North American F-82 Twin Mustang Part I

At the beginning of the Second World War American radar technology and night fighter development was considerably inferior to that of the British. By 1943, however, American technology began to surpass British radar systems with the introduction of the SCR-720. Throughout the Second World War aircraft companies in the United States produced 900 night fighters for the U.S. Army Air Force (USAAF) while the U.S. Navy and Marine Corps operated a considerably larger number because existing front-line fighters were better suited for adaptation to the night fighter configuration. Late in November 1945, the USAAF approved military characteristics for a jet-propelled aircraft as a post-war successor to the Northrop P-61. At first the all-weather interceptor was conceived as an aircraft that would be effective in daylight as well as at night or during inclement weather. However, by 1946, Major General Curtis LeMay, Deputy Chief of Staff for Research and Development, indicated that this concept be revised due to the added weight of the radar gear which would limit aircraft performance. Because the heavy radar-equipped all-weather fighter would be no match for a small day fighter, ‘all-weather’ was to mean primarily night and inclement weather. Military performance characteristics were then revised to conform to this decision and designs for two experimental all-weather aircraft, the Curtiss XP-87 Blackhawk and Northrop XP-89 Scorpion, were selected for investigation.

Post-war apathy by the American public and government in the wake of the Second World War cut deeply into military appropriations and stifled night/all-weather fighter development, and the newly established U.S. Air Force (USAF) and the Navy continued to rely on piston-driven night fighter aircraft. Changing international situations in Europe and Asia resuscitated interest in night and all-weather interceptors. Soviet aggression with the establishment of communist-bloc countries of Eastern Europe, the Berlin Crisis of 1948, and the Soviet’s testing of a crude nuclear bomb in 1949, forced the U.S. military on a quest to develop superior strategic bombers and jet interceptors, which in turn, resulted in the development of air intercept radar and all-weather aircraft. Early attempts to develop jet-powered all-weather fighters ran into a series of snags and delays. The Air Force ordered the Curtiss XP-87 in December 1945, but it ran into developmental difficulties and the Air Force abandoned the project, which incidentally ended Curtiss’ thirty-year history as an aircraft manufacturer. The P-89 Scorpion seemed to hold greater promise, but it too ran into teething troubles and its acceptance and delivery did not occur until 1952.

Development of jet-powered all-weather aircraft would be slow and, until such time when this type became available, the U.S. Air Force needed an interim aircraft. In the immediate post-war period, the P-61 had formed the bulk of the night fighter force. Due to the lack of any suitable jet-powered replacement, the P-61 soldiered on for a few more years. However, manoeuvres held in the North-western United States early in 1948 quickly confirmed the Black Widow’s limitations and the Air Force deemed the aircraft as having no tactical value in defensive operations. In order to help fill the gap until the F-89 Scorpion became operational, North American Aviation (NAA) developed a night and all-weather adaptation of the piston-engine North American F-82 Twin Mustang.

Since the P-82, like the P-61, would be of little value in daylight operations, the Air Force assigned such jet interceptors as the Lockheed P-80 Shooting Star (later F-80) and Republic P-84 Thunderjet (F-84) to fighter-interceptor squadrons, which began replacing the single-engined, propeller-driven North American P-51 (F-51) Mustang in the Air Force inventory. These jet aircraft possessed the required speeds to combat enemy bombers of the Boeing B-50 type but both fighters lacked the electronic equipment to allow them to operate at any other time than during daylight (again, the weight of 1950s-era airborne radar technology precluded its use in a small high-speed interceptor). In turn, beginning late in 1949, the North American F-86A Sabre replaced the F-80 and F-84. By the end of 1950, of the 365 aircraft assigned to the U.S. Air Defense Command (ADC), 236 were F-86A and E models. Therefore, without a real all-weather interceptor, the Air Force had no other alternative but to place its reliance on a dual fighter force, with jet aircraft for daytime operations and radar-equipped F-82s for night and inclement weather interceptor missions.

Development

Possibly one of the oddest American aircraft to go into full production after the end of the Second World War, the P- (later) F-82 Twin Mustang series was the last mass production propeller-driven fighter acquired by the U.S. Air Force. Originally designed as a long-range bomber escort during the Second World War, it evolved into a night and all-weather fighter during the post-war years. The original concept of the XP-82 traces back to the development of North American Aviation’s XP-51 Mustang in 1940 and the production of subsequent variants of that aircraft as a long-range fighter to protect Allied bombers against the German Luftwaffe and, subsequently, to provide cover for Boeing B-29 bombers in the Pacific. However, the Air Force lacked an interceptor with an extreme-range capability. The USAAF fighters with the longest range during that conflict were the P-51D Mustang, with a maximum range of 1,600 miles, and the Lockheed P-38J Lightning with a maximum range of 2,200 miles. Both aircraft were capable of escorting B-17 and B-24 bombers from bases in England to the heart of Germany; but it was another story in the Pacific.

The vast distances of the Pacific, where missions could last eight to twelve hours, required a fighter with a far better range than any existing aircraft in the Air Force’s inventory at the time, but such a design would need a two-man crew consisting of a pilot and co-pilot/navigator to reduce workload stress and fatigue. The concept for such a radical aircraft design, closely resembling two P-51 Mustang fighters joined together with a common centre wing and horizontal stabilizer, belonged to Edgar Schmued, North American Design Chief, who proposed the idea in November 1943 at the company’s factory in Inglewood, California. Two months later on 7 January 1944, when General of the Army Air Force Hap Arnold was taking a tour of the factory, Ed Schmued showed him the revolutionary design; the General quickly endorsed the project. After viewing a mock-up and wind tunnel model of the design, Air Force brass issued development contract AC-2029 on 8 February 1944 ordering the construction of three experimental prototypes (serial numbers 44-83886 through 44-83888), with the NAA company designation NA-120.

XP-82

North American engineers developed the two airframes and wings for the NA-120 from the basic fuselage and wings of the experimental XP-51F, which was used to develop the P-51H production model. Although the P-51 and XP-82 were quite similar in appearance, very few components were interchangeable. External design changes included lengthening the aft fuselage sections by fifty-seven inches, internal strengthening of the centre and outer wing sections to allow for fuel and armament on external pylons, increasing the length of the ailerons, inclusion of slotted flaps along the trailing edge of the centre section, and enlarging the dual vertical stabilizers to improve stability. Hydraulically operated wing flaps extended from the aileron to the fuselage on each wing panel and between the fuselages on the centre section interconnected and controlled by a lever located in the pilot’s cockpit only. Interestingly the XP-82’s entire wing area of 408 square feet was less than two Mustangs (470 square feet) but the overall length was six feet longer than the P-51H; a nine-foot difference with the F-82G model. The XP-82 prototypes and the subsequent P-82B variant, used counter-rotating Aeroproducts propellers powered by two liquid-cooled, supercharged, two-stage, two-speed, Packard Merlin V-1650 engines with, on the left (portside), a V-1650-23 and right (starboard), a V-1650-25 to compensate for torque. The aircraft’s fuel system consisted of four internal self-sealing wing tanks; one consisting of two interconnected cells in each outer wing panel and two in the wing centre section with a total fuel capacity of 575 gallons. This arrangement allowed each engine to operate with a separate and complete fuel system with the two cells interconnected by a cross-feed line. Range and flight time could be increased by the addition of either two 110, 165, or 310-gallon drop tanks installed under each outer wing panel.

The first prototype, serial number 44-83886, rolled out of the Inglewood factory on 25 May 1945 and flew on 16 June 1945, with NAA test pilot Joe Barton and Edward M. Virgin at the controls. This was the second attempt; the month before it refused to get off the ground due to excessive drag caused by the props’ air flowing upwards to the centre wing section, an effect created by the rotation of the propellers – the left, counter-clockwise, and the right clockwise. Engineers solved the problem by switching the engines to the opposite sides resulting in successful flight testing. The second prototype, serial number 44-83887, made its initial flight of approximately one hour on 30 August 1945. The first and second prototypes showed the aircraft to have exceptional high speed, manoeuvrability, and rate of climb. The USAAF accepted the first prototype in August 1945 followed by the second the following month. The XP-82 was 39 feet in length with a wing span of nearly 52 feet and its two Merlin engines gave it a top speed of 468 mph, almost identical to the P-51H, and a maximum range of nearly 3,500 miles with internal and external fuel stores (over twice the range of the P-51).

The Twin Mustang’s command pilot’s port cockpit contained a full set of flight instruments and controls while the co-pilot/navigator position, although equipped with basic instrumentation to fly the aircraft, lacked other features. Both cockpits provided essential power plant and flight controls with the capability to transfer control of guns, fuel, engine heat, anti-icing gear, and the command radio by shift switches in each cockpit. However, the co-pilot had no control over landing gear and flaps (unless in an emergency), or engine ignition, surface control boost, bombs (except salvo), and rockets. In a situation where the command pilot might become incapacitated, NAA equipped both cockpits with an emergency landing gear release handle located at the right side of both cockpits. Pulling the handle unlocked the gear and fairing doors, and actuated a hydraulic pump valve, which allowed trapped hydraulic fluid in the landing gear and wheel door cylinders to return to the system reservoir. This allowed the doors to open and the gear to extend by gravity without hydraulic pressure. North American also included an option for turning the Twin Mustang into a single-seat fighter by removing cockpit equipment from the copilot’s position, and removing and fairing over the canopy.

The proposed armament package for the XP-82 consisted of a bank of six M-3 .50-caliber machine guns, with 400 rounds-per-gun, housed in the centre wing section. The prototype and subsequent production models allowed for the installation of underwing and centreline racks to carry up to twenty-five 5-inch High Velocity Aircraft Rockets (HVAR), 4,000lbs of bombs – two on each outer wing, two on the centre wing section, or a chemical tank (AN-M10 or AN-M33) which was used to lay smoke screens or dispense chemical agents and was installed on each outer wing rack. North American also provided for an optional removable pod for the centre section that could house eight additional .50-caliber machine guns, radar, or a photographic reconnaissance package. However, except for the radar pod, the gun pod never materialized for operational aircraft while the photographic reconnaissance package was fitted and tested on only one aircraft. Production models were equipped with the K-18 compensating gun sight installed on the instrument panel shroud of the pilot’s cockpit. The sight automatically computed the correct lead angle of fire and consisted of two optical systems, fixed and gyroscopic, contained within the sight. The reticle of the fixed sight, projected on the reflector glass, consisted of a seventy-mil circle with a small cross in the centre, and a rocket scale located below the cross. The fixed sight’s circle and cross was used only when strafing, firing rockets, or when the gyro sight malfunctioned. The reticle of the gyroscopic sight, also projected on the reflector glass, consisted of a circle with six diamond-shaped images surrounding a central dot. Both sights were used together to automatically compute the lead angle needed to fire on a hostile aircraft.

The Air Force accepted the first prototype on 30 August 1945 but NAA retained it for eighteen months and, after a series of airworthiness and stability flights, it was sent to Wright Field, Ohio, for evaluation by the Air Force’s Air Material Command. Afterward, the National Advisory Committee for Aeronautics (NACA) operated it until 1955 when it was scrapped. The Air Force accepted the second prototype on 11 September 1945 and like the first XP-82, NAA kept it for further flight testing until turning back over to the Air Force in March 1946. NACA received it in October 1947, operating it until February 1950 when it sustained major damage after sliding off a runway.

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North American F-82 Twin Mustang Part II

P-82B Model

The USAAF ordered 500 Merlin-powered P-82B Twin Mustangs (Model NA-123) on 8 March 1944 with production contract AC-2384, sixteen months before NAA test pilot George ‘Wheaties’ Welch took the first P-82B, 44-65160, aloft for the first time on 31 October 1945.

The end of the war forced the USAAF to re-evaluate the Twin Mustang’s future and instead of 500 P-82Bs, the Air Force issued a modified procurement order on 7 December 1945 authorizing the construction of 270 P-82Bs, including twenty already under assembly, and 230 P-82E long-range escort fighters. Further production cuts resulted in the delivery of only twenty P-82B aircraft (serial numbers 44-65160 through 65179) with the Air Force taking delivery between November 1945 and March 1946. The entire production block, except for two modified for night fighter evaluation, was assigned to the training of flight crews for the next production variant-the P-82E. The cost for the P-82B was $140,513 per unit. The B-model differed from the XP-82 only by the addition of a pressure carburettor on their Packard-Merlin engines along with the actual provision for underwing pylons for ordnance and improved machine guns (the XP-82 was equipped with Mod-2 machine guns while the P-82B received the Mod-3).

A majority of the twenty manufactured P-82Bs were used as training aircraft by the 27th Fighter Escort Group (FEG) based at Kearney Army Air Force Base (AAFB), Nebraska. Two of the -Bs were actually pulled from the production line and modified for night interception work. NACA used serial number 44-65179 in missile research while the Air Proving Ground at Eglin Field, Florida, modified and tested 44-65170 as a photographic reconnaissance version called the RF-82. Meanwhile, NAA went on to develop and produce the next Twin Mustang variant, the P-82E, and the Air Force withdrew the -B from service in December 1949.

The P-82B might have faded into oblivion and ended on the scrap heap if not for 44-65168’s (the ninth Twin Mustang off the production line) contribution to aviation history by making a non-stop flight on 27-28 February 1947. On that date, Lieutenant Colonel Robert Thacker and Lieutenant John Ard flew 44-65168, named ‘Betty Jo’ after Thacker’s wife, on a non-stop flight from Hickam Field, Hawaii, to LaGuardia Field on Long Island, New York, in fourteen hours thirty-one minutes and fifty seconds at an average speed of 347mph. They accomplished this feat without refuelling by stripping down the aircraft and adding additional internal fuel tanks and four 310-gallon drop tanks. This aircraft is now restored and displayed at the National Museum of the U.S. Air Force.

F-82E Long-Range Escort

Air Force interest with the P-82 program continued as there was no alternative long-range escort for the B-50 Superfortress, an improved version of the B-29 with a noticeably higher vertical stabilizer, and the Convair B-36 Peacemaker, then under development, since early jet fighters didn’t have the range for long-range escort missions. (The Air Force’s front-line jet interceptor, the Lockheed F-80, only had a normal range of approximately 800 miles). Early in the Twin Mustang’s development, the government made it no secret that it wanted Allison V-1710 engines to power the P-82 since it had become doubtful that the Packard-Merlin V-1650 would be available much longer. This was largely due to failed negotiations with Rolls-Royce who owned the rights and wanted Packard to pay $6,000 in royalties for every engine that the company produced. Another reason to switch to the Allison was that General Motors (GM), who owned Allison, also owned forty percent of North American Aviation and, with the end of the war, the aircraft industry went into a nose dive and the company needed to sell more Allison engines and parts to keep investors happy.

The P-82E, designated as model NA-144, became the first mass produced model of the Twin Mustang and was powered by the Allison V-1710-143 (right) and 145 (left) engines, which rotated in opposite directions. In February 1946, North American received an order for 250 Allison-powered P-82Es with a finalized contract (AC-13950) for this procurement signed on 10 October 1946. The $35 million procurement contract covered the cost for 250 P-82Es plus tools and spare parts. North American would be paid $17 million for the first 100 planes, $14.5 million for the remaining 150, and $3.5 million for special tools and ground-handling equipment. The Air Force expected the first deliveries to begin in November 1946 and, after the completion of the first 100 aircraft, NAA and the Air Force would review the contract to adjust requirements which it did by ordering the last 150 E models modified as night fighters. NAA test pilot George Welch took the P-82E on its maiden flight on 17 April 1947. The new Twin Mustang model was slightly slower with a top speed of 465mph and a lower rate of climb by almost 900 feet per minute.

Problems with the Allison engines delayed Twin Mustang production for nearly two years as production costs rose to more than $50 million. The government negotiated with Allison in August 1945 to supply North American with an updated V-1710, since earlier versions of the powerplant had equipped the P-38 and P-40, among other famed aircraft from the Second World War. Allison agreed to purchase government parts to develop the new engine, which proved to be costly with a final price tag of $18.5 million. As previously stated the first flight of the P-82E took place on 17 April 1947; however, engine malfunctions appeared during the flight and continued with the next four aircraft accepted by the Air Force (one each in September and November 1947 and two in December). The updated Allison V-1710 suffered from spark plug fouling, oil leaks, engine backfiring at high and low power settings, auxiliary super-charger failure, and engine power surge. Fouling of the spark plugs caused by oil accumulation was the most serious problem requiring new spark plugs after nearly every single flight.

Because the new engine was not as reliable as the Merlin (it was nicknamed ‘The Allison time-bomb’), problems persisted with the engines that required extensive testing through June 1948 using the first four -82E Twin Mustangs. North American had to accept the first 200 Allison engines, which could only operate at lower power settings, to avoid further F-82 production delays. Meanwhile, as the aircraft company waited for acceptable engines, the cost to North American continued to climb as it had to store uncompleted Twin Mustang airframes in a warehouse owned by the Consolidated-Vultee Aircraft Corporation (Convair) at Downey, California. Assembly lines were set up at Downey to install engines as they arrived and deliver the completed F-82Es rather than truck them back to North American’s facility at Inglewood. NAA engineers were able to fix some of the problems by using Merlin components but the engine, along with a shortage of spare parts, continued to be a problem for the F-82 throughout the aircraft’s operational life. The F-82Es were externally indistinguishable from the F-82Bs except for a reconfigured nose for the Allison engine with twelve exhaust stacks on each side of the cowling instead of the six that characterized the Packard Merlin.

The P-82E became the F-82E, after the newly established U.S. Air Force changed the pursuit ‘P’ indicator to ‘F’ for fighter in 1948. The Air Force accepted 100 F-82Es with serial numbers 46-255 to 46-354, the serial numbers being reduced from 7 digits for the -B series to 5 digits for the E-H series. Actual tail numbering, except for the -B model, consisted of the last number of the relevant fiscal year followed by the three-digit production serial number. Most went to the 27th Fighter Escort Group (FEG) which was comprised of the 522nd, 523rd, and 524th Fighter Interceptor Squadrons (FIS) and were assigned to the newly established Strategic Air Command (SAC) as long-range escorts for B-29, B-50, and B-36 bombers. The F-82E often flew long-range demonstration flights as a propaganda weapon against the Soviets to show the Air Force’s ability to protect its strategic bomber force. By the end of fiscal year 1948, North American had delivered seventy-two E-Model Twin Mustangs with a further twenty-four in fiscal year 1949 at a cost of $215,154 per unit (this was the same cost as applied to the F through H series). The 27th FEG conducted over-water Very Long Range (VLR) training missions beginning in January 1949 which encompassed a five-leg flight starting from Kearney Air Force Base (AFB), Nebraska, to MacDill AFB, Florida, then to Ramey AFB, Puerto Rico, to Howard AFB Panama, then to Jamaica, and then back to Kearney – a trip that took a few days to complete. One VLR mission starting from Bergstrom AFB in Austin, Texas, to Ramey AFB – a distance of some 2,300 miles – was accomplished without refuelling.

The Air Force regarded the F-82E as a short-term interim fighter, and with the promise of jets with longer range plus the arrival of mid-air refuelling with Boeing KC-29 and KC-97 aerial tankers, the Air Force had begun phasing out the F-82E by March 1950, less than a year after the final unit rolled off the assembly line. The 27th FEG started transitioning to the F-84E Thunderjet in the spring of 1950 and by September 1950, the Group’s last F-82Es were flown to Warner-Robbins AFB, Georgia. The Air Force made the decision to scrap all of the Twin Mustang escorts, retaining the engines and other usable parts for the remaining F-82F/G/H night and all-weather fighters stationed in Alaska and the Korean War zone.

Night and All-Weather Fighter

The Air Force’s first aircraft specifically designed as a night fighter was the twin-engine P-61 Black Widow equipped with the SCR-720 airborne radar. Two prototypes were ordered in January 1941 but, due to technical issues, a prototype did not take to the air until May 1942. Labour and material shortages delayed delivery of the first production P-61A until October 1943 followed by the P-61B in July 1944 and a C-variant in July 1945. The twin-boom Black Widow, armed with 20mm cannons and .50-caliber machine guns, proved far superior to the P-70 – a stop-gap night-fighter adaptation of the Douglas A-20 Havoc/Boston light bomber. Powered by two 2,000-hp Pratt & Whitney engines with two-speed General Electric superchargers, the P-61 had a top speed of 367mph with a rate of climb of 1,775 feet-per-minute. Unfortunately it proved to be a poor interceptor against Japanese bombers above 20,000 feet and the Black Widow’s radar operated satisfactory only eighty-one percent of the time, making that system responsible for more abortive missions than any other malfunction. The SCR-720 had a forward search azimuth of 180-degrees with a maximum search range of five to seven miles. However, the Black Widow was the best the Air Force could hope for during that period and it would rely on the P-61 after the war until 1948 when the F-82F and G Twin Mustangs, specially equipped for night fighting duties, became operational.

In November 1945, the Air Force requested an evaluation of the P-82B to see whether it could be adapted to replace the P-61 night fighter. Consequently, North American pulled the tenth and eleventh of the twenty production P-82Bs for conversion into night fighters as the P-82C (serial number 44-65169) and P-82D (serial number 44-65170) in late 1946. The P-82C’s maiden flight occurred on 27 March 1947 and the P-82D followed two days later. Both experimental night fighters featured a large radar pod, nicknamed the ‘pickle’ or ‘dong,’ under the centre wing section with the C-model housing the SCR-720 radar while the P-82D used the AN/APS-4 radar. The large nacelle, adopted for the production models F-82F, G, and H, and somewhat resembling a drop tank, protruded forward past the propellers to eliminate interference. A radar operator’s position, with related equipment, replaced the co-pilot’s instrumentation and controls in the right-hand cockpit.

One hundred examples of the D variant were produced as the P-82F (model NA-149 with serial numbers 46-405 to 46-504) equipped with the AN/APG-28 – an improved version of the APS-4 radar – with an additional forty-five of the C variant as the P-82G (model NA-150 with serial numbers 46-355 to 46-383 and 46-389 to 46-404 equipped with the SCR 720). The additional weight of the radar pod created very few performance problems with the F-82F having a top speed of 460mph. The G’s SCR-720 radar weighed slightly less than the APG-28 and thus the aircraft’s performance was slightly better. Before NAA delivered either the F or the G, the Air Force requested an additional requirement for modifying a small number of the night variants into all-weather fighters for service in Alaska; nine F-82Fs (serial numbers 46-496 through 46-504) and five additional F-82Gs (serial numbers 46-384 through 46-388). The F-82H was the last Twin Mustang variant produced and was specially equipped with thermal anti-icing gear and de-icer boots on the propeller blades. The thermal de-icing equipment sent hot air from behind the after-cooler radiator and blew it across the wing leading edges and tail surfaces. Other modifications included an improved cockpit heating system, updated radio equipment, plus the SCR-720 radar with which the F-82G was already equipped.

The F, G, and H Twin Mustang was not a pilot’s ideal night fighter due to the cockpit’s limited field of view, and poor landing characteristics especially at night. Moreover, during nocturnal operations, the pilot and radar operator found it difficult to maintain night vision due to engine exhaust flame, instrument glare and the bright flashes from the aircraft’s machine guns. The Air Force accepted the last F-82G and six F-82H Twin Mustangs in March 1949.

By mid-1950, the Twin Mustang had become a second-line aircraft as squadrons began replacing them with the jet-powered F-89 and F-94. From an operational standpoint, some pilots felt a psychological discomfort of impending doom of a midair collision when they caught sight of the co-pilot/radar operator’s fuselage out of the corner of their eyes. Another problem was with the J-8 Altitude Gyro used during instrument flying. Pilots either loved it or hated it because it read exactly opposite to the presentation of conventional gyroscopic instruments. When the miniature aircraft on the gyro appeared ‘below’ the reference line, instead of descending the F-82 was actually climbing and so, during an instrument landing approach, the pilot had to remain cognizant of what the aircraft was actually doing.

The F-82F first flew on 11 March 1948 and entered service in September with the Air Defense Command to replace the P-61 Black Widow, while the F-82G had become operational by the end of 1948 with the Caribbean Air Command: the Fifth, and Twentieth Air Force for the Far East Air Forces (FEAF). The Air Force established two all-weather fighter groups – the 52nd Fighter (All-Weather) Group (F(AW)G) and 325th F(AW)G – with the first F-82Fs going to the 52nd F(AW)G. These F-82 night fighter air groups provided air defence of the CONUS (Continental United States) from early 1948 to mid-1952 when conversion to the Lockheed F-94A/B was completed. The first F-82H flew on 15 February 1949 and all fourteen went to the 449th Fighter (All-Weather) Squadron (F(AW)S) based at Ladd AFB, with detachments operating from Galena, Davis, and Mark Fields, Alaska. The last F-82H remained on the USAF inventory until June 1953. The 449th flew periodic armed-reconnaissance missions over the coastline of western Russia (Chukchi Peninsula), between May 1949 and July 1950, along with challenging Soviet reconnaissance aircraft that neared Alaskan airspace. An unusual series of missions flown by the 449th during May 1949 was bombing ice jams in Alaskan rivers to prevent flooding.

Problems with the lacklustre performance of the Allison V-1710 engine caused nearly a two-year delay in the production and delivery of the F-82E, and by that time the Air Force had reduced the procurement order to 250 E through H variants. The F-82 was the last piston-engined fighter accepted by the Air Force in large numbers; it was an interim fighter, a stop-gap measure needed to fill a void until the arrival of modern jet fighters with greater range and night fighting capabilities. The Twin Mustang would have faded into oblivion except for the record-breaking flight of the F-82B ‘Betty Jo,’ delays in the production of the Northrop F-89 and Lockheed F-94 all-weather jets, and the unforeseen Korean War. F-82-equipped USAF squadrons saw intense service in the Korean War flying escort, weather reconnaissance, night combat air patrol (NCAP), and interdiction missions between June 1950 and February 1952 before being phased out and replaced by the F-94B. The principal variant of the Twin Mustang to operate in Korea was the F-82G night fighter which, in the new age of jet interceptors, scored the recently established Air Force’s first aerial kills only two days after the war began. Ultimately, the lack of spare parts, maintenance issues, and the arrival of jet all-weather fighters ended the F-82’s combat duty over Korea.

Twins over Korea

KATANGESE AIR FORCE

Force Aérienne Katangaise

The second phase the fight for Katanga commenced with Security Council authorization to take “all appropriate measures” to prevent the occurrence of civil war in the Congo, including “the use of force, if necessary, in the last resort”.  This resolution was used to justify UN military operations to end the Katangan secession. Ironically, Prime Minister Lumumba’s death triggered the fulfillment of his demands that the United Nations forcefully support his country’s campaign against the secession. Also looming large was the threat of intervention by the Soviet Union, which was emboldened and angered after Lumumba’s murder, and Moscow’s offer to provide the Congolese government with personnel and materiel to suppress the secession. These developments combined to mobilize Western powers to request the United Nations to fulfill that role.

Katanga’s leader, Moise Tshombé, professed anti-Communism and was backed by powerful Belgian and other Western interests, especially the company Union Miniere du Haute Katanga. Also Tshombé controlled Katanga’s gendarmerie and a large cadre of mercenaries. The resolve of his secessionists hardened after some 1,500 of the central government’s troops reached north Katanga in January 1961. Until that initiation of hostilities, the neutral zone negotiated by the United Nations with Tshombé on 17 October 1960 had held up but “it all came apart as pro-Lumumba troops captured Manono” in north Katanga. After Manono, the situation deteriorated rapidly and negotiations broke down.

On 28 August 1961, the United Nations launched Operation Rumpunch to arrest and deport mercenaries in Katanga. Then, in September, the Indian-led UN forces in Katanga launched Operation Morthor (“morthor” is the Hindi word for “smash”), to further round up foreign mercenaries and political advisers and to arrest Katangese officials. The “arrest” operation, which violated Hammarskjöld’s explicit directions to ONUC, quickly escalated into open warfare.

Almost immediately, air power in Katanga was brought in as a game-changer – but not by the United Nations. At this early stage of the conflict, the Aviation Katangaise (Avikat), also known as Force Aérienne Katangaise (FAK), held air superiority, though it consisted of only three Fouga Magister jet trainers. Remarkably, these aircraft were brought to Katanga in February aboard a Boeing Stratocruiser by the Seven Seas Charter Company, later identified as a US Central Intelligence Agency (CIA) contractor and possibly a front company. After UN officials observed the unloading of the aircraft, the mission grounded the company’s entire fleet of planes, which the United Nations had earlier contracted to carry food. President John F. Kennedy decried the jet delivery and alleged in correspondence with President Kwame Nkrumah of Ghana that the transaction had taken place before the US government could stop it.

In any case, the KAF fleet was quickly reduced in effectiveness: one Fouga Magister was lost when its pilot tried to fly under (rather than over) a power line; and UN forces captured another when they seized the airfield at Elisabethville, the Katangan capital, on 28 August 1961. This left the FAK with only one plane, but this single aircraft attained world renown during the hostilities of September by paralyzing UN supply efforts, which were mostly conducted by air transport aircraft. The single jet, flown by a Belgian mercenary from the Kolwezi airfield, also strafed UN positions, including the UN Headquarters in Katanga, and helped isolate a company of Irish troops who were forced to surrender to Katangan forces. Furthermore, the Fouga jet destroyed several UN-chartered aircraft at Katangan airports, including Elisabethville, the Katangan capital. A US State Department official, Wayne Fredericks, commented: “I have always believed in air power, but I never thought I’d see the day when one plane would stop the United States and the whole United Nations”.

Deadlock prevailed throughout 1961, and the indecisive outcome of the UN’s August and September 1961 ground initiatives in Katanga (Operations Rumpunch and Morthor) spurred Hammarskjöld to try to negotiate a ceasefire with Tshombé. As the Secretary-General was flying to meet with the Katangan leader at the border town of Ndola, Northern Rhodesia, his plane crashed on the night of 17 September 1961, killing all onboard. Complicating the rescue effort, the plane had largely maintained radio silence and flew a circuitous route mostly at night in order to reduce the possibility of an attack by the “Lone Ranger” Fouga Magister. The Katangan jet had shot bullets into UN aircraft only days before. And Hammarskjöld’s aircraft had been damaged by ground fire but was quickly repaired before take-off. The cause of the UN plane crash was never determined with certainty, though a UN commission concluded that it was probably due to pilot error during the approach to Ndola.

With Hammarskjöld’s death, the battle for Katanga entered a new phase. The new Secretary-General, U Thant, did not share Hammarskjöld’s belief that the United Nations should not interfere in Congolese internal politics. Moreover, the general escalation of events spurred the Security Council to pass Resolution 169 on 24 November 1961, strongly deprecating the secessionist activities of Katanga and authorizing ONUC to use “the requisite measure of force” to remove foreign mercenaries and “to take all necessary measures to prevent the entry or return of such elements”.

Meanwhile, the United States, fearful of communist encroachment on the continent, was resolved in the Congo to keep the Soviet Union out, the United Nations in, and Belgian interference down in the former colony. The Americans also wanted to stop the country from falling apart, viewing secession of mineral- rich Katanga as a threat to the economic vitality of the new country. In the background, decolonization was one of the great movements of the era and the United States was keen to show newly independent countries that it supported integral, viable new states. The disintegration of the Congo was a major concern, as was Soviet intervention. Therefore, international (United Nations) intervention in Katanga was deemed necessary, even if it meant intervention into the internal affairs of a new state (although at the request of that state). Thus the United States, which had previously refused Hammarskjöld’s requests to ferry troops within the Congo and had only brought troops to the Congo from abroad, now provided four transport planes without conditions. President Kennedy even offered to provide eight fighter jets if no other member nations were willing to do so. The US Joint Chiefs of Staff suggested these jets could “seek out and destroy, either on the ground or in the air, the Fouga Magister jets”. However, Thant sought to avoid direct superpower involvement in combat. Having promises of fighter jets from other nations, the American offer was turned down. Instead, the United States provided over 20 large transport planes to ferry reinforcements and anti-aircraft guns into Katanga.

Before his death, Hammarskjöld had managed to obtain from several UN member states promises of combat aircraft, which were desperately needed for the field mission. In October 1961, Sweden provided five J-29 Tunnan (“The Flying Barrel”) fighter jets. Ethiopia sent four F-86 Sabre jets, and India backed the mission with four Indian B(I)58 Canberra light bombers. These aircraft became what mission personnel dubbed the first “UN Air Force”.

The UN’s aerial assets soon joined the fray. In December, they attacked a military train east of Kolwezi and Katangan airfields at Jadotville and Kolwezi. The United Nations created havoc among Katangan forces in much the same way that the armed Fouga Magister had earlier done to the UN mission. Charanjit Singh, one of the Indian UN pilots, described his attack on a Katangan camp in Elisabethville on 8 December 1961 in a cavalier fashion:

…attacked an army police camp 2 km NE of old runway. Some vehicles were parked outside what looked like a headquarters building. I fired a full burst on those and saw them going up in smoke and flames. As I pulled out of the dive, I saw hundreds of men running out in utter panic. As I flashed past them, I gathered an image of men running in all directions, some in undies, others in halfpants, some in uniforms. I saw some enter a billet. Attacked the HQ building and vehicles again. Saw a vehicle turn over. At the end of four attacks, the whole thing looked like the Tilpat [air-to-ground practice firing range near Delhi] show.

The net result of the UN buildup and its December 1961 offensive was that Katanga’s “air superiority” was temporarily ended. The fate of the infamous jet trainer became an object of much speculation. The UN pilots claimed to have destroyed it on the ground in an air attack on the Kolwezi airfield, but they actually hit a carefully crafted dummy. It was then believed that the Katangan Fouga had crashed while its South African mercenary pilot had parachuted to safety, but this too was found to be false.

But even the UN’s new aerial hardware was deemed insufficient for the robust mandate. The UN field mission pressed headquarters to obtain bombs for the Indian Canberra jets. “We need those bombs”, Secretary-General U Thant would insist to the British government. After weeks of stalling, the government of Prime Minister Harold Macmillan finally agreed on 7 December 1961 to supply 24 1,000-lb bombs. But the offer came with the condition that they could only be used “against aircraft on the ground or [against] airstrips and airfields”. Even still, Macmillan worried that his government might fall over its handling of the Congo crisis, given the fierce support in some Conservative quarters for the anti-communist Katanga regime. In the end, the United States transported bombs directly from India.

Realizing what an enormous role a single Fouga jet had played in the success of Katangan operations in September 1961, Tshombé began purchasing new aircraft and hiring foreign mercenary pilots of various nationalities to fly them. Indeed, throughout 1962, UN Air Command desperately tried to monitor the Katangan aerial buildup through both aerial surveillance of Katangan airfields and intelligence gathered by ONUC’s Military Information Branch (MIB). In an attempt to procure immediate intelligence on Katanga’s air capability, a desperate ONUC on 9 March 1962 noted that aircrews from UN military air units and from its charter companies were making “important observations during their flights and stops at various airfields in the Congo”. The mission began mandatory debriefings of aircrews after landing. The mission also sought to create an air reconnaissance unit capable of meeting both long-term reconnaissance and immediate operational requirements. One memo dated 10 March 1962 stated “it becomes imperative that the air recce unit should be allotted with both C-47s and jet recce aircraft such as S-29s or photo-recce Canberras”. ONUC’s Chief of Military Intelligence requested three C-47 aircraft “to check the Katangan air movements through systematic visual reconnaissance of their airfields”. On 6 June 1962 the ONUC Force Commander cabled Ralph Bunche, the Under-Secretary-General at UN Headquarters responsible for peacekeeping operations that:

ONUC suffers from a grave lack of reconnaissance facilities. As a result even the photographs available may contain much more information which it is NOT possible to get because of inadequate facilities in equipment and personnel for interpretation.

In 1962, Sweden provided two J-29Cs, the photo-reconnaissance versions of the J-29 jet aircraft that proved of great worth. The mission consequently added personnel designated as air intelligence officers. At the same time, the threat of re-emerging Katangan aerial capabilities was real. ONUC concluded in May 1962:

[M]ercenaries, fighting for money and receiving higher salaries as FAK pilots than even Generals receive in UN service, are ruthless, cunning, non- conventional, clever and inventive. They have war experience, and they know where, when and how to hit. there is no alternative but to consider FAK as a dangerous enemy in the air.

ONUC had success uncovering the extent of Tshombé’s aircraft acquisitions through intelligence gathered by the MIB. Defectors and informants interviewed by the MIB revealed a wealth of information about Katangan aircraft both in Katanga and neighbouring countries. Lieutenant-General Kebbede Guebre (Ethiopia), the ONUC Force Commander, cabled Bunche at UN Headquarters on 24 August 1962, referencing a report that Katanga-owned jet fighters were hidden in Angola and/or Rhodesia. Kebbede requested Bunche to “check with Australia [about] the possibility of Australian trained jet [mercenary] pilots being available to Tshombe”. In another cable to Bunche dated 27 September 1962, he stated that:

a fully reliable source reported…that twelve Harvard aircraft have recently left South Africa, bound for Katanga…equipped with guns and French rockets…[and that] an unspecified number of P-51 Mustangs may have left South Africa recently…intended for Katanga.

Clearly, the United Nations perceived itself in an aerial arms race with the Katanga government. It was trying to persuade its member states to provide aircraft while the Katanga government was purchasing them clandestinely wherever possible.

General Kebbede again cabled Under-Secretary-General Bunche on 1 October 1962, comparing the air capabilities of the two protagonists. Katanga (FAK) was now estimated to have twelve Harvard single-propeller aircraft, eight or nine Fouga Magister trainer jets, four Vampire jet fighters and a large number of P-51 Mustang single-propeller fighters (being delivered). The UN mission possessed six Canberra jet fighter-bombers, four Saab J-29B fighter-bombers, and four Sabre F-86 jet fighters. At the time, the UN Air Division possessed no bombs – a serious deficiency, as it was considered the weapon needed to neutralize air bases and enemy forces on the ground. Great Britain was still dithering on UN pleas for bombs for its Canberra aircraft. ONUC concluded once again that air resources were inadequate to meet the FAK threat. Due to serviceability problems, only about 60 to 70 percent of ONUC aircraft would be available for operations, which would make it impossible to keep even a section of fighters on readiness and thus impossible to simultaneously defend even one airfield, conduct offensive sweeps, and escort transport aircraft. Moreover, since ONUC was entirely dependent on supplies delivered by air, of which 95 percent were lifted by civil chartered companies, a Katangan air threat would ground essential supply planes in the absence of UN fighter escorts.

In the same October 1962 report to Bunche, General Kebbede recommended immediate steps be taken to reinforce the UN Air Division. The first recommendation was for the acquisition of two S-29E photo-reconnaissance aircraft and a complete photo-interpretation unit to monitor developments and activities at Katangan air bases. The second was to increase two UN fighter squadrons to eight fighters each (for a total of 16 fighters). The third was the addition of two additional Canberra aircraft. Also recommended was the acquisition of anti-aircraft defences for UN air bases and radar for Elisabethville, as well as heavy-calibre and napalm bombs for the Canberra bombers and additional communications equipment. These recommendations were considered to be the bare minimum necessary for the operation.

Things became even worse when Ethiopia abruptly withdrew its Sabre aircraft after losing one in an accident. Furthermore, India experienced an urgent need to repatriate its Canberra bombers to fight in a border war with China. On the positive side, Sweden promised more Saab jets and Norway offered an anti-aircraft battery. New air surveillance radars were deployed at Kamina and Elisabethville.

A few days following Kebbede’s UN requests, a cable from Robert Gardiner, the UN representative in the Congo, to Bunche reported that a South African aircraft company had offered Katanga 40 Harvard aircraft, each equipped with 40 rockets, for US$27,000 each. The planes were thought to be transported into Katanga through Angola, a Portuguese colony. Moreover, intelligence reported that the same company had previously sold 17 aircraft to Katanga. On 17 October, Gardiner cabled Bunche that aerial photography had confirmed the presence of six Harvard aircraft at Katanga’s Kolwezi-Kengere airfield.

The UN mission was clamouring to increase its air force, particularly its fighter strength, despite UN Headquarters’ concerns about costs, having overcome earlier inhibitions on combat. Intelligence evidence mounted regarding the acquisition of new aircraft by Katanga. The growing strength of Katanga’s air force relative to ONUC’s had immediate military and strategic consequences. The ANC were frequently bombed and harassed by Katangan aircraft. The UN Commander’s assessment was that:

Due to ONUC’s limited strength of four fighters, we have to confine our action to Recce the area in question as often as possible during daylight and attack any Katangese aircraft flying in that area. We are not attempting to destroy any aircraft found in the airfield in the vicinity of that area because if we do locate one or two aircraft and destroy them, we feel that FAK will react against [our] Kamina Base and also disperse their aircraft from Kolwezi to other airfields, thereby making our task of locating and destroying these aircraft on the ground very difficult. Please advise dates by which additional four Swedish fighters, as promised, will be available and if any additional aircraft expected from other nations.

The UN Commander’s strategy was to wait until the new aircraft gave ONUC a fighter force capable of destroying the bulk of Katanga’s air force on the ground in one overwhelming surprise attack. Another cable from Kebbede to Bunche on the same day (24 November 1962) stated that:

on request from the ANC, air recce missions over Kongolo area are being provided by UN fighters. Missions will be confined to recce and destroying any Katangese aircraft if found flying over that area. Instructions have been issued NO repeat NO ground targets to be attacked.

The ONUC Commander did not want to give the Katangese any reason to disperse or hide their aircraft but rather wanted them to feel that they were safe and secure when on the ground at their major airfields.

 

Douglas C-47 Skytrain (1935)

C-47A serial FAC-681 of the Colombian Air Force is seen as it appeared in the 1980s. A former RAF machine, it was later converted as an AC-47 gunship. In 2014 six AC-47T Fantasma gunships remained in Colombian Air Force service.

Wearing D-Day recognition stripes, C-47A Buzz Buggy of the 81st Troop Carrier Squadron, 436th Troop Carrier Group was based at Membury, England, from March 1944 to February 1945.

 The word ubiquitous has been associated with a number of aircraft in wide-scale use during World War II, but the most ubiquitous of all has to be the Douglas DC-3/C-47 Skytrain. This superlative wartime transport aircraft, produced in greater numbers than any other in this category, with almost 11,000 manufactured by the time production ended in 1945, but whatever name you choose, it can be spelled ‘dependable’, for this was the secret of the type’s greatness and enduring service life.

Its design originated from the DC-2/DST/DC-3 family of commercial transports that followed in the wake of the DC-1 prototype which flew for the first time on 1 July 1933. The US Army, had gained early experience of the basic aircraft after the acquisition of production DC-2s in 1936, followed by more specialised conversions for use as cargo and personnel transports. In August 1936 the improved DC-3 began to enter service with US domestic airlines, its larger capacity and enhanced performance making it an even more attractive proposition to the US Army, which very soon advised Douglas of the changes in configuration which were considered desirable to make it suited for operation in a variety of military roles. These included the provision of more powerful engines, a strengthened rear fuselage to cater for the inclusion of large cargo doors, and reinforcement of the cabin floor to make it suitable for heavy cargo loads. Much of the bagic design work had already been completed by Douglas, for a C-41 cargo prototype had been developed by the installation of 1,200 hp (895 kW) Pratt & Whitney Twin Wasp engines in a C-39 (DC-2) fuselage. Thus, when in 1940 the US Army began to issue contracts for the supply of these new transport aircraft under the designation C-47, the company was well prepared to meet the requirements and to get production under wily. The only serious problem was lack of productive capacity at Santa Monica, where European demands for the DB-7 light bomber had already filled the factory floor, resulting in the C-47 being built in a new plant at Long Beach, California.

Initial production version was the C-47, of which 953 were built at Long Beach, and since the basic structural design remained virtually unchanged throughout the entire production run, this version will serve for a description of the structure and powerplant. Of all-metal light alloy construction, the cantilever monoplane wing was set low on the fuselage, and provided with hydraulically operated split type trailing-edge flaps. The ailerons comprised light alloy frames with fabric covering. The fuselage was almost circular in cross-section. The tail unit was conventional but, like the ailerons, the rudder and elevators were fabric- covered. Pneumatic de-icing boots were provided on the leading edges of wings, fin and tailplane. Landing gear comprised a semi-retractable main units which were raised forward and upward to be housed in the lower half of the engine nacelles, with almost half of the main wheels exposed. The powerplant of the C-47 comprised two Pratt & Whitney R-1830-92 Twin Wasp engines, supercharged to provide an output of  l,050 hp (783 kW) at 7,500 ft (2285 m), and each driving a three-blade constant-speed metal propeller. The crew consisted of a pilot and co-pilot/navigator situated in a forward compartment with the third member, the radio operator, in a separate compartment.

The all-important cabin could be equipped for a variety of roles. For the basic cargo configuration, with a maximum load of 6,000 Ibs (2722 kg), pulley blocks were provided for cargo handling and tie-down rings to secure it in flight. Alternative layouts could provide for the transport of 28 fully-armed paratroops, accommodated in folding bucket type seats along the sides of the cabin or for 18 stretchers and a medical team of three. Racks and release mechanism for up to six parachute pack containers could be mounted beneath the fuselage, and there were also under fuselage mountings for the transport of two three-blade propellers.

The first C-47s began to equip the USAAF in 1941, but initially these were received only slowly and in small numbers, as a result of the establishment of the new production line at Long Beach which, like any other, needed time to settle down to routine manufacture. With US involvement in World War II in December 1941, attempts were made to boost production, but in order to increase the number of aircraft in service as quickly as possible DC-3s already operating with US airlines, or well advanced in construction for delivery to operators, were impressed for service with the USAAF.

As Douglas began to accumulate contracts calling for production of C-47s in thousands, it was soon obvious that the production line at Long Beach would be quite incapable of meeting requirements on such a large scale, so a second production line was established at Tulsa, Oklahoma. The first model to be built at Tulsa was the second production version, the C-47A, which differed from the C-47 primarily by the provision of a 24 volt, in place of a 12 volt electrical system. Tulsa was to build 2,099 and Long Beach 2,832 of the type, 962 of them being delivered to the RAF which designated them Dakota IIIs. Last of the major production variants was the C-47B, which was provided with R-1830-90 or -90B engines that had two-stage superchargers to offer high altitude military ratings of 1,050 hp (783 kW) at 13,100 ft (3990 m) or 900 hp (671 kW) at 17,400 ft (5305 m) respectively. These were required for operation in the China-Burma-India (CBI) theatre, in particular for the ‘Hump’ operations over the 16,500 ft (5030-m) high Himalayan peaks, carrying desperately needed supplies from bases in India to China. Long Beach built only 300 of the model, but Tulsa provided 2,808 C-47Bs plus 133 TC-47Bs which were equipped for service as navigational trainers. The UK was to receive a total of 896 C-47Bs, which in RAF service were designated Dakota IV.

The availability of such large numbers, in both US and British service, meant that it was possible to begin to utilise the C-47s on a far more extensive basis. The formation in mid-1942 of the USAAF’s Air Transport Command saw the C-47s’ wide-scale deployment as cargo transports carrying an almost unbelievable variety of supplies into airfields and airstrips which would have been complimented by the description ‘primitive’. Not only were the C-47s carrying in men and materials, but were soon involved in a two-way traffic, serving in a casualty-evacuation role as they returned to their bases. These were the three primary missions for which these aircraft had been intended when first procured (cargo, casualty evacuation and personnel transports). However, their employment by the USAAF’s Troop Carrier Command from mid-1942, and the RAF’s Transport Command, was to provide two new roles, arguably the most important of their deployment in World War II, as carriers of airborne troops. The first major usage in this capacity came with the invasion of Sicily in July 1943, when C-47s dropped something approaching 4,000 paratroops. RAF Dakotas of Nos. 31 and 194 Squadrons were highly active in the support of Brigadier Orde Wingate’s Chindits, who infiltrated the Japanese lines in Burma in an effort to halt their advance during the winter of 1942-3, their only means of supply being from the air. Ironically, Wingate (by then a major general) died on 24 March 1944 when a Dakota in which he was a passenger crashed into cloud camouflaged jungle-clad mountains.

The other important role originated with the C-53 Skytrooper version, built in comparatively small numbers as the C-53B/-53C/-53D. Seven C-53s supplied to the RAF were redesignated Dakota II. These were more nearly akin to the original DC-3 civil transport, without a reinforced floor or double door for cargo, and the majority had fixed metal seats to accommodate 28 fully-equipped paratroops. More importantly, they were provided with a towing cleat so that they could serve as a glider tug, a feature soon to become standard with all C-47s, and it is in this capacity that they served conspicuously in both USAAF and RAF service during such operations as the first airborne invasion of Burma on 5 March 1944 and the D-Day invasion of Normandy some three months later. In this latter operation more than 1,000 Allied C-47s were involved, carrying paratroops and towing gliders laden with paratroops and supplies. In the initial stage of this invasion 17,262 US paratroops of the 82nd and 101st Airborne Divisions and 7,162 men of the British 6th Airborne Division were carried across the English Channel in the greatest airlift of assault forces up to that time. Not all, of course, were carried in or towed by C-47s, but these aircraft played a most significant role in helping to secure this first vital foothold on European soil. In less than 60 hours C-47s alone airlifted more than 60,000 paratroops and their equipment to Normandy.

Other C-47 variants of World War II included the XC-47C, prototype (serial 42-5671) of a projected version to be equipped as a floatplane or, as was the prototype, with convertible amphibious floats of all-metal construction, these single-step twin Edo Model 78 floats each had two retractable wheels, and housed a 300 US gallon (1136 litre) fuel tank. While this version was not built as such by Douglas, a small number of similar conversions were made by USAAF maintenance units for service in the Pacific. Douglas were also contracted to build 131 staff transports under the designation C-117, these having the airline-standard cabin equipment of a commercial DC-3, plus the improvements which were current on the C-47. Their numbers, however, had reached only 17 (one C-ll7B built at Long Beach and 16 C-117As from Tulsa) when VJ-Day brought contract cancellation. The requirement for a large-capacity high-speed transport glider, to be towed by a C-54, resulted in experimental conversion of a C-47 to serve in this role under the designation XCG-17. Early tests had been conducted with a C-47 making unpowered approaches and landings to confirm the feasibility of the project, followed by a series of flights in which one C-47 was towed by another. For take-off the towed aircraft used some power, but shut down its engines when airborne. Conversion of a C-47 to XCG-17 configuration began after completion of these tests, with engines, propellers and all unnecessary equipment removed, and the forward end of the engine nacelles faired over. This was undoubtedly aerodynamically inefficient, and contributed to a reduction in performance of the XCG-17, but it was a USAAF requirement that any production aircraft should be capable of easy reconversion to powered C-47s. Despite any inefficiency the the embryo cargo glider had a successful test programme, demonstrating a towed speed of 290 mph (467 km/h), stalling speed of only 35 mph (56 km/h) and a glide ratio of 14:1. Payload was 14,000 lbs (6350 kg), permitting the transport of 40 armed paratroopers. No production aircraft were built, however, as a result of changing requirements.

In addition to the C-47s which served with the USAAF and the RAF, approximately 600 were used by the US Navy. These comprised the R4D-1(C-47), R4D-3 (C-53), R4D-4 (C-53C), R4D-5 (C-47A), R4D-6 (C-47B) and R4D-7 (TC-47B). US Navy and US Marine Corps requirements resulted in several conversions with designations which include the R4D-5E/-6E with special-purpose electronic equipment; the winterised and usually ski-equipped R4D-5L/-6L; the R4D-4Q/-SQ/-6Q for radar countermeasures; cargo versions re-equipped for passenger carrying as the R4D-5R/-6R; the air-sea warfare training R4D-5S/-6S; the navigational training R4D-5T/-6T; and the VIP-carrying R4D-5Z/-6Z. R4Ds were used initially by the Naval Air Transport Service that was established within five days of the attack on Pearl Harbour, equipping its VR-1, VR-2 and VR-3 squadrons, and soon after this by the South Pacific Combat Air Transport Service which provided essential supplies to US Marine Corps units as they forced the Japanese to vacate islands which stretched across the seas that led like stepping stones to that nation’s home islands.

In addition to US production, the type was built in the USSR as the Lisunov Li-2 (2,000 examples or more) and in Japan as the Showa (Nakajima) L2D (485 examples).

C-47s had been involved from the beginning to the end of World War II, and that is but a small portion of their history in both military and civil service. Since VJ-Day military C-47s have supported the Berlin Airlift, Korean and Vietnam wars, to mention only major operations. It would not be too far from the truth to suggest that in the 42 years to 1982 there have not been many military actions or major civil disasters in which the enduring C-47 has not played some part.

Specifications (Douglas DC-3/C-47A Skytrain)

Type: Three Seat Military Transport, Paratroop Carrier & Glider Tug

Accommodation/Crew: Pilot, Co-pilot/Navigator (side-by-side with dual controls) and Radio Operator

Design: The Douglas Aircraft Company Incorporated based on the DC-2 design by Donald W. Douglas

Manufacturer: The Douglas Aircraft Company Incorporated with factories in Santa Monica (California), Long Beach (California), Tulsa (Oklahoma) and Oklahoma City (Oklahoma)

Powerplant: (DC-3) Two 1,000 hp (746 kW) Wright GR-1820-G102A Cyclone or 1,100 hp (820 kW) Wright GR-1820-G202A 9-cylinder or two 1,200 hp (895 kW) Pratt & Whitney R-1830-S1C3G Twin Wasp 14-cylinder radial engines. One oil tank of 29.25 US Gallons (110.5 litres) was located in each nacelle. (C-47 typical) Two Pratt & Whitney R-1830-92 Twin Wasp 14-cylinder two-row air-cooled geared and supercharged radial engines rated at 1,200 hp (895 kW) for take-off and 1,050 hp (793 kW) at 7,500 ft (2285 m) driving three-bladed Hamilton Standard constant speed propellers. One oil tank of 29 US Gallons (109.6 litres) was located in each nacelle.

Performance: Maximum speed 229 mph (369 km/h) at 7,500 ft (2285 m); cruising speed 185 mph (298 km/h) at 10,000 ft (3050 m); stalling speed 67 mph (107.8 km/h); service ceiling 23,200 ft (7070 m); climb to 10,000 ft (3050 m) in 9 minutes 36 seconds; initial rate of climb 1,130 ft (345 m) per minute.

Fuel: (DC-3 civil) Two main fuel tanks were located forward of the centre-section spar each with a capacity of 210 US Gallons (794 litres) and two auxiliary fuel tanks aft of the spar each with a capacity of 201 US Gallons (760 litres). (C-47 military) Two main fuel tanks were located forward of the centre-section spar each with a capacity of 202 US Gallons (763.7 litres) and two auxiliary fuel tanks aft of the spar each with a capacity of 200 US Gallons (756.2 litres). Each engine was served by a separate fuel system but cross-feed permits both engines to be supplied by either set of tanks in case of an emergency. Some military aircraft had provision for a single auxiliary fuel tank in the fuselage.

Range: 1,500 miles (2414 km) on normal fuel. Range of 2,125 miles (3420 km) with maximum fuel.

Weight: Empty 16,970 lbs (7698 kg) with a maximum take-off weight of 26,000 lbs (11793 kg); useful load 8,600 lbs (3904 kg); wing loading 25.3 lbs/sq ft (123.5 kg/sq m); power loading 12 lbs/hp (5.45 kg/hp).

Dimensions: Span 95 ft 0 in (28.96 m); length 64 ft 2 1/2 in (19.57 m); height 16 ft 11 in (5.16 m); wing area 987.0 sq ft (91.69 sq m).

Armament: (AC-47D) The 1965 designation for gunship conversions with three 7.62 mm (0.30 in) General Electric Miniguns firing through the fourth and fifth windows and from the open door on the port side of the fuselage. Some of the Soviet aircraft were armed as well. Apart from the above exceptions all other aircraft had no armament.

Equipment/Avionics: Full radio equipment includes radio compass, marker beacon receiver and receivers for localised and glide-path reception for the instrument-landing equipment. Glider-towing cleat in tail. De-icing equipment includes airscrew anti-icing system, rubber de-icer shoes on outer wings, tailplane and fin leading edges and alcohol-type windscreen de-icer. Oxygen equipment. Some aircraft were equipped with H2S radar for training purposes and others had “Rebecca” navigational radar for use as pathfinders.

Fuselage/Cargo Area: Main cargo hold equipped with snatch block, idler pulley and tie-down fittings for cargo handling. Large freight door on port side. Cargo load of 6,000 lbs (2725 kg) that may include three aero-engines on transport cradles, or two light trucks. Folding seats down sides of cabin for 28 fully-armed airborne or parachute troops. Alternatively fittings for eighteen stretchers together with provision for a medical crew of three. Racks and release mechanism for six parachute pack containers under fuselage. Also under the fuselage are fittings for carrying two three-bladed airscrews.

Wings/Fuselage/Tail Unit: The wings were of a low-wing cantilever monoplane design with a rectangular centre-section and tapering out sections with detachable wing-tips and Douglas cellular multi-web construction. The ailerons were fabric covered with controllable trim-tabs in the starboard aileron. Hydraulically operated all-metal split trailing-edge flaps. The fuselage was an almost circular-section structure built up of transverse frames of formed sheet longitudinal members of extruded bulb angles, with a covering of smooth sheet metal. The Tail Unit was of the cantilever monoplane type with the tail-plane and fin of multi-cellular construction. The rudder and elevators have aluminium-alloy frames and fabric covering and are aerodynamically and statically balanced. There are trim-tabs in all the control surfaces.

History: First flight (DST – Douglas Sleeper Transport) 17 December 1935.

Operators: United States (USN, USAAF, USMC), United Kingdom (RAF), Canada (RCAF), Australia (RAAF), Soviet Union, India, Romania, Germany, Japan.

The Eighth Air Force 1942-3

Certainly the most celebrated B-17, the Memphis Belle, B-17F-10-BO 41- 24485, fought through 25 grueling missions over Europe. Hollywood director William Wyler documented one of the plane’s last missions in a color film that, together with the crew’s subsequent cross-country war bond tour, made Memphis Belle a household name. Today, the fabled aircraft resides at the National Museum of the United States Air Force near Dayton, Ohio.

They say it gets darkest before it becomes light, and that’s a good way to describe World War II for the Allies in 1942. Pearl Harbor had been attacked on Dec. 7, 1941, drawing the United States into the conflict. Stunned by the attack, Americans began mobilizing for war. On Jan. 28, 1942, the Eighth Air Force was formed at Savannah, Georgia.

While mobilization was gaining momentum, the Axis were expanding their territory. In North Africa, the Germans and Italians forced the British out of Benghazi (January 21). On February 15, the Japanese captured Singapore, and two months afterward on April 9, the U.S. and Filipino armies on the Bataan Peninsula surrendered. Forces on Corregidor held out until May 6 when they, too, surrendered. It looked like the Axis were unstoppable. The outlook for the Allies was indeed dark.

But one victory led to another for the Allies, beginning with the May 4–8 Battle of the Coral Sea when the American aircraft carriers USS Yorktown (CV-5) and USS Lexington (CV-2) faced off in the first naval battle in which surface ships never fired at each other. All of the action took place between ship-launched American and Japanese aircraft. Although many consider the action a draw, the Battle of the Coral Sea put an end to Japanese plans for an invasion of Australia. The United States lost the carrier Lexington, the destroyer USS Sims (DD-409), and the oiler USS Neosho (AO-23), and the Japanese saw the light carrier Shoho, one transport, two destroyers, and a light cruiser sent to the bottom during the engagement. This battle was followed one month later on June 4 with the American victory over the Japanese during the Battle of Midway. The Japanese lost four aircraft carriers (Akagi , Hiryu, Kaga, and Soryu) and the cruiser Mikuma, while the United States lost only the USS Yorktown and the destroyer USS Hammann (DD-412).

On July 2, the first B-17 arrived in England, flown across the Atlantic Ocean under Operation Bolero. In this first stage of the American buildup of air groups, 119 B-17s (92nd, 97th, and 301st Bomb Groups), 164 P-38s (1st and 14th Fighter Groups), and 103 C-47s (60th and 64th Troop Carrier Groups) were flown across the Atlantic Ocean. Thousands more would follow. On August 17, 12 B-17s of the 97th Bomb Group, led by Gen. Ira C. Eaker in B-17E 41-9023 Yankee Doodle, attacked the railroad marshaling yards at Rouen-Sotteville, France. By October 9, the Eighth Air Force was able to muster more than 100 heavy bombers for a raid on the industrial areas of Lille, France. The first P-47 Thunderbolts arrived in England on Christmas Eve 1942, ready to escort bombers across the channel and into Nazi-occupied territory.

The first Eighth Air Force raid inside Germany took place on Jan. 27, 1943, when fifty-five B-17s attacked the naval base at Wilhelmshaven. A combination of sixty-four B-17s and twenty-seven B-24s were launched on the raid, but the B-24s were unable to find the target because of weather, and only fifty-five of the B-17s were able to drop in the target area, with two of the B-17s dropping on Emden. Two Liberators and one Flying Fortress were lost on the raid.

On May 14, 1943, the Allies had driven Axis forces out of North Africa with the surrender of the Afrika Korps in Tunisia the day before. Also on May 14, the Eighth Air Force sent 198 bombers to attack the port city of Kiel. Three days later, the crew of the Memphis Belle were credited as having finished their combat tour of twenty-five missions. Simultaneously, on the night of May 16–17, British Bomber Command Lancasters from 617 Squadron carried out Operation Chastise, breaching Germany’s Möhne and Eder dams and flooding parts of the heavily industrialized Ruhr Valley.

In June, the 100th, 381st, and 384th Bomb Groups, all equipped with B-17s, joined the Eighth Air Force, flying their first mission on June 22. While three B-17 groups stood up, three groups of B-24s (44th Bomb Group, 93rd Bomb Group, and 389th Bomb Group) were sent to North Africa for the August 1 attack on the oil fields at Ploesti, Romania. The three bomb groups would return to England and the Eighth Air Force on Sept. 8, 1943.

August 1943 saw the Luftwaffe take a heavy toll on Eighth Air Force aircraft. On August 17, 315 bombers flew across Germany to attack the ball bearing factories at Schweinfurt (230 B-17s from the 1st Combat Wing) and the Messerschmitt Bf 109 factory at Regensburg (4th Combat Wing). Losses amounted to 36 aircraft for the 1st Combat Wing and 24 for the 4th Combat Wing: a total of 60 bombers and more than 600 men on a single mission. The 1st and 4th Combat Wings also flew the Eighth Air Force’s first mission against V-weapon targets when 224 bombers were dispatched to hit Watten, France. More than 360 general-purpose 2,000-pound bombs were dropped on the site with a loss of 4 B-17s.

In September 1943, the first of many thousands of P-51 Mustangs arrived to escort Eighth Air Force bombers on missions. Later that month, the first blind bombing mission for the Eighth was flown on September 27, when 308 B-17s were dispatched to attack the port city of Emden. Two H2S radar-equipped pathfinder Flying Fortresses led the way, with 246 planes dropping their bombs on target.

The Eighth Air Force returned to attack the ball bearing factories at Schweinfurt on October 14, losing sixty bombers in the process. Known as the “Second Battle of Schweinfurt,” the raids on the area’s ball bearing factories reduced output by 66 percent of prewar production levels and forced the Germans to distribute production sites. The following day, the Eighth’s first P-38 fighter group, the 55th Fighter Group, achieved operational status.

Three major raids in November saw the Eighth Air Force attack Wilhelmshaven and the heavy-water production plants and airfields in Norway. The raid on Wilhelmshaven on November 3 marked the Eighth’s first raid of more than five hundred bombers dispatched to attack the U-boat facilities in this port town. It was also the first time the Eighth’s Pathfinder Force used H2X radar to bomb a target.

In the final month of 1943, the Eighth Air Force’s strength grew, culminating in the December 13 attack on the port cities of Bremen, Hamburg, and Kiel. And on Christmas Eve, 670 bombers were dispatched to attack 23 V-weapons sites along the English Channel.

By the end of 1943, enough men and aircraft had arrived at Eighth Air Force bases to demonstrate that the principles of sustained strategic bombardment could be used to cripple the warfight capabilities of an antagonist nation.

BOMBER ESCORTS: EXPERIMENTING WITH THE B-40 AND B-41

I n 1942 and 1943, as the Army Air Forces took the fight deeper and deeper into Axis territory, German Bf 109s and Fw 190s were extracting a heavy price in men and aircraft on every raid. The Army Air Forces needed a fighter that could escort bombers to and from the target.

At this point in the war, the only Army Air Force fighters escorting the bombers were P-38 Lightnings and P-47 Thunderbolts. Royal Air Force Supermarine Spitfires had been flying escort for the American daylight bombers while the American force was assembled, trained, and shipped to the United Kingdom; however, Spitfires had an extremely short range and were not suitable for escorting bombers to targets deep in Germany.

When the Thunderbolts joined the fray in May 1943, they were capable of escorting the bomber formations to most coastal targets in France, Belgium, the Netherlands, and back—about 175 miles from base to target and return. In July 1943, Thunderbolts received 75-gallon drop tanks, which extended their escort radius to 230 miles. It was not until February 1944, when two 150-gallon wing tanks were added, that the P-47’s escort range was extended to 475 miles, enabling them to escort bomber formations as deep as the synthetic oil factories at Magdeburg, Germany. When not having to shepherd the bombers, P-47s could fly greater distances on fighter sweeps and were able to destroy a large number of aircraft as well as targets on the ground. North American P-51 Mustangs began flying escort duties beginning in January 1944. In March 1944, P-51s were equipped with two 108-gallon wing tanks, enabling them to escort bombers on 850-mile missions.

While the single-engine bomber escort was being sorted out in 1942–43, the Army Air Forces decided to experiment with upgunned B-17s and B-24s. The idea was to remove the bomb load, increase the number of guns and the amount of ammunition carried, and add additional armor plate. To the Germans, the bomber escorts would look like regular Flying Fortresses and Liberators, but as the Fw 190s and Bf 109s got closer, they’d be in for a surprise. The bomber escort B-17s and B-24s would, in theory, be flown at the front, sides, and rear of the formation, in the most vulnerable positions. These bombers could increase the firepower of the formation and reduce the effectiveness of the enemy’s fighters.

The first of the modified bomber escorts was Boeing–built Flying Fortress B-17F 41-24341. It was modified by Lockheed Aircraft at Burbank, California, with two power-operated twin 0.50-cal. waist gun mounts manufactured by United Shoe Machinery Corp., a twin 0.50-cal. machine-gun Bendix chin turret, and a Martin 250CE (two 0.50-cal. machine guns, cylindrical, electric) top turret added in the radio room to supplement the bomber’s existing Sperry top turret. Dubbed the XB-40, for a standard mission it was to carry eleven thousand rounds of ammunition with the capability to carry an additional six thousand-round overload if needed.

The XB-40 underwent tactical trials at the Army Air Forces Proving Ground Command, Eglin Army Air Field, Florida. In the final report, dated Dec. 5, 1942, the Proving Ground Command recommended the bomber for further development with the proviso that the waist positions be staggered and that additional armor plate be provided to protect the crew during frontal attacks. Flight testing showed that the fully loaded XB-40 cruised at the same speed as a fully loaded B-17F, although the XB-40’s rate of climb was 10 percent less. If the ball turret was retracted, the XB-40 was 4 miles per hour faster in cruise.

The recommendations from the Proving Ground Command led to a prototype program, designated the YB-40, with twenty Vega–built B-17Fs transferred to Douglas Aircraft’s Tulsa, Oklahoma, facility for modification. An additional four B-17s were converted to TB-40 trainer configuration. After modification, thirteen YB-40s departed the United States between May 8 and 18, 1943, for operations with the 92nd Bomb Group at Alconbury, England. Following local familiarization flights and more training, the YB-40s flew their first combat mission on May 29, 1943, to bomb the submarine base at Saint-Nazaire, France. Bombers on that mission dropped 277 bombs, each weighing 2,000 pounds, and covered 1,000 miles during six hours of flying time. Of the eight YB-40s dispatched, one aborted the mission because of mechanical failure, and only four were able to return to Alconbury; the remaining three ran short of fuel and landed at alternate fields. After this mission, a number of deficiencies in the YB-40’s armament were discovered, including the need to re-rig the ammunition feed chutes and to change the location of the ammunition feed booster motors and connections to make the guns more reliable. After these changes were incorporated, the YB-40s flew thirteen more missions.

Only one YB-40 was lost during combat trials with the 92nd Bomb Group. On the June 22 mission to bomb the synthetic rubber plants at Huls, Germany, YB-40 42-5737 Wango Wango was hit by antiaircraft, starting fires in the number one and four engines. The bomber lagged behind the formation and was finished off by Fw 190s near the Dutch border. Five of the crew bailed out shortly after the engine fires started, and the other men parachuted to safety before the plane went down. All ten crewmembers were taken prisoner.

After flying combat missions, it was determined that the heavily armed YB-40s were only 10 percent more effective than standard B-17s at combating enemy fighters, and that once the B-17 formation dropped its bombs and became lighter, the heavier YB-40s lagged behind. From the YB-40 program, the Bendix chin turret was recommended for installation on all future Flying Fortresses.

The last of the fourteen YB-40 missions was flown on July 28, 1943, to Kassel, Germany; the program was subsequently terminated and the bombers sent stateside. (Three YB-40s, including 42-5736 Tampa Tornado and 42-5741 Guardian Angel, were transferred to the 91st Bomb Group, and 42-5739 Lufkin Ruffian saw service with the 303rd, 379th, and the 384th Bomb Groups.)

LIBERATOR BOMBER ESCORT

While the XB-40 and YB-40 program was underway, a San Diego–built Consolidated B-24D Liberator, 41-11822, was converted to XB-41 bomber escort configuration. The modification included the addition of a Bendix chin turret, Motor Products tail turret, additional Martin upper turret, and power-operated United Shoe Machinery Corp. M5 waist gun mounts. The bomber had the capacity to carry fifteen thousand rounds of 0.50-cal. ammunition.

Once tested at the Proving Ground Command at Eglin Field, it was determined that the XB-41 was 15 miles per hour slower than a B-24D, had a greatly decreased rate of climb, a service ceiling of only 22,000 feet, and would not fly above 25,000 feet with the new ammunition load. Flying in formation with other B-24s, the XB-41 required 4 to 5 more inches of manifold pressure and an additional 150 propeller rpms to maintain position. The increased power settings consumed fuel at a greater rate, thus limiting the XB-41’s range. In addition, the XB-41’s center of gravity was dangerously aft—more than 37 percent of the mean aerodynamic chord—with anything greater than 35 percent considered extremely dangerous; this impacted the bomber’s flying characteristics and placed high negative loads on the tail surfaces. After concluding the tests, the Proving Ground Command recommended that development of the XB-41 be canceled.

With both the YB-40 and the XB-41 canceled, bomber crews would have to wait until the P-51 Mustang arrived in large numbers for long-range escorts capable of flying deep into the heart of Germany.

Woldemar Voigt and a Swing-Wing

Skyraider’s 3D Aviation Art!

Who invented variable wing-sweep? Barnes Wallis? Maybe not, for Voigt’s Messerschmitt Me. P. 1101 prototype must be the basis, not just of a swept and variable wing idea, but also of a sharply swept, ducted engine, single-seat fighter design. The fact the American `copy’ that was the Bell X-5 seemed identical was of no accident, for the Me P. 1101 was also seized and shipped back to America. Intriguingly, much of Voigt’s Messerschmitt P. 1101 research fell into French hands, who, unlike the British, had no need, nor compunction, to hand it to the Americans, and refused to do so. The Me P. 1101 was not without problems, it was far too heavy for a glider designer like Willi Messerschmitt to countenance and the 40° wing sweep, with proposed variable or `swing-wing’ mechanism, defied solution in the ill-funded dog days of a war about to end. Yet, with its internally- mounted wing geometry gearing design, the P. 1101 would signal the successful 1960s use of such. So, the P. 1101 would be no last-ditch wonder weapon, and was not suited to rough-and-ready construction and short airframe life. Yet within the Me P. 1101 lay many future design trends; the P. 1101 still looks like a 1980s airframe.

Strangely, yet somewhat unsurprisingly, the Bell Aircraft Corporation’s chief designer, Robert Woods, just happened to find himself standing in a barn in Oberammergau, in early 1946, staring at the Me P. 1101. It was, of course, an expensive and difficult journey from the USA to the hills of southern Germany, but someone had to do it. The consequent Bell X-5 was, even to the most pro- American observer, an alleged blatant copy. Other 1950s American swept-wing fighters look like crosses between the Me P. 1101 and the Multhopp Ta 183. In doing so they would take on the MiG-15s that were also blatant copies of German design.

Although ultimately unsuccessful in terms of being directly copied, the effect of the Me P. 1101 would also lead to its designer, W. Voigt, finding himself at Wright Field, Dayton, Ohio, in 1946 – thence to a career in the US aerospace industry. And the P. 1101 was not to be Messerschmitt’s final fling in design terms either, because the ultimate route that Messerschmitt advanced design was to take, followed the all-wing path. From the P. 1101 came the P. 1102 as a tailless all-wing idea (with vertical fin) and a series of jet-powered all-wing airframe proposals designed to meet the Reich’s last final struggles for a weapon to strike fear into American hearts.

Messerschmitt had not been an avid follower of the all-wing and his thoughts on tailless design included a vertical fin or `tail’, but not a drag inducing horizontal stabiliser tail unit. Yet, as a glider designer prior to his powered-designs, Messerschmitt had kept a close eye on the Hortens and Lippisch. Ultimately, the P. 1111/12 design proposals of early 1945 were advanced all-wing ideas and again, looks like an early iteration of a later British idea, the DH 108, and the American Northrop X-4. Of significance, here too, in the P. 1112, we saw the annular, wing root/leading edge/engine air intake concept for the first time – later seen in the de Havilland Comet, Vickers V. 1000 and Valiant, and in production in the Handley Page Victor – as well as a host of American machines.

Of the world’s first swept-winged jet fighter Me 262 (and the even more aerodynamic Me 262 HG), we can say that this airframe taught others more about wings and high-speed flight than can be easily grasped. The Me 262s stepping stone was a monumental moment of learning for the Allies that seized it and its technology. Overnight, straight-winged jets from de Havilland, Gloster, Lockheed and others, were utterly redundant, thrown upon the dustbin of design. The Vampire might not have been rendered useless, but we can say it was of restricted ability no matter how much it was loved. De Havilland soon designed the DH 101 and the key DH 108 and then the DH 110 Vixen. Glosters, Lockheed, North American et al, all went swept-winged `overnight’. For the British, the Hawker P. 1067 Hunter became their swept-winged dream machine, despite its `borrowed’ technology.

Crescent-Shaped Planforms – The Often-Forgotten Advance

The idea of a swept-back, crescent-shaped wing was seen in the works of early pioneers, not least Weiss and Handley Page, but a reverse crescent- shaped planform wing – one where the sweep reduced towards the wingtips – was shaped in Germany and applied by the Arado company and its chief designer, Walter Blume, deputy Hans Rebeski, and the aerodynamicist Rudiger Kosin. Kosin had studied forward-sweep and varying back-sweep. Arado proposed a crescent- winged two, and then four-engined bomber with a sweepback angle of 37° on the inboard wing and two cranks to 29° and 25° towards the outboard wing section.

The benefits of the compromise of a crescent wing was the reduction in wing sweep near the wingtips and that it moved the load on the wingtips forwards of the axis of the wing and improved airflow near the tips, rather than degrading it. This also reduced unfavourable behaviour near the stall and at high Mach numbers, yet retained the advantages of sweep more generally. Tip-stalling and spinning risks at low speed were thus reduced and a better-handling machine created. The wing might have to be a bit stronger and the wingtips thinner to ensure good airflow, but the crescent wing would be lighter in construction than a delta-wing and did provide another solution to how long, thin, highly swept-wings could be made to work and to do so safely across the speed graph – not just at high velocity and high-altitude cruise. Of interest, the `kinks’ in the varying sweep of the crescent wing do not seem to produce significant localised airflow disturbances.

There is little surprise to be found in the claims by the British Handley Page company who built the superb Victor bomber with its crescent wing, that it says it started investigating the crescent wing in 1946. Yet it omits to mention that just a few months earlier, in April 1945, the British had scooped up many drawings and research data on crescent wing design from the Arado company and its aerodynamicist Kosin, in Berlin – when the Arado factory was seized by British troops and accompanying experts. By 1946, Handley Page were looking at that data, and by 1951 were proposing a crescent-winged bomber – which became the `Victor’ – also using a T-tail and wing-root buried engines.What of straighter, less swept, or even unswept-wings, surely they could not offer the aerodynamic advantages of the swept-wing? Science soon revealed that after the benefits of a swept-wing at supersonic speed, an (almost) unswept, short, low aspect ratio wing planform could, with very thin aerofoil (as thin as 3 or 4 per cent thickness/chord ratio), also offer lower supersonic drag. Such `stub’ wings stemmed in part from the short stub wing learning as applied to von Braun’s rockets. At Mach 1.5, the lowest drag came from a highly swept-wing, but the next lowest drag, could, said the experts, come from a small, unswept-wing that, instead of delaying compressibility, just `fought’ through it into the supersonic airflow advantage.

It was at approach and landing speeds that such highly swept and, also unswept but thin aerofoil section wings, became problematic – unless dangerously high, thrust and fuel-hungry landing speeds were to be used. All sorts of lift generating – yet ultimately drag and weight inducing – flaps and slats might be used. But surely the advantages of a moderately swept all-wing could solve all these conflicting themes?

In terms of the powerplant revolution, the likes of Flight, and Mr Keith-Lucas, also postulated on two themes of great note, given the date of 1952. The first was Keith-Lucas’ suggestion that swivelling engine thrust/exhaust might be used to assist landing and the second was what type of airframe might be able to house an atomic reactor powerplant? An atomic-powered aircraft would require a large deep receptacle to house the reactor – was the answer the deep-hulled flying boat with all its internal room for a massive atomic engine? Or was the more likely receptacle for an atomic powerplant the deep wing box of a massive all-wing machine?

Yugoslavian Sabres

During 1958-59, Yugoslavia’s air arm, the Jugoslovensko Ratno Vazduhoplovstvo (JRV), got 122 of the ex-RAF Sabre F.4s which had been returned to the USAF. Yugoslavia was one of the few nations with an air force that flew both Western and Soviet Bloc combat aircraft side-by-side. During a border incident in the late 1950s, a JRV Sabre shot down a Hungarian MiG-15.

One of many paradoxes of the post WWII Yugoslavia was being the only eastern European country that called itself communist, but wasn’t the part of Warsaw pact, and furthermore it was receiving western military support. Yugoslavia was called “east for the west, and west for the east”. On reflection, those grounds had the same role throughout history. Being on the crossroads did not bring much luck to its people.

As such, the Yugoslav Air Force in fifties, and sixties managed to paint red stars on some very advanced flying machines from the American inventory of the day. The last in the line of western fighter jets sent to Yugoslavia was F-86D, Sabre Dog. It remained in Yugoslav service until the 1970s, and for a while it flew together with MiG-21. This was a unique occurrence in the world.

The F-86D Sabre Dog was a development of the successful F-86 family. It was an interceptor, utilizing sophisticated radar equipment for tracking enemy targets (mainly strategic bomber formations). It was not designed for dogfights. The sole armament consisted of 24 unguided Mighty Mouse rockets. Pilot had a tough job of flying the aircraft, and aiming at the same time using its radar. After depressing the trigger imbedded algorithm determined the final moment for releasing the rockets.

As part of MAP arrangements, Yugoslavia was allocated a fleet of former Royal Air Force Canadair Sabre Mk. 4 aircraft, all modified to F-86E(M) standard with unslatted “6-3” wings.

Refurbishment was undertaken by a number of companies, at Stansted, Dunsfold, Gatwick, Speke and Merryfield. Deliveries began in May 1956 although substantial deliveries didn’t begin until May 1957 and by the end of that year some 37 Sabres were in service. By this stage, relations with the Soviet Union had improved and Yugoslavia announced that all military aid from the USA would end, and deliveries of Sabres ended with the 43rd aircraft.

However, the political situation soon changed and the US agreed to supply a further 78 former RAF Sabres in 1959, together with 130 former USAF F-86D aircraft. Some of the latter variants were modified in service to operate in the reconnaissance role (IF-86D), with three K-24 cameras replacing the standard Mighty Mouse rocket pack. The gradual development of an indigenous aircraft industry led to the introduction of the Galeb and Jastreb, and as these aircraft came into service the F-86E fleet was gradually withdrawn, the last examples being retired in 1971. The F-86D fleet remained in use until the end of 1974. Four F-86D aircraft were sold to Honduras during 1976.