Craft, vehicles and weapons of War and Peace.

Boeing RB-50F (S/N 47-144, originally B-50B-50-BO) "Macs Effort" with armament. (U.S. Air Force photo)

The evolution of nuclear-armed bombers began with the use of the Boeing B-29 Superfortress, an aircraft designed in World War II to carry conventional weapons. Crews flew this aircraft to drop the 13-kiloton Little Boy atomic bomb that destroyed Hiroshima on August 6, 1945, and the 23-kilotonyield Fat Man that shattered Nagasaki eight days later. The B-29 and a variant, the B-50, then served as the U.S. Air Force’s only nuclear-capable bombers, under the Strategic Air Command, well into the early 1950s. Despite improvements to the propeller engine aircraft and the refinement of operations such as aerial refueling, they were too slow to avoid jet interceptors and lacked the range to hit targets from bases in the continental United States.

The B-50's development was approved in 1944, when the aircraft was known as the B-29D. Still in the midst of war, the Army Air Forces (AAF) wanted a significantly improved B-29 that could carry heavy loads of conventional weapons faster and farther. As World War II ended, the production of thousands of B-29s was canceled. The B-29D survived, but its purpose was changed. Redesignated as the B-50 in December 1945, the improved bomber was now earmarked for the atomic role. The decision was prompted by the uncertain fate of Convair B-36, the first long-range, heavy bomber produced as an atomic carrier. Of course, some of the B-29s that had been modified to carry the atomic bomb remained available, and surplus B-29s were being reconfigured for the atomic task. Just the same, the B-29s of war vintage were nearly obsolete. Hence, they would have to be replaced by a more efficient, atomic-capable bomber pending availability of the intercontinental B-36 or of another bomber truly suitable for the delivery of atomic weaponry.

While the short-range B-50 was immediately recognized as a stopgap measure, the magnitude of the aircraft's development problems proved unexpected. The B-50's first difficulties stemmed from its bomb bay which, like that of the B-29, was too small to house the new bomb and its required components. The fast development of special weapons created more complications, since the individual components of every single type of bomb had to be relocated within the bomb bay's narrow confines.

In keeping with the usual vicissitudes accompanying the development of any new or improved aircraft, the B-50 soon exhibited engine malfunctions. Then, cracking of the metal skin on the trailing edge of the wings and flaps dictated extensive modifications. And while these problems were being resolved, new requirements were levied on the aircraft. In 1949, as the proposed RB-36 remained a long way off, and because of the older RB-29's deficiencies in speed, range, and altitude, some B-50s had to be fitted for the reconnaissance role. To make matters worse, fuel tank overflows, leaking fuel check valves, failures of the engine turbo-chargers, generator defects, and the like continued to plague every B-50 version.

Meanwhile, contrary to plans, most B-50s came off the production lines without the receiver end of the new air-to-air refueling system being developed by Boeing. Additional, and successful, modifications therefore ensued. Nevertheless, the Strategic Air Command (SAC) had no illusions. The B-50, along with the B-36 (first delivered in June 1948), would be obsolete in 1951. That the B-50 did not start leaving the SAC inventory before 1953 was due to the production problems and many modifications of its replacement: the subsonic B-47.

It began as an outgrowth of the B-29, the B-50 can be traced back to July 1939, when Boeing Airplane Company introduced Model 334A, the B-29's first direct ancestor. Specifically, however, the B-50 bomber stemmed from a B-29 conversion, initiated in 1944.

Requirements for the B-29 Superfortress, from which the B-29D (later known as the B-50) derived, were issued in February 1940, when the Army Air Corps asked the aircraft industry to submit designs for a "Hemisphere Defense Weapon." Boeing Model 345 (a further development of Model 334A) was adjudged best of all proposals for bombers with very-long-range characteristics, and the company was authorized in September 1940 to produce the first very heavy bomber to incorporate pressure-cabin installations and other radical changes in design and armament. Development of an improved version of the famed B-29 began in 1944, as a so-called Phase II evolution of the basic design. No specific requirements ensued, but the main intent was to equip the improved bomber with the new Pratt & Whitney R-4360 Wasps and to do away with existing and often troublesome versions of the Curtiss-Wright R-3350 radial engines. The B-29A assigned to the Phase II development project, once reconfigured with the new Wasp engines, was flown by Boeing as the YB-44 prototype. The AAF approved within a few months a production version of the YB-44, which was then designated as the B-29D, and ordered 200 production models of the improved bomber in July 1945.

Japan's surrender on 14 August 1945, 3 months after the defeat of Nazi Germany, prompted the cancellation of military procurement. In the process, the 200 B-29Ds on order since July 1945 were reduced to 60 in December of the same year.

The B-29D became the B-50 in December 1945. Officially, the aircraft's new designation was justified by the changes separating the B-29D from its predecessors. However, according to Peter M. Bowers, a well-known authority on Boeing aircraft, "the redesignation was an outright military ruse to win appropriations for the procurement of an airplane that by its designation appeared to be merely a later version of an existing model that was being canceled wholesale, with many existing examples being put into dead storage.

In any case, the former B-29D featured many changes. The redesignated aircraft, built with a stronger but lighter grade of aluminum, had larger flaps, a higher vertical tail (that could be folded down to ease storage in standard size hangars), a hydraulic rudder boost, nose wheel steering, a more efficient undercarriage retracting mechanism, and a new electrical device to remove the ice from the pilot's windows. The new aircraft's wings and empennage also could be thermally de-iced. Finally, the 4 higher-thrust Pratt & Whitney R-4360 engines that replaced the standard B-29's R-3350s gave a power increase of 59 percent, and electrically controlled, reversible-pitch propellers allowed the use of engine power as an aid to braking on short or wet runways. There was also some rearrangement of the crew. Yet, no matter what designation, there was no doubt that the piston-powered B-29D/B-50 would seem antiquated in the post-war era of jet bombers.

The AAF began to plan for an atomic strike force in the first few months of peace that followed the end of World War II. It ordered that 19 additional B-29s be reconfigured as atomic carriers in July 1946, six months after the improved B-29D had become the B-50. Most likely, the AAF already planned that the redesignated bombers would first supplement the reconfigured B-29s and then replace them until a better atomic carrier became available. But the AAF at the time was not in a particularly strong position to press for what it believed to be essential. Hence, the true purpose of the B-50 program did not become official until the spring of 1947.

Variants

* XB-44: One B-29A was handed over to Pratt & Whitney to be fitted with the new Wasp Major 28-cylinder engines. Initially designated B-29D, this was eventually changed to B-50A in December 1945. (x1, converted)

* B-50A--First production version of the B-50. It had new wings that were stronger and lighter than the units on the B-29. It also had taller vertical tail than the B-29. (x60)

* B-50B--Increase in gross weight over the A model, from 168,480 lb (76,420 kg) to 170,400 lb (77,290 kg). Also included a new type of lightweight fuel cell. (x45)

* B-50D--Definitive production version of the B-50. The 7-piece nose cone window was replaced by a single plastic cone and a flat bomb-aimer's window. Many included the new boom-type refueling system. (x222)

* DB-50D--Drone director conversion of a B-50D, to be used with the GAM-63 RASCAL missile. (x1, converted)

EB-50B with track-tread undercarriage

* EB-50B--Single conversion of a B-50B to be fitted with a track-tread undercarriage. (x1, converted)

* KB-50--Air to air refueling tanker conversions of the bomber. (x134, converted)

An F-101A Voodoo (top right), B-66 Destroyer (top left) and F-100D Super Sabre refuel from a KB-50J tanker at an RAF open day in England, 1963

* KB-50J--Tanker B-50s with improved performance, via two extra General Electric J47 turbojets under the outer wings. (x112, converted)

* KB-50K--Tanker conversions of the TB-50H trainer aircraft. (x24, converted)

* RB-50B--All but one of the B-50Bs were converted into the recon role. These were fitted with nine cameras in four stations, weather instruments, and a bomb bay capsule holding the extra crew members. (x44, converted)

* RB-50E--Special photographic conversions of the RB-50B, modified at Wichita. (x14, converted)

* RB-50F--Conversions of the RB-50B, fitted with SHORAN navigation radar for special missions. (x14, converted)

* RB-50G--Conversions of the RB-50B, fitted with electronic countermeasures stations along with the SHORAN radar. (x15, converted)

Boeing WB-50D of 53rd Weather Squadron at RAF Burtonwood in May 1957

* TB-50A--Trainer conversion of the B-50A. (x11, converted)

* TB-50D--Trainer conversion of the B-50D. (x11, converted)

* TB-50H--Newly built trainer planes. (x24)

* WB-50 --Weather reconnaissance conversion of the B-50.

* WB-50D--Weather reconnaissance conversions of outdated B-50Ds, fitted with meteorological equipment. (x36, converted). Some of these flew highly classified missions for atmospheric sampling between 1953 and 1955 to detect Soviet detonation of atomic weapons.[3]

* YB-50C--Version to be fitted with the Variable Discharge Turbine version of the R-4360 engine. None were built.

* B-54A--Proposed version of the YB-50C.

* RB-54A--Proposed reconnaissance version of the YB-50C.

Specifications (B-50D)

Boeing B-50D

General characteristics

* Crew: 8: Pilot, co-pilot, flight engineer, radio/electronic countermeasures operator, two side gunners, top gunner and tail gunner

* Length: 99 ft 0 in (30.2 m)

* Wingspan: 141 ft 3 in (43.1 m)

* Height: 32 ft 8 in (10.0 m)

* Wing area: 1736 ft² (161.3 m²)

* Empty weight: 80,610 lb (36,560 kg)

* Loaded weight: 121,850 lb (55,270 kg)

* Max takeoff weight: 173,000 lb (78,470 kg)

* Powerplant: 4× Pratt & Whitney R-4360 radial engines, 3,500 hp (2,600 kW) each

Performance

* Maximum speed: 395 mph (343 kn, 636 km/h)

* Cruise speed: 244 mph (212 kn, 393 km/h)

* Combat radius: 2,100 NM (2,400 mi, 3,860 km)

* Ferry range: 5,000 NM (5,760 mi, 9,270 km)

* Service ceiling: 36,650 ft (11,170 m)

* Rate of climb: 2,225 ft/min (11.3 m/s)

* Wing loading: 70.19 lb/ft² (343 kg/m²)

* Power/mass: 0.115 hp/lb (193 W/kg)

Armament

* Guns:

o 12× .50 in (12.7 mm) M2 Browning machine guns in remote controlled turrets

o 1× 20 mm (0.787 in) cannon in tail

* Bombs:

o 20,000 lb (9,100 kg) internally

o 8,000 lb (3,600 kg) on external hardpoints

The Vietnam air war changed dramatically on 24 July 1965 when a Soviet SA-2 [(Russian С-75, NATO reporting name SA-2 Guideline] missile downed an Air Force F-4 and damaged three others. Proving this shoot down was no fluke, two days later an SA-2 destroyed an American drone. US reconnaissance spotted construction of the first SAM site in early April and watched it and three other sites progress throughout the spring. But the decision makers would not permit the airmen to attack the missile sites, one of the many political restrictions on the air war. Secretary of Defense Robert McNamara argued that if the airmen attacked the SAM sites, they must also attack the MiG fields, which would be a major escalation of the air war. The leaders also feared that such attacks might cause Soviet casualties. Besides, one of McNamara's chief assistants, John T. McNaughton, believed that the SAMs only represented a bluff and would not be used.

The Soviet antiaircraft missile evolved from German World War II programs. The first Soviet SAM, the SA-1 [Soviet designation S-25 Berkut, NATO reporting name is SA-1 Guild], was inspired by the German Wasserfall [1] with ground (command) guidance. It became operational in early 1954. The West first saw its successor, the SA-2, in 1957. The Soviets designed this missile to defend against high-flying, essentially non-maneuvering, strategic bombers. The SA-2 measured 35 feet in length and weighed 4,875 pounds with its booster. It could carry a 288-pound warhead at Mach 3 .5 out to a slant range of 24-25 miles and was effective between 3,000 and 60,000 feet. The SA-2 first achieved prominence by knocking down an American U-2 over the Soviet Union in the spring of 1960 and downing another U-2 over Cuba in October 1962.

Despite knowledge of the missile since 1957, and its potential (similar to the Nike Ajax), the United States made only mixed progress with countermeasures. Tight budgets in the late 1950s hampered these efforts. Airmen assigned high priority to countermeasures against the SA-2 in budgets for fiscal years 1964 and 1965, but had nothing effective in hand when the need arose. As a result, in 1964, some airmen believed that aircraft could not operate in SAM protected areas. Although it is easy and partially correct to blame the tight funding, it is also true that the airmen underestimated the requirement for countermeasures. Although the US Air Force equipped strategic bombers with warning and jamming devices in the late 1950s, it did not similarly equip tactical fighters and bombers. Whatever the reason-money, obsession with nuclear weapons delivery, electrical power requirements, trust in fighter maneuverability and speed-the tactical air forces were unprepared for combat.

The potential SAM threat grew as the North Vietnamese incorporated more missiles into their inventory. North Vietnamese SAM battalions increased from one in 1965 to 25 the next year, to 30 in 1967, and to 35-40 in 1968. This growth in units permitted the North Vietnamese to increase their missile firings from 30 per month in the first 11 months of operation to 270 per month between July 1966 and October 1967. The latter month, with between 590 and 740 SAMs fired, was the peak month of firing until the Linebacker II operations of 1972. From October 1967 to the bombing halt on 1 April 1968, SAM firings averaged 220 per month. During this period, the American airmen observed 5,366-6,037 SAMs, which downed 115-128 aircraft.

Despite the increase in SAM firings, their direct effectiveness declined. In 1965 it took almost 18 SAMs to down each American aircraft, a figure that rose to 35 in 1966, to 57 in 1967, and to 107 in 1968. A number of factors contributed to this decline.

The airmen quickly learned that the SA-2 could be outmaneuvered. The Soviets designed the SA-2 to destroy highflying, non-maneuvering, strategic bombers; but until 1972 it engaged primarily low-flying, very maneuverable, tactical fighters. On clear days, alert airmen could spot SA-2 launches as the missile was large, described by most flyers as a flying telephone pole, and left a visible smoke trail.

The pilots would rapidly dive toward the missile, and when it changed direction to follow the aircraft, the pilot would pull up as abruptly and as sharply as possible. The SA-2 just could not follow such maneuvers. But such action required sufficient warning, proper timing, and, of course, nerve and skill. To give pilots adequate time to maneuver, procedures prohibited the pilots from flying too close to clouds between them and the ground. Later, the airmen received electronic devices that gave a visual and aural warning when a SAM radar was tracking (painting) an aircraft.

The American airmen also directly took on the missiles. On 27 July, 46 US Air Force fighter-bombers attacked two missile sites, met disaster, and according to a CIA report, hit the wrong targets. North Vietnamese gunners downed three aircraft while a midair collision accounted for two others. Nevertheless, the anti-SAM attacks continued. In the first nine months of 1966, the airmen launched 75 strikes against 60 sites and claimed to have destroyed 25 and damaged 25. Such attacks proved unprofitable because of the mobility of the SAMs-they could be relocated within hours.

One effort to counter North Vietnamese SAMs was standoff ECM: aircraft crammed with electronics gear that orbited a distance from the defenses and interfered with Communist radar and SAM signals. The Marines employed EF-1011s in this role between April 1965 and 1969. The Douglas Skyknight was ancient, having first flown in 1948 and seen action in the Korean War as a night fighter. It was joined in the ECM role in late 1965 by another Douglas product, the Skywarrior, which first flew in 1952. The Navy employed the Skywarrior as an electronic warfare aircraft designated as the EKA-3B. The Air Force adopted the Navy aircraft and also used it in the ECM role as the EB-66C, which carried a crew of seven, including four ECM operators in a crew compartment fitted in the bomb bay. Joined by other ECM versions of the B-66, it served throughout the war. However, the North Vietnamese moved their SAMs, forcing the EB-66 in turn to move away from North Vietnam to orbits over both Laos and the Gulf of Tonkin. In January 1968 a Vietnamese MiG downed an EB-66C (fig. 63). In late 1966 the Marines introduced the EA-6A in the jamming role.

A third American measure against the SAMs was codenamed Wild Weasel. The Air Force installed radar homing and warning (RHAW), electronics equipment that could detect SAM radar and indicate its location, into F-100Fs, the two-seat trainer version of its fighter-bomber. Wild Weasel I went into action in November 1965, flying with and guiding conventionally armed F-105s against SAM positions. These operations, known as Iron Hand (SAM suppression), preceded the main force by about five minutes, attacked and harassed the SAMs and thus permitted operations at 4,000-6,000 feet above the light flak into which the SAMs had forced the American aircraft.

In April and May of 1966 the American airmen first used the Navy's AGM-45A Shrike missiles. Now the anti-SAM crews had a standoff weapon that homed in on the SAM's radar signal. However, the Shrike had limited range and maneuverability and could be confused. These liabilities reduced the anti-radiation missile's (ARM) effectiveness as did Communist countermeasures. The North Vietnamese crews soon learned that by limiting emissions and coordinating several radars, they could still operate the SAMS and yet limit their vulnerability to the Wild Weasels. Just as the North Vietnamese used decoys to neutralize and ambush American air strikes, SAM operators sometimes turned on their radar to provoke an ARM launch and then turned it off before missile impact. The Shrike's kill rate declined from 28 percent of those launched by Air Force and Navy crews in 1966 to 18 percent in the first quarter of 1967. In the fall of 1967 SA-2 crews began using optical aiming, which rendered American ECM efforts useless; however, optical aiming required visual conditions, which also reduced SAM effectiveness. In March 1968 the Americans introduced the longer-range and more capable AGM-78 Standard ARM. Although it was constrained by reliability and size problems, nevertheless, the AGM-78 gave American airmen another weapon against the SAM.

In the summer of 1966 Wild Weasel III appeared in the form of the two-seat F-105 trainer, re-designated F-105G. Iron Hand operations were now easier as compatible aircraft were flying together. In late 1966 US airmen began using cluster bomb units (CBU-antipersonnel munitions) against North Vietnamese positions. But in the period following the 1968 bombing halt, 1969 until summer 1972, free-fall munitions were removed from Iron Hand aircraft, degrading their effectiveness. By then, however, the airmen had another weapon with which to combat the SAMs.

The Navy in mid-1966 and the US Air Force in October tested ECM pods carried beneath the fighters. A formation of fighters using the pods, the Navy's ALQ-51 and the Air Force's QRC-160-redesignated ALQ-71-seriously inhibited radar-directed defenses. The pods permitted operations between 10,000-17,000 feet, above the reach of light and medium flak. Put into service in January 1967, the pods further neutralized Communist defenses. But unfortunately for the airmen, the formation required for the best ECM results made the aircraft vulnerable to MiG attack. The various jamming devices forced the SAM operators to adopt a new procedure, track-on jamming. They fired the SA-2s at the jamming signal, but as it gave azimuth and not range information, it proved much less accurate than the normal method.

[1] The Wasserfall was most effective in providing a baseline for postwar US and Soviet SAM designs.

LINK

LINK

LINK