This book had to be written now, as the advent of AEW aircraft is still within living memory, just. The Air and Ground Crews who operated the very early aircraft described in this book have either already left or not far away from that final flight to that great Mess Hall in the sky. It is vital that their anecdotes are gleaned and recorded before they depart so that their stories are not lost to the mists of time, being replaced by speculation and assumptions or deliberate misleading. The famous British historical writer Max Hastings commented during a recent BBC Radio 4 literary programme, that “if anyone sent him a book to read that had on the dust jacket that it was the definitive history or version of a subject then he immediately threw it in the bin” Why? Because there is no such thing as a definitive history, and he’s right. As any author writing such a tome as this soon discovers that everyone’s perception and impressions of what was going on around them at a particular time and place may be different from someone else’s who was also there. The only thing an aspiring author can do is listen to what the participant is saying and ask the right questions, then produce the account without bias or embellishment. That is what the Authors here have tried to do. Wherever possible we have spoken the men and women who were there and took part but as the story has progressed towards today’s Operations, because of the need for secrecy and security, it has got a lot harder. Some nations will just not let their Operational Crews talk to anyone at best quoting the former reasons at worst just ignoring requests and stonewalling. Which personally being only 5 years away from the military myself I suppose I can understand. So, much of our recent data is from “Official Sources” so that we don’t fall foul of any Official Secrets Act and get anyone into trouble. Believe us we tried, so maybe one day in 40 – 50 years time those crews who operated over Libya and Afghanistan in the recent past will be liberated enough to talk about their exploits.
There are very few books written purely about Airborne Early Warning (AEW) aircraft and their history, which is unusual as in modern air warfare very few nations would even consider conducting defensive or offensive air operations without a viable AEW platform in their arsenal. Those that have taken up arms in the past few decades without an AEW capability have often suffered grievously from their enemy’s low level strike aircraft because they just didn’t see them coming. Since World War Two AEW development has not exactly been rapid and has experienced a few false starts and some developmental disasters along the way. Such failures did not come cheap and governments have learnt costly lessons. So as in many other military fields the small players have tended to let America and Russia and more recently China, Brazil and Sweden get on with it and then try to negotiate the purchase or loan of the fully developed AEW aircraft once it has gone into production. However, in today’s world of rapid electronics development, miniaturization, and multi lateral collaboration between smaller nations things are changing. Some of the previous lesser players whose economies are emerging are starting to produce very effective and relatively cheap systems that they are more than willing to sell. This book for perhaps the first time will give a complete and unbiased account of the early history and development of AEW aircraft and their systems without baffling the reader with science and swamping them with technical jargon. It does not have any national slant, the authors are determined that credit will be given where it is due and all nations that have been involved since WW2 will be covered comprehensively.
At the start of WW2 the British had installed around their coasts a comprehensive, functioning ground based radar system mounted on high lattice work towers primarily looking towards the continent of Europe. By the late summer of 1940 this defence radar chain was ready to track the German Lufwaffe’s formations of bombers and their fighter escorts as they left northern France to mount their air raids on the Royal Air Force’s (RAF) Fighter Command airfields. This vital warning time that the early detection gave the RAF Sector Fighter Controllers to launch squadrons of Hurricanes and Spitfires position and point them at the oncoming enemy piston engine powered formations cannot be stressed enough and alongside the other elements of Britain’s air defences saved Britain from imminent invasion. The Germans who knew what radar was and had been trying to develop functioning systems themselves just did not realize early enough that the British had actually created, installed and tested a functioning defensive radar chain and as such the Luftwaffe virtually left the strange tall lattice towers alone during the battle. The problem with fixed ground based radar stations however, is that they cannot see over the horizon, the radar towers can be raised high above the ground but there is a limit and it didn’t take aviators long to realize that they could fly below the radar beams when at distance from them and the lower they flew the longer it was before the radar controllers saw them coming. The answer was of course if you mount the radar in an aircraft it will be able to see further beyond the horizon and look down on the hostile aircraft as they try and sneak towards whatever assets you are trying to defend, simple!
There was a big problem to be solved though as that early radar equipment was heavy, bulky, not very powerful, and didn’t like being bumped around in an aircraft. So the race began to develop a small, light, powerful, robust, reliable, air portable radar system that worked. One thing that can be said about wartime is that it accelerates development and focuses clever minds. Not only was the goal to find a system that fulfilled the former criteria but at the same time make such a system multi functional and also have the ability to see enemy ships and submarines. Then to have a means to pass the information on those enemy units to friendly assets who can best deal with the threat and more importantly update and direct those assets towards the target, the idea of AEW&C was born.
So what is an Airborne Early Warning and Control system (AEW&C)? Essentially it is a mission complex installed aboard an aircraft, designed not only to detect enemy forces located at a long distance, but also to direct (or “control”) its friendly assets against those targets. It was first conceived in the United Kingdom during WW2 to fulfill an urgent requirement: to provide early and useful alert to Trans Atlantic Allied convoys of incoming German anti-ship aircraft and guide fighters to counter them. By the end of the war, British/Canadian forces had also deployed the AEW&C concept against Luftwaffe Heinkels carrying V1 flying bombs in seek-and-destroy sorties. Then after technological improvements, it was proposed to be used by American naval forces to find and shoot down the Japanese suicide pilots responsible for the heavy losses imposed on the U S Navy’s ships in the Pacific, however, the war ended before the USN could deploy their new AEW aircraft operationally in theatre.
We hope we have managed to tell, as complete a story as possible but not definitively, the history and evolution of an essential war asset, whose overarching importance is often forgotten or underrated.
Searching for Condors: the first Airborne Early Warning and Control missions
In April 1940 not long after the start of the Second World War, the Luftwaffe commenced its first Focke-Wulf FW-200C-1 “Condor” combat sorties against Allied merchant convoys. These long range German anti-shipping aircraft were operated by I/KG-40, which were based at Aalborg-West/Kalstrup, in the occupied Danish territories. After the Nazi invasion of France in June 1940 this unit was moved to a captured aerodrome at Bordeaux-Merignac, nearer to the Atlantic, much to the consternation of the British.
Armed with a couple of SC 500 bombs, each containing 440 pounds (220kg) of Trialen explosive and other lighter weapons, the Condors, originally designed as civil transports, had by August, 1940, sunk nothing less than 99.000 tons (990,000 metric tones) of shipping in the English Channel and surrounding waters. Only one of the “Condors” had been hit by the Fleet Air Arm’s 804 Squadron’s Flt Lt Robert W.H.Everett flying a Sea Hurricane fighter, which had been launched from small escort aircraft carrier earlier the same month. A British countermeasure that would later evolve and be developed against these Luftwaffe Condor sorties. These very effective enemy attacks were soon to be described as “the Scourge of the Atlantic”, by the British Prime Minister Winston Churchill. In addition to their anti-shipping role, the “Condor” also relayed by radio the positions of Allied convoys to the waiting German Navy submarine Wolf Packs
This stifling of the flow of supplies, essential to the war effort entered an even more critical phase during March 1940, when the “Flieger Führer Atlantik” a Command that unified all the naval strike/recce forces based along the coasts of the German-occupied countries bordered by the Atlantic Ocean was established at Lorient. This new unified command was given authority to manage a total of 256 aircraft. In addition to the “Condor” it was tasked to operate the Arado Ar-196, Dornier Do-17/17Z, Heinkel He-111/115 and the Junker Ju-88A. Their bases were distributed throughout France at the previously mentioned Bordeaux-Merignac, Brest, Cognac and Lannion. In Denmark at Aalborg, Amsterdam in the Netherlands and Westerland and Wilhelmshafen in Germany itself. On 21 March, just before the new command had been established, Churchill had claimed, in a hand written minute addressed to both the First Lord of Admiralty and the State Secretary for the Air that; “No efforts to destroy the Focke-Wulfs should be spared”.
By early April 1940, the scientific and military staff of Telecommunications Research Establishment (TRE) located at Malvern in Worcestershire, in the Midlands determined that the American Consolidated B-24 “Liberator” bomber would be the best available platform. It was to be equipped with an Air to Surface Vessel ASV Mk.II radar receiver, a transmitter device, a cathode ray tube monitor (which were both still under development), and an external Yagi-type turning antenna. The whole set would be powered by an onboard petrol electric motor. However, it soon became apparent that the B-24 could only be operated in such a configuration if a lighter radar set could be developed.
In August, 1940, the TRE was directed to continue developing this concept and in that same month the CinC Coastal Command, during the first meeting of the Aerial and Naval Interception Committee which had been formed to establish the main operational requirements of the new lighter system. It was to provide radar cover beyond the range of ground based stations, specifically in the northwestern and northeastern approaches and was to have the low-flying target detection capabilities, needed to protect the convoys around the coasts and have a radar range of 50 miles (80 kilometers).
During the definition phase of the aerial platform, the TRE was put in charge of the design and performance evaluation of the new equipment, while the “Royal Radar Establishment” (RRE) was assigned the aerodynamic design, manufacture and installation of the rotating antenna. For the first time ever the receiver, transmitter and Plan Position Indicator (PPI) screen apparatus would be deployed together in a single airframe.
All this development of a Metric radar system took time, during which the Merchant ship catapult mounted Hurricane fighter project and the introduction of small Escort Carriers into the vulnerable convoys were being introduced to counter the Condor threat. Another seaborne threat to the British supply convoys was proving a harder nut to crack. As the convoys approached UK waters they were being attacked by German navy E-Boats that were fast, well armed and deadly to the slow moving convoys and their protective screens. TRE however, continued to design and develop the proposed new airborne radar to the Interception Committee’s specification and in just over a year were ready to test it aboard an aircraft.
A new antenna was already under development for the land base “Chain Home Low” radar stations, which was being designed to detect low-flying enemy intruders. The acceleration of that development process led to the design of an aerial of metallic aerodynamic structure with a width of 15 inches (38 cm) in its centre and 9 inches (23cm) at the tips and a length 15 ft (4.6 M). On each side there were eight separated elements, designed to increase the signal reception. This “Yagi” type antenna was mounted on a rotating spindle installed atop of pyramid shaped fairing on the upper mid fuselage of the mother aircraft. Which by late October1941, had been decided upon as a Vickers Wellington Mk1c bomber serial number R1629. The B-24 Liberators were proving to be impossible to obtain due to the requirements of RAF Coastal Command who used them as anti submarine aircraft in the Atlantic gap. The rotating aerial was fixed to a reduction gearbox that had been re-cycled from a downed German aircraft. The rotary system was powered by a 24 volt engine fed by the 1.2kvA Type U generator installed in one of the Wellington’s engines. The antenna turned at 25 RPM and could be deactivated by a hand brake. No height finder gear was fitted.
To control the interception, the tracks of the interceptor and its target aircraft needed to be continuously monitored, this required the use of a Plan Position Indicator (PPI) display. Which had a 9 inch (23 centimeter) diameter cathode ray tube that was vertically mounted, the PPI was cable connected to the antenna, both being orientated to an imaginary line perpendicular to the Wellington. The screen was divided into 5 Mile (8Km) Range Rings, with a 360 degree scaled calibrated outer rim with North being orientated to the 12 O’clock position on the screen. This became the standard configuration for rotating time base PPI’s ever after. All the main components of the radar equipment were accommodated inside a tubular framed rack which was located in the port side of the fuselage immediately forward the Wellington’s main spar. The complete system weighed less than 705 pounds (320 kilos), which was less than half of the originally specified weight.
The flight tests to assess the aerodynamic effects of the antenna and the additional weight on the Wellington’s performance took place during February 1942. Three months later, the aircraft was evaluated in it’s abilities to detect German E-Boats and it’s effectiveness in the vectoring of friendly aircraft against them, but the antenna’s weak insulation reduced its potential performance by 30 per cent. During the same month R1629 was deployed on an operational sortie for the first time. During the night of 19th-20th May 1942 the Wellington took off from the Royal Air Force (RAF) aerodrome at Wick in Scotland, under the command of Group Captain Jack Ruttledge. Its mission was to attempt to find with its radar the German heavy cruiser“Lützow”, which was threatening the artic merchant convoys then supplying the Soviet Union with vital war goods. Unfortunately, due to ground clutter created on the PPI by the high sided Norwegian fiords where the vessel was hiding the Wellington crew could not find the German vessel. At around the same time the Luftwaffe Condors operating in the Eastern Atlantic started to suffer increased losses from the Allied fighter aviation operating from the Escort Carriers and the Hurricat fighters. As a result the Condors were gradually withdrawn to mainly transport duties.
The death knell for the metric radar equipped Wellington was sounded very soon after the Norwegian mission when the Aerial and Naval Interception Committee put an end to the Metric Radar ACI program. The committee issued a directive that “all equipment that operated above the 10-cm wavelength should be labeled obsolete (the wavelength in which the Air to Surface Vessel ASV Mk.II operated was in the 10 meters range). As 10cm was the wavelength used by the new radars then under development by the TRE for aero naval platforms. The H2S bombardment radar later to be used by the RAF’s Bomber command and its variant ASV Mk.III which was to be used by Coastal Command both used this new reduced wavelength. Hence, the Metric radar era was over and Centrimetric radars had arrived.
Nevertheless, there was one final swansong for the concept when it was re-evaluated on 22nd–23rd September, 1942, at RAF Valley under the direction of a Squadron Leader (Sqn Ldr) Craig who still believed that the concept could work with some improvements and could be operationally deployed. This was not to be and consequently, all of the ACI hardware was removed from R1629 in February, 1943, seven months later. This historic Wellington was returned to the aircrew training role with 105 Operational Training Unit (OTU) at RAF Bramcote in Warwickshire, it was later written off after have been damaged by another Wellington in a landing accident. The idea though had not died and although not an outstanding success the seeds for the concept of airborne controlled interception in the future had been set by the RAF and TRE.
Project Cadillac - Airborne and ship installed equipment - operational characteristics
Despite some level of skepticism, the MIT AEW&C system was cleared to enter into pre production testing in May 1944. Codenamed “Project Cadillac” (a symbolic reference to a mountain in the state of Maine, where some of the equipment testing had taken place) it involved several private and public scientific research institutes. A slightly less powerful variant of the radar was installed on the peak of mount Cadillac as it if were installed in an aircraft and was successfully tested between July and August 1945, the full power version of this kit was put into production for service use as the AN/APS-20 radar system.
The aircraft chosen to be fitted with the system was the Grumman TBM-3 Avenger, a carrier borne torpedo bomber that had already met with some success using ASV radar installations and had a proven reliability and a good combat record. It was roomy and powerful enough for the new radar equipment to be carried. The prototype AEW&C airframe was completed as the XBTM-3W (W for Warning). Its first flight was on the 5th August 1944 in which it carried the serial number “NN12”. A fiberglass radome containing the AN/APS-20 radar was installed at the front of the Bombay and in between the main wheels; it had a modified cockpit, housing only the pilot. A couple of radar specialists were ensconced in a turtle backed compartment in the rear fuselage. It had nine external antennas and in order to maintain the required aerodynamic yaw control, which had been affected by the large belly radome, a pair of finlets was added above and below the horizontal stabilizers. The AN/APS-20 radar was just a part of a new package of mission avionics installed aboard the TBM-3W. It was complemented by the AN/APX-13 Identification Friend of Foe (IFF) system. The IFF used the United States Navy “A” and “G” frequency bands to distinguish whether a contact was a friendly or enemy aircraft. The radar contact information was then relayed by the AN/ART-28 “Bellhop” data link (which replaced the older AN/ART-22), the Bellhop relayed the AN/APS-20 Plan Position Indicator (PPI) picture down to the aircraft carrier’s CIC. Where ship board radar operators could interpret the raw battle space picture and direct air defense assets accordingly. The AN/ARW-35 receiver and the AN/ARC-18 VHF voice transmitter system completed the package aboard the aircraft and enabled it to operate as a forward radio relay station when airborne at distance away from the fleet. The two radar operators aboard the TBM-3W had three screens in front of them: the first, an A-Type screen, presented the targets as horizontal deflections on a vertical line. The same screen also monitored the overall system performance, including the Bellhop system. It also determined the size of the formation of the targets. The middle screen, was a PPI which measured 4 inches (10.16cm)in diameter, had a circular range scale divided into 20, 50, 100 and 200 nautical mile range rings (37, 92, 185 and 370 kilometers). The third screen was the same size and displayed a time delayed presentation of the situation out to a range of 20 miles with a rectified picture that compensated for the movement of the transmitting aircraft. As there was no video defining the nature of the detected primary radar contacts, their tracks, courses and speeds were marked and updated by the operators using yellow fluorescent wax pencils, these symbols written onto the screens became known as “bananas".
On the CIC’s screens, the received images were oriented to true north and stabilized with the earth’s surface. The screens could have their range zoomed right into a minimum of 20 nautical miles and additionally could be divided into sector areas that could be examined in detail, the distortion generated by the aircraft’s movement was nullified by electronic filters in the equipment.
Tests and Service Debut
Soon after its first flight, NN12 started evaluation flights of the production standard radar kit, they took place during the winter of 1944. After these successful trials the first production aircraft was delivered to the US Navy in March, 1945 with a further 39 examples being eventually delivered. Production aircraft and CIC equipment included enhanced hardware that was more resistant to external electronic interference.
Full operational trials were conducted aboard the USS Ranger between January and April, 1945, they revealed that a single aerial target
could be detected at twice the range of a radar picket ships radar range whilst an enemy formation could be located from two to four times
farther out still. Also an enemy surface vessel could be picked up six times further away that was possible before with surface radars. The
second world war was to end before the Cadillac 1 aircraft could be used against the Japanese, that said the lesson had been learned and in
the future nations who were serious about operating large fleets including aircraft carriers in deep ocean deployments knew that an AEW
element was essential for early warning of potential enemy air attack against its ships. Sadly the British Admiralty had forgotten this fact
when they deployed a naval task force against Argentina to regain the Falkland Islands in 1982, an omission they were to pay a very heavy
price for, in lives and ships during the conflict.
|An ASW Hunter/Killer team photograph taken in 1950 The "Hunter" in the photograph was a Composite Squadron Eleven (VC-11) Aircraft; TBM-3W Bu.No.85840/ND-66 from NAS North Island. The "Killer" was a Anti-Submarine Squadron Twenty Five (VS-25) Aircraft; TBM-3S (number unk) /SK-410 also from NAS North Island. Picture provided via George E. Stewart (US Navy)|
As the TBM-3W Avenger was replaced by other types in the American inventory, the surplus airframes were sold to other nations. The French Navy was the TBM-3W’s first foreign operator, receiving its AEW Avengers on the 27th AUGUST 1953, its Flotille (wing) 9F went on to deploy the type during “Operation Musketeer” , also known as the “Suez Crisis”,which was the French and British Operation which took place between 29th October and 5th November, 1956. A combined mission against Egyptian forces that attempted to take control of the Suez Canal zone. During these actions, 5 TBM-3W Avengers supported another five TBM-3S (anti-submarine variants) operated under the call sign “Sapho”. They were launched from the Arromanches aircraft carrier, performing four hour patrols, up to 50 nautical miles away from their mother ship. As a result of these offensive missions, the Egyptian Navy’s El Nasser (ex Soviet “Skory” class) destroyer and the Tarik (ex British “Black Swan” class) frigate were both attacked and damaged during the early hours of 1st November 1956.
The Dutch Navy also operated 25 examples of an upgraded variant, the TBM-3W2, which was optimized for ASW operations, the Dutch Navy finally retired their last example in 1961. The Royal Canadian Navy operated five of the type between 1955 and 1958, and the re-established Japanese Navy (formed on 1 July, 1954, as the Japanese Maritime Self Defense Force) also received ten TBM-3Ws at its inception and flew them for a year. The TBM-3W was finally retired from United States Navy active duty in 1954. A venerable and distinguished aircraft the AEW Avenger was the trail blazer and concept prover that made service chiefs around the world sit up and take notice of what AEW and ASW radar could achieve. It was a relatively basic system that gave a very raw battle space picture but it concreted the foundation of what was to become the absolute core of air operations over land and sea in the coming decades.
AN/APS-20 Aboard Larger Platforms
After the TBM-3W had been widely evaluated by the US Navy, some of its drawbacks became apparent, it was found that the radar operator had to track a single target in a high traffic density area for around 3 minutes to be sure he had identified the correct track. There were difficulties in vectoring friendly fighters onto “bogey”tracks and intermittent losses of transmission of the Bellhop data-link picture to the CIC; the system was far from perfect.
In wartime situations the best had to be made of the equipment available and the Cadillac 1 system was better that none at all. The planner’s thoughts now began to turn to how the available early warning system could be operated once the Allied ground forces had started the invasion of main land Japan in late 1945 or in 1946. At the forefront of their thoughts were the terrible losses the invading Americans had suffered during the campaign to take Okinawa. This was just a taster for what the casualties and losses were likely to be once ashore on Japanese home soil. A report was compiled by the MIT’s Radiation Laboratory and sent to the United States Army, stating the impossibility of establishing a ground/air operations coordination center to manage and direct the air assets of the invasion forces on the mainland once the invasion had started. The first priority of this airborne CIC had to be the detection of enemy low flying aircraft that would do their utmost to attack the invasion forces. In an effort to enhance these capabilities over those of the TBM-3W, high priority given to the development of a Moving Target Indicator (MTI) device that would filter a rapidly moving target out of the ground clutter on the radar picture.
After quick evaluations of the Consolidated B-24 bomber, the Douglas C-54 transport (military cargo version of the DC-4) and the
Boeing B-17 bomber as possible platforms for the new system.. The B-17 “Flying Fortress” was confirmed as the chosen airframe, due
to its range, tail wheel configuration giving room for a nose mounted radome and its abundant availability (or so the US Navy thought). As
such the B-17 was to be the third aircraft to adopt the AEW role and was to be the focus of “Project Cadillac 2”. In all 22 examples of
the various subtypes from “F” and “G” series B-17s were delivered from the factories, put on charge and re-designated by the United
States Navy as the PB-1W. In July 1945 20 of these airframes were taken to the Naval Aircraft Modification Unit (NAMU) based at Philadelphia
Naval Air Station, for extensive modification to their new flying CIC roles. Due to the lack of available AN/APS-20 radar sets and the
imminent ending of the war after the dropping of the atomic bombs, the conversions were a long drawn out process. The first PB-1W BuNo 77242
did not emerge complete from NAMU until 5 February 1946.
Below is a mapof the PB-1W DetachmenttoKorea in 1953 thatGeorge EStewart refers to:
Douglas AD-3W, AD-4W and AD-5W
The Douglas Aircraft Company had met with major success with its SBD Dauntless series of Carrier based dive bombers before and during the early part of World war Two. Six months before the Japanese attack on Pearl Harbour on 7th December 1941 it had become obvious to the US Navy that a new series of attack/Scout/Dive Bombers would be needed to replace the SBD with was rapidly becoming obsolescent. Therefore a specification had been released to the American aviation industry to design a replacement. Several companies had put forward proposals for the radical new concept of a single crewed dive bomber that could also carry out a torpedo attack if necessary. There is an in famous story of how Douglas’s chief designer Ed Heinemann and his colleagues Gene Root and Leo Devlin drew up the design for the XBT2D-1 on bits of paper during the evening before they gave their new design presentation to the US Navy in Washington in June 1944, that is absolutely true. The Navy procurement team went on to give Douglas the go ahead to build a series of prototypes on the strength of those drawings as Douglas was “the carrier bomber designer of the era”.
The XBT2D first flew on 18th March 1945 and after some strengthening of the undercarriage and wings went on to be an overwhelming success; it was to enter service as the AD-1 Skyraider. It soon became obvious that this powerful, rugged airframe could be put to several uses and Douglas was further contracted to design and build several sub-variants for a variety of different missions. There were Photo Reconnaissance, Night Attack, ASW and AEW versions of the prototypes produced by Douglas all of which ultimately proved successful. For the purposes of our story we will concentrate on the natural successor to the TBM-3W Avenger, the AD-2W, 3W, 4W and ultimately the 5W Douglas Skyraider. The prototype AD-2W was converted from an early example off AD-2 production line and given the serial number “09107” and the type designation XBT2D-1W.
This new aircraft was immediately recognizable by the addition of a couple of side by side crew positions for radar operators situated inside the rear fuselage, behind and below the pilot’s seat. The pilot’s canopy was changed from a bubble canopy to a faired- in projection of the turtle back that covered and cooled most of the avionics behind the pilot. Initially the AEW version had been fitted with an AN/APR-1 radar, inside the lower fuselage. As the development progressed, that radar was replaced by an AN/APS-20, accommodated inside a glass fiber belly radome, fitted under the nose between the main landing gear legs similar to the TBM-3W’s arrangement. After the fitting of this radome the type designation was changed to “XAD-1W”.
In this configuration the type first flew on 5 September 1947. The same modifications were also extensively evaluated on an AD-2 Bureau Number “122226” in aerodynamic tests to assess the airflow interference caused by the ventral dome. Douglas’ wind tunnel testing had not supplied the required data to the engineers so flight tests were organized to see if the radome affected the aircraft’s handling. As a result of these evaluations and in order to enhance lateral stability, a pair of fins were added to the upper and lower surfaces of the tail stabilizers (as had also been required on the TBM-3W). Also to compensate for the weight added by the extra crew members and the radar kit the main undercarriage doors were removed and the AD-3W was born !
More evaluations, a new version and combat debut
During October, 1948, more tests were conducted on the AEW Skyraider at the US Naval Test Center, at Patuxent River (Maryland) under the control of Aerial Development Unit VX-1. There is a couple of interesting post scripts to these aerodynamic test flights. It was found that in the “Guppy” configuration (nicknamed due its radome, which gave it the appearance of a pregnant fish) this version of the Skyraider turned out to be the easiest version of the aircraft to land aboard an aircraft carrier at sea. On one of the test flights the pilot LT Cdr Wheems flying out of Patuxent River on 15 October 1948 ran into difficulties when a full fuel tank turned out to be empty ! He bought his aircraft down to ditch on the surface of the river, on touching down he found that the belly radome allowed him to skip across the water surface almost like a seaplane and allowed him to safely slide the aircraft intact onto the river bank. The subsequent board of Inquiry discovered from the intact aircraft that the radome shape had caused a reduction in air pressure that had sucked the fuel out of the fuel vent pipe and caused the fuel starvation, needless to say rectifying modifications were rapidly made to the production AD-3W’s fuel vents!
In October 1953 Squadron VW-3 was commissioned and became the first AD-3W operational unit, based on the United States Atlantic coast and tasked with all-weather/all-time early warning. They were deployed aboard Atlantic Fleet aircraft carriers as 3-5 ship detachments. By early 1949, a further AEW Squadron, VAW-1, had been established on the opposite Pacific coast, and tasked with the same role as VW-3, but supporting the Pacific Fleet carriers. That same year saw the appearance of a new version of the “Early Warning Skyraider”, the AD-4W, which had an improved arrestor hook, an AN/APN-2 radar altimeter (which replaced the AD-3W’s AN/APN-1 and was essential for flying a carrier approach at night), P-1 autopilot and an armored windshield.
Royal Navy Skyraiders
At the end of the Second World War the British electorate expressed a desire for change and on 5 July 1945 voted in a Labour Government lead by Clement Attlee. Although a National hero, Winston Churchill was tainted by his party’s pre-war appeasement policies and the millions of serving British servicemen and women truly wanted a land fit for heroes this time and not the depression that followed the first World War. Labour’s flagship policy was that of a creation of a National Health Service and a Welfare State, both of which would cost billions of pounds to establish. Military spending in World War Two and the Lend Lease policy with the Americans had left the country with a huge national debt, there was to be almost no money for spending on defense and it’s associated systems so a massive draw down in the 3 services commenced as soon as peace was declared.It was also unforeseeable that Britain would get involved in another war for at least a decade so development of virtually all military systems was put on the back burner. The British had never actually achieved a land based or Naval AEW capability during the war and the British Admiralty was worried, they had experienced at first hand what the Kamikazes had achieved in the Pacific Theater, fortunately the Royal Navy Fleet carriers were built with steel decks and as result were spared the catastrophes the befell the USN Carrier force with their vulnerable wooded decks when hit by Japanese suicide bombers. The Telecommunications Research Establishment (TRE) was still hard at work developing Air, Gound and Maritime Radars at Malvern post- war but development funding was scarce. The Americans however had the funds and determination to develop their Fleet protection as a natural follow on from project Cadillac and as has been seen were progressing well with their AEW version of the new Skyraider all the Royal Navy could do was watch with envy.
When the Cold War erupted into a full blown shooting war on the 25Sth June 1950 the UK Government was caught cold in the middle of its draw down of the military. At the end of the Second World War the Korean Peninsula had been divided laterally along the 38 parallel. The North being supported materially and financially by the Communist Soviet Union and the South by the Capitalist United States. The area became an unstable boiling pot with several cross border skirmishes and arguments over free elections before the North Koreans finally invaded South Korea. The Americans immediately invoked United Nations support from the Security Council turning the war into a fully international engagement. Initially UN Forces faired badly and by September 1950 they had been pushed back by the Communists to a pocket around the town of Pusan of the south east tip of the Peninsula, for 6 weeks in August and September 1950 the conflict was in the balance but despite massive assaults the UN forces held out and the North Koreans retreated back north when faced with the UN’s overwhelming replenishment of resources and Air Power. Britain fought alongside the American and South Korean troops in the Pusan pocket and deserved much credit for their stoic resistance.
The rapid development and spread of the Korean conflict required the British to halt their force reductions and moratorium on development and rapidly re-equip with the modern armaments required. Again the thorny issue of Fleet protection arose. There were Air Staff and Admiralty requirements in place to provide AEW aircraft for the Royal Navy and a new Maritime Patrol aircraft for the R.A.F but both were not yet in production, the prototype Shackleton had actually flown but the Fairey Gannet AEW was still some years off. If the Royal Navy was going to get involved in the Oceans around Korea an AEW asset was needed and quickly. The American Government came up with a solution, as part of their Mutual Defence Aid Programme (MDAP) The MDAP programme was part of an Act passed by the American Congress in 1949 in an effort to ensure that it’s allies could help it fight the spread of Communism and to help European countries modernise their defence systems. It was agreed that Britain would be supplied with the much coveted AD-4W Skyraiders, which the Royal Navy promptly re-christened Skyraider AEW Mk 1.
In November, 1951, four AD-4Ws were unloaded onto the dockside from the hold of the “SS American Clipper” a cargo ship, moored in the Scottish port of Glasgow, after a fifteen day voyage from the Norfolk Naval Base to deliver the aircraft to the British Fleet Air Arm (FAA). These Skyraiders were being supplied to the FAA by the Americans under the Mutual Defence Aid Programme. They were the first batch of what was to eventually to total 50 aircraft. On the following day, the two pairs of AEW Skyraiders were transported to the Royal Naval Air Station (RNAS) Abbotsinch, where their anti-corrosion coating was removed and they were prepared for their first ferry flight. They were flown to RNAS Culdrose, where they were assigned to 778 Squadron FAA, a squadron formed specifically on 1f October 1951, to test the American AEW system in preparation for its use aboard RN carriers. The Americans had so far only used their carrier borne AEW systems as a relay station, remotely transmitting their radar pictures to a carrier installed CIC where any interceptions required were controlled by officers aboard the ship. The British intended to utilize the system in a totally different way. Their plan was to put the interception controllers aboard the aircraft to control strike missions and Combat Air Patrols (CAPs) directly from the aircraft much as the RAF had intended with the ACI Wellington.
In July 1951 Royal Navy air and ground crews slated for the Skyraider squadrons had attended a familiarization and operational conversion program established at Quonset Point (Norfolk Virginia). The ninety day training course in the USA was followed by a practical course involving a ground phase at RNAS Culdrose (also known as HMS Seahawk) and a flying phase aboard the carrier HMS Eagle lasting 20 weeks for the pilots and 21 weeks for the observers.
When the new aircraft systems and flying characteristics of the aircraft, now designated by the RN as the Skyraider AEW Mk1 had been completely mastered, the type took part in exercises against the Anti-Submarine Tactics School at Eglinton, these trials were then followed by training with aircraft from the Royal Air Force. On 7 July 1952 the 778 Sqn was reformed as 849 Sqn and declared as an operational unit. However 849 Sqn only had the original 4 aircraft available to it at this stage as the next batch of 13 Skyraiders were not delivered from the USA until 19 March 1953 and by the end of September in the same year the British had received a total of 39 aircraft. The remaining 11 aircraft of the 50 aircraft total were finally delivered in early 1956 after being overhauled at NAS Quonset Point. The squadron eventually comprised of six Flights, HQ flight an A to D flights, with the aim of providing an AEW detachment aboard all of the modern RN carriers then under construction, eventually the number of flights was reduced to four as the new carriers had been significantly delayed after changes in their design. Over the next few years the flights system of 849 Sqn was amended several times to comply with fleet requirements and a lack of serviceable airframes, mainly caused by an acute lack of spare parts. Various measures were tried to alleviate the parts shortage the most drastic was the grounding of some aircraft so that they could be robbed for spare parts to keep the others flying.
In 1956,“A Flight”, operating from HMS Eagle, provided AEW cover to the British Fleet during the previously mentioned Suez Crisis labeled by the British as “Operation Musketeer”, in which, 849 Sqn’s “A, B, C and D Flights ” all took part in combat sorties. Some Suez missions were more hazardous than others, an important one being when it was discovered that if one of the radar operators seat were removed from the fuselage then over 1,000 cans of beer could be loaded into the rear compartment and flown to the thirsty ground troops in the canal zone, to improve their morale!
The final batch of Skyraiders was delivered to the RN in early 1956. In addition to the AEW taskings the RN Skyraiders were used in a variety of other roles, they included ASW, MET Flights, airborne radio relay and Carrier On board Delivery (COD) flights in which they transported mail and personnel from shore to ship and vice versa. They were also used as missile trackers in the evaluation trials of the RN’s new Sea Slug surface-to-air missile fired from HMS Girdlle Ness in the waters surrounding Malta. The last operational cruise for 849 Sqn and its Skyraiders was when D Flt embarked aboard HMS Albion from February to December 1960. On 15 December the final four Skyraiders flew back to RNAS Culdrose to be de-commissioned and withdrawn from RN service. After nine years of proving the concept that a carrier borne AEW aircraft could not only detect enemy aircraft, but on board controllers could also vector friendly assets to intercept them, a point not lost on the American navy. The venerable Skyraiders were replaced by the first British indigenous AEW roled aircraft; the double turbo prop powered Fairey Gannet AEW Mk3.
During the war in the Korean Peninsula, the AD-4W operated from October 1951 to June 1952 as part of the United States Marine Corps VMA-121 Squadron. They had been detached to K-3, a forward land based airfield, near to Pohang. Where the Marine aircraft provided radar cover for their own AD-4Ns, which were another night medium bomber version of the Skyraider, used by the “Heavy Haulers” attack squadron. Later in the Vietnam War (1961-1975), the AD-4W was not deployed as by the end of 1963 VAW-11 had replaced their AD-4W Skyraiders in the AEW role with the Grumman E-1B “Tracer”a twin engined AEW variant of the S-2 Tracker. However the final AEW version of the Skyraider the AD-5W was to continue on for some years serving with the US Navy in an ASW role aboard specially designated Anti Submarine Aircraft Carriers.
A radically different type
In 1950, Douglas decided to attempt to concentrate the search-and-destroy functions of the ASW mission into a single airframe by
redesigning the Skyraider completely. The airbrakes were also deleted from this version of the Skyraider as they were superfluous to the new
role of the aircraft, the ventral recess left behind by the removal of the belly airbrake enabled an emergency exit to be cut in the floor
of the rear fuselage, allowing quick and safe egress for the rear compartment crew in an emergency which is more than can be said for the
chances of the pilots who were in danger of striking the massive vertical fin or empennage in the event of a bail out.
Other new equipment installed in the dash 5W was an AN/APN-22 radar altimeter and an AN/ARA-25 directional homer. The venerable AN/APS-20 radar kit was still employed as the AEW radar in the same belly radome between the main wheel legs. This revised version of the Skyraider first flew on 17 August 1951. Although in service too late to see action in the Korean War, in this guise the Skyraider continued to provide AEW coverage for US Navy fleets, in Marine and Navy units right up until 1963. The AD-5 non radar versions went on to serve with success and distinction with US and South Vietnamese Air Forces in the Vietnam War in a variety of roles, but that is another book!
Diagram below shows a cutawayof an AD-5W Skyraider (US Navy)
Below is what was going to be Appendix II in the book but it had to be cut out due to space limitations. It
is a table of all AEW operators by country, the squadrons, the aircraft they operated and the base locations.