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the total lift at 403,000 pounds it is merely an attempt to state an average figure.
The other complaint of Mr. Link is that the Akron will not cruise as far as has been stated. The cruising range of an airship depends, first, on the fuel carried and, second, on the rate at which that fuel is burned. An airship will burn more fuel per hour going at 50 knots than going at 40 knots. Mr. Link's statements, as I understood them when he was on the stand, were vague as to the speed at which his complaint was directed. Nevertheless, with a combination of eight engines, such as the Akron had, you can get 50 knots speed with a variety of engine combinations, or propeller combinations. For example, the Akron can be driven 50 knots with 4 engines going, say, 1,500 r.p.m. (not stating precise figures) or 6 engines going at 1,400 r.p.m. or 8 engines at 1,200 r.p.m. You get a different fuel consumption per nautical mile traveled, depending upon the particular engine combination that you use. I think Mr. Link must have chosen an unfavorable engine combination to arrive at his figures.
Colonel BRECKINRICGE. What do you say is the cruising radius of that ship?
Commander FuLTON. I should say 8,000 miles at 50 knots; more than 10,000 miles at 40 knots.
Colonel BRECKINRIDGE. Commander, as I read the report of Mr. John Simon on the R-101 disaster, that was held to be due to the loss of gas; is that accurate?
Commander FULTON. That idea was very definitely set forth in the report; yes, sir.
Colonel BRECKINRIDGE. You have heard all of the testimony in this hearing before this committee, have you not?
Commander FULTON. I think so.
Colonel BRECKINRIDGE. Do you conceive that it is possible that the loss of helium was a primary or contributing cause of the crash of the Akron?
Commander FULTON. No, sir; I do not, for the reason that if there had been any excessive loss of helium in the Akron, it would have been evidenced in the ship's operation for a considerable period of time before the Akron finally crashed. I cannot conceive of anything that would have caused so sudden a less of gas as to precipitate the Akron into the attitude she took in the last 5 minutes of her flight, and had there been any loss of gas I am sure it would have been reported to the control car and Lt. Commander Wiley, who was in the position as executive officer, would have known about it. Deal, another survivor, was a rigger; his duties involved his having some intimation if there has been an excessive loss of gas in the ship.
Representative ANDREW. You do not think that the cracking of a girder, if it actually broke, would produce such a tear in one of these big gas cells as to have allowed the gas in that cell rapidly to escape?
Commander Fulton. No, sir; nothing like that has been brought forth in the evidence. The rate at which the gas will escape from a tear in a gas cell is a widely varying matter; it depends on the location of the tear. If the tear is located near one of the corridors the amount lost would be rather small; that is, it would pour out rapidly for a wbile, and upward beyond the tear as gas passed it would remain in the cell above the point where the tear occurred.
Representative ANDREW. My recollection was that some one testified that a large tear might allow the escape of gas from one of these bags in 2 minutes.
Commander Fulton. That is again a difficult matter to figure. It has been approximated, and one approximation that I have seen made is that a hole--say the size of your hat-in the top of a cell will allow gas to flow out at a rate of about 10,000 cubic feet per minute; one of the large cells holding 900,000 cubic feet of gas, that would be 90 minutes for that cell to deflate through that particular hole.
Representative ANDREW. If a girder broke in such a way, it might conceivably tear 2 or 3 yards, might it not?
Commander FULTON. We had a case in Akron recently in the Macon, where in handling one of the cells there was a tear like a barn door, 20 feet on one side and 30 feet on the other side, and it took them about half an hour, I imagine, to get the edges pulled together temporarily, and there was a loss of about 200,000 cubic feet of gas; the rest of the gas remained in the cell.
Representative ANDREW. Well, if one of those center cells lost all of the gas, that would be about one sixth of all of the gas in that ship?
Commander FULTON. Yes, sir. Representative ANDREW. Well, if it lost one sixth of its gas, we will say one of the big million cubic feet cells, if that were all gone, the gas escaped, would that bring the Akron down very rapidly?
Commander Fulton. No, sir; not if the members of the crew took precautions to adjust the loading conditions along the keel. The
Akron was structurally strong enough to fly with any one of her cells completely deflated.
Representative ANDREW. Do you mean if they kept the engines going?
Commander FULTON. Not so much that as dropping ballast along the keel to ease the loads that come on the different parts of the structure. There are different instructions and different plans made for taking care of just that emergency should it arise. I cannot conceive of anything happening in the Akron that would cause a loss of gas so sudden that the crew, commanding officer, and executive officer in the control car, would not have ample time to take the necessary ste to adjust the load and continue to fly the ship.
Representative ANDREW. That would be a very sudden operation if two girders broke and tore a great gap in the cell, there would not have been very much time, would there, for orders to have been given?
Commander FULTON. There would have been reasonable time, sir; it is hard to believe the breaking of two girders as described by Deal could have caused any damage to a gas cell, because they are located several feet away from the gas cell; the girder is so restrained by the other parts of the structure that it cannot fly apart, so to speak.
Representative ANDREW. Do you mean the girders are so tied together that they would not bend in and the lower end of the girder puncture herself?
Commander FULTON. I think that is hardly possible.
Colonel BRECKINRIDGE. Would the escape of a large quantity of gas have been noticeable by the personnel?
Commander FULTON. Yes, sir; it would have been noticeable to people walking along the corridor, because the percentage fullness of the cell would have decreased very rapidly.
Colonel BRECKINRIDGE. Would it have had any physical effect on that personnel?
Commander FULTON. No, sir; the escaping helium would go upward. There are men on watch in the keel at all times to keep an eye on the gas cells; unless we admit those men failed in their duty, there would certainly have been some warning, several minutes' warning, of any rapid escape of gas.
Representative ANDREW. With the ship tossing around in the middle of the night, would there have been light through there so that they could keep watch on the gas cells?
Commander Fulton. Yes, sir; there are lights.
Representative HARTER. If those two girders that were alleged to have broken by Mr. Deal, it would seem as though the gas cell would not have been immediately adjacent to the girders at the point of the alleged fracture?
Commander Fulton. No, sir; it could not have been; if it had been, it would have obscured his vision.
Representative HARTER. Now, there was considerable testimony yesterday with reference to the radio equipment of the Akron, and we have had testimony that the outlying antenna was hauled in on account of supposed danger from lightning. Where was the auxiliary antenna located in the ship?
Commander Fulton. There was a fixed receiving antenna which led from two short struts, one located about abreast the control car on the port side to another strut near the equator of the ship on the port side; that antenna was about 100 feet long, I believe. That was what you might call a horizontally disposed antenna. The other antennas were trailing type antennas which could be lowered and reeled in as occasion required. They were located--the reels were located in the radio room. In addition there were one or two smaller antennas for special equipment. The crew, I believe, had a radio receiver and there was a small antenna for it.
Representative HARTER. I have no further questions. Colonel BRECKINRIDGE. Thank you very much, Commander. Mr. Chairman, there are one or two little administrative details I would like to talk to the committee about.
Senator Walsh. Mr. Chairman, I have been necessarily absent from the committee, attending the sessions of the Finance Committee. I would like to inquire as to what extent the committee have given study and consideration and heard evidence on the question of the importance in value of dirigibles for commercial and defense purposes.
Representative DELANEY. That matter has been discussed, as far as the use of these dirigibles in case of war or for war purposes; the resolution provides only for the investigation of the disaster and future development of this craft; we are bound by that resolution and the question of commercial airships only enters it collaterally, Senator.
Senator Walsh. It seems to me that our work, our findings so far as it relates to reaching a decision as to how this accident happened, is of less importance than it would have been some time ago, perhaps, but I do think whatever decision we may reach as to the future policy of our Government in connection with the use of dirigibles is of great importance.
Representative DELANEY. That is the plan of the committee, Senator.
Senator Walsh. So that there has been considerable evidence in the record, pro and con, on that subject?
Representative DELANEY. Absolutely; we have 2,500 pages of testimony dealing almost exclusively on that particular subject.
Senator Walsh. I am very glad to hear that. Representative ANDREW. Especially from a military point of view. Senator Walsh. Rather than commercial? Representative ANDREW. Yes, sir. Representative DELANEY. Before the committee adjourns, Senator King has just paid your vice chairman a tribute. I think it is in order for me to extend to the members of this committee, both Senators and Representatives, my thanks for your unselfish work for the last 3 weeks. It has been a trying time for all of us, especially for the Senators, because of the congestion of the work that they have in their branch of Congress, and I think that the thanks of the vice chairman, and I think the chairman will agree with me as well, should go to the committee for its work in this investigation.
Senator KEAN. Mr. Chairman, I would like to move that the thanks of the committee be tendered to counsel of the committee who has done such a magnificant piece of work for the committee; he has been at our call and conducted this investigation very ably, and I would like to move that a vote of thanks be extended to him.
Representative HARDER. I will second that motion.
Representative DELANEY. A motion has been made by Senator Kean and seconded by Congressman Harter, that it be the expression of this committee that a vote of thanks be extended to the counsel of this investigating committee for his untiring efforts during these past 3 weeks. Do I hear any objection to that motion?
The Chair hears none, and the thanks of the committee, Mr. Counsel, are extended to you.
Colonel BRECKINRIDGE. Counsel appreciates that very much, Mr. Chairman, and also the indulgence and patience of the committee.
(Lieutenant Commander Rosendahl supplied the following data as previously requested by the chairman: The maximum altitude attained by the U.S.S. Akron on its flight to the west coast in 1932 was 7,000 feet above sea level. The amount of helium valved in crossing the mountains and in mooring at Camp Kearney was 20 percent of the total carried from Lakehurst, N.J.:)
CONFIDENTIAL MEMORANDUM SUBMITTED TO THE SECRETARY OF THE NAVY
FEBRUARY 26, 1931
UNITED STATES NAVY AIRSHIPS “ZRS-4" AND "ZRS-5"
INFLUENCED BY THE DESIGNS OF THE BRITISH AIRSHIP “R-101 " In the designs of the U.S. Navy airship ZRS-4 basically are constituted the fundamental principles, essential elements and constituent features of the superairship designed and developed in 1914 by the Schuette-Lanz Airship Building Co. of Germany which have been accepted, established, and recognized throughout the world as basic and indispensable in the construction of rigid airships. However, radical departures have been instituted in the skeleton structure of the airship ZRS-4 by incorporating the inherent characteristics of the fated British Admiralty airship R-101, the designs of which were obviously the basis for the design of the United States naval airships ZRS-4 and ZRS-5.
The outstanding radical departure in the skeleton structure of the British airship R-101 was the substitution of the shallow ring of inherently heavy construction of small triangular cross section, without any vitally essential internal transverse bracing. According to eminent aerostatic authorities, this disregard of a fundamental requisite was one of the causes for the collapse of the skeleton structure of the airship R-101.
This heavy construction characteristic of the British resulted in a much overweighted airship of 230,720 pounds, with a buoyancy factor or useful load of but 27 percent of the gross lift.
In consequence, the airship R-101 was reconditioned and its volume increased from 5,000,000 cubic feet to 5,500,000 cubic feet capacity in order to obtain a needful useful load of only 35,000 pounds-still a very low buoyancy factor or useful load of but 36 percent of the gross lift.
In the Navy airship ZRS-4 of 6,500,000 cubic-feet capacity, gross lift 406,250 pounds, the basic, universally adopted, Schuette-Lanz method of construction as exemplified in all Zeppelin superairships including the Los Angeles and the Graf Zeppelin has been set aside for the radical methods of construction typical of the British Airship R-101—the shallow, inherently heavy, triangular section, ring structure of practically the same dimensions also without internal transverse bracing, a fundamental requisite for the insurance of the integrity and efficiency of the airship as a whole.
The weight of the Navy airship ZRS-4 of 221,000 pounds approximates the weight of the British Admiralty airship R-101 of 230,720 pounds, but when compared with the basic type of the Schuette-Lanz Navy design, with a weight of 182,655 pounds and the Burney-Vickers airship R-100 with a weight of 184,000 pounds, it represents an excess of 83 percent over the weight of the basic type of airship required by the Navy competition of 1928.
The weight of the Navy airship ZRS-4, 221,000 pounds, amounts to 55 percent of the gross lift, with a buoyancy factor or useful load of but 45 percent, while the requirements specified for naval airships demand a buoyancy factor or useful load of not less than 55 percent, which is unattainable in an airship of such excessive weight, with consequent limited endurance and restricted radius of action.
The basic type of the rigid airship has been universally recognized in the 20 Schuette-Lanz airships SL-2 to SL-22, which type was accepted and wholly adopted and exemplified in the 45 Zeppelin airships from L2-72 to LZ-126—the Los Angeles and LZ-127--the Graf Zeppelin, also in the Shenandoah and in the basic design of Schuette-Lanz tendered, informally, in 1928, in the “Navy Department airship design, data competition.”
The Burney-Vickers British airship R-100 of 5,000,000-cubic-feet capacity closely follows the basic type of rigid airship construction. The airship R-100 weighs 184,000 pounds with a buoyancy factor or useful load of 41 percent of the gross lift, and compares favorably in design with the basic design of Schuette-Lanz for the United States Navy airship of 6,500,000 cubic-feet capacity, weighing 182,655 pounds with a buoyancy factor or useful load of 55 per cent of the gross lift.
Comparative analysis U.S. Navy designs with the British designs (U.S. ZRS-4, 1928; Schuette, U.S. Navy, 1928; British Admiralty R-101, 1924; Burney-Vickers R-100, 1924)
785 777 709 784
4, 480 4, 200 4, 200 4, 800
Feet 221, 000 230, 720 184, 000 182, 655
Load 185, 250 129, 805 128,000 214, 597
33 133 134
1 Dimensions Schuette U.S. Navy design specified by the Navy airship design, data in the competition of 1928.