The Spyplane Codenamed "Pie Face": The Birth of the Big Safari Program

The Big Safari emblem
(Big Safari Association)

At the end of the Second World War, Germany was divided into four occupation zones administered by the victorious Allied powers. The capital, Berlin, was in turn also divided into four zones. When The Soviet Union established East Germany from its occupation zone, West Germany was formed from the American, British and French occupation zones. Berlin was also divided into East Berlin and West Berlin with the western part of the capital surrounded on all sides by East Germany. By agreement, there were travel corridors to allow surface and air connections to West Berlin from West Germany. The air corridors were only 20 miles wide at a maximum altitude of 10,000 feet. The northern air corridor followed a Hamburg-West Berlin line, the central air corridor followed a Hannover-West Berlin line and the southern air corridor followed a Frankfurt-West Berlin air corridor. In the summer of 1952, the head of United States Air Forces Europe, General Lauris Norstad, made a special request to the USAF Chief of Staff, General Hoyt Vandenberg, for reconnaissance aircraft to use in Europe that in particular, could fly unnoticed in the West Berlin air corridors as a routine courier flight. Vandenberg convened a group of specially selected officers and civilians who would develop not just the aircraft needed for the requested USAFE mission but also a set of rule and procedures in order to field such an aircraft quickly and in secrecy. Lieutenant General Thomas Rhodes worked with a reconnaissance systems specialist, Furman E. O'Rear, to develop the procedures that would get the specialized aircraft into service. 

Rhodes and O'Rear laid down the "ground rules" for the project: 

1. Only the minimum amount of documentation was needed. Personal contact and direct communication was preferred. 
2. Strict security clearances would be issued on a need to know basis with a minimum of personnel. 
3. No limit on funds for the project. Special capabilities needed in the field shouldn't worry about funding. 
4. Primary responsibility for the program lay with the Director of Air Force Maintenance and Engineering (this later became Air Force Systems Command) who would direct the Air Force Materiel Command (this later become the Air Force Logistics Command in 1961).
5. Coordination was the utmost importance between the different commands of the USAF and the intelligence community. A single project head would act as the point of contact for all the diverse interests involved. 
6. Aircraft contractors selected would also issue strict security clearances to a closed off work area for any aircraft modifications. 
7. The contractor selected would be responsible for yearly upgrades to any aircraft system. 
8. It was agreed upon ahead of time that any modifications or changes needed to the aircraft systems would be approved to expedite the fielding and subsequent upgrades to any special capability aircraft. 

In addition to these ground rules, it was also agreed that any project would make use of an existing aircraft rather than develop a new aircraft. The project office was authorized initially with a five year commitment on the reconnaissance aircraft that would be fielded by the USAFE for use in the Berlin air corridors. When it was realized in 1953 that the program's set up lent itself well to other special projects, it was given its own code name by which it is still known today: BIG SAFARI.

The Boston Camera the USAF Museum
(USAF Museum)

The year before General Norstad's 1952 special request for a reconnaissance aircraft, a very large special optical camera had been flight tested on a Convair B-36. The camera, developed by optical scientists and engineers at Boston University in 1947-1949, was designated the K-42 but was known as the Boston Camera as well as the code names BIG BERTHA and DAISY MAE. With a 240 inch focal length (6096mm), it weighed nearly three tons and used very large 18x36 inch frame film. It would be the largest aerial camera ever built. The lens was fixed at f/8 with an electrically tripped shutter speed of 1/400 second. Allegedly it had the resolution to image a golf ball on the ground from 45,000 feet. During the flight test program it was decided that a bomber carrying the Boston Camera would have been conspicuous if not downright provocative and it would be better used mounted in a transport aircraft. The aircraft had to be large so as not to have any external modifications that would give away its carriage of the large camera. PIE FACE was the code name assigned to the effort to mount the camera in a transport aircraft. The first PIE FACE contractor was actually Boeing who had offered a YC-97 Stratofreighter- one YC-97 in fact had flown a handful of Berlin Airlift missions. Boeing at the time was preoccupied with other programs and afforded the PIE FACE program little attention to the point that security was constantly being compromised with the aircraft frequently parked in the open at the property perimeter fence line in Seattle. 

As a result, the PIE FACE contractor was changed from Boeing to Convair Fort Worth. This would become Detachment 1 of the Big Safari program. The general manager of Convair, August Esenwein, took a personal stake in the project and made sure the USAF had the necessary secure hangar space as well as any engineering personnel needed make sure PIE FACE was fielded quickly. Esenwein's personal involvement pleased the USAF and the working relationship between the USAF and Convair at Detachment 1 set the standard for future contractor relationships in the Big Safari program. In fact, Detachment 1 would run for twenty years with 87 different aircraft passing through Convair Fort Worth over that time span. 

PIE FACE would have looked just like this KC-97
(Wikipedia)

While the Boston Camera did fly in Europe for six weeks on the YC-97, it was clear that as an early variant of the Stratofreighter it was less capable than the later KC-97 variants already in service. With less powerful engines, the YC-97 with the Boston Camera onboard was significantly altitude restricted. Given that the camera was used for stand-off oblique photography, a higher altitude meant that more of East Germany could be photographed from the air corridors. From 19 December 1952 to 23 February 1953, the Boston Camera was moved from the YC-97 to a KC-97 that had its boom removed, 49-2592. Both aircraft were literally cut in half behind the cockpit to move the camera from one aircraft to the other. The manual controls of the camera were upgraded with electrical and electromechanical controls as it was installed on the KC-97. Covert sliding doors were used to cover the camera ports when it wasn't in use. In addition to the installation of the Boston Camera, a 100-inch K-30 camera and a trimetrogon system of three K-17 cameras were also installed, all synchronized with the Boston Camera to give wider angle photographic coverage of the target areas and assist with mapping. A camera operator's station was installed in the cockpit with a special slaved sight to trigger the camera system. 

West Berlin air corridors
(German History in Documents and Images,
 http://germanhistorydocs.ghi-dc.org)

After flight testing with specially selected USAF crews, the PIE FACE KC-97 was assigned to 7499th Support Squadron (later renumbered to the 7405th) at Rhein-Main AB, the main USAFE transport hub in Europe. With each of the three air corridors to West Berlin being 20 miles wide, that was already 1/6th of East Germany that lay underneath any aircraft within the corridors. The addition of oblique photography added tremendously to the area surveilled- at the 10,000 foot maximum imposed by the Soviets, the majority of East Germany could be photographed by the PIE FACE aircraft. In addition to flying in the air corridors, perimeter flights along the border were also flown at altitudes as high at 32,000 feet. Just in the last six months of 1953 when it was first fielded, the specially-equipped aircraft had flown 13 missions (quite remarkable given the complexity of maintaining the camera system). The aircraft also stood alert for short notice missions and flew as far as the Arctic and the Middle East. Intelligence requirements soon outpaced the abilities of the aircraft and eleven other aircraft were added to supplement PIE FACE starting in 1954. Those aircraft will be the subject of a future article here at Tails Through Time, so stay tuned!

PIE FACE was scheduled to end in 1962 and 49-2592 was flown back to Convair Fort Worth for demodification. By that point the aircraft had already rotated through Fort Worth eight times for upgrades and further modifications. Engineers there had developed a pneumatic shutter system for the cameras in only 28 days that became the standard for any Big Safari photoreconnaissance system. But PIE FACE wasn't over just yet as the Cuban Missile Crisis erupted just as the aircraft was about to be demodified. Approximately 17 missions were flown from MacDill AFB in Tampa around the periphery of Cuba, PIE FACE's imagery supplementing that taken by the Lockheed U-2 overflight missions. In March 1965, 49-2592 returned to Convair Fort Worth for good as the airframe was worn out and given over for salvage. The Boston Camera ended up at the National Museum of the United States Air Force in Dayton, Ohio, where it can be seen today displayed with a Convair B-36 Peacemaker. 

Source: The History of Big Safari by Col. Bill Grimes, USAF (Ret). Archway Publishing in cooperation with the Big Safari Association, 2014, pp 1-16. 

Rockwell Builds the Shuttle by Farming Out the Work

The Grumman Shuttle Orbiter design

On 26 July 1972, NASA announced that Rockwell International had been selected as the prime contractor for the Space Shuttle (specifically the Shuttle Orbiter) after an intense competition with Lockheed, Grumman, and McDonnell Douglas. Each contractor proposal also had to detail management of the complex program as well as its technical aspects and the lengthy proposals then went to a specially convened selection board at NASA which evaluated each submission. The top two proposals belonged to Rockwell and Grumman and showcased the effect that a good management proposal could have in winning the competition. From a technical standpoint, NASA scored the Grumman proposal the best, with Rockwell's orbiter design coming in second. Rockwell's submission, however, impressed the NASA selection board with its management system. With the cost overruns on several military programs like the Lockheed C-5 Galaxy on everyone's mind, Rockwell's management proposal stressed cost controls for what was to be the biggest aviation contract in years. With a technical design not much more inferior that the Grumman design, Rockwell was awarded the contract. 

In the industry slump as Vietnam was winding down, the Orbiter contract was a very big prize for any firm that could clinch the award. At the time of the selection, Rockwell had 6,200 employees in their Space Division and with the award, plans were in place to hire as many as 16,000 by 1975. Priority would given to anyone who had worked on the Apollo program. Despite the buoyant mood at Rockwell, things were considerably more glum at the losing contenders, Grumman, Lockheed, and McDonnell Douglas. Grumman had been a mainstay of the US space program from its early days, best known for its work on the Apollo Lunar Module. Company officials made plans for Grumman to be out of the space business by December 1972 along with the attendant layoffs. 

McDonnell Douglas (via McDonnell) had built the Mercury and Gemini spacecraft and was in the midst of winding down its work as the prime contractor for Skylab. The company was also suffering from a downturn in the world commercial aviation market that was affecting most greatly its Douglas DC-9 program. 11,000 layoffs were planned at McDonnell Douglas by 1973.

While Lockheed didn't have as prominent a role in the US manned spaceflight program in the 1960s as McDonnell Douglas or Grumman, their expertise in high speed flight as well as thermal protection systems was unparalleled in the industry at the time. 

Rockwell, however, recognized two realities that came with winning the Shuttle Orbiter contract. The first one was the limitations of its in-house expertise. Quite simply, Rockwell would need other aerospace companies for their skills and expertise to bring the Orbiter to fruition. The second reality was a bit more prosaic but nonetheless vital. Keep in mind that in the early 1970s there was an atmosphere of budget austerity and NASA was no less exempt from financial realities than any other government agency at the time. Subcontracting work on the Orbiter to other companies in effect would spread the footprint of the endeavor across the districts of multiple Congressional representatives who would be routinely voting on NASA's budgetary allocations for the Space Shuttle program. Subcontracts were a common way as well in the industry of building goodwill- by farming out work to competitors and keeping them active and in business, today's winner might one day become tomorrow's loser on a another program and could hope for subcontract work from a rival. 

Rockwell planned to subcontract at least 53% of the work on the Shuttle Orbiter and this had NASA's blessing as a means of preserving the American industrial base for spaceflight. Just weeks after winning the contract as the prime, Rockwell was already conducting seminars across the nation for potential subcontractors. By March 1973 Rockwell began selecting subcontractors for the program with NASA's approval. Grumman would work on the delta wing, McDonnell Douglas got the OMS (Orbital Maneuvering System), Fairchild Republic got the vertical fin, and the Convair Division of General Dynamics got the mid-fuselage/payload bay. Rockwell would be responsible for the nose and crew compartment as well as the aft fuselage that would house the three Rocketdyne SSME (Space Shuttle Main Engine) packages. Lockheed would get the External Tank while Thiokol got the contract for the SRB (Solid Rocket Booster). 

By the summer of 1975, 34,000 workers across 47 states and a broad host of companies across the American aerospace industry were working on the Space Shuttle program. The peak would be in 1977 with 47,000 workers. The post-Vietnam slump, the Space Shuttle program was very much the crown jewel of the US aviation industry. 

Source: Development of the Space Shuttle 1972-1981: History of the Space Shuttle, Volume Two by T.A. Heppenheimer. Smithsonian Institution Press, 2002. Illustration: Aerospace Projects Review

The Mach 3 Phantom

In the 1960s the development of high-performance reconnaissance cameras offered greater resolution, but at a price- many of these systems were large and heavy and the current high-altitude spyplane of the time, the first generation variants of the Lockheed U-2, were unable to carry them. One of the premier recon optical systems developed at this time was the General Dynamics HIAC-1- a long range, oblique camera with a focal length of 66 inches that allowed stand-off reconnaissance from high altitudes. The first examples of HIAC-1 were heavy- the prototype camera system weighed over 3,500 lbs, much more than any other camera system in use at the time (excepting the very big Boston Camera carried by the B-36 and C-97 in the 1950s that weighed 3 tons and had a focal length of 240 inches). The only aircraft in the USAF inventory that could carry the HIAC-1 was the RB-57F, a modification of the Martin B-57 Canberra. In 1962 General Dynamics in Fort Worth, Texas, had the contract to maintain the RB-57D fleet which suffered from wing spar fatigue. Since General Dynamics had acquired quite a bit of experience in working on the long-span RB-57Ds, they were asked by the Air Force for an evolved version of the D that could fly higher, carry a heavier load (like the HIAC-1) and not have the same wing spar problems that plagued the RB-57D. The RB-57F was the result- with a longer wing, more powerful TF33 turbofan engines and auxillary J60 turbojets, it was what the USAF needed until the later generation of U-2 spyplanes entered service. In fact, two RB-57Fs are still used today by NASA. 

USAF RF-4C with the large G-139 pod.

Over the course of the RB-57F's operational career, Israel had made repeated requests of obtaining the RB-57F and the HIAC-1 for its own reconnaissance needs, but the requests were always denied by the US State Department and the Defense Department on the grounds that the technology used in the RB-57F would upset the strategic balance in the Middle East. However, a compromise was reached- by 1971 the HIAC-1 had been steadily improved and lightened to the point that it weighed just under 1,500 lbs and that a pod-mounted HIAC-1 carried by the McDonnell Douglas F-4E Phantom, already in the Israeli inventory, would be permissible. Also developed by General Dynamics, the pod-mounted HIAC-1 was designated G-139 and underwent an intensive flight test program with a USAF RF-4C aircraft and the first G-139 pods were delivered to Israel in October 1971. The Israelis found the G-139/HIAC-1 system useful as it allowed the Phantoms to get imagery of Egyptian defenses along the Suez Canal without having to enter the SAM umbrella. But there was a significant issue, the pod was still a heavy store and it generated a significant amount of drag- it limited the Phantoms to a maximum speed of Mach 1.5 and a maximum altitude just under 50,000 feet, not to mention the challenge of handling a G-139-laden F-4E at high altitude. As a result, the special projects division of General Dynamics began work in January 1972 on ways to improve the F-4E's performance to offset the burden of carrying the pod. 

Overview of the modifications to make the Phantom Mach 3-capable.

The first improvements came with getting the most out of the Phantom's J79 engines. Engineers found that the Phantom's intakes were limiting the performance possible from the J79. A new inlet was designed that was not only larger than the standard F-4 inlet, but it featured a new shape that better managed the airflow to the engines with series of new variable-geometry ramps. The standard Phantom inlet did have a variable geometry ramp, but it was much simpler than the General Dynamics design which also featured a large bypass door downstream from the inlet to help manage the internal shockwaves that helped slow the air down before it reached the engines. A series of vortex generators down the inlet also helped improve engine performance. The second improvement was based on 1950s research done by NASA's predecessor agency, NACA, called pre-compressor cooling (PCC). PCC was a form of water injection but used the water to cool in the inlet air before it reached the engines. By reducing the inlet air temperature, it increased the mass of the air akin to taking off on a cold day- engine air flow and thereby thrust would be increased. At high altitudes, PCC would boost engine performance starting at Mach 1.4 as the inlet air started to heat up due to friction. 

General Electric, the manufacturer of the J79, was less than enthused about General Dynamics' work on PCC, but did provide some consultations. Work had already been done with PCC on another of General Dynamics' products, the Convair F-106 Delta Dart, but it never was incorporated into the design. In addition, the USAF's Arnold Engineering Development Center in Tennessee had tested PCC in engine test cells with both the J57 and J75 engines. One J75 engine was run at maximum afterburner for 40 hours with PCC! It had also been looked at by Vought for the aborted F8U-3 Crusader III design (though never flown) and McDonnell had used a rudimentary PCC system in 1962 to break several world speed records with the pre-production F-4 Phantom. Based on all this body of work, General Dynamics refined the PCC system so that the water droplets were very fine at 10 microns to cool the air without having any pooling of water in the engine. Two large water tanks were installed on external blisters along the sides of the F-4E, each blister with three tanks. Each blister could carry 2,500 lbs of demineralized water- since the interior of the Phantom was pretty packed as it was, scabbing these blisters on the fuselage eased the modification and engineering process. 

GD wind tunnel model of the RF-4X.

General Dynamics' modifications led to this version of the Phantom being unofficially designated the F-4X- at this point still carrying the large G-139/HIAC-1 pod underneath on the centerline station. With Israeli funding supplementing internal corporate, work on the F-4X continued through 1972 and refinements to the PCC system and inlets led to a calculated increase in the J79 thrust at high altitude well over 150 percent! On 12 April 1973 the company formally submitted the F-4X proposal to the USAF. Additional funding for more work then came from the USAF which was using the podded HIAC-1 system for stand-off reconnaissance in Korea and were encountering the same issues the Israelis were having in using standard Phantoms with the large camera pod. The following year the design was further refined, but with the Israelis having continued misgivings about using the HIAC-1 in a pod, the design leap was made to incorporate the HIAC-1 into F-4X's nose- with the latest HIAC-1 versions getting even lighter than the 1,500 lb version used in the G-139 pod, integrating the camera into the nose improved performance by eliminating the drag-inducing pod. Designated RF-4X, this version of the Phantom was now capable of cruising at Mach 2.4 at high altitude with burst capability to Mach 3.2. This level of performance now began to alarm the US State Department- up to this point Mach 3+ aircraft were the sole purview of the United States and Soviet Union and in some diplomatic circles there were concerns about the Israelis integrating nuclear weapons delivery with the RF-4X. To allay the State Department's concerns, General Dynamics removed the AN/APQ-120 radar from the nose which would now only house the HIAC-1 and its associated environmental control systems. Permission to sell the RF-4X to the Israelis was approved and on November 1974 an Israeli F-4E was flown to General Dynamics in Fort Worth for a mock up study. For five months engineers used the F-4E as the basis of a full-scale mock-up created with cardboard and tape- both the Mach 3 intakes and the PCC water tanks were mocked up on the Phantom on one side as well as the modified nose housing for the HIAC-1 camera. 

Israeli F-4E with the PCC and intake mock-up on one side.

By 1975 several factors were now working against the RF-4X, the biggest of which was time. The Israeli Air Force wanted the system as soon as possible but it was clear that the integration of the camera, intakes and PCC system was going to take more time than originally estimated. With the McDonnell Douglas F-15 winding up its flight test program and soon to become operational in the following year to replace the Phantom in USAF service, it was politically unpalatable to keep funding the RF-4X which offered a level of performance that exceeded that of the Eagle in some flight regimes. The USAF insisted upon further studies of the PCC system despite the fact that there were already nearly 20 years of data on pre-compressor cooling, some of which done by the USAF itself. Compounded with the engineering delays, Israel and the RF-4X proponents in the USAF lost interest and it was quietly canceled later that year.

Despite the cancellation of the RF-4X, General Dynamics did continue work on just the nose-mounted HIAC-1 component of the design for Israel. Three F-4E Phantoms were modified as F-4E(S) aircraft and delivered to the Israeli Air Force from late 1975 to early 1976. It turned out that the Israelis were unable to fund the RF-4X in its entirety and were only able to afford the HIAC-1 component. As a result, the three F-4E(S) aircraft had standard J79 engines. In IDF service the HIAC-1 was code-named "Shablul", the Hebrew word for "snail". The first operational flights began in 1976 with the aircraft capable of flying at 60,000 feet at Mach 1.9. The pilot and systems officer wore full pressure suits from the David Clark Company which also made the pressure suits used by USAF U-2 and SR-71 crews as well as Space Shuttle crews. Many of the missions flown still remain classified but it is known that Iraq was a frequent target through the 1980s. One of the aircraft is now on public display at the Israeli Air Force Museum. 

Source/Photos: Israeli Phantoms- The 'Kurnass' in IDF/AF Service 1989 Until Today by Andreas Klein and Shlomo Aloni. Double Ugly Books/AirDOC, 2009, p44-70.

The First Steps to a Turboprop Transport, Part One

The YC-131C in flight. Note the 3-bladed propellers.

By the time of the Korean Armistice in 1953, the US Air Force was busy absorbing the lessons of airlift accrued over a less-than-ten-year span from the logistics flights to support World War II to the Berlin Airlift to the strategic airlift partnership forged with the commercial airlines in the Korean War. In pace with advances in aerodynamics and propulsion, the USAF began a four-step process in exploring the possibilities of turboprop propulsion given that pure jet engines of the day were still incredibly fuel-thirsty. The first steps were taken in 1945 with the test program of the Convair XP-81 turboprop fighter that also had an Allison J33 jet engine for additional power. The next steps were the testing of turboprop engines on existing high-speed jet designs that would result in the XF-84H "Thunderscreech and test versions of the Boeing B-47 Stratojet and the McDonnell XF-88 that flew with turboprop engines. The third step was the installation of turboprops on existing transport designs to evaluate their performance on large transports. And the final step was the introduction of production-standard turboprop transports which would result in the Lockheed C-130 Hercules and the Douglas C-133 Cargomaster. 

On 15 June 1954, the headquarters of the Military Air Transport Service (MATS) activated the 1700th Test Squadron (Turboprop) at Kelly AFB, Texas, with the task of developing maintenance procedures and techniques for the employment of turboprop transport aircraft pending the arrival of the C-130 and C-133 into the USAF service. The squadron had three flights with each flight dedicated to a single type for the testing of standard transport aircraft that had been converted to turboprop power. The first of the three flights to be activated would operate the Convair YC-131C. Two aircraft were converted from standard C-131 Samaritan transports (the USAF version of the CV-340 airliner) to use early test versions of the venerable Allison T56 turboprop. The YT56 turboprops replaced the piston engines of the C-131 and drove three-bladed Aeroproducts propellers. As this was the combination planned for the Lockheed C-130A, Allison was, needless to say, keen on being involved in getting flight time for the new engine. Tail numbers 53-7886 and 53-7887 were pulled from USAF service and modified by Convair at their Fort Worth facility at Carswell AFB. After initial flight testing at Edwards AFB, the first YC-131C was flown to Kelly AFB on 20 January 1955 with the second aircraft arriving three days later. 

Ground run of the YT56 engines at Convair Fort Worth.

As the goal of the test program set up by the 1700th TS was to fly the turboprop aircraft assigned to it as much as possible, the YC-131Cs were assigned to a scheduled military passenger service that operated between Kelly AFB in San Antonio and Andrews AFB outside of Washington, DC. The first services began on 14 March 1955 as the first scheduled turboprop passenger services in the United States. Covering a distance of just over 1,200 miles, the YC-131Cs took 4 hours 20 minutes on the first flight, approximately 20 minutes faster than a piston C-131 on the same route. By May of that year a regular flying schedule was established that would have the 1700th TS flying the two YC-131Cs 3,000 flight hours in nine months. As maintenance at destination stations was not expected to be adequate, each scheduled route flown by the YC-131C always returned back to Kelly AFB where the squadron had proper maintenance facilities. By July the Civil Aeronautics Administration (the CAA, the predecessor agency to the FAA) assigned four pilots to the 1700th TS to gain knowledge and experience in scheduled turboprop transport operations. That particular month, the second YC-131C became the first American-built turboprop aircraft to exceed 1,000 flight hours. 

The second YC-131C being handed over the USAF.

In the first six months the YC-131Cs were flown intensively, sometimes over 30 hours per day between the two aircraft. The initial time between overhaul (TBO) on the Allison YT56 engines was set at 100 flight hours at the start of the program but the engine proved to be highly reliable and as the program progressed, the TBO was increased progressively up to 200 flight hours. Though the engines could have safely flown with a longer TBO than 200 hours, Allison engineers were anxious to teardown and study the engines to improve the planned production T56 that would be used on not just the Lockheed C-130 but also on the same company's L-188 Electra airliner. During the nine month test program, 55 engines were changed out and sent back to Allison for analysis. The three-bladed Aeroproducts propellers also had TBO limits, starting at 300 hours and then extended out to 1,000 hours by the end of the test program. With a reliability well in excess of what was possible with piston engines, the two YC-131Cs also became the first USAF turboprops to exceed 1,000 flight hours with one day a record being set with an astounding 46 hours and 20 minutes flown in a 24-hour period, evenly split between the two aircraft. 

On 15 December 1955 the test program with the YC-131C ended, 45 days early thanks to the reliability of the YT56 engine. The USAF gained important data on fuel planning for turboprops, ATC procedures, holding patterns and ground operations that was also shared with the airline industry. In addition, the first squadrons that would be receiving the first C-130A Hercules aircraft at Sewart AFB, Tennessee, Ardmore AFB in Oklahoma, and Eglin AFB in Florida, sent their initial cadre of maintenance personnel to the 1700th TS in San Antonio for familiarization with the T56 engine. Both aircraft were eventually declared surplus and passed on to civilian owners before being scrapped. 

The next blog post will look at the second of the three turboprop conversions operated by the 1700th TS. Stay tuned!

Source: Remembering an Unsung Giant: The Douglas C-133 Cargomaster and Its People by Cal Taylor. Firstfleet Publishers, 2005, p29-43. Photos: Smithsonian Institution, SDASM.

Sunset of the Seaplane- The Convair P6Y

With the rapid expansion of the Soviet submarine fleet in the 1950s, the US Navy embarked on a series of programs to improve its anti-submarine warfare capabilities. Some of these efforts paid off handsomely with the development of new detection equipment and the rise of the nuclear-powered hunter-killer submarine (SSN). At the time, though, what the Navy really wanted was a means to quickly detect and prosecute enemy submarines as far away as possible from the carrier task forces. This meant the use of aircraft to cover the distances involved and to search the large areas of open ocean. At the time the furthest advances were being made in sonar technology and the Navy began work on the concept of using a dunking sonar on a seaplane. The seaplane could seed an area of interest with sonobuoys and then land on the water and use a dunking sonar to further track an enemy submarine. Dunking sonars had already come into use in helicopters but these were strictly short range options as helicopters didn't have the speed and range of a conventional aircraft. 

In 1954 the US Navy's Bureau of Aeronautics (BuAer) met with Convair which had long established its credentials in the seaplane field from before World War 2 onward with legendary aircraft like the PBY Catalina and an aggressive postwar program of hydrodynamics research for flying boat aircraft. Convair developed what was called the "Dunker" which was to be powered by two Wright R-3350 Double Cyclone radial engines and capable of operating from rough ocean seas. Tested in model form, the Dunker's most distinctive feature was a very deeply sculpted hull form designed to "cut" through the waves. The wing was high-mounted above the fuselage on a pylon like that of the PBY Catalina to provide the necessary clearance for the engines when operating in rough seas. By 1956 the Dunker's design refined further to a three-engined aircraft using three Pratt & Whitney R-2800 radial engines which allowed for a larger and more capable design. 

As a result of Convair's ongoing work, BuAer issued a Request for Proposals (RfP) in May 1956 for an advanced ASW seaplane of flying boat configuration capable of operating from rough ocean seas to use dunking sonar. Martin submitted a four-engined design that was designated the P7M Submaster and was based in large part on Martin's existing work on the jet-powered P6M Seamaster. Convair's submission was a further refinement of the Dunker design and was designated P6Y. Convair's design was much more advanced that Martin's submission. The P6Y retained the three R-2800 radial piston engines, but in order to allow slow flight and softer landings in rough seas, an innovative full-span boundary layer lift control (BLC) system would be installed. Two General Electric J85 turbojet engines were installed side-by-side in the central engine nacelle behind the R-2800 engine. The inboard flaps of the 127-foot wing used both suction above and just ahead of the flaps and jet exhaust from the J85s blowing head of the flaps to dramatically increase the effectiveness of the flaps. The wings outboard of the left and right engine nacelles used BLC to blow a sheet of high-velocity air across the top of the flaps. Wingtip mounted swivelling jet nozzles were used to augment the control authority of the ailerons in low speed regimes. Convair estimated that the BLC system on the P6Y would allow landings as slow as 40 kts, impressive for an aircraft with a crew of 10 and a gross weight of over 100,000 lbs. The design of the P6Y was led by German engineer Hans Amtmann, who during the Second World War had designed a flying boats for Blohm und Voss. Reportedly Amtmann even spent time on US subs to see first hand the challenges of hunting submarines in the open ocean!

The dunking sonar and sonobuoys were housed in the center of the fuselage with a weapons bay aft of the sonar compartment that could carry depth charges, torpedoes or even nuclear weapons. A rotating bomb bay door was used to create a smooth and watertight seal on the bottom of the hull. The P6Y would have been able to operate in rough seas up to 12 feet with its deeply cut hull and BLC flap system. 

By 1957 despite advanced design work, the maritime patrol community in the US Navy was less-than-enthused about open ocean rough water operation. Experience in the Second World War showed this to be highly uncomfortably and extremely rough on the structures and systems of even the most robust flying boats. With a general lack of support from the US Navy's operational patrol squadrons, the Convair P6Y was canceled in December 1957. From that point on, the role of maritime patrol and ASW would pass on to landplanes. That same year the Navy issued an RfP for successor to both the Lockheed P2V Neptune and the Martin P5M Marlin and specified a land-based aircraft to satisfy the demands of the patrol community. This aircraft would be a derivative of the Lockheed Electra and first flew in 1958 as the YP3V. In production the P3V was named Orion and after 1962 it was redesignated P-3. 

Though the cancellation of the Convair P6Y marked a turning point in naval aviation as landplanes took over roles traditionally assigned to seaplanes, the concept behind the P6Y didn't die there. In 1966 the Japanese Defense Agency issued a contract to flying boat builder Shin Meiwa for an ocean-going ASW flying boat which became the Shin Meiwa PS-1. The PS-1 was powered by four General Electric T64 turboprop engines, but like the P6Y, it had an extra engine in the form of a T58 turboshaft mounted in the dorsal center fuselage to drive a powerful BLC system that allowed the PS-1 to land as slowly as 50-55 kts. Robustly built with a deep hull form influenced by the P6Y, the PS-1 could operate in seas as rough as 14 feet. Like the P6Y, the PS-1 would alight on the ocean and use a dunking sonar to prosecute submarine contacts. 

The last PS-1 was delivered to the Japanese Martime Self-Defense Force in 1978. Further procurement after only 21 airframes ended after the open ocean ASW mission went to the Lockheed P-3C Orion which cost much less to procure and operated than the PS-1. However, 12 examples of a search and rescue version of the PS-1 were built starting in 1975 and remain in service to this day as the US-1. In 2003 Shin Meiwa first flew an upgraded version of the US-1 flying boat designated the US-1 Kai ("Kai" meaning upgraded) that kept the deep hull form and BLC system but mated the design with advanced Rolls-Royce AE2100 turboprop engines and a Lycoming CTS800 turboshaft driving the BLC system. 

Source: Convair Advanced Designs: Secret Projects From San Diego, 1923-1962 by Robert E. Bradley. Specialty Press, 2010, p99-102.

Alaska Airlines' First Jet, "Seventy-Seven Hotel"

Throughout the 1950s, Alaska Airlines' propliners wore a very elegant blue scheme with a golden eagle logo on the tail. The services from the lower 48 states to Alaska as well as on internal Alaska routes were advertised as "Golden Nugget" service in reference to Alaska's rich prospecting history. But despite popular services, Alaska in the 1950s was financially strapped and woefully unable to finance new equipment. At one point, Howard Hughes even offered to lease Alaska up to six Convair 880s to get into the jet age at very reasonable prices that unfortunately, were still too stiff for Alaska's austere budget.

But jets were what were needed and Alaska's competitor, Pacific Northern Airlines, had just ordered the Boeing 720 for delivery in 1962. There was simply no way for Alaska's DC-6s to compete with PNA's 720s on the Anchorage-Seattle run.

Charlie Willis, then Alaska's president, approached Convair to plead for very favorable financial terms to get jet equipment as Alaska saw the greater speed of the CV-880 as one way to meet the threat to market share posed by PNA's Boeing jets. Fortunately for him, Convair's sales team was desperately looking for a sale as the Convair jet was facing tough competition from the larger Boeing 707s and Douglas DC-8s. Willis returned to Anchorage with a contract for one Convair 880M, which boasted a whole range of improvements over the first baseline 880 model.

Of course, Convair was more than happy to be able to place one of their jets right in Boeing's hometown of Seattle where Alaska had a large presence in the late 1950s and early 1960s. N8477H (often called Seventy-Seven Hotel by Alaska crews) inaugurated Golden Nugget Jet services between Seattle, Anchorage and Fairbanks on 30 August 1961 and the service was cleverly pitched as "Four Jets Daily to Alaska".

Alaska's single CV-800 had high utilization as it was Alaska's only jet until the first Boeing 727s arrived in 1966 and Seventy-Seven Hotel was sold to Cathay Pacific. At one point, Alaska's sole 880 even carried cargo in the lounge area of the aircraft when demand was down in the winter months. The livery Alaska used on the CV-880 was based on the stylized eagle logo used on the DC-6s, but instead of blue, a very attractive red/gold scheme was used that was unique to Seventy-Seven Hotel and was not used on the rest of Alaska's fleet. The 727s that replaced the 880M had a Golden Nugget "meatball" style logo on the tail instead of the eagle on a red field. So not only was Alaska's 880 unique, it also wore a livery unique to it as well.

Source: Convair 880 & 990 (Great Airliners Series, Volume 1) by John Proctor. World Transport Press, 1996, p27.

The Convair Model 6: A Jumbo Before Its Time

People sometimes ask me how I decide what to feature on Aviation Trivia of the Day. I'd say that the majority of the time it's something I've come across as I'm reading one of my aviation-related books. I'm one of those sub-clinical attention-deficit types who can't finish one book before starting another. I'll quite literally have quite a handful of books that I'm rotating through at any given moment. If I run across an interesting bit that I want to feature sometime in this blog, I'll make a small dog ear at the bottom corner of the page. So yeah, I have lots of books with lots of those little lower corner dog ears. But sometimes it can come from more unconventional directions.

I'm on Twitter as @SentinelChicken and the other day I was exchanging tweets with a fellow avgeek, @flyingwithfish who has a great blog here (Flying With Fish: The Blog for Those Who Fly & Those Who Want to Fly Smarter) about an entry he had on his blog regarding double-deck jets that came before the Airbus A380. His blog entry discusses the McDonnell Douglas MD-12 and I had tweeted to him about the Convair design that combined the fuselage of the production version of the XC-99 transport with the wings, jet engines and empennage of the YB-60 which was designated the Convair Model 6. He's going to be doing a write up in his blog on my artwork, so it wanted to return the favor the best I could be crediting him with giving me the idea for today's entry.

But before I can talk about the Convair Model 6, I have to jump back a bit and talk about both the XC-99 and the YB-60 as they're both derivatives of the B-36 Peacemaker. Convair's work on the B-36 began in the midst of the Second World War as there was a concern that Great Britain would fall to the Reich and we would need strategic bombers that could reach Europe from the United States. But in parallel to the development of the B-36 there were design efforts that looked at passenger versions of the B-36. As early as May 1942 Convair had been looking at a transport version of the B-36 called the Model 37 that combined the wing, six pusher piston engines and empennage of the B-36 to a new fuselage unit. In December 1942 the USAAF signed a contract with Convair to build a single example of what was designated the XC-99 on the stipulation that the XC-99 would not divert resources from the B-36 project. Convair saw the XC-99 as a way to validate some of the design concepts of the B-36 quickly as it would not need military equipment (what's called government-furnished equipment) for the transport role.

Despite the ongoing war, Convair pitched the XC-99 as a passenger transport to the airlines, even succeeding in getting 15 orders from Pan American World Airways for what the airline was calling the "Super Clipper". Production was to begin at the end of the war and the Convair Super Clipper would have carried 204 passengers in luxury across the Atlantic.

As the B-36 was built in Fort Worth, the XC-99 would have to be built at Convair's San Diego Lindbergh Field facility. The wings and empennage were shipped to San Diego from Fort Worth and on 23 November 1947 the XC-99 made its first flight. The XB-36, by comparison, made its first flight in Fort Worth on 8 August 1945. By January 1949 the XC-99 was retrofitted with four-wheel main bogies that allowed it to use any airfield in the United States and abroad that could accommodate the production B-36. The following year it got fitted with production standard Pratt & Whitney R-4360 radial engines that were more powerful than the earlier version installed.

In its 1950 incarnation, the XC-99 could carry over 100,000 lbs of cargo or 400 fully-equipped troops, or 300 litter patients on a double deck layout. Based at Kelly AFB and operated by the San Antonio Air Materiel Depot, the XC-99 flew on operational transport missions in the United States for several years before being retired. A production version of the XC-99 proposed by Convair would have moved the flight deck to a B-36 "bubble" atop the fuselage with the nose gear installed in a bulge under the nose (similar to what you see on the Lockheed C-5 Galaxy). Moving the flight deck upward to the top deck allowed straight through loading via aft clamshell doors and a ramp and nose doors and a ramp, a feature that the USAF didn't have at the time in its transport aircraft. This production version would have had a range of 3,800 miles with a full payload. The USAF, however, decided on the Boeing C-97/KC-97 Stratofreighter and the Douglas C-124 Globemaster II for its long distance heavy airlift needs, both aircraft that paled in performance of the proposed production version of the XC-99.

Now the YB-60 is often seen as the competitor to the Boeing B-52 Stratofortress on account of having the same eight engines in the same four paired nacelles, but the USAF never conducted a true competition for the role filled by the Boeing B-52, though Douglas and Convair did work on designs to fill that role even though Boeing was set to build the replacement for the Convair B-36. In August 1950, Convair submitted an unsolicited proposal for a jet-powered, swept-wing version of the B-36 Peacemaker. As Convair intended to use many B-36 components, the USAF was sufficiently interested to order two YB-60s (the original designation being B-36G). Using many of the structural components of the B-36F, construction of the first YB-60 began in Fort Worth in the spring of 1951 and it made its first flight on 18 April 1952, only three days after the first flight of the Boeing YB-52 Stratofortress.

Although there was no formal competition between the YB-60 and the YB-52, it was quite obvious that by using B-36 components, the YB-60 was significantly cheaper than the Stratofortress. But as the Stratofortress was designed from the outset as high-speed jet intercontinental jet bomber, its performance blew the YB-60 away. The YB-52 was 100mph faster (the thick B-36-based wing of the YB-60 was one of its biggest liabilities) and it had more refined aerodynamics as the YB-60 flight test program turned up multiple stability and control deficiencies. As a result, after only 66 flight hours the USAF canceled the YB-60 program with the second YB-60 being 95% complete.

So here's where the XC-99 and the YB-60 meet. Given the parallel design efforts taking place with several key personnel in common, it was inevitable that Convair would propose an all-jet version of the C-99 production version transport. First proposed in 1950, the jet-powered C-99 combined the swept-wings and eight jet engines in paired nacelles and swept empennage of the YB-60 with the production version fuselage of the C-99. It would have been an impressive transport with both nose and aft loading cargo doors, a double deck with the upper deck being pressurized and it jet form. And this was in the early 1950s- the USAF didn't have intercontinental jet cargo capability until the first flight of the Lockheed C-141A in December 1963 and while the Starlifter would have been faster than the Convair Model 6 jet transport, it didn't have the immense load capacity, being only able to carry about 70,000 lbs compared to 100,000 lbs of the Convair Model 6. And it wouldn't be until the first flight of the Lockheed C-5A Galaxy in June 1968 that the USAF had a double deck jet transport with straight through loading via the nose and tail! The Galaxy showed the march of technological progress by being able to carry over two and a half times the payload of the Convair Model 6 at higher speeds and farther distances.

But considering the technology of the day, the Convair Model 6 wasn't out of reach as it used components from both the XC-99 and the YB-60 that were already flight proven.

Source: Cold War Peacemaker: The Story of Cowtown and the Convair B-36 by Don Pyeatt and Dennis R. Jenkins. Specialty Press, 2010, p176-191.

The 1952 Carswell AFB Tornado

Prior to the arrival of the Boeing B-52 Stratofortress, the responsibility for the long-range strategic deterrent of the United States rested with the Convair B-36 Peacemaker in the 1950s. The Atlas ICBMs were still years away from becoming operations and the first Polaris submarine-launched ballistic missiles were still on the drawing boards. The other bombers of the USAF's Strategic Air Command, the Boeing B-50 Superfortress and the Boeing B-47 Stratojet, were medium range bombers that could not strike Soviet targets from the United States. Only the B-36 had the range to reach the Soviet Union and the capacity to carry any of the nuclear bombs in the US stockpile.

As the B-36 was built and flight tested in Fort Worth at Convair's mile-long plant at Carswell AFB, the first of SAC's bomb wings to receive the Peacemaker were based at Carswell. The 7th Bomb Wing was the first to put the Convair's "big stick" into service, followed by the co-located 11th Bomb Wing. With Convair right across the runway at the base, any technical problems could be readily addressed. As a result, the majority of the United States' long range striking power was concentrated in Fort Worth.

On Labor Day, 1 September 1952, many of the base personnel and flight crews had the long weekend off. Weather forecasters had predicted severe thunderstorms for North Central Texas that afternoon with estimated winds of 60mph. As few personnel were on duty, few precautions were taken other than securing the B-36 aircraft with 3/8 inch steel cables. At 6:42pm, a tornado touched down on the base perimeter and struck the B-36 flightline directly. Maintenance docks used to work on the large bombers outdoors were thrown about and the steel cables tying down the bombers snapped as the planes were thrown about by the tornado like toys. Ruptured fuel tanks spilled thousands of gallons of high octane avgas all over the ramps. The anemometer on the Carswell control tower registered sustained winds over 90mph before being torn away by the storm. As the storm subsided, operations had to be transferred to nearby Meacham Field and other bases in the Southwest.

Two-thirds of the entire B-36 Peacemaker force was either damaged or destroyed in the tornado. One aircraft was completely shattered and would have to be written off while 72 bombers on the flightline and adjoining aprons were damaged and unflyable. Fortunately there were no fatalities given the long holiday weekend. Another 10 B-36s parked at the Convair plant were also damaged. Some of the bombers were shoved on top of each other and many had lost wings, empannages, or large fuselage sections. Because of the national priority placed on the B-36 fleet, by 5:30 the next morning a repair plan was underway with 1/3 of the repairs to be carried out by SAC, 1/3 of the repair work to be done by repair teams dispatched from Kelly AFB in San Antonio (the site of one of the USAF's heavy logistics centers), and remaining 1/3 would be carried out by Convair. So urgent was the matter than a 1-page typed letter was the basis of a multi-million dollar contract for Convair for its share of the repair work. Project FIXIT returned one bomber to operational service the first week, and nine more B-36s in the second week after the tornado. In less than a month, the 7th Bomb Wing was back at full operational strength of only one B-36 had to be written off out of the 83 damaged. By the end of the month, the round-the-clock effort had the 11th Bomb Wing operational and by the first week of October, 51 more aircraft were returned to service. The last repaired B-36 returned to duty on 11 May 1953.

Having 2/3 of the B-36 force knocked out in less than 30 minutes taught SAC a lesson. Each time severe weather threatened Carswell AFB, as many B-36s as possible were flown out to other bases and would return the next day. 

Senator Lyndon B. Johnson of Texas and his Military Preparedness Committee conducted an investigation that concluded the base commanders had taken all the adequate measures proscribed at the time with an approaching storm. The investigations called for improved weather forecasting and an increase in the research of tornadic thunderstorms which over the years would not only benefit the USAF, but the general public as well.

Source: Cold War Peacemaker: The Story of Cowtown and the Convair B-36 by Dennis R. Jenkins and Don Pyeatt. Speciality Press, 2010, p149-151.

Extending the Range of Escort Fighters: Wingtip Coupling

In the immediate postwar period the performance of jet engines was such that they weren't economical and for the nascent USAF needing high performance escort fighters for its bomber fleet, they simply didn't have the range to accompany bombers like the Convair B-36 Peacemaker and the Boeing B-50 Superfortress on their projected missions. While the idea of a parasite fighter like the McDonnell XF-85 Goblin represented one approach, it represented a loss of bombload as the parasite fighter had to be carried under the fuselage, the most ideal location being where the bomb bay was located, near the bomber's center of gravity.

Dr. Richard Vogt, a German engineer who had headed the design work at Blohm und Voss during the Second World War, was brought the United States under Operation Paperclip (which also resulted in Werner von Braun coming to America) and his first posting was with the Air Force Research Laboratory at Wright-Patterson AFB in Dayton, Ohio. While continuing his research on unorthodox aerodynamic concepts there (he had designed the asymmetrical BV 141 while at Blohm und Voss), he developed the idea of increasing the range of an aircraft by attaching free-floating wings to the wingtips of the existing aircraft. Extra fuel tanks formed the body of the wing extensions and the aerodynamic lift from the extensions supported their weight in flight without significant structural penalty to the main aircraft. In addition, these extensions increased the wing aspect ratio, thereby reducing drag and improving the range.

While this idea was first applied to the early candidate designs for the USAF WS-110A program that resulted in the North American XB-70 Valkyrie bomber, the concept also got the Air Force's attention as a means of extending the range of its new jet fighters by substituting escorting jet fighters for Vogt's free-floating wing extensions. In 1949 the first flight trials took place using a Douglas C-47A and manned Culver PQ-14B drones. A simple coupling device allowed three degrees of freedom for the attached PQ-14B- a small ring on a short boom was attached to the wingtip of the C-47 and the PQ-14B had a rear-facing lance that engaged the ring and the drag of the PQ-14B kept it locked on the wing of the larger C-47. To disengage, the PQ-14B pilot simply throttled up and moved forward, sliding the lance out of the ring on the coupler. Since the PQ-14B was supported by its own lift, no structural reinforcements were needed on the PQ-14B or to the C-47 for that matter.

Flight tests began on 19 August 1949 and the first successful coupling was made by Second World War ace Clarence "Bud" Anderson at the controls of the PQ-14B on 7 October 1949. Problems were encountered with the wing tip vortex from the C-47 and the solution was to move the coupler outboard of the wingtip.

The USAF then initiated Project TIP TOW using a Boeing B-29 Superfortress and two Republic F-84 Thunderjets with development assigned to Republic Aviation. Two F-84Ds were modified into EF-84Ds with special wingtips that could attach to a coupling on the modified B-29 which was designated EB-29A. The wingtip vortex from the larger Superfortress made the coupling process hazardous and there were doubts as to whether service pilots with less experience than test pilots could accomplish the process. Despite 15 hours of coupled flying time with both EF-84Ds attached, on 24 April 1953 during the test of autopilot system to lessen the fighter pilot's workload one of the EF-84Ds rolled over onto the wing of the EB-29, causing a structural failure of the left wing and the loss of both aircraft in the process. The pilot of the EF-84D was killed instantly and only one of the five crew on the EB-29 survived.

Despite the loss the USAF persevered and proceeded with Project Tom-Tom- as the design was the brainchild of Major General Thomas Gerrity and Convair manager Tom Sullivan, it was spelled without all caps as was the standard USAF custom for project names. A Convair B-36 was assigned to Project Tom-Tom in May 1954. The coupling provision not only would grapple and hold onto the Republic RF-84F Thunderflashes used in the tests, but they could also provide fuel, power, pressurization and heat to the coupled jets. The first hookup was made on 2 November 1955 but again, the wingtip vortex from the significantly larger B-36 made it a dangerous affair for the pilot of the smaller aircraft. On what ended up being the final Tom-Tom flight in September 1956, Convair test pilot Beryl Erickson found his RF-84F oscillating violently but fortunately for the flight crews involved the coupling broke off and Erickson was able to land safely.

By this point the USAF's parallel experiments in inflight refueling were proving to be more practical and much easier to accomplish with much less risk to the flight crews and the Project Tom-Tom was canceled, ending work on tip-coupling.

Source: Cold War Peacemaker: The Story of Cowtown and the Convair B-36 by Don Pyeatt and Dennis R. Jenkins. Specialty Press, 2010, p224-226.

The Centaur Upper Stage

During the early days of the American space program, there were two schools of thought in liquid-fueled rocket design. One group, represented by Werner von Braun and his team of NASA engineers at the Marshall Spaceflight Center, favored rockets with strong internal structures similar to that of monocoque aircraft. The other group, represented by the Atlas missile engineers at Convair, favored rockets with a thin aluminum shell that used pressurization of the tank and its propellants for structural integrity- what was called balloon skin construction.

The Atlas team had already proven their structural technique would work as the Atlas had already entered service as the first American ICBM and it was already being used for space launches from satellites to the manned Mercury program. The main engineers behind the Atlas, Charlie Bossart and Kraft Ehrlicke, were planning a high-energy liquid fueled upper stage that could be used on the Atlas to boost its orbital payload. This was the Centaur upper stage and it would use the first rocket engine to use liquid oxygen and liquid hydrogen- while liquid oxygen was commonly used as an oxidizer, the Centaur and its Pratt & Whitney RL10 rocket engines pioneered the use of liquid hydrogen- it was much colder and tricker to handle, but combined with liquid oxygen it offered a quantum leap in performance.

Early in the Centaur program the USAF was the main customer, but bureaucratic changes and shifts in mission funding requirements led the Centaur program to be transferred from the Air Force to NASA. As a result, the two main schools of thought in liquid-fueled rockets came to clash in 1962.

Von Braun's team offered a more conservative approach that was being incorporated in their work on the Saturn launch vehicle. Von Braun, now being placed in the position of overseeing the Centaur program, sent his structural engineering chief, Willie Mrazek, to San Diego to review the progress on the Centaur program. Convair's engineers by that point had already developed a reputation as being the "unruly wards" of the Marshall Spaceflight Center and while the USAF was willing to push the technological envelope, the safety-minded culture of NASA desired a less risky approach. Mrazek came to Convair in 1962 not terribly pleased with the balloon skin design of the Centaur.

The heads of Convair tried their best to keep Charlie Bossart and Kraft Ehrlicke clear of Mrazek during his visit. During a technical presentation on the Centaur's construction, unbeknown to Mrazek who was seated in the audience, Charlie Bossart managed to sneak into the presentation and took the seat right to Mrazek. As the presentation proceeded, Mrazek was constantly shaking his head and muttering to himself what he thought was wrong with the Centaur's design. By this point, Bossart had had enough despite his explanations to Mrazek (imagine these two men arguing in a loud whisper in the back of an auditorium) and took him outside. Deane Davis, Convair's deputy director for technical control and Ehrlicke's immediate superior, was convinced that Bossart was taking Mrazek outside to settle the score with fisticuffs.

Bossart took Mrazek to the outdoor factory yard where a brand-new Centaur upper stage sat, its polished thin aluminum skin gleaming in the sunlight. "What's inside it?" asked Mrazek. "Just nitrogen" replied Bossart, at which point he handed Mrazek a hammer and invited him to pound a hole into the side of the Centaur. Without the nitrogen pressurization, the Centaur would collapse under its own weight. Mrazek couldn't believe that gaseous nitrogen was keeping the Centaur's structure, so he took a swing at the rocket stage. The first hit was only a glancing blow and hardly scratched it. I can only picture Bossart at this point egging Mrazek on to hit it harder- which he did. The hammer rebounded off the skin and hit Mrazek in the face, knocking his glasses off. Again, the skin remained unscathed.

Bossart's point was made at the expense of Mrazek's ego and his glasses. The Centaur program proceeded onward from that day in 1962, and the Centaur is still in use today as a second stage on launch vehicles like the Atlas V. It was successfully used on the Titan series of launch vehicles and is currently under consideration as a high-energy upper stage on the new Delta IV rocket.

Source: To Reach the High Frontier- A History of US Launch Vehicles, edited by Roger D. Launius and Dennis Jenkins. The University Press of Kentucky, 2002, p344-345.

Convair's Lenticular Defense Missile: Pye Wacket

Pye Wacket high speed wind tunnel model

In 1947 researchers at Wright-Patterson AFB in Dayton began investigations into the possibility of using missiles for bomber defense as the speed of jets and the weight of gun turrets made existing systems for bomber defense impractical. General Electric was the first to receive a USAF contract to pursue such studies, but soon transferred the work to Hughes where the missile developed didn't end up on bombers but on interceptors as the Falcon missile. McDonnell was next in 1952 to try and develop a jet-vane controlled defensive missile for the Convair B-58 Hustler, but the work was canceled in 1956. By that time, however, work began on the WS-110A project that would result in the North American XB-70 Valkyrie and more contracts were issued to study what the Air Force was calling DAMS- Defense Anti-Missile Subsystem, a system that fired a stream of pellets at inbound missiles. Again, those studies ended in 1959 despite some encouraging tests.

The USAF wasn't deterred, though, starting a program in 1958 in cooperation with North American and Convair called Pye Wacket for a defensive missile for the XB-70 Valkyrie. Three basic shapes were first evaluated by North American and Convair- a standard but modified version of the AIM-47 designed for the F-108 Rapier, a cylindrical missile using jet vane directional control, and an unusual saucer-shaped missile called a "lenticular defense missile". Studies showed the lenticular design the most promising as its shape allowed it to be pointed in any direction and fired, not wasting kinetic energy on turning towards the incoming threat.

By 1959 the USAF did a considerable amount of wind tunnel work at the Arnold Engineering Development Center in Tennessee of the lenticular Pye Wacket design. It was stable all the way to Mach 6. It had a diameter of 70 inches, was 9 inches deep at its thickest portion and weighed only 510 lbs. One end of the saucer shape housed the infrared seeker and two rocket motors were on the opposite end to give the Pye Wacket a range of approximately 72 nautical miles. A set of spoilers built into the curved surfaces of the missile provide directional control.

North American began to seriously consider the Pye Wacket missile for the XB-70 Valkyrie- posts were mounted vertically in the forward section of the weapons bay and the missiles were mounted on the posts via a screw thread that ran through the center of the missile. This way the saucer-shaped missiles could be threaded on the post and stacked. Two stacks of five missiles each would fit in the Valkyrie's weapons bay. When needed, the post rotated to point the lowest missile in the stack in the direction of the inbound target. The missile was then dropped out of the bay already pointed at the target at which point the rocket motors fired.

In the summer of 1959 Convair was awarded a design contract to further study the lenticular Pye Wacket design and modified the saucer shape to incorporate a blunt trailing end where the rocket exhaust was located. This improved the supersonic drag as well as the controllability of the missile. Roll reaction thrusters were added along with small lateral vanes as well as the original spoilers used on the original design. With over 80 hours of wind tunnel testing from speeds as low as Mach 0.6 to Mach 5, sled tests then took place at Edwards AFB on a full-scale article powered by three Thiokol solid rocket motors, the same type used singly on the AIM-4 Falcon air-to-air missile.

The tests reported accelerations on the order of 60G with the ability to make sharp high-G turns at supersonic speed without loss of control. An operational version of the Pye Wacket arming the Valkyrie would be 48 inches in diameter, carry a 50 lb warhead and be capable of extreme maneuvers up to Mach 6. Convair recommended that the Air Force procure 12 missiles for continued testing, but no documentation has been found that further details work done from that point on on the lenticular defense missile.

Convair also had proposed a strike version of the Pye Wacket that would allow a bomber to easily strike targets on each side of its flight path without having to overfly enemy defenses. A version was also suggested by the company to use as a highly maneuverable re-entry warhead for ballistic missiles.

It's always been a point of curiosity to me as an aviation geek why a weapon as promising as the Pye Wacket never got developed further. Or did it? Conspiracy theorists might think the Pye Wacket was classified and modern versions of the lenticular defense missile moving at speeds unattainable by manned aircraft might account for a good portion of the UFO sightings pointing to a super-maneuverable vehicle. Considering that the basic layout was stable at hypersonic speeds, it certainly would make a very capable rapid-strike weapon.

Now if you'll excuse me, I have to go fetch my tinfoil hat.

Source: Valkyrie: North American's Mach 3 Superbomber by Dennis Jenkins and Tony Landis. Specialty Press, 2005, p220-226. Photo: NASA

Following the October 1957 launch of Sputnik 1, the US was badly in need of a morale boost in the nascent space race. The Navy's Vanguard rocket program was given the green light to launch in December 1957 and the first stage failed on the launch pad, giving the Soviets a propaganda coup as the launch was publicized in advance. The Army's Jupiter program led by Werner Von Braun had been given the green light after the failure and on 1 February 1958 a modified Jupiter IRBM designated Juno I put the Explorer 1 satellite into orbit.

By the summer of 1958 the Soviet Union had already orbited Sputnik 2 (carrying the dog Laika and the first satellite to weigh over 1,000 lbs) and Sputnik 3, the first satellite to weigh over a ton. It didn't take much to realize that the Soviet Union had already put over 3,000 lbs worth of satellites in orbit using the massive R-7 ICBM and the United States only had less than 70 lbs in orbit, Explorer 1 and the diminutive Vanguard 1 weighing only 3.5 lbs. The head of the Advanced Research Projects Agency (ARPA, which later became DARPA), Roy Johnson, contacted the Air Force about the possibility of orbiting an entire Atlas ICBM which would put four tons into orbit and constitute a huge morale boost for the struggling US space effort.

The concept of putting an entire Atlas missile into orbit was radical- only eight Atlas missiles had been test-flown up to that point and only three were successful. Those early Atlas missiles were the Atlas A variant which had only two engines while the Atlas B had three engines (two of which were dropped as boosters, leaving the center engine to act as the sustainer) and it had just failed on its maiden flight. But Roy Johnson, having seen the Atlas A test data, knew that the performance estimates were conservative and that the Atlas A test flights indicated that the three-engined Atlas B could do it, particularly if all the heavy test and telemetry instrumentation were removed from the missile. But if it could be down, it would but the entire missile and a 300-lb payload into orbit minus the two booster engines. It would be in his words "A master-stroke in the space war" against the Soviets.

ARPA and the USAF agreed on the plan to secretly prepare an Atlas B for launch into orbit. Along the way it was decided that the payload would be a recording and transmitting package that would broadcast a message of peace from President Eisenhower. It would orbit the Earth every 90 minutes at an altitude of 100 miles. The program became Project SCORE (Signal Communication by Orbital Relay Equipment).

Only 88 engineers at Convair and the USAF worked on Project SCORE. Atlas missile 10B was selected for the mission and Rocketdyne, the maker of the Atlas engines, introduced performance enhancements and tweaks to a select group of engines called "Hotrods". Eisenhower, however, was reluctant to lose any more face in the competition with the Soviets particularly in light of the failure on the maiden flight of the Atlas B (designated 3B). The successful test flight of Atlas 4B failed to sway the President but ARPA and the USAF convinced him that the SCORE payload was a crucial test of communications technology and if the missile failed to reach orbit, they could always say that it was a successful ballistic missile test down the Atlantic Missile Range from Cape Canaveral.

Reducing the weight of the Atlas was essential and many systems planned for the Atlas C were incorporated into the 10B vehicle. As it was necessary to allow the various other personnel and contractors to go about their usual work, the 88 individuals (who called themselves the "88 Club") who knew of Project SCORE had to give excuses to non-cleared staff to allow the project to move forward. The head of the project, Col. Asa Gibbs, and his counterparts at Convair kept a notebook of all the excuses they used in an effort to be consistent while guarding the secrecy of the project.

The SCORE package developed by the Army Signal Corps had two tape recorders with one acting as back up as well as the necessary communications equipment to be activated from ground stations. The recording from President Eisenhower arrived at the Cape on the eve of the flight on 18 December 1958 but the SCORE payload was already buttoned up on the Atlas. So the Army had to transmit the message from a trailer hidden in a swamp near the launch pad, but when they did so, part of the President's message got erased. No problem, they could re-upload the recording once the Atlas was in orbit.

The following day on 19 December 1958 the Atlas successfully reached orbit and for many years it was the largest object ever put into orbit with a weight of 8,660 lbs. The command channel to upload the President's message, however, was inadvertently triggered by a radio station in New England that by coincidence happened to be on the same frequency broadcasting a dance band. It took two orbits to get the dance band recording erased and the President's message uploaded. This was President Eisenhower's message:
"This is the President of the United States speaking. Through the marvels of scientific advance, my voice is coming to you from a satellite circling in outer space. My message is a simple one. Through this unique means I will convey to you and to all of mankind America's wish for peace on Earth and goodwill toward men everywhere."

Project SCORE made 34 orbits broadcasting Eisenhower's message repeatedly before the batteries ran out and the Atlas burned up over Africa just over a year later. Even though SCORE was more a propaganda victory for the United States, it was the first demonstration of the potential of space-borne communications relay. While the SCORE payload was active, more than 78 transmissions were made between the satellite and ground stations making it the first communications satellite in the world.

Roy Johnson as the prime mover behind Project SCORE was invited to autograph the side of the Atlas before its launch and after it success, he had commemorative plaques made, one each for the members of the "88 Club" that worked in secrecy in addition to their regular duties to Convair and the USAF.

Source: Atlas- The Ultimate Weapon by Chuck Wallace with John Powell. Apogee Books, 2005, p224-230.