Among the arrows in the quiver of our national defense the rigid airship seems neglected, largely because of little knowledge of its capabilities. In presenting this article, the purpose is to give information concerning airships and it is the intention to confine the contents to facts so far as humanly possible. It is well known by serious-minded proponents of the dirigible or any other new endeavor that extravagant and imaginary claims of enthusiastic friends do more harm than good and leave so much misinformation and delusion that a careful analysis of the real value of the project cannot be made. It is unfortunate that the general public, and even naval officers, have little reliable knowledge of airships.
Most people have had to depend upon the public press for their ideas and knowledge of these scouts of the air. These press reports are usually written by persons not familiar with the technical aspects of aviation and bring out more of human interest than of knowledge useful to a naval observer. The Zeppelin type is so new and unusual and grips the imagination of the public to such an extent that news of any casualty becomes a front-page story. A few years ago a mistaken order during ground handling of the Akron caused damage which cost $8,000 to repair. This was big news. During the same week on one day three Navy planes, one of which cost $60,000, were demolished in the neighborhood of Washington and this news took only two inches of one column. Thus the public gets its information concerning airships!
So far as real naval tests and problems are concerned there have been few opportunities for the collection of facts and data on performance, and even for this meager employment, the reports unfortunately have been confidential and available to only a few. Of course there is no reason for publishing it to the world if our Navy has a new weapon of value, but at the same time, unless this information is available to our naval officers, our assets in airships will be unknown, and snap decisions, perhaps of condemnation, will prevail. The higher commands thus would not be familiar with this weapon's potentialities and therefore unable to employ it to advantage and give it a fair trial. If all the facts are taken into consideration, it can be shown that in scouting problems so far actually worked out the Zeppelin has acquitted itself with great credit and shown valuable ability.
One of the first objections to the use of airships is the cry of vulnerability! The airships are comparatively vulnerable, but not to the extent of the seemingly common opinion of the man in the street. Many think that a few machine-gun holes in the gas bag and the machine is done for. They do not realize that there is little pressure even in the top of a gas cell (and none at all at the bottom) and that gas escapes very slowly through a hole, thus allowing time for repairs or return to base. Witness the four large (32 in. in diameter) gas valves in the top of a large gas cell of the Maeon, and still, with all valves open in all cells, several minutes are required to make a very appreciable change in the lift of the airship. A few years ago a man dropped a file in a propeller and did not report it for fear of punishment. Two days later it was noticed that the cell near the propeller had lost 2 per cent of its gas. On examination 19 holes from 1 to 9 in. long were found in it. Many machine-gun holes will not do serious damage to the buoyancy, nor can they do much harm to the structure.
The danger of the present gasoline installation is that of a gasoline fire from incendiary bullets. In spite of the fact that great attention has been given to the installation of fire extinguishing apparatus, a gasoline fire might be a very serious thing and cause an emergency landing and destruction of the ship. However, a light Diesel engine is being developed and it is hoped that soon a change may be made to use of heavy oil instead of gasoline, which will reduce this hazard to a great extent.
The delivery of a bombing attack is a different thing. Although the structural members are far apart and one bomb probably would not be serious, several bombs might be compared to a torpedo hit on a cruiser so far as buoyancy and structural damage are concerned. During the World War, Zeppelins returned to base badly shot up and with nearly one-third of the gas cells deflated. Similar to the bombing attack is the encountering of anti-aircraft fire of high-explosive shell. The remedy, of course, is to avoid localities where such may be expected, and the usefulness of the airship is limited thereby—if there exists any usefulness in trying to be in those localities.
Another cry sometimes raised is the vulnerability to weather. This has been almost totally overcome by weather information, greatly improved air-keeping structural qualities, and skill of handling. There are some atmospheric disturbances that tear down trees, wreck buildings, etc. However, the strain on an airship in the air in a storm is comparatively light for it is submerged in the moving medium and, if it had no motion from its engines, would suffer only from the turbulence of the atmosphere. Strains will be set up on the structure if the ship progresses at high speed from one air current to another, but these stresses are well cared for in modern airship design. If the ship is attached to the ground, as is a tree or building, it will suffer the full effect of the wind. To illustrate the difference there is cited the experience of the Shenandoah several years ago. While moored to the mast the upper fin covering was exploded (due to lack of ventilation holes) and this threw the ship off wind. An ensuing 75-m.p.h. gust broke her away from the mast, tearing out the nose and the forward two gas cells. As soon as she was in the air, the engines were kept at low speed with the ship headed into the wind. All strain on the structure was immediately eased, and in spite of the serious damage, loss of lifting gas, and with half the rudder gone, she was able to return to the landing field when the wind abated.
Ground handling also has been greatly improved by the working out of mechanical means which give greater security in bad weather as well as reduce the required ground crew to not more than threescore men. The knowledge gained by our operations has also led to the proper location of hangars and operating bases, taking into consideration the surrounding terrain, etc., so that at these properly located bases, an airship can moor or depart in any given 24-hour period and can show a very high percentage of on-schedule operations. It may have to delay departure at times just as surface vessels await favorable tides. On the other hand it may be able to takeoff in certain conditions of fog, etc., when other aircraft are held on the ground.
The size of target and its visibility are also held as a disadvantage, and so they are. It is admitted at once that the Zeppelin has no business within range of a surface ship, but ordinarily there is no reason for it to come within range. The airship will remain out of range the same as any ordinary carrier which must remain undamaged to perform its full mission. It can do its work as a scout out of range. In a fog or low visibility it takes the same handicap as a surface vessel, but this does not condemn its usefulness any more than it condemns any other scout cruiser. No warship can be of much use in a fog. Certain types of clouds and visibility are a very great aid to it. Clouds afford concealment from which momentary emergence may be made for examination of the locality. In addition, the use of a "spy basket" or observation car enables the airship to cruise in the clouds and lower an observer with a telephone below the cloud layer. He can report his observation, conn the airship as desired, and even direct the dropping of bombs from the invisible carrier. It is often the case, particularly on the Pacific coast, that "high fog" or low ceiling practically causes the cessation of airplane flying both from ships and from the shore. In the case of a fleet approaching the land, the admiral wishes to know the concentration of aircraft on the fields in the vicinity and whether or not they are operating. The forces on shore wish information of the approaching fleet. Both are in the dark. This illustration is taken from an actual circumstance that occurred in maneuvers a few years ago, and perhaps has occurred since. For either side, the airship with its spy basket could obtain the information so urgently desired.
Even if we should assume the airship so vulnerable that the chances of her destruction are more than 50 per cent, if she makes an effective contact with an enemy fleet, is she not still worth the investment? In nearly every scouting exercise, the scouting vessels suffer losses of a few destroyers and/ or cruisers in making or developing contact and gaining information. This is taken as a matter of course and little comment ensues. Such casualties are expected. War cannot be waged without taking risks. Even one destroyer represents more men and more dollars invested than an airship. Would it not be better to sacrifice an airship than a destroyer or cruiser? The chances are that the Zeppelin will have forwarded accurate and comprehensive information before she can be driven down.
Another disadvantage sometimes cited is the comparatively low altitudes to which the dirigible is confined. There is no valid reason for this objection. Any experienced airplane pilot will tell you that 90 per cent of his scouting is done at altitudes below 1,500 feet. The horizon is 90 miles distant from an altitude of 6,000 feet but the atmosphere is seldom clear enough to see that far. During the World War, airships could ascend above the altitude to which most planes could fly but such is not the case with modern planes. Since the airship cannot get higher than a fighting plane, it is of no consequence if it can ascend only 10,000 or 15,000 feet, for there is no other reason to gain these altitudes, except the seldom encountered circumstance of seeking concealment in very high clouds. Airships can be built for an altitude of 25,000 feet if such is required in their employment. They can climb as fast or faster than the average plane of today, but this loses all advantage if a higher altitude cannot be reached. However, a loaded bomber or patrol plane still can be outclimbed both in rate of climb and altitude.
Criticism of the speed of the airship as compared with the plane is hardly justified. Higher speeds for airships are desirable and improvements are made progressively in this direction. However, the discrepancy between the speeds of the two aircraft is not so great as to limit the value of the dirigible to a great extent. The speed available is sufficient for nearly all missions in view. Even if speeds of 300 m.p.h. were available, an increase over this still would be desirable.
The main use of speed for the airship other than that of scouting over large areas in short time is to escape from airplane attack. For the service plane of today, the discrepancy in speed between it and the airship is about 30 knots. If one takes the plane's radius into consideration and the maximum distance the plane desires to go from its carrier, it can be seen that in average visibility the airship can come close enough to obtain visual information and still escape. In addition, other considerations come into play regarding the dispatch of planes to attack an airship. Many times the planes are required to remain in the immediate vicinity of the carrier for protection of that craft from aircraft or other attack. Again, approaching darkness may make the execution of attack on the airship undesirable. The planes may be required for other missions such as impending action of surface forces so that it is not desired to have them pulled out of the area.
On days of good visibility, the airship can remain well clear of dangerous areas and still give effective information of what is going on in these localities. In a recent problem the air scout was able to take station where it could see both the convoy and main body of an attacking force which were separated by 100 miles. On this day effective visibility from the airship was 70 miles. In another case, the airship made contact reports unobserved from a distance of 55 miles. Remember that the airship has a comfortable" crow's nest" and high-power glasses.
At distances at which the airship can identify surface craft, she should be seen equally well. However, she is close enough to observe the area and far enough to escape planes launched for pursuit. Taking this into consideration along with other demands upon the planes, it is understood why it may be possible for an airship to maintain observation without being attacked. This has happened in exercises. It is realized that a number of planes will be necessary to overcome the fighting planes and machine guns of the Zeppelin, and the enemy commander will have several important premises to consider before he detaches a number of planes to drive off the airship.
The hoped for performance of airships has not been realized as soon as promised by their supporters. This is true in any line of pioneering and development. All such efforts have their trials and tribulations. The submarine and torpedo have the same history. The airplane has progressed faster because more effort and resources have been expended upon it. The airplane also has been helped by commercial development. Given the same impetus in development of design, new construction, and employment as heavier-than-air, the airship would be far superior to what it is today. Practically all the development of the airship since 1920 has been by our Navy Department. This includes hangars, mechanical ground handling, reduction of ground crews, production of detached operating bases at small cost (stub mast), and design and operation of the craft. Working out problems has been intensely interesting to the personnel involved.
While solutions to some of the problems seemed very slow, a review of accomplishments shows a record of which our Navy can be proud. Delays were disheartening, but advance really has been steady and rapid. We have gained knowledge primarily from experience, but many other sources have contributed and we always have gained lessons from casualties.
Their primary mission is long-range scouting. We send cruisers, destroyers, and submarines out long distances to obtain information of the enemy. In most cases airships could get the information much more quickly and without the detachment of so many combatant ships from the fleet concentration. Even if the dirigible were of value only for negative information, it is worth the investment. If it can assure the commander in chief that the enemy is not in a certain area, it allows him to concentrate his surface vessels in the most probable area with the consequent valuable advantage. Information has everything to do with disposition of our own forces. In several of the fleet problems, the defending forces have been divided into several small groups and scattered over large areas contiguous to the coast, and no knowledge of the movements of the approaching fleet was available to them. Economical use of surface vessels and demand for information from long-distance scouts point to the necessity for the use of the rigid airship. Fast scouts are in demand and here we have one with speeds somewhat comparable to that of the airplane, and of vastly greater radius. In addition, the habitability of the airships affords space for complete navigation facilities, communication facilities equal to that of any cruiser, and hence the forwarding of accurate information over long distances immediately after contact is made. The navigation of airships is approximately as accurate as that of surface ships.
Cruising in fog, rain, darkness, low temperature, etc., offers no more disadvantage than the surface craft experiences. In addition, the ability to slow down and even to hover can be used to advantage in certain circumstances.
Many missions besides long-range scouting may be executed under favorable conditions. Tactical scouting can be carried out efficiently when the airship lies back and sends in its planes. During darkness, tactical scouting by any form of aircraft is almost impossible. Reconnaissance, bombing, photographic missions, submarine patrol, offshore patrol, convoy escort, decoy work, can all be carried out. If demanded, transportation of officers and troops and even important supplies can be undertaken on short notice. Thirty tons of supplies, ammunition, or troops could be transported from San Francisco to Hawaii by the Macon within 33 hours. What would 6 ships do?
So far little has been said concerning the carrying of planes. The uses of airship-based planes compare to those of any other carrier. While the surface carrier is generally well protected by combatant vessels of its own fleet, the airship ordinarily has to operate independently and depend upon its armament and planes for defense. Occasionally it can seek protection of its own fleet as does the surface carrier. The airship mounts heavy machine guns and can give a good account of itself against a small number of planes. Except in unusual circumstances, a large squadron of planes would not be sent to attack an airship.
The use of airplanes from a carrier is much more valuable and continuous than from other ships. The airship carrier even has certain advantages over ·the surface carrier. It does not have to head in to the wind to launch or to recover its planes as both craft are floating in the same medium and, relative to each other, there is no wind. Planes can be operated from it at night with facility equal to that of daylight operation and without bright lights on the airship.
The use of planes to enlarge the scouting area gives enormous advantage to the airship. With five planes, the outfit at present (and more could be provided on present or future ships), one plane can be stationed continuously on each side of the airship. If the visibility is 40 miles and the planes are 80 miles abeam of the airship, this allows the sweep of an area 240 miles wide at a cruising speed of 60 knots.
Covering 172,000 square miles in a day's work is quite a feat for a vessel costing less in men and money than a destroyer! X cruisers or other surface scouts would be required to do the same! How much is it worth to have X ships concentrated with the fleet and not far away on a scouting line?
Now it is a mistake to take one example and say that the dirigible is worth X cruisers. Sometimes this is so, and sometimes not. But for some circumstances and for limited periods, it might be worth 50 cruisers. The performance of airships may be so far superior to anything else existing we cannot afford to gamble by not having them with the fleet. If two scout cruisers costing 30 millions and with 1,200 officers and men are sent to scout a certain area or maintain a certain line, they can cover about 0.3 as much as one airship costing 3 millions. The speed of the surface vessels is such that they can advance the line only a few miles a day. If the area is well out to sea, the airship will have it searched and begin its return before the cruisers arrive. The airship can cover in 3 days what the cruisers do in 10 days. Range in visibility does not always permit this superiority, the airship's area being reduced a greater percentage of its total than that of the cruisers' as visibility decreases. It is not contended that airships can supplant cruisers and the need for cruisers is as great as ever in our Navy.
One suggested employment of the Zeppelin type is to guard a train or convoy and supply information of impending attacks, thus allowing concentration of the screen and protecting force. This might also prevent the detachment of part of the escort to chase suspicious ships. Of course, if the airship stationed itself directly over the convoy at all times it would mark the convoy's position, but such would not be done. In addition, the enemy does not know whether or not the airship is with the convoy and it may be a decoy to lead them away or tempt them to divide forces.
We are notoriously short of modern destroyers and will never have the desired number of fast cruisers which are important at the scene of action and needed for support of destroyer attacks and tactical work. Using airships as scouts allows more use of these surface scouts near the main body and we need more destroyers and cruisers. Where speed and radius are paramount nothing takes the place of the airship. It can travel long distances rapidly and give quick, accurate, positive, and up-to-the-minute information immediately. Scouting is important—information is everything! Witness the demands for more cruisers, for more airplanes, and for flight-deck cruisers. Accepting certain objections and weaknesses which are much over-balanced by the demonstrated usefulness, is it not advisable to have airship scouts for what value is now apparent?
If airships promise so much to us, why has Great Britain abandoned her program; Italy confined herself to small semirigids; France and Japan done nothing at all? This may be answered with one word—helium! No other country has this noninflammable gas and a hydrogen-filled craft has no place where it is liable to be attacked. This knocks out the argument and foreign propaganda of those who hold up the examples of other powers which are making no attempt to develop lighter-than-air craft. Nevertheless, it is noted that those countries do expend considerable money in trying to locate helium resources, and helium is in little demand except for lighter-than-air craft.
England does consider airships of value, but, principally on account of economic conditions, has abandoned them. However, she has naval bases suitable for cruiser and converted merchant-vessel operation all over the world. She has no intention of scouting an enormous area of desert sea like the Pacific. Another thought that applies to these countries of small area and close proximity to probable enemies is that their home hangars and operating areas are so close to the enemy that they could be the principal targets of the first enemy attacks. Their bases are within a short airplane hop of the powers on the continent. These countries are not isolated by the large expanse of oceans that surround the United States. In the Pacific an enemy fleet could disappear for a few days or weeks and arrive either at Panama or Puget Sound without being intercepted. Italy and France have no such possible scouting problems confronting them. Italy has no naval problem that requires airships with 8,000- or 9,000-mile radius. Her airplanes can cover her immediate coasts. Japan probably would go ahead with them if she had the helium. The Pacific is too big for us to scout completely with any number of scout cruisers we could build. It has been calculated that 12 rigids could cover continuously any possible fleet approach to our Pacific coast. Thus we find the airship the only scouting vessel within our means that might cover these vast areas in which a hostile fleet might be proceeding. The location of that fleet would determine the entire strategy of the commander in chief, and his disposition of our fleet.
What price information? The fleet may be equal or superior to the enemy but it cannot be victorious if it must be split into a number of divisions and disposed to protect each possible destination of the enemy. Public sentiment has demanded and would demand such protection of our coasts.
The Navy has assisted and does aid industrial development by its endeavors along certain lines. The development of airship operating and ground handling by our Navy has paved the way for commercial transoceanic airship transportation lines. The Graf Zeppelin uses the mooring facilities developed by us on its scheduled trips from Germany and Spain to South America. Economic conditions have delayed the establishment of these commercial lines. If we give further encouragement to them by further progress we develop an asset of untold value in time of war. A commercial airship can be quickly adapted to naval purposes. We control the helium. We have an airship construction company completely outfitted and ready to work. We could keep it alive and prevent the disbanding of its talent if we ordered two more ships at once. More than one ship in operation is needed to demonstrate their uses and possibilities. Two ships can do more than twice as much as one. Prices for labor and materials are the lowest in history. What dividends we would receive if we provide our Navy with a small airship force and establish a commercial project which affords us aerial cruisers instantly available in case of hostilities! We all realize the need of a merchant marine. Here is a chance to support our knowledge of its value. We must give the airship a fair chance to demonstrate its worth. We cannot, in the present state of the art, expect it to go out under every condition and serve every day without asking favors. It has not been tried properly and is still being developed. We learn by using and doing. The one ship has little opportunity to prove its capabilities.
We now have a complete airship operating and repair base on each coast in addition to the commercially owned construction dock in Ohio. There are available now servicing bases in Florida, Cuba, southern California, and Panama with the investment already made. Little further investment is needed in bases or other assets. Our urgent need is more ships to operate for training and development. With these assets and this background we should go ahead building at once. No studious naval officer is convinced of the lack of usefulness of this arm to the fleet. The doubters all say, "I'm willing to be convinced by demonstration."
Now is the time to have a demonstration at small cost. The dividends may be very great and give our Navy a tremendous advantage! If we were to embark on a naval war today we would order more airships and start feverishly to train crews. We would wish to use every arrow in our quiver, and here is one that flies far and true.