Heavy, long-range military or commercial aircraft are designed to carry large loads at relatively moderate speeds. Small, high performance aircraft, such as fighters and dive bombers, must have a high speed, high maneuverability, moderate load capacity, and moderate range.
The performance of each of these two general types is largely limited by the same factor, which is the highest possible landing speed consistent with the safe operation of the aircraft, considering its probable operating circumstances. For a considerable period of their development, performance increase could result in higher landing speeds without arousing misgivings. Today landing speeds have reached values above which it is undesirable to go because of difficulties which would be met in operation under all but ideal circumstances. Military aircraft can frequently expect unfavorable operating conditions. The limiting effect of this factor on aircraft performance has been greatly diminished by general design progress and such engineering expedients as wing flaps, slots, etc., and will doubtless be further reduced. Its importance has increased accordingly, for an increase in landing speed today, if it could be achieved without introducing unwarranted operating difficulties, would allow a much greater increase in top speed, load, and other performance characteristics than the same increment would have permitted 20 years ago.
The aircraft carrier, which is the Navy's primary means of exerting air power at sea, imposes further restrictions upon the performance characteristics of the planes which must operate from them. The lack of space for landing and take-off is compensated for by other means, but the relatively unhampered shore-based landplane enjoys a considerable superiority over its carrier-based counterpart in almost every respect. The desirability of operating higher performance aircraft at sea is obvious. But how are we to get them there?
This is clearly the role for the rigid airship. It alone can satisfy the desirable but not quite attainable conditions unfulfilled in the problem of exerting air power at sea by other approaches. It is the natural vehicle from which aircraft can operate at sea entirely unhampered by wind, sea, and visibility conditions. In 1936 the Hindenburg had a cruising radius of nearly 8,000 nautical miles at a speed of 60 knots, with a pay load of 20 tons. Even this performance is sufficient to carry 6 dive bombers, fully loaded, from Europe to the United States and back. This fact is universally overlooked by the experts who tell us that today we cannot be attacked by air from Europe. It was possible in 1936.
In visualizing the airship as an aircraft carrier, the Hindenburg's capacity of 7,000,000 cubic feet must be considered small. For instance, an airship of 20,000,000 cubic feet capacity having a useful load of 400 tons would be able to cruise well over 10,000 nautical miles at 60 knots, and have a top speed of 80. It could carry, service, and operate 50 planes averaging 3 tons each. To visualize this airship requires a degree of imagination less than one might have been led to suspect, for while it is three times the volume of the Hindenburg, the latter was three times that of the standard World War airship. But imagination has always been important, for without it there can be no progress.
The aircraft based on board an airship would be free of the restrictions which hamper carrier-based planes. Landing speed can be raised to equal or exceed the top speed of the airship. In the case of the Macon , planes could land at speeds considerably in excess of the airship's. With the use of arresting gear, there is no reason why this speed increment could not be brought up to 20 knots or better, allowing planes of 100 knots landing speed to be developed. It is even a little startling to comprehend a seagoing fighter plane capable of 400 knots or better, which could unquestionably be built today. Nor will they be overweight, "beefed up" planes to withstand the rigors of carrier-based or cow-pasture operation. The advantages of doing this are obvious. The latitude permitted the plane designer would bear fruit in producing aircraft superior not only to carrier-based, but shore-based types as well.
Of the several objections which are sure to be made to investing in airships as a major weapon, two are as follows: (1) The past record of our rigid airships; and (2) their assumed vulnerability.
The first is a matter of record, but so is the fact that the airship can be built and operated with the highest degree of reliability. It is logical to assume that we can at least duplicate this success. Vulnerability has always been the great cry against the airship. It may well be analyzed then, especially in the light of its probable role.
In general, vulnerability is a function of the proper, or improper, employment of any type in question. For instance, the submarine which finds itself in position to attack a battleship does not surface and open fire with its 3-inch gun, but relies upon the torpedo, which it was developed to employ. Similarly, the airship must be developed for the plane to utilize and toincrease its efficiency. The airship's defense lies not in a great thickness of armor belt but in its ability to stay out of the contested area, which it possesses to a much greater degree than its surface-bound counterpart, the aircraft carrier.
As to this naval type, a brief study of its vulnerability is appropriate here. The known loss of two aircraft carriers during the current conflict affords interesting and significant reflection. The Courageous, for instance, was torpedoed by a submarine while engaged in the recovery of aircraft. The Glorious was sunk by gunfire from a superior force of surface vessels. The airship is not vulnerable, obviously, to the torpedo, nor need it be to anti-aircraft fire. The wind, into which the Courageous steamed to recover her planes, caused her to cross the path of a watching submarine. Wind, being nonexistent for the airship, except as concerned with its track over the ground, is no factor in its choice of course during the recovery or launching of aircraft. The airship, favored by this fact and a speed of at least twice that of any vessel that may fire on it, should be able to keep clear regardless of the phase of operations.
The vulnerability of the carrier to aircraft attack was well illustrated by the recent example of the Illustrious. According to the widely published account of the American reporter who was on board, the vessel could do nothing but fight a defensive battle for seven consecutive hours. This attack was reportedly carried out by 50 planes, less than the Illustrious herself carried. Although the ship was not destroyed, her primary function was completely, for operation from such a riddled and harassed flight deck became an impossibility. The protection of topside personnel is particularly difficult of solution and perhaps even more essential for an aircraft carrier than for other naval types. There was no mention of the return to the carrier of the few fighters which got off before the onslaught and which accounted for some of the 12 bombers destroyed.
The airship, carrying aircraft superior in range and speed, should be able to launch them farther from the combat area and, by virtue of its own speed, remain out of it.
To supply a sufficiently large number of aircraft to ensure superiority of numbers at any point at sea will require a large number of airships. Much has been made in the press of the mysteries of the construction of airships and the almost supernatural genius necessary to operate them. During the World War, quite average naval officers did a good job of operating rigid airships which had been slapped together in six weeks. In Germany, the three erecting hangars of the Zeppelin organization each produced a 2,000,000 cubic foot airship every 6 weeks, providing a new ship every two weeks for the greater part of the war period. Twenty Schutte-Lanz rigids were built during the war, raising the actual number constructed to almost 100, or one airship every two weeks during the 4-year struggle. Fifty airship crews were trained during the same period. The construction problem for the larger ships discussed here simply involves the employment of more facilities and men. We are naturally endowed with the possibility of providing both in abundance. Both procurement and replacement factors, vital to the vigorous employment of any weapon, are capable of satisfactory solution for the airship, more so than for most naval types. For operating personnel, certainly the man power of this nation, of which naval personnel is typical, can provide men whose enthusiasm and pride will grow with the greatness of the project, as it has already for our expanding aviation arm.
For any power intending to utilize the airship, these essential considerations are similar. Construction sites, since the airship must reside there for a time and is helpless during its building, must be well inland. The hangar must be considered as a dry dock is for surface vessels, in which the airship is constructed or overhauled. Normally, airships can operate from mooring-out bases at or near the coast, from which their departure can be made at any time, to carry out a mission or to avoid attack. Drogue mooring, which was discussed by Lieutenant Rounds in his article, "Teaching an Old Dog New Tricks," in the August, 1940, issue of the Naval Institute PROCEEDINGS, was developed at Lakehurst in the ancient non-rigid J-4, and the fundamental principles demonstrated can be applied to the rigid airship. Moored to this apparatus, the airship is kept at a constant altitude, having been previously "weighed off" light, by suspending from the car a conical-shaped ballast bag which fills with sea water. The ship rides to a drogue type sea anchor by means of a line leading to its bow mooring point. In this manner the ship could be moored for hours at a time with only minor attention to application of controls. A water pickup device was provided which pumped water into the ship while under way or stopped to compensate in a few minutes for weight of gasoline consumed over a period of hours. The corresponding essential equipment will enable the rigid to remain away from her base indefinitely, mooring at sea to replenish fuel, supplies, personnel, etc., from a tender in the same manner as any other vessel.
In the close-coupled European theater of warfare, where most naval action has been confined to coastal or restricted waters dominated by shore-based aircraft, there is little use for the airship. However, in the important and bitterly contested blockade and counter-blockade at sea, both sides could use it to great advantage. For escort purposes it would provide a unit capable of keeping the convoy and the waters in the vicinity under constant scrutiny, and of delivering a powerful blow in the event of attack by submarine or surface raider. The effectiveness of such an attack against a cruiser or perhaps a group of raiders should be high, witness the fate of the Southampton. The military economy of the airship escort would permit release of many cruisers and destroyers for other pressing duties. It could undoubtedly be used effectively for hunting down and destroying surface raiders. Properly equipped, the airship could become itself a most efficient raider.
Since the loss of R-101, Britain's general attitude on airships has been apathetic, although recently the desirability of having them has been expressed in certain quarters. During the winter of 1937 airplane-carrying experiments were carried out with the Hindenburg. It is not likely that the military possibilities of the combination were entirely overlooked.
Intercontinental warfare would render more obvious the desirability-perhaps even the necessity-of making extensive use of the carrier airship. It would provide relatively unmolestable bases from which to operate which only England, of the warring nations, enjoys today. The phrase "Hemisphere Defense" admits the possibility of such a war.
Events in Europe clearly demonstrate that the air struggle is not concerned merely with mass production, but also, and very vitally so, with the development and constant improvement of the performance characteristics of each basic type of aircraft, that it may more efficiently do its job. To provide such aircraft at sea is difficult of attainment. Vastly better ones can be provided by the airship, and at twice the speed and range of today's carriers.
At a time when all weapons, new and old, must be developed to their utmost efficiency, it is difficult to understand how we can overlook the possibilities offered by the airship. To achieve these possibilities, the sense of rivalry which still is found in considerable measure between airship and airplane factions must be completely submerged. Returning to a submarine analogy, there is no more justification for such rivalry than there is between the submarine and the torpedo. As the performance of aircraft progresses it becomes clearer that the functions of the two are almost entirely complementary. The heavy advantage to be gained by air supremacy at sea must focus attention on the airship once more, not in the half apologetic role of a negative scout, but as a naval auxiliary making possible a far-reaching, fast, and powerful striking weapon in a balanced program of total defense.