POWER PLANT: One Argus As 10C-3 liquid-cooled engine, rated at 240 hp
PERFORMANCE: Na data available
COMMENT: The Sack AS-6 was a German prototype circular-winged aircraft built privately during the Second World War. It did not see production.
The aircraft was designed by Arthur Sack, a farm owner and amateur engineer from a little town near Leipzig. In his attempts to create a circular-winged aircraft he built five model aircraft, each with little success. He entered his fifth model, with a 1.25 meter diameter wing and 1.5 horsepower engine, in a 1939 competition for remotely controlled models with combustion engines. The models were to take off and land at the same point. None of the entries managed to do so. Sack’s model was unable to take off from the ground but flew when released by hand.
At the end of 1940 Sack started design of the AS-6, a full-sized, manned aircraft and successor to the earlier models. Its wing diameter was four times larger than the last model. He built it privately in a shed at his farm, using a wood construction. The Argus As 10 engine as well as the main landing gear from a Messerschmitt Me 109 was sponsored by ATG, a company at Leipzig, that assembled Junkers bomber aircraft. In 1944 the AS-6 prototype was finished and its design documents provisionally approved. Arthur Sack enlisted the help of the chief test pilot of ATG to test the aircraft. Approximately a dozen tests revealed multiple failings, especially in the undercarriage, and managed little more than a hop off the ground. The tests continued at an airbase in Brandis by a pilot in a Messerschmitt Me 163B unit based there. As the AS-6 did not appear on an inventory of seized items when US forces captured the airbase it is assumed that the plane was destroyed to prevent capture (Ref.: 24).
It is to note that the US Navy also planned to realize a disc-shaped Short Take-off/Landing (STOL) aircraft. In the late 1930s the Vought Company was working on an experimental twin engine, circular winged aircraft, the V-173 Flying Pancake. After successful and promising flights the US Navy placed an order for two prototypes of a new carrier-based fighter aircraft, larger, heavier and more powerful than the V-177. Two prototypes oft he Chance Vought XF5U-1 Flying Flapjack were built made only ground runs and never lifted into the air. Due tot he end of WW II and with jet aircraft coming into service, the Navy finally canceled the project in 1947. Possibly a turbojet powered variant, the Vought Jet skimmer, was on the drawing board. Exact data are not available.
POWER PLANT: Two Daimler-Benz DB 601E liquid-cooled engines, rated at 1,175 hp each
PERFORMANCE: 385 mph
COMMENT: The Arado Ar 240 was a German twin-engine, multi-role heavy fighter aircraft, developed for the Luftwaffe during WW II by Ardo Flugzeugwerke. Its first flight was in 1940, but problems with the design hampered development, and it remained only marginally stable throughout the prototype phase. The project was eventually cancelled, with the existing airframes used for a variety of test purposes.
The Ar 240 came about as the response to a 1938 request for a much more capable second-generation heavy fighter to replace the Messerschmitt Bf 110, which was becoming outdated. Both Arado and Messerschmitt responded. Messerschmitt’s response, the Me 210, was a totally new design, but thanks to Messerschmitt’s experience with the Zerstörer (“Destroyer”) concept, it would be able to enter service quickly. Arado’s design was considerably more ambitious for the smaller firm, a dream project of Arado’s chief designer, Walter Blume, since the mid-1930s. While it would take some time before deliveries of the Arado design could begin, the Reichsluftfahrtministerium (RLM, German Aviation Ministry was nevertheless interested enough to order prototypes of both designs.
Prior to this point, Arado had invested heavily in several lines of basic research. One was the development of the “Arado travelling flap” which offered excellent low-speed lift performance. Another was ongoing work in the design and construction of pressurized cockpits, which dramatically lowered pilot fatigue for any flight above about 14,760 ft. Finally, they had also invested in a technically advanced remote-control defensive gun system, which they had been experimenting with for several years. The system used a gunsight located in the rear cockpit, operated by the navigator/gunner, which had optics on both the top and bottom of the aircraft, allowing aim in any direction. The gunsight was hydraulically connected to well-streamlined pancake-shaped, remotely-operated turrets on the top and bottom of the aircraft. For the Ar 240 design, the Arado engineers combined all this research into a single airframe.
For outright performance, they used as small a wing as reasonable, thereby lowering parasite drag (at the expense of greater lift-induced drag). Normally this would make the plane have “impossibly high” landing speeds, but this was offset by the use of a huge travelling flap and leading edge slats for high low-speed lift. When the flaps were extended, the upper portion of the ailerons would remain in place while the lower portion extended rearward, essentially increasing the wing area. A Jumo 222-powered Junkers Ju 288 prototype with ducted spinners, of a similar type to that intended for the Ar 240.
The Daimler-Benz DB 601 inline engines were conventionally installed and equipped with three-blade, fully adjustable propellers. The radiators were somewhat unusual however, quite similar to those fitted to the Junkers Ju 88 which pioneered them – but much more closely resembling the intended installation of the radiators intended for the junkers Ju 288, when powered by its intended multibank Junkers Jumo 222 liquid-cooled 24-cylinder engines – for both types, consisting of an annular block located in front of each engine, but with the Ar 240 partially covering each of them with an oversized, ducted flow-through propeller spinner forward of each radiator unit, with air entering through a large hole in the front of the spinner and exiting out of the cowl flaps, as the Jumo 222-powered Ju 288 design was intended to have. As with the Jumo inline-powered versions of the Ju 88, this made the plane look as if it were mounting a radial engine, and the Ar 240, like later Jumo inline-powered fighter aircraft from the Focke-Wulf firm (the Fw 190D, Ta 152 and twin-engined Ta 154) also benefitted from the simpler setup of an annular radiator just forward of the engine.
The fuel cells in the wings were provided with a newly developed self-sealing system that used thinner tank liners, allowing for more fuel storage. The liners could not be easily removed as they stuck to the outer surface of the tank, so in order to service them, the wing panelling had to be removable. This led to a complex system for providing skinning stiff enough to be handled in the field, complicating construction and driving up weight.
As with all German multi-use aircraft designs of the era, the aircraft was required to be a credible dive bomber. The thick wing panelling was not suitable for piercing for conventional dive brakes, so a “petal”-type brake was installed at the extreme rear of the fuselage — appearing much like what had been trialled with the Dornier Do 217 — which, unlike the Do 217’s vertically-opening “petals”, opened to the sides instead when activated. When closed the brake looked like a stinger, extending beyond the horizontal stabilizer and twin fins.
Finally, the cockpit was fully pressurized. This would not have been easy if the armament had to be hand-operated by the gunner, as it would have required the guns to penetrate the rear of the cockpit canopy. However, the remote control system allowed them to be located in turrets in the unpressurized rear of the fuselage.
All of this added weight, and combined with the small wing, led to a very highwing loding of 330 kg/m2, compared to an average of about a 100 for a single-seat fighter.
Technical specifications were first published in October 1938, followed by detailed plans later that year. In May 1939, the RLM ordered a batch of six prototypes. The first Ar 240 V1 prototype took to the air on 25 June 1940, and immediately proved to have poor handling in all axes, also tending to overheat during taxiing.
The handling was thought to be the result of the ailerons being too small, given the thick wing, so the second prototype was modified to have larger ones, as well as additional vertical fin area on the dive brakes to reduce yaw. In addition, small radiators were added to the landing gear legs to improve cooling at low speeds, when the gear would normally be opened. Ar 240 V2, first flew on 6 April 1941, and spent most of its life at the factory in an experimental role.
Ar 240 V3 followed, the first to be equipped with the FA 9 rear-firing armament system, developed jointly by Arado and DVL, armed with a 7.92 mm MG 81Z machine gun. Ar 240 V4 was the first to include an operational dive brake, and flew on 19 June 1941. Ar 240 V5 and the V6 followed in December and January, including the upgraded FA 13 system, using two 13 mm MG 131 machine gun in place of the MG 81Z for a considerable boost in firepower. Ar 240 V7 and V8 acted as prototypes for the planned Ar 240 B, which was to use two Daimler Benz DB 605As, while Ar 240 V9, V10, and V11, and V12 served as prototypes of the Ar 240 C.
The Ar 240’s excellent performance quickly led to the V3, V5 and V6 being stripped of their armament, including the defensive guns, and used as reconnaissance aircraft over England, where no other two-seater could venture by 1942. A number of pre-production Ar 240As served on the northern part oft he Eastern Front overflying Soviet military positions. In grand total 14 Arado Ar 240 were built (Ref.: 24).
POWER PLANT: Two Pratt & Whitney R-1830-90 Twin Wasp radial engines, rated at 1,200 hp each
PERFORMANCE: 224 mph at 10,000 ft
COMMENT: The Douglas C-47 Skytrain or Dakota (RAF, RAAF, RCAF, RNZAF, and SAAF designation) was a military transport aircraft developed from the civilian Douglas DC-3 airliner. It was used extensively by the Allies during WW II and remained in front-line service with various military operators for many years.
The C-47 differed from the civilian DC-3 by way of numerous modifications, including being fitted with a cargo door, hoist attachment and strengthened floor – along with a shortened tail cone for glider-towing shackles, and an astrodome in the cabin roof.
During World War II, the armed forces of many countries used the C-47 and modified DC-3s for the transport of troops, cargo, and wounded. The U.S. naval designation was Douglas R4D. About 10,174 aircraft were produced in four US factories.
The specialized C-53 Skytrooper troop transport started production in October 1941 at Douglas Aircraft’s Santa Monica plant. It lacked the cargo door, hoist attachment, and reinforced floor of the C-47. Only 380 aircraft were produced in all because the C-47 was found to be more versatile.
The C-47 was vital to the success of many Allied campaigns, in particular, those at Guadalcanal and in the jungles of New Guinea and Burma, where the C-47 and its naval version, the R4D, made it possible for Allied troops to counter the mobility of the light-traveling Japanese Army. Possibly its most influential role in military aviation, however, was flying “The Hump” from India into China. The expertise gained flying “The Hump” was later used in the Berlin Lift, in which the C-47 played a major role until the aircraft were replaced by Douglas C-54 Skymasters.
In Europe, the C-47 and a specialized paratroop variant, the C-53 Skytrooper, were used in vast numbers in the later stages of the war, particularly to tow gliders and drop paratroops. During the invasion of Sicily in July 1943, C-47s dropped 4,381 Allied paratroops. More than 50,000 paratroops were dropped by C-47s during the first few days of the D-Day campaign also known as the Invasion of Normandy, France, in June 1944. In the Pacific War, with careful use of the island landing strips of the Pacific Ocean, C-47s were used for ferrying soldiers serving in the Pacific theater back to the United States.
About 2,000 C-47s (received under Lend-Lease) in British and Commonwealth service took the name „Dakota“, possibly inspired by the acronym “DACoTA” for Douglas Aircraft Company Transport Aircraft.
The C-47 also earned the informal nickname “gooney bird” in the European theatre of operations. Other sources attribute this name to the first aircraft, a USMC R2D—the military version of the DC-2—being the first aircraft to land on Midway Island, previously home to the long-winged albatross known as the gooney bird which was native to Midway
After World War II, thousands of surplus C-47s were converted to civilian airline use, some remaining in operation in 2012, as well as being used as private aircraft (Ref.: 24).
POWER PLANT: Four Junkers Jumo 211J inline engines, rated at 1340 hp each or four BMW 801G radial engines, rated at 1,750 hp each.
PERFORMANCE: 339 mph at 36,000 kg at 20,015 ft
COMMENT: The Messerschmitt Me 264 was a long-range strategic bomber developed during World War II for the German Luftwaffe as its main strategic bomber. The design was later selected as Messerschmitt‘s competitor in the RLM (Reichsluftfahrt-ministerium, German Air Ministry) Amerikabomber programme, for a strategic bomber capable of attacking New York City from bases in France or the Azores.
Three prototypes were built but production was abandoned to allow Messerschmitt to concentrate on fighter production and the Junkers Ju 390 was selected in its place. Development continued as a maritime reconnaissance aircraft instead.
The origin of the Me 264 design came from Messerschmitt’s long-rangereconnaissance aircraft project, the P.1061, of the late 1930s. A variant on the P.1061 was the P.1062 of which three prototypes were built, with only two “engines” to the P.1061’s four, but they were, in fact, the more powerful Daimler-Benz DB 606 “power systems”, each comprising a pair of DB 601 inverted V-12 engines. These were also successfully used in the long-range Messerschmitt Me 261, itself originating as the Messerschmitt P.1064 design of 1937. The DB 606’s later use in the Heinkel He 177A‘s airframe design resulted in derision by Reichsmarschall Hermann Göring as „welded-togehter engines in August 1942, due to badly designed engine installations. In early 1941, six P.1061 prototypes were ordered from Messerschmitt, under the designation Messerschmitt Me 264. This was later reduced to three prototypes.
The progress of these projects was initially slow, but after Germany had declared war on the United States four days after the Pearl Harbor attack by Imperial Japan, the Reichsluftfahrtministerium started the more serious Amerikabomberprogramme in the spring of 1942 for a very long range bomber, with the result that a larger, six-engine aircraft with a greater bomb load was called for. Proposals were put forward for the Junkers Ju 390, the Focke-Wulff Ta 400, a redesign of the unfinalized and unbuilt Heinkel He 277 design, and a design study for an extended-wingspan six-engine Messerschmitt Me 264B. The need for six engines was prompted by the ongoing inability of Germany’s aviation powerplant designers to create combat-reliable powerplants of 2,000 PS and above power output levels, thwarting efforts to do the same with just four engines instead. As the similarly six-engined Junkers Ju 390 could use components already in use for the Junkers Ju 290 this design was chosen.
The Me 264 was not abandoned, however, as the Kriegsmarine (German Navy) separately demanded a long-range maritime patrol and attack aircraft to replace the converted Focke-Wulf Fw 200 Condor in this role. As a result, the two pending prototypes were ordered to be completed as development prototypes for the Me 264A ultra long-range reconnaissance aircraft.
The Me 264 was an all-metal, high-wing, four-engine heavy bomber of classic construction. The fuselage was round in cross-section and had a cabin in a glazed nose, comprising a “stepless cockpit” with no separate windscreen section for the pilots, which was common for most later German bomber designs. A strikingly similar design was used for the Boeing B-29 Superfortress, of slightly earlier origin. The wing had a slightly swept leading edge and a straight trailing edge. The empennage had double tail fins. The undercarriage was a retractable tricycle gear with large-diameter wheels on the wing-mounted main gear. . In order to provide comfort on the proposed long-range missions, the Me 264 featured bunk beds and a small galley complete with hot plates.
The Me 264’s first prototype was originally fitted with four Junkers Jumo inverted V12 engines using the then-new Kraftei (or “power egg”) unitized powerplant installation as standardized for the earlier Junkers Ju 88A Schnellbomber, but inadequate power from the Jumo 211 engines led to their replacement on the Me 264 V1 first prototype with four similarly unitized 1,700 hp BMW 801G engines. The first prototype, the Me 264 V1, bearing the Stammkennzeichen factory code of RE+EN, was flown on 23 December 1942. It was powered at first by four Junkers Jumo 211J inline engines of 1,340 hp each. In late 1943, these were changed to the BMW 801G radial engines which delivered 1,750 hp each.
Trials showed numerous minor faults and handling was found to be difficult. One of the drawbacks was the very high wing loading of the Me 264 in fully loaded conditions at some 356 kg/m2. Comparable aircraft, such as the Boeing B-29 Superfortress with a wing loading of 337 kg/m2, the redesigned Heinkell He 277 at 334.6 kg/m2 and the Junkers Ju 390 at 209 kg/m2 had lower wing loadings. The relatively high wing loading caused poor climb performance, loss of manoeuvrability, stability and high take-off and landing speeds. The first prototype was not fitted with weapons or armour but the following two prototypes, the Me 264 V2 and V3 had armour for the engines, crew and gun positions. The Me 264 V2 was built without defensive armament and vital equipment and the Me 264 V3 was to be armed and have the same armour.
In 1943, the Kriegsmarine withdrew their interest in the Me 264 in favour of the Ju 290 and the planned Ju 390. The Luftwaffe indicated preference for the unbuilt Focke Wulf Ta 400 and the Heinkel 277 as Amerikabomber candidates in May 1943, based on their performance estimates. Further payments for development work to Messerschmitt AG for its design were stopped. Late in 1943, the second prototype, Me 264 V2, was destroyed in a bombing attack. On 18 July 1944, the first prototype, which had entered service with Transportstaffel 5, was damaged during an Allied bombing bombing raid and was not repaired. The third prototype, which was unfinished, was destroyed during the same raid. In October 1943, further Me 264 development was stopped to concentrate on the development and production of the Messerschmitt Me 262 turbojet fighter-bomber.
Following the cancellation of the competing He 277 in April 1944, on 23 September 1944, work on the Me 264 project was officially cancelled. Messerschmitt proposed a six-engine version of the Me 264, the Me 264/6m (or alternately Me 364), but it was never built (Ref.: 24).
POWER PLANT: One Allison V-1710-87 liquid-cooled engine, rated at 1,325 hp
PERFORMANCE: 365 mph
COMMENT: The North American A-36 (listed in some sources as “Apache“ or “Invader”, but generally called Mustang) was the ground-attack/dive bomber version of the North American P-51 Mustang, from which it could be distinguished by the presence of rectangular, slatted dive brakes above and below the wings. A total of 500 A-36 dive bombers served in the Mediterranean and Southeast Asia theaters during WW II before being withdrawn from operational use in 1944.
The A-36 project was a stopgap measure intended to keep North American (NAA) assembly lines running during the first half of 1942 despite the US having exhausted its funds earmarked for fighter aircraft. When the order came for more P-51s in June 1942, the NAA workforce was thoroughly experienced.
With the introduction of the North American Mustang Mk.I with the Roya Air Force’s Army Co-operation Squadrons in February 1942, the new fighter began combat missions as a low-altitude reconnaissance and ground-support aircraft. Supplementing the Curtiss P-40 Tomahawks already in service, Mustang Mk Is were first supplied to No. 26 Squadron RAF, then rapidly deployed to 10 additional squadrons by June 1942.
Despite the limited high-altitude performance of the Allison V-1710 engine, the RAF was enthusiastic about its new mount, which “performed magnificently”. During the Mustang Mk. I’s successful combat initiation, North American’s president pressed the newly redesignated U.S.Army Air Forces (USAAF) for a fighter contract for the essentially similar P-51, 93 of which had passed into the USAAF when the Lend-Lease contract with Britain ran out of funds. The Mustang Mk IA/P-51 used four 20 mm Hispano wing cannon in place of the original armament, a combination of four wing-mounted 7.62 mm M1919 Browning machine guns and four 12.7 mm M2 Browning machine guns, two of which were mounted in the wings, while the second pair was mounted in the “chin”, or lower engine cowling, and synchronized to fire through the propeller. No funds were available for new fighter contracts in fiscal year 1942, but General O. P. Echols and Fighter Project Officer B. S. Kelsey wanted to ensure that the P-51 remained in production.
Since appropriations were available for an attack aircraft, Echols specified modifications to the P-51 to turn it into a dive bomber. The contract for 500 A-36A aircraft fitted with bomb racks, dive brakes, and heavier-duty wing, was signed by Kelsey on 16 April 1942, even before the first flight of the first production P-51 in May 1942. With orders on the books, North American Aviation (NAA) began modifying the P-51 to accept the bomb shackles which had already been tested in a “long-range ferry” program that the RAF had stipulated. Utilizing the basic P-51 airframe and Allison engine, structural reinforcing “beefed up” several high stress areas and “a set of hydraulically operated dive brakes were installed in each main wing plane”. Due to the slightly inboard placement of the bomb racks and unique installation of four cast aluminum dive brakes, a complete redesign of the P-51 wing was required
The first A-36A was rolled out of the NAA Inglewood plant in September 1942, rapidly going through flight testing with the first flight in October, with deliveries commencing soon after of the first production machines. The A-36A continued the use of nose-mounted 12.7 mm machine guns along with wing armament of four 12.7 mm caliber machine guns. The USAAF envisaged that the dive bomber would operate mainly at altitudes below 12,000 ft and specified the use of a sea level-rated Allison V-1710-87, driving a 10 ft 9 in-diameter three bladed Curtiss-Electric propeller and delivering 1,325 hp at 3,000 ft The main air scoop inlet was redesigned to become a fixed unit with a larger opening, replacing the earlier scoop which could be lowered into the airstream. In addition the A-36 carburetor air intake was later fitted with a tropical air filter to stop sand and grit being ingested into the engine.
The USAAF later ordered 310 P-51As, which were essentially A-36s without the dive-brakes and nose-mounted weapons, leaving an armament of four wing-mounted 12.7 mm Browning machine guns. An Allison V-1710-81 1,200 hp was fitted and used the same radiator and air intake as the A-36A. The P-51A was still fitted with bomb racks although it was not intended to be used primarily as a fighter-bomber and the racks were mainly used to carry drop tanks
Besides dive bombing, the A-36A racked up aerial victories, totaling 84 enemy aircraft downed. As fighting intensified in all theaters where the A-36A operated, the dive bomber began to suffer an alarming loss rate with 177 falling to enemy action. The main reason for the attrition was the hazardous missions that placed the A-36A “on the deck” facing murderous ground fire. German defenses in southern Italy included placing cables across hill tops to snare the attacking A-36As. Despite establishing a reputation for reliability and performance, the one “Achilles’ heel” of the A-36A (and the entire Mustang series) remained the ventral-fuselage location of the radiator/cooling system, leading to many of the losses. By June 1944, A-36As in Europe were replaced by Curtiss P-40 Warhawks and Republic P-47 Thunderbolts.
The aircraft model shown here was a North American A-36 Apache of the 86thFBG, 527th FBS showing with only approx. 100 sortie markings in winter 1943/44. In the end the whole side was full of 190 bombing logs, before it was struck off charge. Because it was such a long-lasting aircraft the late-war blue markings were painted over the temporarely red-framed markings anf therefore appear distinctive darker as the blue in the disk (Ref.: 24).
POWER PLANT: One Argus As 10P liquid-cooled engine, rated at 237 hp
PERFORMANCE: 136 mph
COMMENT: The Fieseler Fi 256 was a multipurpose aircraft designed for the German Luftwaffe to replace the extraordinary successfull Fieseler Fi 156 Storch (Stork).
Aerodynamically cleaner, with automatic slats and a more spacious cabin for four passengers, the Fi 256 was supposed to enter the Luftwaffe, replacing its previous sibling. Although the new Super-Storch repeated the layout of the previous model, it was a completely new aircraft with non-interchangeable components in its design.
The first flight of the prototype took place on July 9, 1941, but one of its next flights ended in an accident, which forced the developers to make significant changes in the aircraft design. After the alteration, a pre-production batch of 13 aircraft was ordered, of which six were to be produced by Fieseler, and the rest by Schwade in Erfurt (in France, not a single aircraft was built at Morane-Saulnier). Serial production was planned for 1943, however, only two prototypes and at least 14 aircraft were completed. Production was ceased due to the high priority of the Jägernotprogramm (Ref.: 24).
POWER PLANT: Two Rolls-Royce “Merlin” X liquid-cooled engines, rated at 1,145 hp each
PERFORMANCE: 230 mph at 16,500 ft
COMMENT: The Armstrong Whitworth Whitley was one of three British twin-engined, front line medium bomber types that were in service with the Royal Air Force (RAF) at the outbreak of the Second World War. Alongside the Vickers Wellington and the Handley Page Hampton, the Whitley was developed during the mid-1930s according to Air Ministry Specification B.3/34, which it was subsequently selected to meet. In 1937, the Whitley formally entered into RAF squadron service; it was the first of the three medium bombers to be introduced.
Following the outbreak of WW II in September 1939, the Whitley participated in the first RAF bombing raid upon German territory and remained an integral part of the early British bomber offensive. By 1943, it was being superseded as a bomber by the larger four-engined “havies” such as the Short Stirling, Handley Page Halifax and Avro Lancaster.
Its front line service included maritime reconnaissance with Coastal Command and the second line roles of glider-tug, trainer and transport aircraft. The type was also procured by British Overseas Airways Corporation as a civilian freighter aircraft. The aircraft was named after Whitley, a suburb of Coventry, home of one of Armstrong Whitworth’s plants.
The Armstrong Whitworth Whitley was a twin-engined medium bomber, initially being powered by a pair of 795 h.p. Armstrong Siddeley Tiger IX radial engines. More advanced models of the Tiger engine equipped some of the later variants of the Whitley; starting with the Whitley Mk IV variant, the Tigers were replaced by a pair of 1,030 h.p. Rolls-Royce Merlin IV liquid-cooled engines. The adoption of the Merlin engine gave the Whitley a considerable boost in performance.
The early examples had a nose turret and rear turret, both being manually operated and mounting one Vickers machine gun. On the Whitley Mk III this arrangement was substantially revised: a new retractable ventral ‘dustbin’ position was installed mounting twin Browning machine guns and the nose turret was also upgraded to a Nash & Thompson power-operated turret. On the Whitley Mk IV, the tail and ventral turrets were replaced with a Nash & Thompson power-operated turret mounting four Browning machine guns; upon the adoption of this turret arrangement, the Whitley became the most powerfully armed bomber in the world against attacks from the rear
The fuselage comprised three sections, with the main frames being riveted with the skin and the intermediate sections being riveted to the inside flanges of the longitudinal stringers. Extensive use of Alcad sheeting was made. Fuel was carried within a total of three tanks, a pair of 182 gallon tanks contained within the leading edge of each outer wing and one 155 gallon tank in the roof of the fuselage, over the spar centersection; two auxiliary fuel tanks could be installed in the front fuselage bomb bay compartment. The inner leading edges contained the oil tanks, which doubled as radiant oil coolers. To ease production, a deliberate effort was made to reduce component count and standardised parts. The fuselage proved to be robust enough to withstand severe damage.
The Whitley featured a large rectangular-shaped wing; its appearance led to the aircraft receiving the nickname “the flying barn door”. Like the fuselage, the wings were formed from three sections, being built up around a large box spar with the leading and trailing edges being fixed onto the spar at each rib point. The forward surfaces of the wings were composed of flush-riveted, smooth and unstressed metal sheeting; the rear 2/3rds aft of the box spar to the trailing edge, as well as the ailerons and split flaps was fabric covered. The inner structure of the split flaps was composed of duralumin and ran between the ailerons and the fuselage, being set at a 15–20 degree position for taking off and at a 60 degree position during landing. The tailplanes employed a similar construction to that of the wings, the fins being braced to the fuselage using metal struts the elevators and rudders incorporated servo-balancing trim tabs
Designed for service with Coastal Command and carried a sixth crew member, capable of longer-range flights of 2,300 mi compared to the early version’s (1,250 mi) having additional fuel tanks fitted in the bomb bay and fuselage, equipped with Air to Surface Vessel (ASV Mk II) radar for anti-shipping patrols with an additional four ‘stickleback’ dorsal radar masts and other antennae:
Long-range Coastal Command Mk VII variants were among the last Whitleys remaining in front-line service, remaining in service until early 1943. The first U-boat kill attributed to the Whitley Mk VII was the sinking of the German submarine U-751 on 17 July 1942, which was achieved in combination with a Avro Lancaster heavy bomber. Having evaluated the Whitley in 1942, the Fleet Air Arm operated a number of modified ex-RAF Mk VIIs from 1944 to 1946, to train aircrew in Merlin engine management and fuel transfer procedures. Production ended in June 1943 after 1.814 Whitleys being built (Ref.: 24).
POWER PLANT: Two BMW 801L radial engines, rated at 1,560 hp each
PERFORMANCE: 324 mph in 17.100 ft
COMMENT: The Dornier Do 217 was a bomber used by the German Luftwaffe during World War II as a more powerful development of the Dornier Do 17, known as the Fliegender Bleistift (German: “flying pencil”). Designed in 1937 and 1938 as a heavy bomber but not meant to be capable of the longer-range missions envisioned for the larger Heinkel He 177 Greif (Griffon), the Do 217’s design was refined during 1939 and production began in late 1940. It entered service in early 1941 and by the beginning of 1942 was available in significant numbers.
The Dornier Do 217 had a much larger bomb load capacity and had much greater range than the Do 17. In later variants, dive bombing and maritime strike capabilities using glide bombs were experimented with considerable success being achieved. Early Do 217 variants were more powerful than the contemporary Heinkel He 111 and Junkers Ju 88, having a greater speed, range and bomb load. The Do 217 served on all fronts in all role as a strategic bomber, torpedo bomber and reconnaissance aircraft. It also performed tactical operations, either direct ground assault or anti-shipping strikes. The Do 217 was also converted to become a night fighter and saw considerable action in the Defence oft he Reich campaign until late in the war.
In 1943, the Do 217 was the first aircraft to deploy precision-guided munition (PGM) in combat, when Ruhrstahl Fritz X radio-guided bombs sank the Italian battleship Roma in the Mediterranean.
To replace the Do 217E, the RLM planned for the He 177A-3 and A-5 to be the long-range carrier aircraft for missiles, owing to the lack of BMW engines to power the Dornier but problems with the engine reliability of the He 177A led to the failure of the plan.
In early 1942, tests on a new and improved, completely glazed cockpit for the Do 217K series had been underway at the Hamburger Schiffbauanstalt (Hamburg Shipbuilding Institute). Do 217E-2s were fitted with a new streamlined “stepless cockpit” following its conceptual debut in January 1938 for the Heinkel He 111P, as this design philosophy became the standard for almost all German bombers later in World War II, which eliminated the separate windscreen panels for the pilot of earlier versions of the Do 217. The lower nose of the Do 217K-version also retained the Bola (Bodenlafette, ventral gun mounting) inverted-casemate gondola for a rearwards-aimed ventral defensive armament emplacement, with its forward end fully incorporated with the new nose glazing design. The cabin design passed the tests easily. Initial flights took place on March 1942 after teething problems had been resolved. The Do 217K V1 flew with BMW 801A-1s from Erpobungsstelle Rechlin. This was followed by the ten-airframe pre-production batch, Do 217K-01 to K-010. BMW believed that the type could reach an operational ceiling of 25.000 ft, notwithstanding an A.U.W of 16.8 t. Tests at Peenemünde in June and July 1943 showed that while the Do 217K could carry and deploy a Ruhrstahl Fritz-X precision guided munition, it was still controllable.
The Do 217K-1 was a bomber version and was powered by two BMW 801L engines with GM 1 nitrous oxide boost. This increased the Do 217K-1s maximum speed by 53 mph at 26.250ft at a rate of 100 g/s. With 50 g/s the aircraft’s operational ceiling could be extended from 27.560 ft to 32.152ft.
In total 220 Do 217K-1 were built followed by Do 217K-2 with extended wings (Ref.:24)
POWER PLANT: Two Bristol “Pegasus” XVIII radial engines, rated at 1000 hp each
PERFORMANCE: 247 mph at 13,000 ft
COMMENT: The Handley Page HP.52 Hampden was a British twin-engine medium bomber of the Royal Air Force (RAF). It was part of the trio of large twin-engine bombers procured for the RAF, joining the Armstrong Whitworth Whitley and Vickers Wellington. The newest of the three medium bombers, the Hampden was often referred to by aircrews as the “Flying Suitcase” because of its cramped crew conditions. The Hampden was powered by Bristol Pegasus radial engines but a variant known as the Handley Page Hereford had in-line Napier Daggers.
The Hampden served in the early stages of the Second World War, bearing the brunt of the early bombing war over Europe, taking part in the first night raid on Berlin and the first 1.000 bomber raid on Cologne. When it became obsolete, after a period of mainly operating at night, it was retired from RAF Bomber Command service in late 1942. By 1943, the rest of the trio were being superseded by the larger four-engined heavy bombers such as the Avro Lancaster and Handley Page Halifax.
The Hampden Mk I had a pilot, navigator/bomb aimer, radio operator and rear gunner. Conceived as a fast, manoeuvrable “fighting bomber”, the Hampden had a fixed forward-firing Browning machine gun in the upper part of the fuselage nose. To avoid the weight penalties of powered turrets, the Hampden had a curved Perplex nose fitted with a manual Vickers K machine gun and a Vickers K installation in the rear upper and lower positions. The layout was similar to the all-guns-forward cockpits introduced about the same time in Luftwaffe medium bombers, notably the Dornier Do 17.
The Hampden had a flush-rivette stressed skin, reinforced with a mixture of bent and extruded sections in an all-metal monocoque design. A split-assembly construction technique was employed: sections were prefabricated and then joined, to enable rapid and economic manufacture. The fuselage was in three big sections – front, centre and rear – that were built using jigs The centre and rear sections were made of two halves, which meant that the sections could be fitted out in part under better working conditions prior to assembly. All possible assembly work was performed at the benches prior to installation upon each aircraft.
The wings were made up of three large units: centre section, port outer wing and starboard outer wing, which were also subdivided. Each section was built around a main girder spar, leading edge section and trailing edge section. The wing made use of wingtip slots and hydraulically-actuated trailing edge flaps; the flaps and ailerons had stress-bearing D-spars. The configuration of the wing was a key feature of Hampden, being highly tapered and designed to exert low levels of drag; these attributes were responsible for the aircraft’s high top speed for the era of 265 mph while retaining a reasonably low landing speed of 73 mph.
The Hampden’s flying qualities were typically described as being favourable; It was extraordinarily mobile on the controls. Pilots were provided with a high level of external visibility, assisting the execution of steep turns and other manoeuvres. The control layout required some familiarization, as some elements such as the hydraulic controls were unassuming and unintuitive. Upon introduction, the Hampden exhibited greater speeds and initial climb rates than any of its contemporaries while still retaining favourable handling qualities.
The slim and compact fuselage of the aircraft was quite cramped, wide enough only for a single person. The navigator sat behind the pilot and access in the cockpit required folding down the seats. Once in place, the crew had almost no room to move and were typically uncomfortable during long missions. Aircrews referred to the Hampden by various nicknames due to this, such as Flying Suitcase, Panhandle, and Flying Tadpole.
The last Bomber Command sorties by Hampdens were flown on the night of 14/15 September 1942 by 408 Squadron, RCAF against Wilhelmshaven. After being withdrawn from Bomber Command in 1942, it operated with RAF Coastal Command through 1943 as a long-range torpedo bomber. These Hampden TB Mk I had a Mk XII torpedo in an open bomb bay and a 230 kg bomb under each wing. Furthermore, the Hampdens were in action as maritime reconnaissance aircraft. Between 1936 to1941 a total of 1,430 Hampdens were built; 500 by Handley Page, 770 by English Electric, and 160 by Canadian Associated Aircraft (Ref.: 24).
POWER PLANT: Four Daimler-Benz DB 603E liquid-cooled engines, rated at 1,777 hp each
PERFORMANCE: 447 mph
COMMENT: The Dornier Do 635 was a WW II long-range reconnaissance aircraft of the German Luftwaffe proposed by Dornier Company, as two Dornier Do 335 fuselages joined by a common center wing section.
In 1944, designers of Dornier Flugzeugwerke proposed the RLM a long-range reconnaissance aircraft with a range of 2.480 mi under the designation Dornier Do 335Z (Z for Zwilling ; “Twin”). Similar to the Heinkel He 111Z, a combination of two Heinkel He 111 bombers joined by a common center wing section, two Dornier Do 335B fuselages were connected by a center wing section. The pilot was seated in the left fuselage, the radio operator/navigator sitting in the right fuselage. Armament was not envisaged. The RLM confirmed the design provided the range was increased to app. 3.720 mi. Further modifications changed the design from the original Do 335 into a completely new aircraft; the new RLM designation was now Dornier Do 635. Four prototypes were ordered and begin of production was planned for June 1945.
On order of the RLM and representatives of the Luftwaffe the cooperation with Dornier was cancelled and all further development was transferred to Heinkel Flugzeugwerke.
Reason might be that Heinkel’s team had much experience with the Heinkel He 111Z and its twin fuselage combination. The designation of the project was internally changed to Heinkel He P.1070, officially Heinkel He 535 (or He 635, depending on literature). Again, profound changes were required. In order to increase range three external fuel tanks under the outer and center wings were provided, the wing span was reduced and the fuselage length was increased.
All these changes did not satisfy the RLM, so the design was revised again. The crew compartment was now solely positioned in the left fuselage and enlarged to seat three crew members: pilot, copilot and observer/navigator. Wing span was increased again, the center wing section was shortened to bring both fuselages closer together and the inner tail planes were provided as a common sector.
Meanwhile, a lot of time was wasted due to permanent changes in the requirements of the design. Finally, all further development was transferred to Junkers Flugzeugwerke. Prof. Hertel and his team refined the design once again, now under the designation Junkers Ju 635. The aim was to simplify the aircraft for easier production and an increase of range to app. 7.200 mi.
As its predecessor the Junkers design used two modified Dornier Do 335 fuselages, joined by a center wing section of constant chord, the outer wing panels were tapered back. Four Daimler-Benz DB 603E-1 engines supplied the power, one in each forward fuselage pulling and two in each rear fuselage driving a pusher propeller via a long drive shaft. Fuel was carried in ten internal wing tanks, four in the fuselages and possibly one in each fuselage bay. The port fuselage bay carried two Rb 50/30 cameras and the starboard bay contained five 60 kg marker bombs. A crew of three was envisioned, although this could be increased to four eventually. The pilot and the radio operator sat in the port fuselage and a second pilot sat in the starboard fuselage. The fourth crew member (navigator) was also to sit in the starboard fuselage. The landing gear was to consist of two nose wheels under each fuselage nose, two main wheels which were fitted with mud guards to protect the rear radiator intakes, and a jettisonable fifth wheel located beneath the center wing, which was fitted with a parachute for recovery. The main wheels were modified from the Junkers Ju 352 transports wheels. Two Walter HWK 109-500 RATO (Rocket Assisted Take Off) units could be fitted to assist take off. No armament was included due to the fact that this was a long-range reconnaissance aircraft and thus all weight was reserved for fuel and speed.
Four prototypes and six preproduction aircraft were orderd, the first example planned to take-off on February 1945. By early 1945, wind-tunnel models had been tested and cockpit mockups had been constructed. But by February 1945 due to the worsening war situation all further work on the Junkers Ju 635 was stopped.
The model shown here is the first design of the Dornier Do 635 (Ref.: 17, 24).
Scale 1:72 aircraft models of World War II
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