The End of the Line for Curtiss Aircraft

XP-87 Blackhawk prototype
(USAF Museum)

In the summer of 1945 the US Army Air Force was in the process of outlining its combat aircraft needs in the post-war world. For fighter aircraft, there were three classes of aircraft that the USAAF wanted- an all-weather offensive fighter, a point-defense interceptor, and a long-range penetration fighter. It was expected that because of the state of the technology of the day that the all-weather offensive fighter would be the biggest of the three. On 28 August 1945 the USAAF issued its RfP (Request for Proposals) for the all-weather offensive fighter- a speed of 525 mph at 35,000 feet, 12 minutes to reach 35,000 feet and a 600-mile combat radius. It was thought at the time that piston engines would be necessary, but a refinement of the USAAF requirements a few months later laid out the service's desire for an aircraft that could seek out and destroy both enemy aircraft and ground targets in all weather conditions, day or night. Bell, Consolidated (Convair), Curtiss, Douglas, Goodyear, and Northrop submitted entries; Bell, Convair, and Goodyear were eliminated quickly due to performance deficiencies. Curtiss submitted a large four jet design based on the XA-43 attack jet design they had been working on for a different ground attack specification. Douglas submitted a land-based version of their F3D Skyknight, and Northrop submitted three designs- a refined version of the P-61 Black Widow, one based on the XP-79 flying wing fighter, and an all-new twinjet design. 

The political winds of change meant that the USAAF favored Curtiss heavily for the reasons that the previously dominant aircraft manufacturer had no contracts to sustain it in the postwar period and no civilian designs readily available for the growing passenger market. What was left of the funding for the XA-43 project was used to contract with Curtiss for prototypes of their design to be designated the XP-87. But the USAAF was sufficiently interested in Northrop's all-new twinjet design to contract for prototypes of that design as well to be designated XP-89. The USAAF also contracted with Martin Aircraft for a nose mounted turret that would allow the cannons to be swiveled to off-center targets that was to be fitted to both the XP-87 and XP-89. 

The XA-43. Note the differences from the XP-87 design.
(The Unwanted Blog at up-ship.com)

The designation XA-43 is often and mistakenly used interchangeably with the XP-87 designation- they were in fact two different aircraft that only resembled each other in basic layout. The XA-43 had a tandem cockpit, oval cross-section nacelles that were mounted inline with the wing, and was 65% larger than the XP-87 which had a side-by-side cockpit, rectangular nacelles under the wing. The XA-43's horizontal tail was low set and the design also featured a tail gun. The fact that the first XP-87 prototype was contracted with XA-43 funding led to the confusion that still is seen to this day. The XA-43 was ordered in November 1944 for a jet-powered ground attack bomber but it soon outgrew its proposed powerplants. By the time of the all-weather fighter RfP, the USAAF had lost interest in the XA-43 and allowed Curtiss to redirect its XA-43 efforts to the XP-87. But since policy of the time dictated two prototype aircraft in case of the loss of one, the original XA-43 contract was amended to allow for the construction of a second XP-87 prototype. In August 1946 Curtiss requested to name the XP-87 the Bat, but as there was already a US Navy glide bomb called the Bat, the request was turned down and a month later the XP-87 was given the name Blackhawk. 

By 1947 a review was underway to determine which of the fighters under development at the time might be suitable as a tactical reconnaissance aircraft- due to the size and carrying capacity of the XP-87, it was decided that it would also be developed into a reconnaissance version designated the RP-87. In order to not slow down the development, Curtiss was to complete both prototypes as all-weather fighters and then convert the second aircraft into the reconnaissance configuration at the completion of the prototype flight tests. In June 1947 Curtiss raised concerns with the USAAF on the power output of using four Westinghouse J34 engines in the paired nacelles and suggested changing to the Allison J33 as a single J33 engine had the power of two J34s not to mention the simplification of maintenance having only two engines instead of four. The change was approved for the production model but the prototypes would be completed with the four J34 engines. 

Only the XP-87 prototypes were to have four paired engines
(USAF Museum)

The first prototype was built at Curtiss' production facility in Columbus, Ohio, that once housed wartime production of the SB2C Helldiver. Taxi testing and ground tests took place at Columbus, but the USAAF wanted all flight testing to occur at Muroc AAF (later renamed Edwards AFB) in California. The first XP-87 was partially disassembled and loaded onto a trailer for transport to California- on going under the first highway overpass near the Columbus plant, the height was misjudged and the vertical fin hit the overpass, resulting in significant damage. With the damaged fin removed, he convoy headed out again and outside of Tulsa, Oklahoma got into an accident that damaged the nacelle for the left two engines. It was felt repairs could be made at Muroc and after month, the convoy reached the base where a new vertical fin and a team of  engineers were waiting to repair the prototype. The first flight was finally made on 1 March 1948 on a reasonably uneventful 58-minute maiden flight. The next several flights discovered buffeting in the tail due to it having a lower critical Mach number than the rest of the aircraft. Curtiss proposed a redesigned swept empennage for the production aircraft that was also duly approved by the USAAF. A total of 55 contractor test flights were made with the Blackhawk prototype and the flights confirmed the need to change to the Allison J33 on the production fighter- the Westinghouse J34s were unreliable and needed constant repair and replacement. By the time of the next series of flights with service test pilots, the USAAF was now the US Air Force and the first USAF flights were made on 3 June 1948. A week later the USAF placed a preliminary order for 57 P-87B Blackhawks (J33 engines and swept empennage were features of the production "B" version) and 30 RP-87B photo-recon aircraft. The following day the USAF switched from P-for-pursuit to F-for-fighter, the Blackhawk becoming the XF-87.

The now-designated XF-87 from the rear
(USAF Museum)

After 19 USAF test flights, a recommendation was made to Curtiss for a slightly larger wing to help reduce the stall speed and it was agreed that the second prototype XF-87 under construction would have the larger wing, the J33 engines, the swept empennage and reconnaissance modifications and would be designated XF-87C. In October 1948 the USAF held a fly-off evaluation with the XF-87 Blackhawk prototype, the Northrop XF-89 which got the name Scorpion, and a borrowed Navy F3D Skyknight to represent the Douglas submission as it was felt the Douglas design was close enough to the production Skyknight that it could act as a stand-in. With pilots of the Air Defense Command participating, while the XF-87 Blackhawk and F3D Skyknight had their strong points (side-by-side seating being one of the strongest suits of both designs in the opinion of the ADC pilots), the Northrop XF-89 Scorpion came out overall ahead in the evaluation and it was selected for production as having the best development potential. 

It was a crushing blow for Curtiss-Wright as the XF-87 was its only postwar jet design to take to the air. The Navy had canceled the XF15C mixed-propulsion fighter a few years earlier after only three examples were built. The company, in effect, was betting its future as an aircraft manufacturer on the XF-87 Blackhawk. The first prototype was  ferried to Wright-Patterson AFB in Ohio in December 1948 and was eventually scrapped by 1950. The second unfinished prototype was never completed and what was done got parted out for other projects that the company was attempting. With no other designs in advanced development, Curtiss-Wright was forced to shut down its Airplane Division and its assets were sold to North American Aircraft and the Columbus plant would be used for the manufacture of the F-86 Sabre. Curtiss-Wright's propeller division remained active into the 1960s and was responsible for the X-19 radial lift test aircraft. Some feel the X-19 was Curtiss' last aircraft design, but in reality it was the XF-87 Blackhawk that represented the end of the line for Curtiss-Wright Aircraft, a company that just ten years earlier was one of the dominant aircraft manufacturers of the United States. 

Related Reading:

The Massive Curtiss XP-71 Fighter
The Barrier Patrols: Extending the US Radar Net Out to Sea

Source: Experimental & Prototype U.S.Air Force Jet Fightersby Dennis R. Jenkins and Tony R. Landis. Specialty Press, 2008, p95-101. 

The Daring Rescue of a Downed Pilot at the Battle of A Shau Valley

Major Bernard Fisher, first USAF Medal of Honor recipient of the Vietnam War

In 1961 the CIA, in cooperation with the US Army Special Forces teams, began to set up a network of surveillance camps along the borders of South Vietnam to monitor North Vietnamese infiltration of South Vietnam. Located primarily in the remote highlands of South Vietnam, the special forces camps were manned by a mixture of US Army special forces personnel, South Vietnamese special forces personnel, and paramilitary units recruited from the indigenous populations of the area like the Montagnards. By 1962 the US Army assumed full responsibility for the special forces camps. In 1966, one of these special forces camps was the scene of one of the most daring rescues of downed American pilot in the Vietnam War. High up in a remote area of the northwest corner of South Vietnam just two miles from the Laotian border was the special forces camp in the A Shau Valley. If there was a more remote camp that was nearly inaccessible elsewhere in South Vietnam, the A Shau Valley would have given them a run for the money. With steep jungle covered mountains ascending to over 7,000 feet and constant storms during monsoon season, the aerial resupply of the A Shau Valley camp was challenging even under the best of conditions. It had an approximately half-mile long dirt airstrip that sat astride the triangular-shaped fort that served as the special forces base camp. But the camp lay astride three major infiltration routes off the Ho Chi Minh Trail into South Vietnam- one route ran westward from the valley towards the main axis of the Ho Chi Minh Trail and two routes ran eastward towards the city of Hue and the heavily populated areas of the South Vietnamese coast. In early March of that year, two regiments of the North Vietnamese Army set up positions in the mountains above the camp in preparation of an assault. A flak trap was set up in the heights over the camp with 37mm anti-aircraft cannons. On 9 March at 0400, the assault began with a mortar bombardment on the camp with NVA sappers punching holes in the camp's defensive perimeter. An estimated 2,000 NVA soldiers squared off against 360 South Vietnamese and Montagnard soldiers led by 17 US Army Special Forces troops.

Due to poor weather with only 400-foot ceilings (in a valley surrounded by 7,000 foot mountains), the first air support didn't arrive until mid-morning when a USAF AC-47 Spooky gunship arrived over the area in poor weather conditions. On its third pass at low altitude, the NVA flak trap caught the gunship and it crashed into a mountainside. The crew of six survived, but three were rescued thanks to the heroic actions of two of the crew to defend the crash site until they could be rescued. Captain Willard Collins and 1st Lt. Delbert Peterson posthumously earned the Air Force Cross for defending the survivors before they were killed by NVA troops. Two Cessna O-1 Bird Dogs attempted to land on the dirt strip to fly out some casualties, but the heavy enemy fire only allowed them to fly out one wounded special forces soldier. Later that afternoon, the Marines sent two Sikorsky UH-34Ds into the area to evacuate the wounded. One helicopter was shot down but managed to crash land inside the camp perimeter. Its crew was picked up by the other helicopter before it had to withdraw under the thick overcast. That night under cover of darkness a USAF Sikorsky CH-3E managed to land in the camp and fly out 26 causalities. The following morning the NVA pressed their attack against the camp again, managing the penetrate the defensive perimeter. In the pre-dawn darkness, a Marine A-4 Skyhawk two-ship responded and one of the pilots managed to make a low level bombing pass before coming around to strafe the area with the Skyhawk's 20mm cannon. Lt. Augusto Xavier failed to pull out of his strafing run in the limited visibility conditions and crashed into one of the mountains around the camp. He was posthumously awarded the Silver Star. Nearly 200 close air support sorties were mounted that day despite poor weather to keep the camp from falling into NVA hands.

With the arrival of daylight, USAF Major Bernard Fisher (call sign "HOBO 51") from the 1st Air Commando Squadron led a flight of A-1E Skyraiders in 800-foot overcast ceilings to try and assist the defenders of the A Shau Valley camp. Fisher's wingman took 37mm cannon hits to his engine and had to return to base. A second pair of USAF A-1E Skyraiders arrived on scene, led by Major D.W. "Jump" Myers (call sign "SURF 41") from the 602nd Air Commando Squadron. The Skyraiders pressed their attacks as close to the camp as possible to keep the perimeter from falling. Making strafing passes on the NVA troops pushing on the camp perimeter, Myers was hit on his third pass and his Skyraider caught fire. He elected to crash land on the camp's dirt runway and Major Fisher flew along side to give him steering directions as Myers' windscreen got covered in oil when the engine got hit. Myers successfully crash landed his Skyraider on the dirt strip and immediately got out before his Skyraider exploded and took cover in a ditch next to the runway. A team from the camp tried to get to Myers to bring him inside the camp perimeter, but the NVA fire in the area was too heavy to effect a ground rescue. Orbiting above and dodging enemy fire, Fisher directed the other Skyraider pilots' fire to protect Myers and buy time for the inbound rescue helicopter. When he found out a rescue helicopter would take about 20 minutes to reach the area due to the weather conditions, Major Fisher elected to try and land on the strip to rescue Myers himself. 

With debris from the battle as well as Myers' destroyed Skyraider littering the runway, Fisher had to abort his first landing attempt and swung around to land the other direction on the runway. One of the pilots in the area described the scene as like "Flying into Yankee Stadium with everyone in the bleachers firing at you with machine guns!" Fisher managed to land on the runway and in the midst of the heavy fire, taxied back up the runway searching for Myers. Since his Skyraider was the side-by-side two seat version of the A-1, Fisher spotted Myers who sprinted for the aircraft from his hiding place. Fisher had already unharnessed himself thinking that Myers was wounded and needed help when he found the pilot already scrambling up his wing to the cockpit. Fisher grabbed Myers and quite literally threw him into the cockpit headfirst with Myers yelling "You dumb son-of-a-bitch, now neither of us will get out of here!" With Myers scrambling to get himself seated and harnessed into the cockpit, Fisher wheeled the A-1 around and kept the Skyraider in ground effect until he had the speed climb up through the overcast and over the mountains to safety at their base at Pleiku.

Fisher on the left and Myers on the right after the rescue flight

Remember that group of special forces that got pinned down trying to rescue Major Myers? They were able to escape and get back inside the camp perimeter as all the NVA guns that had them pinned down were focused on trying to shoot down Major Fisher's Skyraider.; When his aircraft landed back at its base, the aircraft had 19 holes from ground fire sustained during the rescue flight. Fisher was unlikely Skyraider pilot- he served in World War II as a sailor and on return to the United States, joined the ROTC while in college. He only finished three years at the University of Utah before he was commissioned to fly for the USAF. He had earned his wings flying Convair F-102 Delta Daggers in Europe and Lockheed F-104 Starfighters for the Air Defense Command stateside. He volunteered for combat duty in Vietnam, getting assigned to fly Skyraiders with the 1st Air Commando Squadron at Pleiku. At the time of his epic rescue flight, he had been flying combat missions in the A-1 for eight months. The day prior to his rescue of Major Myers, he earned a Silver Star flying combat missions over the same special forces camp in the A Shau Valley! 

On 19 January 1967, he was awarded the Congressional Medal of Honor for his rescue of Major Myers. This is the citation: 

For conspicuous gallantry and intrepidity at the risk of his life above and beyond the call of duty. On that date, the special forces camp at A Shau was under attack by 2,000 North Vietnamese Army regulars. Hostile troops had positioned themselves between the airstrip and the camp. Other hostile troops had surrounded the camp and were continuously raking it with automatic weapons fire from the surrounding hills. The tops of the 1,500-foot hills were obscured by an 800 foot ceiling, limiting aircraft maneuverability and forcing pilots to operate within range of hostile gun positions, which often were able to fire down on the attacking aircraft. During the battle, Maj. Fisher observed a fellow airman crash land on the battle-torn airstrip. In the belief that the downed pilot was seriously injured and in imminent danger of capture, Maj. Fisher announced his intention to land on the airstrip to effect a rescue. Although aware of the extreme danger and likely failure of such an attempt, he elected to continue. Directing his own air cover, he landed his aircraft and taxied almost the full length of the runway, which was littered with battle debris and parts of an exploded aircraft. While effecting a successful rescue of the downed pilot, heavy ground fire was observed, with 19 bullets striking his aircraft. In the face of the withering ground fire, he applied power and gained enough speed to lift-off at the overrun of the airstrip. Maj. Fisher's profound concern for his fellow airman, and at the risk of his life above and beyond the call of duty are in the highest traditions of the U.S. Air Force and reflect great credit upon himself and the Armed Forces of his country.

Fisher was the first USAF Medal of Honor recipient of the Vietnam War. He finished his tour in Vietnam on the Skyraider with 200 combat missions. His unit, the 1st Air Commando Squadron, had a 40% casualty rate amongst its pilots as they did a lot of low level close air support flying in support of the special forces camps in some of the most inhospitable parts of South Vietnam. He returned to the Air Defense Command until his retirement as a colonel in 1974, having flown the McDonnell F-101B Voodoo. He took up corn and alfalfa farming with his wife in rural Idaho. Every year since his rescue, each March 10th, D.W. Myers called Bernard Fisher to wish him well until Myers died in 1992. Myers' daughter kept up the ritual for another 22 years, calling Fisher on March 10th herself to wish him well. In 2008, the University of Utah awarded a diploma to Bernard Fisher 57 years after he was last a student there in recognition for his achievements and decorated military career. In 2010, the Boise Rescue Mission was established as a homeless veterans' transitional program with Fisher's help and its motto is Fisher's quote after he rescued Myers: "When a man is down, you don't leave him there." Colonel Bernard Francis Fisher flew west on 16 August 2014.

Fisher's A-1E Skyraider at the USAF Museum

You can see Bernard Fisher's A-1E Skyraider today as it has been restored and wears the colors and markings as it looked on the day of his Medal of Honor Mission at the National Museum of the United States Air Force in Dayton, Ohio.

As for the fate of the special forces camp in the A Shau Valley after Fisher's rescue flight? By late afternoon on 10 March 1966, the decision was made to evacuate and abandon the A Shau Valley camp. Sixteen UH-34D helicopters along with six UH-1Es, all from the Marine units HMM-163 and VMO-2 respectively, flew into the valley with 200-foot overcast for the evacuation. Two helicopters were shot down but their crews managed to lead groups of camp soldiers out of the area on foot, evading the NVA units that were closing in on the camp. The NVA flak trap was so intense that three Marine F-4B Phantoms, two A-4 Skyhawks, two UH-1s and three more UH-34D sustained damage. The following morning a second evacuation flight managed to get the rest of the personnel out of the camp. The Marine helicopter squadron HMM-163 needed to have 21 of its 24 UH-34Ds replaced. Interestingly, one of the UH-1s involved in the evacuation of the rest of the personnel from the special forces camp was flown by Brigadier General Marion Carl of the US Marine Corps. Carl was the Marines' first ace of the Second World War and before Vietnam he was a decorated test pilot. Despite his rank as the commander of the 1st Marine Brigade in Vietnam, he often flew combat missions in both helicopters and jet fighters much to the chagrin of his superiors!

Sources: Above and Beyond: The Aviation Medals of Honor by Barrett Tillman. Smithsonian Institution Press, 2002, pp 218-221. Assault from the Sky: US Marine Corps Helicopter Operations in Vietnam by Dick Camp. Casemate Publishers, 2013, pp 64-79. Photos: USAF Museum

The Barrier Patrols: Extending the US Radar Net Out to Sea

The three main continental radar picket lines of  the Cold War

As early as 1946, the US Navy was already examining the possibility of large aircraft equipped with airborne radar as a means of extending the early warning detection times of fleets at sea. American defense planning in the early days of the Cold War assumed that whatever strike capabilities the United States had, the Soviets also had an equivalent. Since intercontinental ballistic missiles had yet to be fielded in significant numbers at the time, long range bombers like the Boeing B-29 Superfortress, its successor the B-50 Superfortress and the massive Convair B-36 Peacemaker formed the main strategic nuclear strike force of the United States. The assumptions of Soviet capabilities were validated with the unveiling of the Soviet reverse-engineered B-29, the Tupolev Tu-4 "Bull". With jet bombers on the drawing boards of US manufacturers, it was assumed that intercontinental jet bombers were also under development in the Soviet Union. Since the predominant Soviet bomber at the time was the Tu-4, its range meant that it would have to come over the North Pole to strike US targets. In November 1950, the United States and Canada agreed to build three lines of radar stations across the northern reaches of North America. The Distant Early Warning (DEW) Line formed the northernmost chain of stations that stretched from Alaska across the Canadian Arctic coast. The second line was the Mid-Canada Line that stretched across the northern parts of the Canadian provinces. The third line of radar stations was the Pinetree Line that stretched across the US-Canadian border. Several major defense studies at the time expressed concern that air refueling by the Soviets or use of bases secured in Alaska or Greenland and Iceland would allow Soviet bombers to fly around the three radar lines across Canada since they ended at the coasts. There was no doubt that there would be a need for a sea-based radar picket line in the Pacific and Atlantic, the problem was who was going to fund it and who was going to run it and on this count, the US Navy and the USAF couldn't agree on anything useful. Each service tried to push off the seaborne radar picket on the other- the Navy felt air defense as the USAF's job, so it should fund and run the system, but the USAF felt since it was sea-based, it should be the Navy's responsibility. 

Both services did come around the need to contribute to some sort of sea-based radar picket to extend the three radar lines in Alaska and Canada to prevent Soviet bombers flying around the land-based radars and approaching towards the west and east coast. The Navy's recommendation was for a combination of radar picket ships and airborne early warning (AEW) aircraft maintaining a barrier line in the mid-ocean in both the Atlantic and Pacific called SEADEW (SEAward-extension of the DEW Line). The AEW aircraft would fly racetrack orbits over the line of radar picket ships. When needed, both the picket ships and AEW aircraft could be called upon to support fleet operations. The USAF recommendation was slightly different, with AEW aircraft orbiting preset locations off the coasts and tied in by data-links to the land-based radar net. While similar in principle, the issue came down to funding as well as control. The Navy favored semi-autonomous ships and AEW aircraft that could also be used for fleet operations, offering flexibility. The USAF's Air Defense Command wanted a system that was tied into the existing radar net. Quite obviously, the Navy didn't want to fund and operate a system that was controlled by the USAF and vice versa. 

US Navy WV-2 Warning Star flies over a DER radar picket ship

Feeling that the USAF was dragging its feet and wanting a system operational that was flexible enough to support the fleet when needed, the Navy went ahead and proceeded to get the SEADEW operational during the Korean War. The Navy converted a number of destroyer escorts to destroyer escort radar (DER) vessels along with putting back into service some wartime radar picket destroyers. The Navy also procured the Lockheed WV-2 Warning Star, an AEW aircraft based on the Lockheed Super Constellation. Airborne early warning squadrons were established for the Atlantic and Pacific. The first units were multi-tasked with not just SEADEW missions but also fleet support and weather reconnaissance. VW-1 and VW-3 were assigned to the Pacific Fleet while VW-2 and VW-4 were assigned to the Atlantic Fleet. It was VW-4 that would become well known as the original "Hurricane Hunters" before the mission was transferred to the USAF. In addition to these initial Warning Star squadrons, additional units were stood up devoted primarily to flying the radar barrier patrols- VW-11, VW-13, VW-15 and a training unit were assigned the Atlantic barrier and the VW-12, VW-16, VW-16 and a maintenance unit were assigned to the Pacific barrier. The Pacific Barrier was headquartered at NAS Barbers Point in Hawaii with the barrier line running between Midway Island to the Aleutians in Alaska. The Atlantic Barrier was based at NAS Argentia in Newfoundland and ran from Newfoundland to the Azores. The DER picket ships patrolled those lines as well. Because the Navy's barrier lines were further out, they offered anywhere from 2-4 hours advance warning time of a Soviet bomber attack. 

A USAF RC-121D Warning Star with two F-104 Starfighters

Despite competing with the Navy, the USAF's AEW line complemented the Navy barrier patrols as it was closer to shore and formed a second radar line behind the SEADEW. The USAF also procured the AEW version of the Lockheed Constellation with the designation RC-121C which was based on the L-749 Constellation and the RC-121D which was based on the longer L-1049 Super Constellation. Called the Contiguous Extension, the RC-121 fleet was the USAF's first organized airborne early warning endeavor. On the West Coast, the USAF Contiguous Extension was based out of McClellan AFB near Sacramento and the East Coast operation was headquartered out of Otis AFB on Cape Cod. Since the Navy was first out of the starting blocks and was further ahead in its AEW operation, until sufficient RC-121s arrived, the USAF had to send its personnel to train with the Navy. At Otis AFB, the 551st Airborne Early Warning and Control Wing had three squadrons and the 552d AEW&C Wing at McClellan AFB also had three squadrons. In less than two years, the USAF had six squadrons of fifty AEW aircraft and over 5,000 personnel operational! 

The Lockheed WV-2/RC-121s had a combat radius of over 1,000 miles which allowed them to patrol for 16 hours before returning to base. Five officers and thirteen enlisted made up the crews, but the aircraft had the room for up to 31 personnel on longer missions needing an augmented crew. Behind the flight deck were five radar stations. There was no automation or filtering of the radar information- what was seen on the scope was the raw feed and it was up to the skill of the operator to sort through the mess to determine what was significant. Each radar station was manned in just one hour stretches to prevent fatigue and inattention. The radar system and its associated electronics had over 3,000 vacuum tubes and two enlisted in the crew were devoted just to inflight maintenance of the electronics. Most of the electronics were in the aft cabin and generated a tremendous amount of heat- it wasn't unusual for the temperature inside the cabin to hit 100F! Weather rarely scrubbed a mission- the joke was that "If you can taxi, you can fly!" Often times USAF or US Navy crews departed in such atrocious weather that they had to divert to an alternate field on return from patrol. 

The Navy's aircraft did a lot of their data interpretation aloft as they operated on the barrier lines autonomously and would radio any findings by HF. The USAF's aircraft were tied in by datalinks to the SAGE (Semi-Automatic Ground Environment) system used by NORAD and operators ashore would sort through the radar data. Despite this level of automation, USAF RC-121s were staffed with full crews in the event the data links went down as well as have onsite personnel who could interpret radar data without waiting for the SAGE operators ashore. The USAF's RC-121s were later re-designated EC-121s and they flew their patrols around 15,000 feet. The Navy's WV-2s flew their patrols at lower altitudes between 5,000 to 8,000 feet. The strategic imperative of these radar missions was such that spare aircraft and crew were often prepared to be able to depart at a moment's notice should an aircraft en route to its patrol area had technical issues- and those were common given the cantankerous nature of the Constellation's Wright R-3350 engines. While the US Navy did its best to keep its barrier lines fully covered, the USAF settled on randomly patrolling parts of its Contiguous Extension, and more so as the main threat to the United States shifted from bombers to ICBMs. Each coast had nine patrol stations, odd numbered 1 through 9 in the Pacific with 1 near the Aleutians and 9 off the coast of Baja California. In the Atlantic, even numbered patrol stations 2 through 8 in the Atlantic were used. Each patrol station was a 100 mile racetrack orbit. In low tension periods, USAF EC-121s would only operated on one station and the station was randomly decided, the crew finding out which station once they had taken off. During periods of higher tension, more stations would be active. During such periods, all of the USAF stations were operated on both coasts and this meant every four hours an EC-121 departed from McClellan AFB and Otis AFB. 

Despite the maximum effort expended by the US Navy and the USAF, several air defense exercises in the late 1950s showed the barrier patrols weren't as effective as hoped. Electronic failures were the most common cause of a degraded mission with engine problems a distant second. At one point in 1959 the USAF's Air Defense Command had gotten so frustrated with electronic and engine issues with the EC-121 fleet a proposal was floated to transfer the Contiguous Extension operation to the US Navy! Fortunately cooler heads prevailed and the USAF wasn't allowed to give its AEW experience. But the strain on men, aircraft, and budgets began to take its toll on both services. In 1960 the US Navy disestablished some Pacific Fleet squadrons, merging them into other units. During the FY1961 budget debate, questions arose as to the wisdom of continued funding of the barrier patrols in light of the shift in Soviet threat from bombers to ICBMs. The USAF and the Navy had other funding priorities and gradually, both the Navy and USAF barrier patrols were wound down. The Atlantic barrier line was pushed further east centered on a Greenland-Iceland-UK axis with the base of patrols at NAS Keflavik in Iceland. On 8 September 1965, the last AEW barrier mission was flown by a Navy EC-121P (in 1962 the Navy and USAF went to a unified designation system) out of Argentia, ending 10 years of barrier patrols over the Atlantic and Pacific by both the USAF and US Navy. 

So was it worth it? That's a tough question. In the 1950s the bomber threat was still the main nuclear threat and certainly there was deterrent value in the barrier patrols as potential adversaries were put on notice the great lengths the US military was taking to insure vigilance. Perhaps more importantly, it gave both the US Navy and USAF practical airborne early warning experience that laid the foundations for modern aircraft like the Grumman E-2 Hawkeye and the Boeing E-3 Sentry. 

Source: AWACS and Hawkeyes: The Complete History of Airborne Early Warning Aircraft by Edwin Leigh Armistead. Motorbooks International, 2002, pp 21-40. Photos: Wikipedia

The U-2's Antecedent: The Martin RB-57D Canberra

In the early 1950s the Strategic Air Command asked Martin, the American license builder of the English Electric Canberra as the B-57, if a modified version of the B-57 could be built that would operate at altitudes in excess of 60,000 as a reconnaissance aircraft. Though not as radically modified as the better-known RB-57F (which were stock B-57s modified by General Dynamics), the RB-57D was unique in its own right and set the stage for high-altitude reconnaissance operations by its successor, the Lockheed U-2. To operate in the rarefied air of the stratosphere, the most noticeable change in the RB-57D was its enlarged wing which resulted in an increase in wingspan from 64 feet in the standard B-57 Canberra to 106 feet. Special lightening measures were taken from skinning over the bomb bay doors to reduce weight and the bomb bay was used to house the reconnaissance equipment. In addition, enlarged nacelles replaced the B-57's Wright J65 engines with Pratt & Whitney J57s (as were used on the KC-135) which offered a 6,000 lb thrust increase and better high altitude performance. 

Despite the massively enlarged wing, an empty RB-57D weight not much more than an empty B-57 due to the lightening measures taken. The most extreme measures were taken with the wings which were thin metal honeycomb sections that formed a full wet wing (even in the leading edges). To avoid the weight of rivets, the wings were assembled with a special glue and the wing skin was waxed for aerodynamic smoothness. With a surface skin of only 0.010 inch thick, even dropping a small tool on the wing could damage the skin. Even deicing fluid used on the aircraft could potentially cause the glue used to lose strength!

Only twenty RB-57Ds were built, but they were built in four groups, each group had a unique set of mission equipment and capabilities that were practically custom-made for missions in specific parts of the world. The first group of RB-57Ds were called "Group A" and "Group B" and only differed in the Group A aircraft being capable of inflight refueling. Four optical cameras were carried in the forward fuselage and a large optical viewfinder was installed in the cockpit for the pilot to use for both navigation and as a viewsight for the cameras. Thirteen aircraft (seven and six respectively) were built to Group A and Group B standards.

The next version was the single Group D RB-57D built which was also single seat and designed for electronic reconnaissance with a nose mounted radar and SLAR built into the lower sides of the fuselage. Capable of inflight refueling, the sole Group C aircraft flew most of its missions over Europe, using its powerful SLAR to peek deep into the Soviet bloc. 

The final variant were the six Group C RB-57Ds which were two seaters with a pilot and electronic warfare officer. These RB-57D were designed as electronic ferrets to collect enemy radar emissions for later analysis in the development of electronic countermeasures. These aircraft were also capable of inflight refueling. 

In 1956 the newly-formed 4028th Strategic Reconnaissance Squadron was assigned to the 4080th Strategic Reconnaissance Wing to operate the unique RB-57Ds. In the space of a year the 4028th SRS would be moved from Lockbourne AFB in Ohio, to Turner AFB in Georgia, and finally settled down at Laughlin AFB in Del Rio, Texas. Despite being moved three times, the squadron would become fully operational with its first six RB-57Ds only 120 days from the delivery of its first RB-57D. Those first six aircraft, all Group A RB-57Ds, deployed to Japan in late 1956 for reconnaissance missions over what is presumed to be China, North Korea and the Soviet Union. A year after the Japan deployment, three of the Group A RB-57Ds were sent to Taiwan wearing Republic of China markings for further missions over China during the Taiwan Straits Crisis. Flown by USAF pilots, two Taiwanese pilots were preparing to fly RB-57D missions after only 30 days of training, but the plans came to end when both the People's Republic of China and Taiwan began dogfighting each other over the Taiwan Straits. 

In  1958 the first atmospheric samplings missions were flown by RB-57Ds in support of nuclear testing in the Marshall Islands, the high flying capability of the RB-57Ds allowed them to get particle samples from high in the atmosphere as part of the post-detonation analysis. At the same time, Several Group B and the sole Group D aircraft were deployed to Europe for missions over Eastern Europe. 

The pace of missions put a strain on the delicate wings of the RB-57D and the first aircraft were put into storage by SAC following two incidents when the wings outboard of the engine nacelles cracked and fell off during landing. Martin had designed the wings for only 500 flight hours and many of them had already exceeded that limit but strategic necessity resulted in the RB-57Ds still flying missions. At this point the USAF was planning for the arrival of the Lockheed U-2 and the Air Defense Command took over the remaining RB-57Ds to act as high altitude targets for the supersonic interceptor force. Fitted out with electronic countermeasures, the 4677th Defense Systems Evaluation Squadron at Hill AFB, Utah, was formed to operate 12 of the 20 RB-57Ds. Martin modified the wings to extend their surface life. However, the high flying capabilities of the RB-57Ds meant that the 4677th DSES was always asked to send aircraft in support of nuclear testing. 

By 1963 wing structural problems cropped up again when one of the RB-57Ds lost its wing at 50,000 feet. But the ADC still needed a high altitude target aircraft and since the last US atmospheric nuclear test had taken place in 1962, Martin agreed to modify the remaining RB-57Ds for another 3,000 flight hours. Upgrades to the electronic countermeasures to challenge the ADC interceptor crews resulted in these aircraft being designated EB-57Ds and they served in this role along with other testing roles until the mid-1970s. 

The big wing and engine power of the RB-57Ds in many ways prepared pilots for what it would be like to fly the Lockheed U-2. On takeoff, only 50% engine power was necessary for takeoff which only needed a ground roll of about 2,000 feet. Climbing at 25-30 degrees, the RB-57Ds could reach 50,000 feet in only 15 minutes. Maximum cruise altitude was 65,000 feet and the pilots wore full pressure suits that were improved for the U-2 and SR-71 programs. With over 200 gallons less than a stock B-57, the RB-57D could fly twice the duration, approximately seven hours compared to four hours for a B-57. Landing was challenging as the big wing didn't lose lift easily. Even with the engines at idle, it was still too much power for landing. Even with the spoilers out and landing gear extended, the plane still had a very low sink rate and pilots resorted to actually holding the RB-57Ds into a series of slight stalls to get the aircraft down to the runway!

Source: Martin B-57 Canberra: The Complete Record by Robert C. Mikesh. Schiffer Military History Press, 1995, p132-141.

 

In October 1952 the US Air Force initiated the development of SAGE (Semi-Automatic Ground Environment), an integrated set of radar, SAMs, and interceptor aircraft all tied together by digital computers and long distance telephone links. At the time of the inception of SAGE, there was only one digital computer in existence, the Whirlwind at MIT. Very quickly the SAGE project would eclipse the Manhattan Project in terms of size and complexity as much of the technology had to be developed to develop the world's first integrated air defense system. IBM would win the contract in April 1953 to develop the computers that would be the core of SAGE.

Called Whirlwind II by IBM but AN/FSQ-7 by the USAF, the FSQ-7 was the world's first production digital computer weighing 275 tons with 919 miles of cable, 50,000 vacuum tubes, 7,300 pluggable units and 170,000 diodes. The computer consumed 3 megawatts of power and required 100 operators.

The magnetic core of the FSQ-7 had 256 kilobytes of memory and was supported by 150 kilobyte magnetic drum as well as 4 tape drives each holding 100 kilobytes of data. One-hundred fifty consoles displayed data on circular CRT screens that used light pens to interact with the screen information. With the light pens, operators could tag radar tracks and issue commands to air defense units. Each of the 24 SAGE director centers built had a large multistory hardened concrete structure housing two FSQ-7 computers- one running and the other one operating as back up to the first. Each of the director centers were then linked not only to each other but to also as many as 100 air defense units by long distance telephone lines.

SAGE was the single most expensive defense project until the development of the ICBM. The first direction center went online at McGuire AFB in New Jersey in November 1956 with the last one completed in 1962. SAGE ran continuously for the Air Defense Command and NORAD until it was decommissioned in 1983.

Much of what IBM learned in the development of SAGE went into its next major computer network project, an airline reservations and booking system for American Airlines that went online in 1960 called SABRE (Semi-Automatic Business Research Environment). Many of the developers of SAGE also went on to establish the ARPANET, the military predecessor of today's Internet.

Source: Valkyrie: North American's Mach 3 Superbomber by Dennis Jenkins and Tony Landis. Specialty Press, 2005, p53-54.