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.

In the early morning hours of 29 August 2005, Hurricane Katrina made landfall near New Orleans as a Category 4 storm. In addition to the widespread flooding and destruction, the storm also destroyed much of the area's communications infrastructure from cellular towers to air traffic control systems. As an integral part of Joint Task Force-Katrina (JTF-Katrina), the US military, civilian agencies, and those nations who came to assist needed airspace coordination with as many as 80 helicopters alone airborne throughout the area rescuing survivors and inbound relief flights and outbound evacuation flights.

Two Navy E-2 Hawkeye squadrons provided air traffic control and coordination as well as a detachment of P-3 AWACS aircraft from the US Customs Service. The two Hawkeye squadrons involved were the reserve unit VAW-77 "Nightwolves" (call sign WOLF) from NAS Atlanta and VAW-126 "Seahawks" (call signs SEAHAWK and CLOSEOUT) from Carrier Air Wing Three embarked on the USS Harry S Truman which was sailing in the Gulf of Mexico assisting with relief efforts. In addition, the US Customs P-3 AWACS (which use a similar radar system as the E-2) from their home base in Corpus Christi (call sign OMAHA) also assisted the Navy Hawkeyes.

The E-2's radar and extensive communications suite allowed the crews to monitor the airspace, assist in location of stranded survivors, direct rescues, air traffic control and even identify with the radar safe landing areas and locations of tall obstructions. The two squadrons adopted the same system used for directing close air support for the New Orleans environment, using a grid and keypad system overlaying the area to coordinate and direct rescue aircraft and deconflict the airspace much in the same way fighters and strike aircraft might be directed to targets. At times a single E-2 might be controlling as many as 80-90 helicopters operating over the metropolitan area.

The E-2 Hawkeye has a crew of five- two pilots up front and three NFOs (naval flight officers) in the back who provide the airborne control and communication. The center seat is usually occupied by the commander or combat information officer who directs the efforts of the two NFOs on each side. Many of the helicopter pilots involved in the relief preferred working with the E-2 Hawkeyes as the smaller number of crew aboard made decision-making quick compared to the larger platforms like the P-3 AWACs. All one of the NFOs would have to do to direct a rescue effort was to turn to his commander and ask for clearance.

Source: Flying the World's Greatest Aircraft: Superlative Military Machines from Sabre to Raptor, James Bennett, editor. Fall River Press, 2009, p81.

Weather Reconnaissance Squadron FOUR (VW-4): The Navy's Atlantic Hurricane Hunters

Navy Weather Reconnaissance Squadron FOUR (VW-4), based out of NAS Jacksonville, Florida, for many years was responsible for the Navy's contribution to the hurricane hunting effort shared with the US Air Force and the Department of Commerce. For most of VW-4 history it flew the Lockheed WC-121N Warning Star, a veersion of the EC-121 airborne early warning version of the Lockheed Super Constellation. While not one WC-121N was ever lost on a hurricane hunter mission, by 1969 the Navy was looking at replacing the venerable old bird with a more advanced weather reconnaissance aircraft.

During the 1969 Atlantic hurricane season, Hurricane Inga formed near the Lesser Antilles and an unusual combination of weather factors had the hurricane wandering in two loops south of Bermuda (Inga would last 25 days, becoming the 4th longest lasting Atlantic hurricane in history). The Navy took the opportunity to perform a unique fly off of two candidate replacement aircraft along with the existing WC-121N Warning Star. They flew a Lockheed C-130 Hercules, a Lockheed P-3 Orion, and a Lockheed WC-121N Warning Star (Huh! All Lockheed products, too. Go figure.) in trail formation on repeated penetrations of the eyewall of Hurricane Inga. Fifteen miles separated each aircraft from the next aircraft in the formation as over twenty low-altitude penetrations were made into the eye. A multitude of factors were evaluated from propulsion systems, flying qualities and general handling in the severe turbulence of the eyewall as well as the structural integrity and payload capacity. The working environment was also taken into consideration considering the long flights that were a routine part of hurricane hunting.

Although both the C-130 and P-3 did well in the evaluation flights into Hurricane Inga, the Navy selected the P-3 Orion as the next Hurricane Hunter. Interestingly the USAF has been using the C-130 since 1960 for the hurricane hunting mission.

Existing P-3As were taken from the Navy maritime patrol fleet and stripped and reworked at Lockheed's Ontario, California, facility. All the ASW and sensor systems were removed and a weapons-bay mounted APS-20 radar was installed with a large M&M-shaped radome (and thus called the "M&M radome"), structural strengthening of the wings and a whole host of meteorological data-gathering sensors. The new WP-3As also had dual INS, Doppler and Omega navigation systems, one of the most extensive and advanced systems to be installed in an aircraft at the time. The interior layout remained essentially the same as that of the fleet P-3 Orions with the operator consoles reconfigured for weather research and data gathering.

The new WP-3A's first taskings with VW-4 were with Project Stormfury, a long running joint Department of Defense/Department of Commerce research project into cloud seeding of hurricane storm bands in an effort to attenuate the storm's intensity. Though the results were inconclusive, the idea of the military being involved with weather modification became a political hot potato with accusations by uninformed quarters of the "weaponization of weather". The WP-3As also participated in polar ice reconnaissance and winter storm studies on the US East Coast. In addition, the WP-3As were also deployed overseas to provide weather support and research for fleet operations.

In late 1974 as the result of post-Vietnam budget cuts, the Navy announced the closing down of VW-4 and its hurricane hunting mission which became official on 30 April 1975 and the WP-3As were pulled out of service and demodified for other roles. The military's contribution to hurricane hunting would be handled entirely by the USAF in cooperation with the National Oceanic and Atmospheric Administration (NOAA). Ironically, NOAA took delivery in 1976 of two even more highly-modified Lockheed P-3 Orions designated WP-3D which were even more advanced the Navy's WP-3As and still serve to this day.

Source: The Age of Orion: The Lockheed P-3 Story by David Reade. Schiffer Publishing, 1998, p119-122.

In an earlier entry I had featured the RB-69 spyplane conversion of the Lockheed P2V Neptune that was the Skunk Work's first CIA contract. That CIA program to operate low-altitude overflights of the People's Republic of China starting in 1957 was codenamed ST/POLLY by the CIA. The program had generated much useful intelligence on the military activities of the the PRC that the CIA contracted with E-Systems of Greenville, Texas, to convert three Lockheed P-3A Orions to a similar configuration but with more intelligence-gathering systems under the codename ST/SPIN, starting with the arrival of the first P-3A to the naval aviation depot in Alameda, California where E-Systems began the conversion work.

The most obvious modification (apart from its all black color and abbreviated tail sting as the MAD sensor wasn't needed on the clandestine overflights) was a widening of the crew entry door on the aft fuselage with a duplicate door right next to the existing door- this gave a just over six foot wide entry with two inward-opening doors- like the earlier RB-69 Neptunes, this was to allow the infiltration of field agents, special equipment, arms and ammunition and on occasion, propaganda leaflets by the boxload.

The ELINT receivers from the RB-69 Neptunes were taken out, upgraded, and installed on the ST/SPIN Orions. Additional sensors were added thanks to the increased performance of the Orion over the Neptune- a SLAR was added for peripheral reconnaissance missions along the Chinese border, communications intercept equipment, an infrared detector and allegedly even a sensitive acoustic detector. Slant-range and oblique photography cameras were also installed and to also perform intelligence on the Chinese nuclear program, air-sampling equipment was also installed connected to ram air scoops near the cockpit.

The first ST/SPIN operational mission took place in 1964. All the personnel aboard the aircraft were Taiwanese trained and led by the CIA. Missions ranged from gathering radar ELINT data for the Strategic Air Command to even flights into Tibet to gather information on the PRC's suppression of Tibetan nationalists.

However, the Taiwanese general running the program would staff each plane with as many as 27 crew when only 13 to 14 were needed. Taiwanese personnel got a bonus for flying on ST/SPIN missions and he was taking a kickback to assign extra crew to each mission. Operatives of the PRC were able to penetrate the ST/SPIN program to the point that during an ST/SPIN mission, PRC radio operators would call out the aircraft and ask to speak to specific crewman by name.

By 1965 the Taiwanese general was arrested and sent to prison for his staffing scheme and the CIA and NRO (National Reconnaissance Office) withdrew funding from the ST/SPIN program before the third P-3A Orion could be completed. The aircraft were returned to the United States.

Source: Wizards of Langley: Inside the CIA's Directorate of Science and Technology by Jeffrey Richelson. Westview Press, 2002, p96-98.

During the Vietnam War, Lockheed P-3 Orions operated primarily in the maritime interdiction role, patrolling the 900-mile coastline of South Vietnam as part of Operation Market Time. Anti-infiltration missions were flown day and night to interdict the supply of arms and supplies to the Viet Cong. In addition, Orions also provided anti-submarine screening for the carrier battle groups operating off the coast of both North and South Vietnam.

But a little known mission of the P-3 Orion during the Vietnam War was that as a "pathfinder". Pathfinder P-3s acted as long range ferry escorts for USAF fighter jets making their way across the Pacific to the Southeast Asian theater. Ferrying aircraft to the war zone was faster than shipping them by sealift and the P-3s would provide navigation and communications relay to the fighter aircraft. During air-refueling, the P-3s loitered in the area in case of an emergency that would result in a pilot ejecting or ditching in the open ocean. The first pathfinder mission was flown on 20 January 1966.

Source: The Age of Orion: The Lockheed P-3 Story by David Reade. Schiffer Publishing, 1998, p23.