of 35 mph at $42,000 each. Under this arrangement Goodyear built an erecting and testing shed at Akron, Ohio, in two months. Goodrich hired an engineer from Lebaudy in Paris. Pigeon Frazer built the cars for the Connecticut Company, while the United States Rubber Company made the fabric. Hall-Scott of San Francisco built motors. Nevertheless, when the Secretary of the Navy proposed that another 24 nonrigids be built, Rear Admiral Taylor made strong recommendations against doing this until the value of the type had been demonstrated. Since the much better "C-type" was soon to follow, it was fortunate that the admiral's recommendations were approved.

The first A-class airship, which would finally be delivered at Pensacola in the spring of 1917, was a failure from the start. It could hardly get off the ground, its motor was poor, and its envelope leaked. Nevertheless, because its builders, the Connecticut Company, had lost so heavily upon it, the contract price was paid. Soon afterward, when its car was being towed over the water, it was so badly damaged as to be not worth repairing; it was deflated and eventually broken up for its parts. That it should have been a failure is understandable after reading what Commander McCrary, who had watched its building, had to say of the builders: "It could hardly be called an aircraft company. It consisted of a New Haven R. R. Lawyer [sic.] as financial backer; an exAmusement Park Concession operator as manager; an Austrian who claimed to have piloted a dirigible and two German mechanics who claimed to have been members of the crew of a Zeppelin. The `plant' was a six-by-eight office . . . and a rented boat-shed."

Some progress in lighter-than-air work was also authorized by the act of 1919, in that it provided for the purchase of one rigid dirigible abroad and the building of another at home. These provisions were timely because interest in dirigibles had received considerable impetus from the visit to the United States of the British R-34, first airship to make a successful crossing. She helped smooth the way to an agreement with the British under which their uncompleted R-38, representing the newest and supposedly best type, was to be finished and turned over to the United States at a cost of $2,000,000. At the same time arrangements were made for the training in England of American personnel for the new ship, which was given the American designation ZR-2. It took two more years to build her and then, on August 24, 1921, when she was making her fourth trial flight, she fell into the Humber River, burst into flames, and killed Comdr. Lewis H. Maxfield and all but five of her crew of 49.

In this same year 1919 the ZR-1, afterward known as the Shenandoah, was begun. It had at first been contemplated that her construction would be by automobile manufacturers, perhaps Ford or Packard, but this plan was abandoned in favor of the Navy's doing its own building, the parts to be made at the Philadelphia factory, their assembly to be at Lakehurst. The final structural design was a combination of the British and the German types, with modification of the fins, strengthening of the longitudinals, and a special nose to permit mooring by the bow. The Maybach motors built by the Germans proved best and the designers returned to them after trying both Liberties and Packards. Built of duralumin furnished by private aluminum firms, the airship would need the largest hangar in the world and this would not be completed at Lakehurst until 1922. It would then serve, after the Shanandoah's tragic end, to house the very successful Los Angeles, built by the Germans at Friedrichshafen under the terms of the Versailles Treaty and originally known simply as ZR-3. For all these ships helium would be unquestionably the best inflating gas, and work upon Texas plants to manufacture it, begun in 1917, was still being pushed in 1919. Within another year 200,000 cubic feet of helium were produced, at a cost indicating that a government plant for this purpose would be a good investment even at a building cost of $7,000,000.

Toward the end of 1919 and in early 1920 Captain Craven was hoping for some progress through using the six airships procured from various European countries under authority of the same Act of 1919. From France came an Astra-Torres, a Vedette-Zodiac, and a Chalais-Meudon, but on their arrival it was discovered that no hangar in the United States was big enough to handle them. This meant that they had to be put into storage, and before any use of them for training purpose could be made their fabrics became so rotten that they had to be destroyed. The "O" type nonrigid, bought from Italy at a cost of $84,000 plus the salaries of two special technicians imported with it, did not reach the United States until the early autumn of 1919, when it carried out a few interesting, instructive tests, especially of radio communication and target gliders, before it crashed and became a total loss. From England came one nonrigid of the "North Sea" type.

Three new classes were designed in the United States. The socalled "G" class, practically a counterpart of the "North Sea," was planned to have a capacity of 400,000 cubic feet, an enclosed car with sleeping quarters for the crew, a three-inch antisubmarine gun, and a heavy bomb load; but it never got beyond the plan stage. The "H" was a self-propelled kite balloon, which could be inflated aboard ship, and it was stout enough to be towed in a strong wind. Because it had an engine it could handle itself in weather much too strong for the ordinary balloon, but its effectiveness otherwise did not prove great enough to warrant building more than one of the type. Third was the "J," a twin-motored affair, not unlike its "C" and "G" predecessors, but fitted with only one ballonet and a simple gondola. With all of these an impressive series of training exercises was planned, but as might be expected from the scanty funds available not all of them could be carried out. Led by McCrary and Lansdowne the lighter-than-air men wanted to learn all there was to know about refueling dirigibles from surface craft or from one another; about the handling of airships by ground gear on trucks, winches, or tanks; about lifesaving possibilities and meteorological usefulness; about landing on roofs and ships as well as on the water; about mooring devices, instruments, and possible new fabrics; about mine laying and bombing; and particularly all about helium gas and the possibility of such static discharges as, in the future, would destroy the famous Hindenburg. Attempts at least were made at all these training experiments and exercises.

It was these exercises that brought the "H" kite balloon into disfavor. As Admiral Mayo had expressed it, the observer in such a balloon found it "an unhappy place" when a battleship's salvo was fired below his basket, while even without that a merely "fresh" breeze would give him so much to do to "stay put" that he could accomplish little else. Most of the ships could see no use for the balloons that would compensate for the time and labor spent in caring for and handling them, a view supported by Adm. Henry I3. Wilson, the new Commander in Chief in the Atlantic, in his conclusion that "the results of trials condemn the balloon as neither practical nor useful . . . on board the fighting units." Hence although the Pacific Fleet continued for some time to make experiments it was inevitable that the "dishing in" of balloons from the Florida and Nevada in the winter of 1920 - accidents in which losses of life were but narrowly averted - should virtually end their use aboard ships.

A conclusion drawn from the Fleet exercises applied to airships and struck what amounted to their death blow. The Macon, sister of the Akron and commissioned on June 23, 1933, not long after the latter was lost, did a little scouting with the Fleet and some excellent reporting of weather conditions. In contact with the "enemy," however, she was invariably "destroyed" by air attacks which her defending planes were unable to repel, and this was duly noted by Adm. David F. Sellers, Commander in Chief during that year and the next. Summarizing her efforts, the admiral described himself as "unaware of any conditions based either upon the record . . . of the Macon," or upon any other experience with airships, justifying further expenditure for them, an opinion fully confirming that of Schofield and others. King, for the Bureau of Aeronautics, suggested that the metal-clad airships then in the design stage, if stepped up to a speed of 100 knots and equipped to use gas fuel, would prove more useful, and he recommended that six of these be built. The General Board, in its turn, amended earlier pronouncements upon naval policy on rigids by recommending their development with an eye to their value for commercial purposes, while nonrigids were employed to train personnel. A proposal that the Macon, in the meantime, be used for longrange patrol flights came to little because before she had been in service for two years altogether a structural failure brought her down off Point Sur, California, where she sank on February 12, 1935, and was lost. Fortunately all but two of her crew were saved.

After this disaster the Secretary of the Navy requested a new study of dirigibles, which was completed in January, 1936, by a group of distinguished scientists headed by Dr. W. F. Durand and including R. A. Millikan, Theodor von Karman, William Hovgaard, Stephen Timoshenko, Alfred V. de Forest, Frank I3. Jewett, and Charles F. Kettering. These gentlemen did not pause to decide whether or not a rigid airship had military value; they assumed that value and then expressed "the unanimous opinion . . . that the best interest of the services . . . both commercial and naval, requires a continuing program of construction and use." This led to plans for all sizes up to 10,000,000-cubic-foot capacity, some prepared in the Bureau of Aeronautics, some under naval contracts with the Daniel Guggenheim Airship Institute at Akron. Notwithstanding the adverse reports of four successive commanders in chief, the General Board then presented its own report, noting all the possibilities of scouting by airships able to make far higher speed than carriers and able to carry and launch their own planes, but also admitting their vulnerability. For commercial use in peacetime and for conversion to war purposes, the board recommended building another rigid of 3,000,000 cubic feet, and for this Congress eventually appropriated $500,000. Her plans and specifications were duly prepared, but since she was never built it remained for the Los Angeles, recommissioned after the loss of the Akron, to play a lone hand in rigids. Other progress in lighter-than-air was limited to the nonrigids, one of these being the Defender, bought from Goodyear in 1935, redesignated the G-1, and used for training with such success that seven others like her were built for World War II. Similarly, the TC-13 and TC-14, nonrigids taken over from the Army in 1937, became the nucleus of a war squadron, while two other types, bought "as is" from Goodyear and modified, became the L-1 and the K-3. The latter is of particular interest because she included all the improvements since World War I that had stood the test of time. Her car, suspended internally, was a frame of welded steel, thinly covered with aluminum alloy and streamlined, as were the outriggers and the cells. Her fuel tanks were built into the car above the control tanks and her bombs, carried beneath the car floor, could be released through bay doors like those on planes. With all these improvements, and a retractable landing gear, she became the model for a whole fleet of nonrigids that would see active war service.

Archibald Turnbull and Clifford Lee Lord. . Yale University Press, New Haven. 1949.

Shenandoah Saga An in-depth narrative of the history, design, construction and short life of the first U.S. built dirigible. Battered by a storm, the broken frame crashed to earth in 1925.

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