One Hundred Years of U.S. Navy Air Power (77 page)

NOTES

    
1
.
  
For more details of ships and of carrier designs see the author's
U.S. Aircraft Carriers: An Illustrated Design History
(Annapolis: Naval Institute Press, 1983). For British development see also this author's
British Carrier Aviation: The Evolution of the Ships and Their Aircraft
(Annapolis: Naval Institute Press, and London: Conway Maritime Press, 1988).

    
2
.
  
The April 1942 Doolittle raid on Tokyo by Army B-25s launched from the carrier
Hornet
seems to have inspired Navy interest in a carrier-borne medium (twin-engine) bomber, the abortive Grumman TB2F. Work on this airplane was cancelled in April 1944 on the explicit ground that, now that the Japanese had early warning radar, surprise air strikes were no longer possible. In 1945 OpNav suggested a program of carrier raids on Japan that, it claimed, would deliver about 60 percent of the bomb load the Army's B-29s could drop. The much smaller bomb loads of carrier bombers would be balanced off by their great numbers and by the much shorter turnaround (and greater readiness) of the carrier aircraft. Presumably the early 1945 carrier air raids on Tokyo were intended to demonstrate this capability. They were not particularly successful, but they did indicate intense interest in a new application of carrier air power. It should be kept in mind that the U.S. Navy had long required its torpedo bombers to fill an alternative heavy bombing role (with 2,000-pound bombs). Navy planning documents for the bombing campaign (Operation Hotpoint) are in the RG 38 collection, College Park division of the National Archives.

    
3
.
  
By way of contrast, the Royal Navy justified its postwar carrier fleet largely as a means of protecting shipping against just this threat. It had experienced large-scale land-based air attack both against convoys to Malta and against those to Russia. Too, the Royal Air Force was quick to slap down Royal Navy attempts to develop carrier-based land attack capability.
The new U.S. Air Force had similar hopes, but found them more difficult to realize, particularly since President Harry Truman explicitly gave both the Navy and the Army (later the Air Force) authority to develop the means to deliver nuclear weapons.

    
4
.
  
The later Maritime Strategy was much closer to earlier classic Navy thinking, which had never received much publicity outside the Navy. One consequence was that the Maritime Strategy was greeted by many in the wider defense world as a new and aggressive departure from a less “provocative” way of thinking. In his memoirs, Admiral Zumwalt explained that his approach had been much affected by his experience in the McNamara Defense Department, which originated the way of describing military forces in neatly defined compartments like “general purpose” and “strategic.” When Admiral Zumwalt first enunciated his new strategy, an anonymous OpNav captain commented that reducing the Navy to a defensive sea control role fatally offered the initiative to the Soviets.

    
5
.
  
For years, readers of Soviet naval literature, such as Robert Herrick and Jamie McConnell, had made this point, but it was difficult to reconcile with the existence of a large Soviet submarine fleet. In recent years writers from the Office of Naval Intelligence have claimed a crucial role in the internal naval debate; sometime early in the 1980s, they say, they obtained direct evidence of Soviet thinking that backed up the U.S. analysts. Some unofficial accounts of U.S. naval activities in that period refer to interception of crucial Soviet undersea cables, which may have provided the evidence in question (alternatively, successful agent operations may have been involved). Exercises seemed to show clearly that, once the U.S. Navy showed its willingness to apply pressure to Soviet naval forces in waters nominally under their control, the Soviets would adopt a defensive stance. Yet another factor was the dawning realization that the one maritime resource the Soviets would feel compelled to defend was their fleet of ballistic missile submarines, which were designed to operate in just those waters.

    
6
.
  
On 27 April 1945 DCNO (Air) set up an informal advisory panel on carrier design. Its first task was to recommend characteristics for a follow-on to the wartime
Essex
class, which was then envisaged as a 35,000-ton carrier. Papers are in a SCB 6A file, naval air history collection, Naval History and Heritage Center. SCB 6A was the abortive supercarrier
United States
. While the new design was being developed, interim improvements to the
Essex
and
Midway
classes were authorized.

    
7
.
  
On 11 December 1945 BuAer Chief, Rear Admiral H. B. Sallada described alternatives to the Chief of Naval Operations: one class of bombers (A) that could operate from a
Midway
-class carrier; another class (B) that could operate from a
Midway
under more restrictive conditions (incapable of being struck below, but capable of landing-on in light condition and of taking off fully loaded); and a third class (C) that would require a new class of carrier. All of these aircraft would be powered by turboprops, and each would carry an 8,000-pound bomb. Class A would take off at 30,000 pounds (the heaviest existing carrier aircraft took off at less than 20,000), would achieve 362 knots at sea level, and would have a combat radius of 300 nautical miles. Class B would take off at 45,000 pounds, would achieve 500 knots at 35,000 feet, and would have a combat radius of 1,000 nautical miles. Class C would take off at 100,000 pounds (landing weight 45,000) and would achieve the same speed, but would have a combat radius of 2,000 nautical miles. Each could carry a single 12,000-pound bomb at a price in range. Alternative designs using piston engines or combining piston engines and jets would sacrifice speed and range. The letter recommended that a program be begun, beginning with an airplane in class B using piston engines and jets (so that it could be completed as quickly as possible). Based on an internal study, it should take off at 41,000 pounds, and should achieve 500 knots at 35,000 feet using jets to boost it; combat radius should be 300 nautical miles. This was the Savage. The follow-on A2J was conceived as the B airplane. A copy of this paper is in the SCB 6A file at the Naval History and Heritage Center, Naval Air Section. Admiral Sallada's letter in turn was probably
based on a 12 October 1945 Aircraft Design Report prepared by the BuAer Aviation Design Research (ADR) Branch to determine the characteristics of a bomber limited by the existing carrier weight limit of 30,000 pounds and the arresting gear limit of ninety miles per hour, carrying a 7,000-pound bomb, responding to a verbal request. ADR practice was to sketch a design to test the effect of stated requirements; in this case it estimated a gross weight of 40,085 pounds and used a combination of two R2800 turbo-charged piston engines and three 24C jet engines (the type that powered the new FD-1 fighter). ADR estimated that such an airplane could reach 520 miles per hour (about 450 knots) at 35,000 feet, and that it would have a combat radius of 300 nautical miles, the minimum acceptable. The study is in the BuAer VV file for 1945 in RG 72 at the College Park National Archives center. Because the longer-range bomber was never designed, BuShips carrier designers used the product of another series of studies (ADR 62 and 64) to provide them with the footprint around which they designed the SCB 6A supercarrier. These studies were ordered on 13 February 1946, and performance objectives for the new airplane outlined in OpNav letters (from Op-05, DCNO for Air) laid out in letters dated 5 January 1948 and 10 March 1948. Of the two ADR studies, only ADR 64 was formally reported (11 June 1948). It became the basis for an informal design competition.

    
8
.
  
An outline specification (which apparently has not survived) dated 23 December 1947 was circulated within BuAer, comments being required by 5 January 1948. Comments from the Aircraft Specifications Branch suggest that maximum weight was 100,000 pounds and that the speed initially demanded seemed low; the branch wanted a minimum of 525 knots at 40,000 feet. Absolute minimum combat radius was set at 1,700 nautical miles. At this point the study was designated ADR 62. Meanwhile a second attack airplane (ADR 56) was also under consideration: the high performance seaplane that later materialized as the P6M Seamaster; however, it was also sometimes designated the attack aircraft with an unorthodox arrangement, a description that would apply to several of the abortive designs for aircraft to operate from the big new carrier. By September 1948, the weight limit was 100,000 pounds and the bomb load 10,000 pounds (i.e., an atomic bomb), with combat radius of 1,700 nautical miles (from a 24 September 1948 letter from the BuAer Chief to the Office of the Secretary of Defense, directed to Captain H. D. Riley, USN); this was Operational Specification OS-111. Lockheed regarded the 100,000-pound limit as impractical, and asked that it be extended to 125,000 pounds (BuAer refused). Several of the designs were clearly unsatisfactory, leaving four: three-engine designs by Convair and by Douglas Santa Monica and twin-engine designs by Curtiss and by Douglas El Segundo. The twin-engine designs offered marginal performance but the three-engine designs were already at the 100,000-pound maximum weight and would not meet the required radius of action. By this time it seemed that lighter nuclear weapons were in prospect, so BuAer suggested reducing the required bomb weight, thus making the twin-engine designs considerably more attractive (the reference to nuclear bomb weight is obvious in retrospect, but was not explicit in the document). The Douglas design was considered superior to the Curtiss. Moreover, the Douglas bomber could fit aboard a
Midway
, and it could operate from that ship if the deck were strengthened and a more powerful catapult installed. A 31 January 1949 memorandum therefore recommended beginning negotiations with Douglas, for what became the A3D (later A-3) Skywarrior. The Curtiss bid was somewhat lower, but Douglas was accepted as superior from an engineering point of view, and also because of Douglas' superior record of designing and building naval aircraft. Heavy attack was so important “to the future of naval aviation, and compromise in an engineering choice because of cost of the experimental airplane is certainly not to the best interests of the government.” It seems clear that by this time the supersonic requirement had been abandoned, but it is not clear when that was done. No formal change was made in the required bomb load (because it would have required re-opening the competition),
but the prospect of a reduced bomb load certainly made the choice more attractive. There was some interest in buying both the Douglas and the Curtiss prototypes; as one senior BuAer staffer put it, “never before has the fate of the Navy been so dependent upon the success of a single ship and to tie the success of that ship down to a single [aircraft] design seems to be considerably less than prudent.” Late in February 1949 Douglas was told to study the effect on range of reducing the bomb load to 6,000 pounds (while retaining sufficient structure to support a 10,000-pound bomb). The object was to reach the desired 1,700 nautical mile figure. In addition to the subsonic long-range bomber, BuAer became interested in a “special attack” airplane (OS-115): a single-shot or composite airplane capable of achieving higher speed over the target, only the crew element returning to the carrier (it was sometimes described as a piloted missile). This requirement was stated in February 1948. BuAer wanted a cruising speed of Mach 1.2 and a maximum speed above that. The competition was limited to seven companies: Martin, Grumman, Douglas El Segundo, Chance-Vought, Douglas Santa Monica, Fairchild, and Consolidated San Diego. Prior to the issue of the specification, three companies had submitted “superficial” studies. All offered composite aircraft that jettisoned most of their airframes before flying back to the carrier. Grumman's piloted module flew in tandem with the bomb carrier, which separated over the target. On this basis it could take off at 97,000 pounds and cruise at Mach 1.13 (which was also maximum speed). Martin, which specialized in flying boats, offered a droppable seaplane hull, taking off at 110,000 pounds, and achieving a cruising speed of Mach 0.85 and a maximum speed of Mach 0.93. Its crew module could operate conventionally from the carrier; otherwise it would drop the hull for the high-speed leg of the mission. Douglas El Segundo offered a piggyback arrangement (its crew module was essentially its X-3 research airplane), taking off at 65,000, cruising at Mach 1.4, and achieving Mach 2.0 over the target. The Douglas proposal showed that the attempt to reach Mach 2 (a remarkable figure for the time) was impracticable: radius was only 459 nautical miles with a 13-nautical mile run-in at maximum speed. Fairchild offered a 10-engine tailless airplane so heavy that it could operate only from the new supercarrier. Radius was given as 1,350 nautical miles with a 650-nautical mile run-in at Mach 1.1. Martin offered the same flying boat it had proposed for the heavy bomber competition, and it was rejected as subsonic. The proposal by Douglas El Segundo was attractive, with 1,700-nm radius (but supersonic run-in was reduced from the specified 1,000 nautical miles to 570 nautical miles). However, its engine ratings were considered unduly optimistic. The proposal was rejected because El Segundo was already heavily loaded with other Navy work. Convair's was the only proposal that met or exceeded the design requirements while showing an adequate understanding of the problem. Its droppable pod incorporated three J40 engines; the escape vehicle on top was much like the XF-92 delta. The bomb was dropped from the pod before the pod itself was jettisoned. Convair was therefore recommended for further development. The use of a pod to make a supersonic bomber practicable suggests the pod Convair incorporated in the B-58 Hustler, designed in the early 1950s. None of the designs incorporated the area rule, which later turned out to be a crucial feature of supersonic aircraft; and probably none could have achieved anything like the expected speed. The special attack project was cancelled on 2 May 1949, officially because of cuts to the FY51 budget, and more probably because the big new supercarrier
United States
had been cancelled. This material, including sketches of the design alternatives, is in the VA (attack aircraft) folder in the BuAer confidential correspondence series (RG 72, Box 158 in this series) in the National Archives College Park, MD, branch. The OS-111 and -115 designs are also illustrated, in greater detail, in Jared A. Zichek,
Secret Aerospace Projects of the U.S. Navy: The Incredible Attack Aircraft of the USS
United States,
1948–49
(Lancaster, PA: Schiffer Books, 2009).