General Giulio Douhet, the First Air Power Visionary

Giulio Douhet, air power visionary
(Wikipedia)

Those of us interested in aviation take it almost for granted the unyielding pace of technological development that has driven aviation forward through time. But even less heralded are those in aviation history who have shaped the thinking of aviation- it's easy for us to lay eyes on an aircraft or even to put our hands on one. They're very tactile and sensory experiences in aviation- to see one, hear one, feel one, even ride an aircraft. But how do you experience aviation doctrine? How do you grasp the thought processes that have shaped aeronautical progress? They're very abstract and not prone to enjoyment and appreciation by most of us. However, technological progress is a rudderless boat in chaotic waters without visionaries and thinkers to provide steering and direction. Of course we can name designers like Jack Northrop or Andrei Tupolev. Or pilots like Charles Lindbergh or Chuck Yeager. But the subject of today's blog posting is none of those- he didn't design any aircraft, he didn't even fly aircraft. But his writings on air power have left an indelible mark on aviation, if not history itself. 

Born in 1869, Giulio Douhet was a rare breed of Italian army officer who was both an infantry and artillery officer and what we might call a technocrat, having studied science and engineering as well. His earliest writings as part of the General Staff of the Italian Army covered mechanization and the incorporation of what would be come tanks in military doctrine. But with the arrival of lighter-than-air aircraft like dirigibles and the first practical biplanes prior to the First World War, Douhet quickly appreciated the advantages of aviation in war- aircraft could move in three dimensions and operate above and out of the reach of ground and naval forces with relative impunity. In 1912 when the Italians first used aircraft in combat in Libya, he wrote Rules for the Use of Airplanes in War, one of the first efforts to create a doctrine for military aviation- despite his own background as an artillery and infantry officer, Douhet felt that the current military leadership lacked an understanding of the inherent advantages of air power and an almost zealous desire to educate the establishment on air power would be Douhet's mission in his life. 

When the First World War broke out in Europe in August of 1914, Douhet was forty-five years old and no less energetic than officers half his age. With a near-insatiable appetite for the latest developments in aviation, he advocated the building of a force of 500 bombers that could bomb enemy forces from above without having to engage in prolonged combat. He worked closely with the Italian engineer Gianni Caproni in advising him on his own Caproni line of bomber aircraft. But Douhet would find the Italian military leadership incompetent as defeat after defeat was suffered by Italian forces. Convinced that aviation technology could reverse the lagging fortunes of the Italian military, Douhet wrote and spoke frequently to anyone and everyone in the military and government establishment. By 1916 his superiors had had enough when he had ordered construction of Caproni bombers without authorization. He was stripped of his rank and imprisoned on charges of "issuing false news" and "disturbing the public tranquility". It didn't stop him, though. He continued to write and refine his theories from his cell. 

In the fall of 1917, the Italian Second Army was completely routed at the Battle of Caporetto (in modern day Slovenia), suffering over 300,000 casualties. The Italian government in desperation released Douhet from prison and commissioned him as a general in charge of coordinating the nation's aviation strategy and doctrine. It would be too little too late as the entrenched Italian bureaucracy was unwilling to enact his plans and he resigned in protest in June 1918. With the Armistice in November of that year ending the First World War, Douhet's trial verdict was reversed and he was promoted, but by this point in his life he had lost faith in the Italian government and refused to return to duty. During the interwar period he traveled Europe visiting other nation's air arms, consulting with air officers and meeting with aircraft designers. In 1921 he wrote his landmark work Command of the Air which advocated an relentless air campaign of bombing an enemy's population and production centers, reducing their moral and material means of resistance. Properly conducted, he reasoned, such an air assault could force a quick decision and save millions of lives in the long run by avoiding a costly ground war. Douhet also pointed out that the efficient and proper means of carrying out such an air campaign would require an independent air arm led by an aviation-minded general staff. At the time, this was a revolutionary concept and only in Great Britain was the nascent Royal Air Force an independent air arm. For other industrialized nations of the 1920s, their air arms were subordinated to the army. 

Billy Mitchell, USAAC
(Wikipedia)

Reception of Douhet's work outside of Italy was mixed. It wasn't even required reading at the RAF Staff College. But his work would find converts primarily in the United States- at the time the Air Force was part of the Army as the US Army Air Corps. One officer in particular would even meet with Douhet- Brigadier General Billy Mitchell. It was the year after Mitchell had demonstrated the vulnerability of warships to bombers by sinking several captured German warships off the Virginia coast. Mitchell had copies of Command of the Air sent to his superiors and he got banished to Hawaii and then Asia as a result. In 1925 Mitchell wrote a book of his own, Winged Defense, in which he refined Douhet's ideas of a strategic air campaign further and even declared the battleship obsolete as aviation technology matured. As a result, Mitchell was demoted in rank back to colonel. He would later be court-martialed for publicly criticizing the US military following the crash of the airship USS Shenendoah in a storm. But his six week court martial provided Mitchell the perfect forum for advocating views shaped by his mentor, Giulio Douhet. 

Sir Hugh Trenchard, RAF
(Wikipedia)

Douhet died of a heart attack in 1930 and Mitchell himself would die in 1936, neither man living to see how their views of air power would come to fruition in the Second World War. While Command of the Air got little attention in the Royal Air Force, the most influential individual in the RAF at the time fortunately was a proponent of Douhet's theories- Sir Hugh Trenchard, Chief of Staff of the RAF and the man known as the "Father of the RAF". Trenchard, like Mitchell, would refine Douhet's ideas. By the time of the Second World War, Trenchard was every bit the irritant to the establishment as Douhet and Mitchell were, but had enough influence to avoid their fate. Following the disastrous loss of Norway to the Germans in 1940, Trenchard used his position in the House of Lords to criticize Prime Minster Neville Chamberlain's prosecution of the war which contributed to his replacement by Winston Churchill. Trenchard used in influence to put like minded officers in key positions in the Royal Air Force. After the war, Trenchard advised General Henry "Hap" Arnold in his own push for an independent United States Air Force.

The same year Mitchell died in 1936, contracts were issued to both Boeing and Douglas for a large four-engined bomber- while both companies' designs, the XB-15 and the XB-19, respectively, remained experimental, the engineering and design work on such a unprecedentedly large bomber would shape aviation technology throughout the Second World War. 

Source:  Whirlwind: The Air War Against Japan, 1942-1945 by Barrett Tillman. Simon and Schuster, 2010, p9-16.

Violet Club: Quite Possibly the Worst Nuclear Bomb Ever Fielded

The warhead, or physics package, of the Violet Club bomb

When taking a look at the development of British nuclear weapons following the Second World War, it has to be viewed in the context of a piece of legislation in the United States that was passed in 1946- the McMahon Act or the Atomic Energy Act. Sponsored by Senator Brien McMahon of Connecticut who chaired the Senate Special Committee on Atomic Energy, this legislation is better known for its creation of the Atomic Energy Commission and the placement of nuclear weapons development and nuclear applications under civilian rather than military control. However, one consequence of the McMahon Act was the stipulation that nuclear weapons development be restricted from US allies- this affect the United Kingdom and Canada who had provided scientists and support to the wartime Manhattan Project. As a result of being shut out of American nuclear weapons development, the British set about to create their own air-dropped weapon which would be fielded in 1953 at RAF Witttering- though somewhat amusingly the first aircraft that could carry the bomb, designated Blue Danube, the Vickers Valiant, didn't become operational until a year later. The purpose of this wasn't just a message to the Soviets, but also to the United States that Britain was more than capable of fielding its own nuclear deterrent despite the McMahon Act. 

On 1 November 1952 the United States detonated its first fusion bomb (H-bomb) in the Ivy Mike test at Eniwetok Atoll in the Pacific. Given that the British were still shut out of US nuclear development by the McMahon Act, despite the fact that the Blue Danube fission bomb (A-bomb) was still a year out from being operational, strategic imperatives meant that Britain had to develop it's own H-bomb and the program was launched in 1954. In the UK, many military systems were assigned code names under the Ministry of Supply's "rainbow codes"- hence, "Blue Danube". In the development of an H-bomb, the casing had its own code name and the actual warhead, called the physics package, had another code name. The casing of the H-bomb was based on the Blue Danube casing and was designated Violet Club while the physics package was designated Green Grass. 

But before the code names had been settled upon, the British H-bomb had a different name- "Interim Megaton Weapon"- implying that it was a high-yield weapon but not a true thermonuclear or H-bomb/fusion weapon. And this is really at the heart of the history of the Violet Club and its historical legacy. First, it indicates that Violet Club was intended to be a temporary weapon and secondly, it wasn't a fusion bomb as was commonly believed by *both* the Soviet Union and the United States. 

The warhead or physics package of the bomb was based on earlier warhead designs that were named Orange Herald and Green Bamboo. Orange Herald was a lighter version of Green Bamboo and the designs were projected to be the new fusion warheads for the Royal Air Force's V-force, the Blue Steel stand-off missile, and the planned Blue Streak intermediate-range ballistic missile. Testing of Orange Herald showed that it had failed to boost the fission reaction to create a fusion reaction. The failure of the warhead designs left the British scrambling for a high-yield weapon and this became the Green Grass warhead of the Interim Megaton Weapon that was based on design elements of the earlier Green Bamboo and Orange Herald designs. As was the case in the United States, interservice rivalries in Great Britain meant that the Army wanted highly enriched uranium (HEU) for nuclear landmines in Europe and the Royal Navy wanted HEU for the reactors for its planned nuclear-powered submarine fleet. The Royal Air Force was of the feeling that the HEU that had so far been produced in British reactors had to be used or it would be lost to rival services, so that was one of several motivations to rush the Interim Megaton Weapon into service as it would use a significant amount of HEU.

Schematic of the Green Grass warhead showing how the ball bearings were used.

It was the design of the Green Grass warhead that went into the Violet Club that made it for all practical purposes a useless weapon. A hollow sphere of HEU was surrounded by a system of 72 explosive lenses that compressed the HEU to critical mass and detonation. But here was the problem. In the Green Grass warhead, the mass of HEU was in *excess* of the critical mass once compressed by the explosive lenses. That meant if the warhead were crushed or damaged during handling, it could partially detonate. American designs avoided this by having an HEU core that was inserted into the physics package usually by the bombardier once the bomber was in flight, thereby "arming" the bomb once the core was inserted. Without the core inserted, the HEU mass in the American designs was below the critical mass. The solution by British designers was to fill the center of the HEU sphere with 20,000 steel ball bearings to prevent the sphere from being crushed and reaching critical mass. To arm the bomb, a plastic plug was removed from the bottom of the warhead (accessible via a hatch on the underside of the Violet Club casing) that allowed the bearings to flow out, thereby arming the bomb. 

While it may sound like a creative solution, there were several issues: 

• The weight of the ball-bearings increased the bomb's weight to 11,250 lbs which was greater than the capacity of not only the bomb release mechanisms of the V-bombers but also the ground-transport equipment of the bomb. 
• The outflow of bearings took at least half an hour under ideal conditions- in cold weather, the bearings could freeze together, making arming the weapon near-impossible. 
• Once the bomb was armed by allowing the ball-bearings to flow out of the center of the warhead, there was on way of making the weapon safe again. In fact, engine running was prohibited even with Violet Club "safed" as it was feared vibration would cause the plastic plug to fall out and inadvertantly arm the weapon. 
• Because the bomb was armed irreversibly, airborne alerts were impossible because take off and landing were too hazardous to attempt with an armed Violet Club. 
• Dispersal of the V-force to outlying fields was impossible as the bomb couldn't be flown to the dispersal airfield and the bomb transport equipment couldn't handle the Violet Club when it had its ball-bearings in place. 

The Blue Danube- the Violet Club looked similar externally.

While the Air Staff of the RAF ordered twelve Violet Club bombs, only five were made and as British author Chris Gibson put it in his book Vulcan's Hammer "From the RAF's point of view, that was five too many." With such an unwieldly weapon, why was it even fielded? First of all, remember that the British were classifying the Violet Club as megaton-class weapon by calling it the Interim Megaton Weapon. It definitely wasn't a megaton weapon, perhaps more 400 kilotons at best, but certainly the Operation Grapple tests at Christmas Island in 1957 did indicate to the Americans the British were succeeding at fielding their own H-bombs- even if those test detonations failed to created the desired thermonuclear reaction. So who was the target of the Violet Club? While serving notice to the Soviet Union that Britain was still a force to be reckoned with, it seems that perhaps the Americans were the target, so to speak- with a weapon in their inventory called Interim Megaton Weapon implying that newer designs forthcoming and the Grapple series of tests in 1957 making a good show of things despite failing to work as planned, in 1958 the United States repealed the McMahon Act and resumed full nuclear cooperation with the United Kingdom. The Green Grass warhead used in Violet Club would be the last all-British nuclear weapon as a new Mutual Defense Agreement signed as part of the repeal of the McMahon Act meant British designers now had access to more advanced and compact American designs. In fact, the successor to the much-despised Violet Club, the Yellow Sun Mk.2, used an Anglicized American Mk.28 thermonuclear warhead. But no other fission weapon ever fielded by any other nation approached the explosive yield of the Violet Club.

Source: Vulcan's Hammer: V-Force Projects and Weapons Since 1945 by Chris Gibson. Hikoki Publications, 2011, p47-51. http://www.nuclear-weapons.info/vw.htm, by Brian Burnell.

RNZAF Squadron Leader Leonard H. Trent and his Victoria Cross Mission

Sqn Ldr Leonard H. Trent

With the drums of war building in Europe in 1939, the Royal Air Force asked Lockheed for a twin-engine bomber to be used for anti-submarine and coastal patrols. Based on the RAF's own experience with the Hudson which was based on the Lockheed 14 Electra airliner, Lockheed offered a bomber version of the Model 18 Lodestar transport as the Ventura. First flying on 31 July 1941, the British were suitably impressed with the Ventura's performance to order 650 of the Ventura I and 487 of the upgraded Ventura II aircraft. Though the bulk of the Venturas were diverted to US forces following Pearl Harbor, a significant number did reach the RAF who needed the Ventura as a replacement for the Bristol Blenheim as a fast, low-level, bomber. Though there were more suitable aircraft for the role, at the time, only the Ventura was available in the numbers needed. In Norfolk, the RAF equipped No. 21 Squadron with the Venturas and co-located were two Commonwealth squadrons also assigned the Ventura- Australian-manned No. 464 Squadron and New Zealander-manned No. 487 Squadron. The three units were tasked with coastal targets in occupied Europe. Despite a high number of accidents and technical issues, the three units pressed ahead in committing the Ventura to combat, being assigned industrial targets primarily in Holland. As the war progressed, the RAF would team up the Ventura units with squadrons flying the faster Mosquito and Douglas Boston (RAF version of the A-20 Havoc) bombers. 

The pilots of No. 487 Sqn and one of their Venturas

On 3 May 1943 the Kiwis of No. 487 Squadron were assigned a diversionary raid against a power station in Amsterdam while an RAF squadron flying Bostons would attack the Royal Dutch Steel Works at low level. Opposition was expected to be heavy but the Venturas despite their poor reliability could absorb a considerable amount of damage and still fly home. The pilots of No. 487 Squadron were encouraged to do what they could to hit the target and complete the mission as a means of boosting the morale of the Dutch population and resistance. Leading the twelve Venturas would be Sqn Ldr Leonard H. Trent. 

As poor luck would have it, that same day the German military governor of Holland would be visiting the area and the Luftwaffe had placed a large number of its fighters on alert. To make matters worse, a squadron of RAF Spitfires assigned to escort No. 487 Squadron arrived at the rendezvous point off the coast half an hour too soon. Not only did this trigger the Luftwaffe alert, but when the Venturas arrived at the rendezvous point, the Spitfires were low on fuel and had to return to base, leaving the Kiwis to hit the power station unescorted in broad daylight. Crossing the Dutch coast at 12,000 feet, the twelve Venturas were in two formations of six and were bounced by seventy Luftwaffe fighters. Trent's second-in-command took hits and had to turn back to return to England- his aircraft would be the only one of the twelve to make it home. As the Venturas fought off the Germans, the fighters savaged the formation, leaving only three aircraft led by Sqn Ldr Trent to complete the mission. Six Venturas were shot down in less than four minutes. As they neared the target, another two Venturas were shot down, leaving Trent and his crew as the only remaining aircraft. Approaching the target and his gunner managing to shoot down a Messerschmitt Bf 109, Trent pressed home his attack and just as his bombs hit the power station, accurate flak destroyed his aircraft with Trent and his navigator being thrown clear of the shattered aircraft. The rest of his crew failed to escape and Trent and his navigator parachuted down and were captured. 

RAF Ventura over its target

After his capture, Trent was sent to the Stalag Luft III POW camp where he participated in the "Great Escape" in March 1944. He avoided getting shot by surrendering right outside of the camp gates. The Gestapo executed fifty escaped prisoners, but Trent only got solitary confinement because of his early capture. On his repatriation did the circumstances of the disastrous Amsterdam raid become known and on 1 March 1946 he was awarded the Victoria Cross, Britain's highest military honor, for his leadership on the raid that claimed 11 of the 12 Venturas sent to hit the power plant. The squadron was virtually wiped out after that raid and the RAF questioned the continued use of the Ventura as a daylight attack bomber. King George VI himself and his daughter, the future Queen Elizabeth II, visited No. 487 Squadron at their base only days later to offer their condolences. 

After the war, Trent remained with the Royal Air Force and in January 1956 he became the first commanding officer of No. 214 Squadron at RAF Marham which was the first to become operational with the Vickers Valiant, the first of the RAF V-bombers that formed Britain's nuclear deterrent until the arrival of the Polaris SLBM with the Royal Navy. He retired in 1965 when the Valiant fleet was retired due to wing spar structural failures and returned to New Zealand where he passed away in 1986. His biography, Venturer Courageous, was published in 1984 and authored by James Sanders and Laddie Lucas.

Source: PV Ventura/Harpoon Units of World War 2 (Osprey Combat Aircraft No. 34) by Alan C. Carey. Osprey Publishing, 2002, p17-19. Photos: Royal Air Force, United States Navy.

How the USS Wasp Helped Defeat Rommel's Afrika Corps

Spitfire Mk.V makes its takeoff run on the USS Wasp

From 1940 to 1942 the Italian Regia Aeronautica and the Luftwaffe mounted over 3,000 sorties against the British fortress island of Malta in the Mediterranean in an effort to secure their supply lines to Field Marshall Erwin Rommel's Afrika Korps in North Africa. Despite repeated attacks, the Allies managed to keep Malta supplied, even with Axis airfields only sixty miles to the north in Sicily. With the coming of the harsh Russian winter in 1941, poor flying conditions put a temporary hold on most air operations over the Eastern Front and Hitler decided once and for all to deal with Malta. Aircraft idled on the Eastern Front were temporarily moved to airfields in Sicily and southern Italy to begin an intensive aerial bombardment as a prelude to an invasion of the outpost. By the end of January 1942, Malta's defenses had been reduced only a few dozen Hawker Hurricanes which were far outclassed by the Messerschmitt Bf 109s that routinely prowled the skies around the British garrisons. The Hurricanes were delivered to Malta by a Royal Navy aircraft carrier- launching from a point 600 miles west of Malta off the coast of Algeria for the long flight to Malta. Now the British planned to send Supermarine Spitfires the same way to bolster the defenses of the island. Supermarine's engineers devised a 90 gallon external belly tank to extend the range of the Spitfire as well as the addition of a dust filter under the nose to keep the carburetor air relatively grit-free.

On 7 March 1942 the HMS Eagle delivered fifteen Spitfire Mk.Vs to the island and by the end of the month, the Eagle made two more deliveries. But the Luftwaffe and the Regia Aeronautica stepped up the pace of their attacks on the beleaguered island fortress and the bombers and torpedo bombers that were based on the island to harass Axis shipping had to be withdrawn, providing a much needed respite for the Afrika Korps who could now be supplied unmolested. The small Spitfire force suffered heavy attrition both in combat and due to air attacks on the island airfields and by the end of the month, the only carrier available to deliver Spitfires to the island, the HMS Eagle, had developed steering problems that would lay her up for four weeks in the dockyard at Gibraltar. As a result, on 1 April 2942 Prime Minster Winston Churchill contacted President Franklin D. Roosevelt for assistance in getting more Spitfires to Malta. No Spitfires were available in Egypt to be spared, and the other two available Royal Navy carriers weren't suitable- the HMS Argus was too small and the HMS Victorious' lifts were too small for Spitfires. The Luftwaffe hoped to knock Malta out before the late spring thaw in on the Eastern Front. 

Spitfires being craned aboard the USS Wasp

On 10 April 1942 President Roosevelt ordered Operation Calendar- on that day the USS Wasp docked in Glasgow and loaded forty-seven Spitfires while retaining twelve Grumman F4F Wildcats for self-defense. Nine days later the Wasp and her escorting force of British warships entered the Mediterranean. On 20 April 1942 at sunrise off the coast of Algeria, the Wasp launched her Wildcat combat air patrol first followed by the twelve Spitfires on the deck and then the thirty-five Spitfires that were brought up from the hangar deck. Alll but one of the Spitfires made it to Malta, greatly bolstering the defenses. Unfortunately the following day the Luftwaffe struck back at the island's airfields and by the end of the day, only seventeen Spitfires were left operational. RAF repair crews labored under constant air attack to cannibalize battle damaged Spitfires that were beyond repair to get the others operational to fight off the next attack. Once again, Churchill contacted Roosevelt and on 29 April the USS Wasp arrived back in Glasgow for Operation Bowery. This time not only did the Wasp take aboard forty-seven Spitfires, but she was joined by the newly-repaired HMS Eagle which took seventeen Spitfires. At dawn on 9 May 1942 a force of sixty-four Spitfires departed; one crashed on takeoff, killing its pilot and a second Spitfire flown by Royal Canadian Air Force pilot Jerry Smith found once airborne that he couldn't draw fuel from the 90-gallon drop tank. Once the deck of the Wasp was clear, he managed to land safely back aboard the carrier despite never having landed on a carrier and his Spitfire not having an arresting hook! No barriers were engaged either, and as result, the US Navy pilots aboard the Wasp "unofficially" awarded him a set of gold Navy pilot's wings. 

Spitfires share the deck with Wildcats with the HMS Eagle following

Of the sixty-two Spitfires that set out for Malta that day, two were lost along the way. As each Spitfire landed, it was immediately refueled and rearmed while a Malta-based pilot replaced the ferry pilot, all while the engine remained running. RAF ground crews had each Spitfire airborne and ready to meet the next Luftwaffe attack in only 15 minutes! Over the next two days, the Spitfires and remaining Hurricanes on Malta exacted a harsh price from the Luftwaffe attackers, but by this point, the weather was improving over the Eastern Front and Hitler ordered the aircraft transferred to the Mediterranean for the Malta operation moved back to Russia. The Regia Aeronautica was given responsibility for knocking out Malta's defenses but never came close to achieving the near-defeat of the fighter defenses of April and May of that year. Between 18 May and 8 June another seventy-six Spitfires were delivered to Malta, this time by Royal Navy carriers, but it never matched the effect of the USS Wasp making just two deliveries, leading Churchill to quip "Who says a wasp can't sting twice?"

The overall effect of having Malta as a base of operations against Axis shipping in the Mediterranean cannot be understated- of the Axis merchant ships that provided the lifeline to Erwin Rommel's Afrika Korps, 70% of Italian merchant shipping was sunk by Malta-based aircraft and 23% of German merchant shipping was sent to the bottom of the Mediterranean by the RAF on Malta. Had the British lost Malta, the outcome of the war in North Africa might have been very different.

Source: Military Aircraft Monthly International, Volume 10, Issue 1. "Air Wars: Spitfires to Malta" by Dr. Alfred Price, p4-11.

British Defenses Against the Summer 1944 V-1 Bombardment

Cutaway view of the Fiesler Fi 103, or V-1 "Buzz Bomb"

Within a week of the Allied landings on Normandy on 6 June 1944, the Germans initiated a new form of bombardment against London, launching ten of Hitler's "Revenge Weapon No.1" or Vergeltungswaffe 1- V-1 for short. Of the V-1s launched in the early morning darkness of 13 June, six suffered failures that prevented them from even reaching the English coast from launch sites at Pas de Calais. Four bombs made it into British airspace, three of them hit in open land causing no casualties. One of those four V-1s, though, hit Bethnal Green, 2 miles from the famous Tower Bridge (which was used as the nominal aiming point) where it killed six people and injured nine more. British intelligence had predicted history's first cruise missile bombardment for a year, but the opening salvoes were far smaller than what was feared. It took three days to resume the launches and by 16 June 244 V-1s had been fired at the British capital. Of those missiles, 153 crossed into British airspace and of those V-1s, 73 hit the London area causing widespread damage and civilian casualties. 

German launcher crew prepare a V-1 on its firing ramp in France

In the three day lull following the first attack, the Royal Air Force and British Army swiftly deployed its defenses to southeast England. The first line of defense consisted of nine squadrons of Supermarine Spitfire and Hawker Tempest fighters as well as two squadrons of De Havilland Mosquito night fighters. The aircraft three lines of standing patrols, the first line 20 miles off the coast, the second line at the coast, and the third line 15 miles inland. Behind the fighter patrols came the gun zone made up of 192 heavy caliber AA guns and nearly 200 light-caliber guns in an area 20 miles deep. If a fighter pursued a V-1 into the gun zone, gunners were ordered to hold their fire to allow the fighter to complete its pursuit. Behind the gun zone on the southeast suburbs of London was the balloon zone made up of 480 barrage balloons. Over a quarter million mothers and children were evacuated out of London itself during the bombardment. Up to the end of June 1944, an average of 153 V-1s were fired at London. One-third failed or were shot down before crossing the English coast. Another one-third crashed or were shot down over southeastern England before reaching London. But that left a significant amount that managed to hit the London area. 

By mid-July, the defenses were revised based on the experience so far. This time each defensive measure was given a predefined zone for unrestricted engagement of any flying targets. The British Army's AA gun batteries were increased to 412 heavy guns and nearly 600 light guns in a 65-mile long strip along the coast that allowed the gun-laying radars of the batteries a clear view over the English Channel. Fighter pilots were prohibited from crossing the new gun zone, knowing that the gun batteries had unrestricted rules of engagement. The fighter zones were now split into two, with an outer zone over the English Channel that stopped five miles from the coast where the gun zone began. The inner zone began at the rear of the gun zone along the coast and extended back to the barrage balloon zone in London. In less than a month the number of barrage balloons increased to over 2,000. With the new defensive layout, over one-half of incoming V-1s were stopped from reaching the capital. 2 August would be the heaviest bombardment day, with 316 V-1s launched from 38 launchers in Pas de Calais. Of that number, 107 would impact in London. On that day, the nominal aiming point for the V-1 batteries in France, the Tower Bridge, took a direct hit from a V-1. 

A Spitfire pursues a V-1 at treetop height

By early August, the first Gloster Meteor jet fighter units were becoming operational and were tasked with V-1 interception. However, there were three developments that would vastly improve the British defenses, all technological wizardry courtesy of the United States. First was the SCR-584 gun laying radar that was the state of the art in 1940s radar technology and could lock onto targets instead of having to be manually directed by operators. A new device called the the Number 10 Predictor was the second device, it could exploit the improved fidelity from the SCR-584 to direct the AA fire more accurately. And the third bit of wizardry would also save many US Navy carriers and warships in the Pacific- proximity-fuzed AA shells that no longer needed a direct hit to bring down a target. With these three advances, the average V-1 engagement by a British Army gun battery only used a mere 156 rounds to bring down a V-1. 

The last V-1 launched from Pas de Calais came on 1 September, by which point the launch sites were all overrun by British Army units on the breakout from the Normandy beaches. From that point on, the V-1s that hit London were delivered by air-launching which was less effective and more prone to interception. During the first phase of the bombardment from June to September 1944, until the British defenses received new radars and proximity-fuzed AA shells, the most effective defense was actually the Allied air attacks on the French rail system. V-1 launch sites often had to wait days before receiving new missiles to fire due to attacks on supply trains and the rail network itself. Throughout this first V-1 bombardment phase, the launchers at Pas de Calais never launched V-1s at their intended capacity. 

The V-1's magnetic compass in the nose was enclosed in a wooden sphere

By far the most interesting defense that nearly got fielded in the summer of 1944 also came from the United States. Dr. Don Hare and his team at the Airborne Instruments Laboratory in New York were working on radio countermeasures systems when they were asked by the US government to assist in developing a counter to the V-1 attacks on London. Since the V-1 required no outside cues, it was invulnerable to jamming. Its direction guidance came via a magnetic compass in the nose that cued the master gyroscope that controlled the rudder. As the V-1 had to be simple to produce, it lacked any ailerons and its straight wing lacked any dihedral to provide stability. RAF pilots had already discovered a V-1 could be thrown off course and downed by forcing the bomb into a steep bank by tipping one wing. Dr. Hare's team reasoned that if a suitably strong magnetic field could be created, the magnetic compass could be tricked into cueing the master gyroscope to put the V-1 into a tight turn, thereby downing it. The American team's idea was to use existing railway lines that formed a loop around London 60 miles in circumference as a giant magnetic loop. By connecting specific rail lines in a giant circuit, it would take 1,000 amps of DC power to create a magnetic field over London that could confuse the V-1's autopilot. It was determined that 20 to 30 megawatts were needed which was within the capacity of a large commercial power station. Design work began on the needed equipment, but the "Mightiest Magnet" program ended when the launch sites in Pas de Calais were overrun by Allied forces. 

Source: International Air Power Review, Volume 27, Winter 2010/11. "Pioneers & Prototypes- Vergeltungswaffe 1- Adolf Hitler's revenge weapon" by Dr. Alfred Price and P.G. Cooksley, p150-159.

The Spitfire Floatplane That Reginald Mitchell Would Have Loved

During the 1940 Norwegian campaign, the RAF found itself at a disadvantage with relatively few airfields to operate from during the German invasion of Norway and Denmark, Operation Weserübung. In fact, on the day of the invasion, 9 April, German paratrooper units seized three main airfields in the southern part of the country near the capital, Oslo. The British Air Staff issued a priority requirement for floatplane versions of both the Supermarine Spitfire and Hawker Hurricane that could operate out of the many fjords of the Norwegian coast. Folland Aircraft began work on a Spitfire Mk.I using floats from a Blackburn Roc, but within 24 hours of the invasion, major cities as far north as Narvik had already been seized by German forces. As result, the requirement faded away and the aircraft was demodified and returned to normal configuration. However, the idea of a Spitfire floatplane resurfaced in 1942 following some low-priority work on the concept at Folland that had continued even after the fall of Norway. This time a Spitfire Mk.V was used and this time, specially designed floats were used that were the brainchild of Arthur Shirvall, who had designed the high speed floats that were used in the 1920s and 1930s on the Supermarine family of racing floatplanes that the Spitfire claimed its ancestry. Additional modifications to the Mk.V Spitfire included a four-bladed propeller to replace the stock three-bladed unit and an extended ventral fin below the tail to counteract the reduced directional stability caused by the twin floats.

On 12 October 1942 the Spitfire floatplane made its maiden flight from Southampton harbor and initial test flights showed the need for a larger ventral fin. After more modifications, the Spitfire floatplane prototype flew again in January 1943 from Glasgow, Scotland, on its first RAF service trials. Fully loaded, the Spitfire floatplane only weighed 1,100 lbs more and only suffered a 40mph reduction in maximum speed, being capable of 324 mph at 19,200 feet. With a rate of climb of 400 feet/minute, it was less than a stock Mk.V Spitfire, but acceptable to the RAF. Surprisingly, there was only a modest reduction in maneuverability and test pilots found the Spitfire floatplane more maneuverable than any other floatplane. Handing both in the air and on the water was found to relatively easy during the service trials. Other than having to compensate for the torque of the engine on the takeoff run by applying 1/3 to 1/2 rudder, the RAF test pilots felt that the Spitfire floatplane could be easily flown by line pilots.

In the summer of 1943, the RAF began planning for an operation that would utilize the Spitfire floatplane against the German garrisons on the Dodecanese Islands in the eastern Mediterranean off the coast of Turkey. Transport aircraft supplied the various garrisons and the plan was to use Spitfire floatplanes hiding at a small, uninhabited island in the area to attack the transport aircraft. A submarine would be used as a base and house the crews and between missions the Spitfire floatplanes would rest at their moorings next to the submarine under camouflage netting. Folland Aircraft was issued a contract to convert two more Spitfire Mk.Vs to floatplane configuration and after the flight testing of the two newer aircraft, all three three were partially disassembled and shipped to the RAF seaplane base at Fanara, Egypt, on the shores of the Great Bitter Lake. The prototype was found to have serious corrosion in the empannage and was set aside until Folland could ship a new tail to the base. The other two Spitfire floatplanes were assembled and test flown with the work finishing up in November 1943. Operational pilots were recruited from Spitfire crews assigned to the Middle East and they received brief seaplane conversion training on a Supermarine Walrus before converting to the Spitfire floatplanes. Four pilots underwent conversion training for the Dodecanese operation. 

During training on the Egyptian lake, the pilots found that the floats leaked more than hoped and the aircraft had to be hauled out of the water to allow the floats to drain. Not an issue at a seaplane base, but at a submarine mooring on a small island in the Dodecanese Islands, it would be an issue. Pilots also found that the Spitfire floatplane only handling vice was trying to take off in crosswinds over 15 mph which was near impossible. Questions arose as to whether a suitable "secret" location could be found in the Dodecanese chain that would allow more flexible takeoffs. Discussions on the matter eventually proved to be moot as the Luftwaffe reinforced the area just a few weeks prior to the planned start of the operation. The four pilots were released back to their original Spitfire units and the three Spitfire Mk.V floatplanes were put in storage. 

It wasn't quite the end of the story yet as during the spring of 1944 the idea of the Spitfire floatplane was re-examined for operations in the Pacific. Once again, the RAF asked Folland to convert a Spitfire and this time a powerful Mk.IX was chosen, making its first flight on 18 June 1944. With a more powerful engine, this version of the Spitfire floatplane could even outperform a standard land-based Hawker Hurricane. However, the pace of the war intervened again as the operational need faded and the Spitfire Mk.IX floatplane joined the other three Mk.V float planes in storage. Eventually all were scrapped, ending the story of a unique Spitfire variant that hearkened back to its roots as one of Reginald Mitchell's inspired Schneider Cup racing floatplanes. 

Source: Model Aircraft Monthly International, Volume 9, Issue 12. "Airwars 16: Spitfires on Floats" by Dr. Alfred Price, p4-9.

The Canceled British Aircraft that Cost the UK Industry

I bet you thought you were going to be reading about the BAC TSR.2 when you came across the title of today's post, but while there's no arguing the effects that the TSR.2 cancellation had on the British aerospace industry, there was a canceled aircraft that came before the TSR.2 that some have argued cost British industry far more than could ever have been imagined. In 1951 the government had issued a specification for a new long range strategic transport that would be able to move 120 troops long distances to replace the elderly piston-powered Handley Page Hastings. It was envisioned that this new transport could also move personnel and equipment rapidly around the world and deploy as necessary with the new V-force bombers that were soon to enter service with the Royal Air Force. The main condition of the specification was that it had be based on existing design. 

Five companies submitted proposals, with Bristol submitting a version of the Britannia turboprop transport, Saunders Roe submitting a variant of their Duchess flying boat, and Handley Page, Avro, Vickers, and Short submitting transports based on their bomber designs (Victor, Vulcan, Valiant, and Sperrin, respectively) and powered by the new Rolls-Royce Conway turbofan. De Havilland submitted a stretched version of its Comet 1 jetliner. Bristol's Britannia variant was eliminated early due to it being too slow, along with Saunders Roe's flying boat. The Sperrin was next eliminated as the transport version had a fuselage only 9 feet wide with accommodation for only 50 passengers or personnel. Handley Page and Avro's submissions were judged too risky for the RAF contract, leaving only Vickers and De Havilland as the remaining designs not eliminated.

It was realized early on after Vickers was named the winner of the RAF competition that what the RAF needed was not terribly dissimilar with BOAC's need for a long range jetliner that offered more capacity and range than the De Havilland Comet 1. The original specifications that Vickers won was then amended with the requirement that the jet transport also earn a certificate of airworthiness from the civil aviation authorities. With the new amended specifications in place, an order was placed with Vickers for the V1000 prototype aircraft, serial number XD662, in March 1953. 

The V1000 would be the RAF transport version and the anticipated civilian version was the VC7. With construction of the V1000 prototype underway in the summer of 1954, the RAF ordered six aircraft with an eventual requirement of twelve aircraft. BOAC was regularly consulted through this phase as they wanted to put the VC7 on the North Atlantic routes to Canada and the United States as well as on the longer Empire routes that couldn't be served by the Comet 1 jetliner. Besides BOAC, Trans Canada Airlines (Air Canada's predecessor) and Pan American showed significant interest in the VC7. Even BEA expressed an interest in the VC7 for its longer European services.

To meet BOAC's wishes, the V1000/VC7 was a bit larger than the RAF desired, mainly out of a need for the wing fuel capacity to meet BOAC's range requirements. Four Rolls-Royce Conway engines were mounted in the wing root similarly to the Vickers Valiant only the wing was larger and more swept with Kuchemann wingtips (similar to the 707-320BAdv and 707-320C's wingtips) and low mounted. The fuselage had six-abreast seating with a 12.5 foot diameter. This was significant at the time, as Boeing was wrestling with the cabin diameter on its anticipated Boeing 707 and Douglas at the time was still contemplating five-abreast seating for its coming DC-8. Unfortunately prototype construction at Vickers' Wisley facility showed that the V1000 prototype's weight would be about 18,000 lbs higher than planned.

It would have been a simple matter to have upgraded the Conway turbofans, but for whatever reason, BOAC's enthusiasm for the VC7 cooled as the planned weight with the intended engine would rule out London-New York nonstop services. Ironically, several years later when BOAC ordered the 707-430, it would have Conway turbofan engines that were upgraded that would have worked on the VC7! Government meetings in September 1955 formalized BOAC's disinterest in the VC7 and suggestions were made that De Havilland put forth a stretched version of the Comet as well as refinements to the Bristol Britannia as being suitable for BOAC's needs. In addition, BOAC looked further ahead to the mid-1960s for a possible supersonic transport. Despite BOAC's incomprehensible stance, Vickers anticipated the V1000 prototype's first flight in June 1956 with the first production aircraft flying in 1959 with inaugural airline services in late 1959/early 1960 (not too far off from when the Boeing 707 began its passenger services). In a bid to maintain the competitiveness of the VC7, Vickers explored other engine options and even looked at a version of the VC7 with each of the Conway turbofans in its own podded nacelle under the wing, not unlike that of the 707 and DC-8's layout.

By this point the RAF was entering a period of fiscal austerity and it's most expensive item to date was the V1000/VC7 project. Without mentioning the V1000/VC7, the British government cautioned the RAF to scale back its expenditures. Politics came into the picture with the prospect of the end of Comet production which would have affected one of the Comet's main subcontractors, Shorts in Belfast. A desire to keep Shorts busy shifted the support amongst some MPs in Parliament against the Vickers jetliner. In addition, the Britannia was having teething problems with its turboprop engines and was selling slow. Some ministers in the government felt that support should be given to the Britannia program instead of embarking on the all-new Vickers jetliner. 

Some historical accounts point the finger at BOAC for planning to procure US jets from the start and with the support of some in the government, did what it could to commit formally to the VC7. A spirited debate in Parliament dragged on for weeks with the supporters of the Vickers projects openly declaring that the VC7's cancellation would "give the large jet market to the Americans for the next 20 years". Rather obtusely, several government officials proclaimed that the planned performance of the Boeing 707 and DC-8 would make them cost-prohibitive for many of the world's airlines and the speed advantage over the Comet and Britannia would not matter to most passengers! With the V1000 prototype 75% complete, the project was ordered shut down by the British government on 11 November 1955, and this was despite intensive lobbying by Trans Canada Airlines. 

For many observers, it was the cancellation of the Vickers VC7 and not the TSR.2 where the British aerospace industry lost its way. Sir George Edwards, managing director of Vickers and the chief designer of the V1000/VC7, had lamented that BOAC and the government had simply handed over the lead in jetliner technology to the Americans for "generations to come."

Source: Stuck on the Drawing Board: Unbuilt British Commercial Aircraft Since 1945 by Richard Payne. Tempus Publishing, 2004, p38-42

Twilight of the Mighty Hunter

I had posted back in December about one of the obscure roles performed by the BAe Nimrod during the 1982 Falklands War. More often with ongoing commitments in Iraq and Afghanistan, maritime patrol aircraft like the Nimrod and the Lockheed P-3 Orion are finding themselves performing missions they were not initially designed to perform. During Operation Enduring Freedom in Afghanistan, the onboard high fidelity EO systems of the Orion proved valuable to US Special Forces teams fighting the Taliban. With long endurance, extensive sensor and communication suites and larger crews able to handle multiple tasks, maritime patrol aircraft became ideal in the role of overland ISR (Intelligence, Surveillance, and Reconnaissance).

In 2003 the RAF issued an Urgent Operational Requirement (UOR) to equip several Nimrods with a late-generation EO sensor system, the Wescam MX-15. Four aircraft had the sensor turret mounted in a fairing installed under the starboard wing just inboard of the pinion tank and deployed to Saudi Arabia to assist joint UK-US-Australian special forces teams in scouring the western deserts of Iraq for Scud missile launchers. After the fall of the Iraqi regime, the Nimrods returned to their home base of RAF Kinloss, but were soon recalled to Iraq in the summer of that year to assist in the fight against the insurgency under Operation Paradoxical. Since the RAF didn't yet have any UAVs in the same class as the MQ-1 Predator, the Nimrods with the MX-15 EO system provided high-fidelity overhead real-time ISR for the coalition forces involved. At the time, an early version of the ROVER (Remote Optical Video Enhanced Receiver) called Longhorn was in use that allowed, with much effort and technical issues, troops on the ground to see what the Nimrod overhead was seeing. The current ROVER system is much more user friendly.

In the spring of 2004 British forces in Basra found themselves battling the militia fighters of Shiite cleric Muqtada al-Sadr and once again the MX-15 equipped Nimrods provided overhead ISR for the troops on the ground. At the culmination of the effort against the Sadr Militia, an overhead Nimrod provided targeting information to an orbiting AC-130 Spectre gunship. As Sadr Militia units dispersed throughout the back streets of the city of Al Amarah, the Nimrod crew used the MX-15 system to identify the militia and then hand off the coordinates to the Spectre for destruction.

In the latter half of that year following the stabilization of the Shiite south, the Nimrods shifted their attention to Baghdad in an effort to combat the increase in Sunni insurgent bombings there. A Nimrod would forward deploy from Oman to Basra International Airport with a British army liason officer aboard. Flying almost nightly from Basra, the small Nimrod force was flying over 200 hours a month.

In the overland mission, the Nimrod's three acoustic sensor operators rotated shifts operating the MX-15 turret. The ESM and Searchwater radar operators were in charge of deconfliction over the crowded airspace over Baghdad. Army liason officers worked with the mission commander at the master display to coordinate and disseminate the information from the EO operators on the nine-hour missions. The MX-15 had three cameras- one narrow band, one wide band and one in infrared that were selectable by the operators. The best image is then displayed on a larger monitor over a moving map display that allowed ground units to easily relay to the operators where to look.

In July 2006 the MX-15-equipped Nimrod force switched its attention to Afghanistan in the intensifying effort against the Taliban. With a grueling schedule divided between Iraq and Afghanistan, the Nimrod force finally gave way with the loss of XV230 in September in 2006 with all of its 15 crew being lost. The cause was traced to persistent problems with the Nimrod's air-refueling plumbing system adjacent to hot air ducting. With 11 aircraft remaining in the overall fleet, the UK Ministry of Defense put those aircraft through a modification project that was completed in 2009, but the Nimrods never returned to Afghanistan, their role being taken up by a trio of new RAF aircraft, the General Atomics MQ-9 Reaper, Beechcraft Shadow R.1 ISR (based on the Beech King Air) and the new Bombardier Sentinel R.1 SAR surveillance aircraft (based on the Global Express business jet). In March 2010 the Nimrod MR.2 aircraft were official retired, ending some 30 years' service which began in the icy waters of the North Atlantic hunting Soviet subs and ended over the harsh terrain of Afghanistan hunting insurgents. It's replacement, the Nimrod MRA.4, won't be due to enter service until 2012 at the earliest.

Source: Air Forces Monthly, July 2010. "Secrets of the Nimrod at War", by Tim Ripley, p38-42.

The Barnes Wallis Swallow

As the Second World War began to wind down, renowed British aircraft designer Barnes Wallis started investigating the challenges of supersonic flight and concluded early on that a variable geometry swing wing was the best way to accommodate the center of gravity changes in moving between the subsonic and supersonic regimes. In 1946 he wrote an engineering paper entitled "The Application of the Aerodynamic Properties to the Stabilisation and Control of Aerodynes" (quite a mouthful) in which he combined his ideas on swing wings with laminar flow studies. Starting out with small hand launched models, Barnes Wallis gradually moved up to larger versions that were launched for a catapult at 100mph. His models had slender, ovoid fuselages with swing wings mounted far to the aft and a single highly swept fin. With the end of the war, the British government was eager to regain research ground lost to the Americans and Vickers was awarded a contract of a half-million pounds to study supersonic flight. With the cancellation of the Miles M.52 supersonic research aircraft, some of Vickers' money was reallocated to Barnes Wallis' project which was given the code name Wild Goose.

The Wild Goose project ran to 1954 and it used progressively larger radio controlled models based on Barnes Wallis' designs. The later models had provisions for rocket engines in the fuselage and the RAF took notice, considering the Wild Goose design as the basis of a long range surface-to-air missile to intercept Soviet bombers before they reached UK airspace. Wild Goose ended in 1954 but the research data acquired went over to a classified project known as Green Lizard. This project called for a compact missile fired from a storable tube with flip out wings for which Barnes Wallis supersonic design work was applicable. Green Lizard was envisioned as both a surface-to-surface missile that could dispense submunitions or a surface-to-air missile powered by turbojet engines for the long range interception of Soviet bombers. It's not known exactly when the Green Lizard project was terminated, but it may have run in parallel to the Wild Goose project.

As the database on his designs grew, Barnes Wallis then moved into a manned aircraft applications of his swing-wing designs. Small aircraft builder Heston Aircraft was a subcontractor on the Wild Goose project and Wallis worked with Heston to build a small flying demonstrator designated JC.9. With a single seat, retractable tricycle undercarriage and 46 feet in length, the JC.9 was planned to fly first as a glider, then have an turbojet engine installed for powered trials. The JC.9 was then shipped in sections to the Vickers Weybridge facility for final assembly, but for reasons unknown, it remained disassembled until scrapped.

By 1954 Barnes Wallis began thinking even bigger, adapting his unique swing wing design to a supersonic intercontinental range aircraft. The RAF had issued OR.330 (Operational Requirement 330) that called for high flying supersonic bomber/reconnaissance aircraft. Although not responsible for Vickers' submission for OR.330, Wallis adapted his design to meet the stringent requirements, coming up with a sleek arrowhead shaped tailless aircraft with slender swing wings pivoted at the aft end of the fuselage. Pod-mounted engines pivoted on the tips of the swing wings and also provided some directional control. Calling his revolutionary design the Swallow, small scale models were tested in Vickers' wind tunnels with encouraging results. Scale flying models of the Swallow powered by rocket engines easily attained Mach 2.5 in flight tests. While the Swallow wasn't selected for OR.330, the RAF was sufficiently interested to continue funding Wallis' work towards a scaled-down flying demonstrator called the Research Swallow that could be readily adapted for military roles. Versions of the Research Swallow were submitted to the RAF and Royal Navy as a supersonic strike fighter.

The most impressive would have been the bomber version of the Swallow and a supersonic military transport. The Swallow bomber would have been approximately the size of the B-1 bomber with 4-5 crew, a cruising speed of Mach 2 and a range of 5,000 miles carrying a single Red Beard nuclear bomb. The military transport was even larger with a civilian airliner version that could have carried 60 passengers between the UK and Australia nonstop. Development work on the bomber and transport versions of the Swallow was estimated at 10 years, but the infamous 1957 Defence White Paper of Duncan Sandys that stated the era of manned military aircraft was being eclipsed by missiles ended funding for the Swallow.

As consolation, Barnes Wallis was allowed to meet with the American Mutual Weapons Development Program to see if the United States was interested in his extensive work. Exchange visits were conducted between Wallis' facility at Vickers and Wallis himself led several teams to the United States to meet with NASA's Langley research facility. A six month joint UK-US development program was conducted at NASA Langley to further refine Wallis' work. By June 1959, NASA's extensive testing uncovered pitch up problems in certain flight regimes as well as higher than expected drag. This effectively killed off the Swallow as an aircraft design, but NASA found the body of work still applicable to a more conventional tailed swing design. This design would eventually evolve into the world's first production swing-wing combat aircraft, the General Dynamics F-111 Aardvark.

Source: Secret Projects: Flying Wings and Tailless Aircraft by Bill Rose. Midland Publishing/Ian Allan, 2010, p27-31.

Several weeks after the disastrous Munich Pact was signed in 1938, the British Air Ministry initiated a massive expansion of the Royal Air Force in anticipation of the coming war. As the planned expansion was beyond the capacity of British aircraft factories at the time, the Air Ministry also looked abroad at foreign sources of aircraft to meet the needs of an expanding RAF. In January 1939, Air Ministry representatives visited the Caproni factory in Milan, Italy to examine the Caproni Ca 310 light twin which had potential as a crew trainer. Surprisingly, in light of the European tensions at the time, the visit by the British was officially sanctioned by the Italian government.

Though no contracts were signed, the interest was significant as high-ranking officials with the Air Ministry visited Caproni again in December of that year (and I should note that the Second World War had already started in September 1939 but Italy had yet to declare war on the Allies) and informed Count Caproni himself that the RAF wished to acquire 200 Ca 310s and a further 300 examples of a more powerful derivative under development, the Ca 313. The French had already placed orders for 200 Ca 313s in September 1939.

In January 1940, an Italian delegation from Caproni arrived at the Air Ministry's headquarters in England to finalize the purchase of the Caproni twins. The RAF submitted a series of changes they wanted on their aircraft and in exchange, RAF representatives were dispatched to the Caproni factory to oversee the RAF-specific modifications. The purchase was confirmed by the end of that month and the aircraft were to be partially-completed in Milan and then shipped to France where the RAF operated out of the airfield at Istres. At Istres the Caproni aircraft would be completed, flight tested, and flown to the UK.

If things weren't surreal already with this deal, the Italian government notified the Nazis that Caproni had a sizeable order on the books with the French and British and if there were any objections in light of the close relationship between Mussolini and Hitler. Surprisingly, the Germans in March 1940 indicated that they had no objections to the deal! However, a month later the Germans indicated that the contracts should be canceled. Count Caproni himself met with the heads of the Air Ministry and arranged for the aircraft ordered to be "completed" by Caproni's subsidiary in Portugal and the UK would then "buy" the aircraft from Portugal instead of the Italians.

However, on 10 June 1940, with France near defeat, Italy declared war on Great Britain which effectively canceled what at the time was the largest aircraft contract ever received by the Italian aircraft industry. It proved to be fortuitous for the Royal Air Force, though. Sweden did take delivery of a substantial number of the Caproni Ca 310/313s and found them to have unreliable engines and poor build quality. The fuel lines to the engines ran right next to the exhaust stacks for the engines which resulted in the Caproni twin having a reputation for being highly flammable. After local modifications to hold the aircraft over until replaced by Saab designs, the Caproni twin was quite robust, but nearly fifty Flygvapen personnel lost their lives in accidents due to the technical deficiencies of the Ca 310/313.

Source: Air Enthusiast, Volume One, William Green, managing editor, Gordon Swanborough, editor. Pilot Press Ltd, 1971, p95-99.

Initially deemed unsuitable as night bombers by the RAF, the first Consolidated LB-30 Liberators were found with their long range to be ideal in the transport role. In mid-1941 the North Atlantic Return Ferry Service began to bring RAF flight crews to Canada where they would pick up US Lend-Lease aircraft to fly back to Europe. As a result, the Liberator was the first aircraft to make the North Atlantic crossing carrying passengers on a regular service. On 24 September 1941 BOAC took over the North Atlantic services from the RAF and also took on the Liberator transports.

The BOAC Liberators wore either civil registrations or RAF roundels but could be identified by the Speedbird logo on the nose of the aircraft. Flights connected Prestwick with St-Hubert in Quebec via Gander, Newfoundland. In January 1942 the first BOAC Liberators started passenger services to Cairo (via North Africa) and in the following year passenger services extended to Moscow (via North Africa and Iran to avoid occupied Europe).

By 1947 the RAF had already withdrawn its own Liberators from service but BOAC continued use of the Liberator in cargo services London and Montreal via Prestwick and Gander. From 4 February to 28 May 1948 BOAC inaugurated nonstop Liberator service between London and Montreal using inflight air-refueling. Flight Refueling Limited, an early pioneer in aerial refueling, purchased four Avro Lancastrians from Trans-Canada Airlines and converted them into refueling tankers. Two of them were based in Shannon, Ireland, and the other two were based in Newfoundland. The Liberators flying eastbound needed only a single refueling usually about 200 miles east of Gander. Flying westbound, two refuelings were needed to fly against prevailing winds- the first one 200 miles west of Shannon and the second one in the vicinity of Goose Bay, Labrador.

Of forty-five refuelings, only three were aborted- one due to radar and heating problems in the tanker, one due to fuel transfer problems and a third one due to a nervous BOAC captain who refused to carry out the aerial rendezvous! Despite the success of the trials and Flight Refueling's attempt to convince BOAC that aerial refueling was feasible for civilian flights, BOAC instead opted to use Lockheed Constellations and Boeing Stratocruisers to carry out nonstop North Atlantic services.

Source: International Air Power Review, Volume 15. AIRtime Publishing, 2005, "RAF Liberators at War- Part 1: UK-based Operations" by Jon Lake, p160-161, 172-173.

While BAe Nimrod maritime patrol aircraft were deployed to the South Atlantic in 1982 Falklands War to protect the British naval task force from Argentine surface vessels and submarines, the Nimrod also had two little-known roles during that conflict. The first role was that of "the largest fighter aircraft" when AIM-9 Sidewinder missiles were cleared for firing from underwing hardpoints with the intent of targeting the Argentinian's Boeing 707s that were being used to shadow the British naval task force. In addition, the AGM-84 Harpoon missile was cleared for use on the Nimrod in the anti-shipping role, though neither the Sidewinder or the Harpoon were fired in anger during the conflict.

The more obscure role of the Nimrod during the Falklands was that as a back up for the Avro Vulcan "Black Buck" bombing missions. The long range of the Nimrod made it a natural for the overland bombing role and a rudimentary bombsight was configured for use by the co-pilot to drop either 1000 lb air-retarded bombs or BL755 cluster bombs. A trial drop was even conducted at the Garvie Island range in Scotland.

Source: Air Forces Monthly, December 2009. "More Than A Sub-Hunter!" by Jon Lake, 32-35.

In 1936 the RAF issued Specification T6/36 for an aircraft designed from the outset for crew training. At the time, air crew training was often carried out retired aircraft types. T6/36 required the new design be a monoplane with retractable undercarriage, side-by-side seating with dual controls, a radio compartment for the training of navigators and radio operators and a manually-operated gun turret. There was to even be provision for a forward firing gun and practice bomb carriage as well. The RAF indicated that well over 100 aircraft would be required.

De Havilland was selected to built its design, an elegant looking aircraft powered by a single 525-horsepower Gipsy King 1 12-cylinder engine. The De Havilland DH.93 Don made its first flight on 18 June 1937. Initial flight testing showed the need for several modifications, including the addition of auxiliary fins under the horizontal tailplane but an order for 250 aircraft went forth.

Once the training equipment including the gun turret was installed, it was found the DH.93 Don was underpowered and suffered from continued stability issues. The order was revised to only 50 aircraft which were to be fitted out as light transports seating four to six individuals. A "turtleback" was fitted in place of the radio compartment and the dorsal gun turret. Of the 50 aircraft delivered, only 30 were delivered as airworthy and distributed quietly across several RAF station flights. The remaining 20 went straight into service as engineless ground instructional airframes.

The RAF's crew training needs shifted over to a design that was not tendered for the T6/36 specification- the Avro Type 652A first flew the year before the issuance of Specification T6/36 and would go into production as the vastly superior Avro Anson while the DH.93 Don faded into obscurity.
Source: Air Enthusiast, May/June 2003. "Out-Moded Teacher- De Havilland's Don Crew Trainer" by Daniel Ford, p74-75.

Probably the first attempt at an all-in-one hunter-killer aircraft to hunt down and destroy enemy radars came in 1944 with the Royal Air Force's Project Abdullah. Unlike US efforts that focused on radar-finding aircraft to cue attacking aircraft, Project Abdullah consisted of an electronic radar hunting device fitted to three Hawker Typhoons of the No. 1320 Special Duty Flight in May 1944.

In the cockpit of the Typhoon was a CRT display connected to a radar homing receiver. The receiver was tuned to the known operating frequencies of the German radar. Once in the vicinity of a suspected radar site, the pilot turned on the Abdullah equipment and once alerted to an active radar site, he would try to visually locate the site and either attack it or fire smoke marker rockets to mark it for further attack by waiting aircraft.

Despite an impressive step forward in the suppression of enemy air defenses (SEAD), the German countermeasures were as simple as either turning off the radar knowing the Abdullah aircraft were in the area to changing the radar frequency as the homing equipment on the Typhoon had to be preset before takeoff.

Source: Wild Weasel Fighter Attack: The Story of the Suppression of Enemy Air Defenses by Thomas Withington. Pen & Sword Books, 2008, p23.