Category Archives: Luftwaffe

Deutschland / Germany

DFS 346 (Huma Models)

TYPE: High-speed, high-altitude reconnaissance aircraft

ACCOMMODATION: Pilot only, in prone position

POWER PLANT: One Walter HWK 109-509 liquid-fuel rocket, rated at 3,400 kp thrust

PERFORMANCE: 560 mph (verified), 1,723 mph (estimated)

COMMENT: The DFS 346 was a German rocket-powered swept-wing aircraft subsequently completed and flown in the Soviet Union after WW II. It was designed by Felix Kracht at the Deutsche Forschungsanstalt für Segelflug (DFS, “German Research Institute for Sailplanes”). The prototype was still unfinished by the end of the war and was taken to the Soviet Union where it was rebuilt, tested and flown.
The DFS-346 was a midwing design of all-metal construction. The front fuselage of the DFS 346 was a body of rotation based on the NACA-Profile 0012-0,66-50. The middle part was approximately cylindrical and narrowed to the cut off to accommodate vertically arrayed nozzles in back. Probably for volume and weight reasons the DFS-346 was equipped with landing skids, both in the original German design and in the later Soviet prototypes; this caused trouble several times.
The wings had a 45° swept NACA 0012-0,55-1,25 profile of 12% thickness. The continuously varying profile shape caused a stall in certain flight conditions, which caused complete loss of control. This was later corrected by use of fences on the top of the wings.
The DFS 346 was a parallel project to the DFS 228 high-altitude reconnaissance aircraft, designed under the direction of Felix Kracht and his team at DFS. While the DFS 228 was essentially of conventional sailplane design, the DFS 346 had highly-swept wings and a highly streamlined fuselage that its designers hoped would enable it to break the sound barrier.
Like its stablemate, it also featured a self-contained escape module for the pilot, a feature originally designed for the DFS 54 prior to the war. The pilot was to fly the machine from a prone position, a feature decided from experience with the first DFS 228 prototype. This was mainly because of the smaller cross-sectional area and easier sealing of the pressurized cabin, but it was also known to help with g-force handling.
The DFS 346 design was intended to be air-launched from the back of a large mother ship aircraft for air launch, the carrier aircraft being the Dornier Do 217K as with the DFS 228. After launch, the pilot would fire the Walter HWK 109-509B/C twin-chamber  engine to accelerate to a proposed speed of Mach 2.6 and altitude of 100,000 ft. This engine had two chambers — the main combustion chamber as used on the earlier HWK 509A motor; but capable of just over two short 2,000 kp of thrust at full power, and the lower-thrust “Marschofen”, (Cruise chamber = throttleable chamber of either 300 kp (B-version) or 400 kp (C-version) top thrust levels mounted beneath the main chamber. After reaching altitude, the speed could be maintained by short bursts of the lower “Marschofen” (cruise chamber).
In an operational use the plane would then glide over England for a photo-reconnaissance run, descending as it flew but still at a high speed. After the run was complete the engine would be briefly turned on again, to raise the altitude for a long low-speed glide back to a base in Germany or northern France.
Since the aircraft was to be of all-metal construction, the DFS lacked the facilities to build it and construction of the prototype was assigned to Siebel Werke located in Halle, where the first wind tunnel models and partially built prototype were captured by the advancing Red Army.
On 22 October 1946, the Soviet OKB-2 (Design Bureau 2), under the direction of Hans Rössing and Alexandr Bereznyak, was tasked with continuing its development. The captured DFS 346, now simply called “Samolyot 346” (“Samolyot” = Aircraft) to distance it from its German origins, was completed and tested in TsAGI wind tunnel T-101. Tests revealed some aerodynamic deficiencies which would result in unrecoverable stalls at certain angles of attack. This phenomenon involved a loss of longitudinal stability of the airframe. After the wind tunnel tests, two wing fences were installed on a more advanced, longer version of the DFS-346, the purpose of fences was to interrupt the spanwise movement of airflow that would otherwise bring the boundary-layer breakdown and transition from attached to stalled airflow with loss of lift and increase of drag.
This solution was used on the majority of the Soviet planes with sweptback wings of the 1950s and 1960s. In the meantime, the escape capsule system was tested from a North American B-25J “Mitchel” piston engine medium bomber and proved promising. Despite results from studies showing that the plane would not have been able to pass even Mach 1, it was ordered to proceed with construction and further testing.
In 1947, an entirely new 346 prototype was constructed, incorporating refinements suggested by the tests. This was designated “346-P” (“P” for planer = “glider”). No provision was made for a power plant, but ballast was added to simulate the weight of an engine and fuel. This was carried to altitude by a Boeing B-29 “Superfortress” captured in Vladivostok and successfully flown by Wolfgang Ziese in a series of tests. This led to the construction of three more prototypes, intended to lead to powered flight of the type.
Newly built “346-1“ incorporated minor aerodynamic refinements over the 346-P, and was first flown by Ziese on September 30, 1948, with dummy engines installed. The glider was released at an altitude of 9700 m, and the pilot realized that he hardly could maintain control of the aircraft. Consequently, while attempting to land, he descended too fast (his speed was later estimated at 310 km/h). After first touching the ground he bounced up to a height of 3–4 m and flew 700–800 m. At the second descent, the landing ski collapsed and the fuselage hit the ground hard.
The pilot seat structure and safety belt proved to be very unreliable, because at the end of a rough braking course Ziese was thrown forward and struck the canopy with his head, losing consciousness. Luckily, he wasn’t seriously injured, and after treatment in hospital he was able to return to flying. Accident investigation research team came to the conclusion that the crash was a result of pilot error, who failed to fully release the landing skid. This accident showed that the aircraft handling was still very unpredictable, as a result, all rocket-powered flights were postponed until pilots were able to effectively control the aircraft in unpowered descent, requiring further glide flights.
The damaged 346-1 was later repaired and modified to 346-2 version. It was successfully flown by test pilot P.Kazmin in 1950-1951 winter, but nonetheless these flights also ended “on fuselage”. Furthermore, after the last flight of these series, the airframe again required major repairs. On 10 May 1951, Ziese returned to the program, flying final unpowered test flights with the 346-2, and from 6 June, unpowered tests of the 346-3 without accidents.
By the mid-1951 346-3 was completed, and Ziese flew it under power for the first time on 13 August 1951, using only one of the engines. Continuing concerns about the aircraft’s stability at high speeds had led to a speed limit of Mach 0.9 being placed during test flights. Ziese flew it again on 2 September and 14 September. On this last flight, however, things went drastically wrong. Separating from the carrier plane at 9,300 meters (30,500 ft) above Lukovici airfield, the pilot fired the engine and accelerated to a speed of 900 km/h (560 mph). The rocket engine worked as expected, and 346-3, quickly accelerating, started ascending and soon had flown in very close proximity of its carrier aircraft. Ziese then reported that the plane was not responding to the controls, and was losing altitude. Ground control commanded him to bail out. He used the escape capsule to leave the stricken aircraft at 6,500 meters (21,000 ft) and landed safely by parachute. With the loss of this aircraft, the 346 program was abandoned (Ref.:24).

Messerschmitt Me 163B V41 “Komet“ („Comet“), Erprobungskommando 16, (Heller)

TYPE: Rocket-powered interceptor

ACCOMMODATION: Pilot only

POWER PLANT: One Walter HWK 109-509A-2 liquid-fuel rocket engine rated between 1,500 kp to 100 kp full variable

PERFORMANCE: 559 mph at all altitudes

COMMENT: The Messerschmitt Me 163 “Komet” (“Comet”) was a German rocket-powered interceptor aircraft. Designed by A. Lippisch, it was the only rocket-powered fighter aircraft ever to have been operational and the first piloted aircraft of any type to exceed 1000 km/h (621 mph) in level flight. Its performance and aspects of its design were unprecedented. The Messerschmitt Me 163 “Komet” was among the most technically advanced and inherently dangerous military aircraft ever to see service. The radical ‘tailless’ design was developed by Dr Alexander Lippisch as the DFS 194 at the Deutsche Forschungsanstalt für Segelflug, (German Research Institute for Sailplanes) at Darmstadt in the 1930s. In January 1939, project work on the DFS 194 was transferred to Messerschmitt AG at Augsburg responsible for fitting a rocket motor. Lippisch also moved to Messerschmitt AG to head the development project team. The rocket-powered sailplane DFS 194 made its first flight on August 1940 what was very successful. Although Messerschmitt was not impressed by the concept of a rocket-powered interceptor, Lippisch and his team continued work on the project. Officially designated Messerschmitt Me 163 the aircraft was first flown under rocket power in 1940 becoming the first aircraft to exceed 1000 km/h, experiencing control problems on the edge of the sound barrier.

Five prototype Messerschmitt Me 163A V-series aircraft were built, adding to the original DFS 194 (V1), followed by eight pre-production examples designated as Me 163 A-0. These aircraft were intensively tested by the Luftwaffe and although its extraordinary acceleration, climbing characteristics and speed inspired the authorities the handling of this tiny aircraft especially during take-off and landing showed tremendous problems. The rocket engine gave power for only a few minutes and the rest of the flight had to be continued as a glider.

Five prototypes and eight pre-production examples were followed by 30 completely redesigned production aircraft Messerschmitt Me 163B-0. These aircraft were armed with two 20 mm MG 151/20 cannon and some of these were allocated to “Erprobungskommando16” (EKdo 16) (“Testing-command 16”) that was formed March 1943 in Peenemünde-West, as a test unit for the rocket fighter, and later based at the Luftwaffe airfield in Bad Zwischenahn for a considerable period of time. This EKdo 16 had some of the aircraft painted completely in red and was the first Luftwaffe unit to perform a combat mission.

The performance of the Me 163 far exceeded that of contemporary piston engine fighters. At a speed of over 200 mph the aircraft would take off, in a so-called “Scharfer Start” (“sharp start”, “sharp take-off”) from the ground, from its two-wheeled dolly. The aircraft would be kept at level flight at low altitude until the best climbing speed of around 420 mph was reached, at which point it would jettison the dolly, retract its extendable landing skid and then pull up into a 70° angle of climb, to a bomber’s altitude. It could go higher if required, reaching 39,000 ft in an unheard-of three minutes. Once there, it would level off and quickly accelerate to around 550 mph or faster, which no Allied fighter could match. Flight endurance under power was just eight minutes after which the aircraft became a glider, and the time available to attack enemy aircraft using  two 20mm cannons was very limited. Once the rocket’s fuel supply was exhausted the Me 163B “Komet” was an easy target for fighter aircraft, particularly during the landing phase (Ref.: 24).

DFS 228 V1 (Huma Models)

TYPE: Rocket powered high-altitude reconnaissance aircraft

ACCOMMODATION: Pilot only in prone position in pressurized cockpit

POWER PLANT: One Walter HWK 109-509 bi-fuel liquid rocket engine, rated at 1,650 kp at 40,000 ft

PERFORMANCE: 435 mph at 75,459 ft

COMMENT:   Beginning in 1940, the DFS (Deutsches Forschungsinstitut für Segelflug, German Research Institute for Sailplanes) started an ambitious program to achieve supersonic flight. Since the only engines powerful enough and available at the time were rocket engines, it was realized that the solution was to have the assault on the sound barrier take place at a high altitude. It was decided to divide the program into three sections:
The first part was concerned with developing and testing of the pressurized cockpit section, the method of pilot escape in case of emergency and performance testing of rocket engines at high altitudes.
The second part was to discover the performance of various sweptback wing configurations. The DFS acquired the Heinkel P.1068 designs for a four-engined turbojet bomber with various wing sweep angles.
The third and last part was to actually build a supersonic aircraft with information learned in the above two steps, which was eventually to become the DFS 346.
The DFS decided to design a new aircraft (although much was learned in an earlier design, the DFS 54) to investigate the first part of their three-step program. Thus, in 1941, the RLM assigned the number 228 to the aircraft, and requested that the DFS 228 also be designed for high-altitude reconnaissance duties as well as research work.
The first prototype of the DFS 228 (coded D-IBFQ) was completed in 1943 by the DFS, although the control sections and landing skid were built by Schmetz Company. The fuselage of the DFS 228 V1 consisted of three circular sections: the nose section containing the cockpit; a center section which contained the landing skid, fuel tanks and a Zeiss infra-red camera; and the tail section with the Walter HWK 509A-1 or A-2 rocket engine. The wing was attached at the mid-fuselage point, and featured 4.5 degrees of dihedral. Wooden construction was used for the entire wing, with a single laminated wooden spar running from wingtip to wingtip, wooden ribs and a plywood covering.  Wide-span divided ailerons were fitted to the wing (the inner section acted as landing flaps), and lift spoilers were also fitted to the upper and lower wings. A conventional tail unit was used, also with all wooden construction. Landing was done on a retractable skid. Since the DFS 228 was to operate in extremely high altitudes, a completely pressurized cockpit was designed. Although it was thought at first that the pressure cabin could be of wooden construction, a metal compartment was built after the wooden one failed to hold sufficient pressure. The nose section was double-walled constructed with aluminum foil insulation. The V1 prototype had a conventional seated pilot’s position, but the V2 and later aircraft were to have a prone pilot position, due to the difficulty of of sealing such a large compartment with the pilot seated upright. All glazed areas were made of double layered Plexiglas and were provided with warm air circulation between layers to prevent frosting of the Plexiglas.
After pressure sealing problems became apparent on the V1 cockpit, it was decided to go with a prone pilot. An adjustable horizontal couch was provided for the pilot to lay on; all controls, oxygen supplies and cockpit equipment mounted directly to the steel tube structure which was then attached directly to the main fuselage bulkhead at the back of the cockpit. This also had the added advantage of keeping the pressurized area small. Thus it was easier to keep sealed. The new cockpit arrangement was incorporated in to the DFS 228 V2 and later aircraft.
A very interesting flight plan was arranged for the operational recognizance DFS 228. It was to be mounted above (or could be towed behind) a carrier aircraft (usually a Do 217K), where it was then carried to approximately 32.808 feet. Upon release, the DFS 228 would then ignite its rocket engine until an altitude of about 75.460-82.021 feet was reached. By this time, the DFS 228 would be over its photographic target area and after its reconnaissance mission was fulfilled, the aircraft would then make a long glide back to base.
In the case of an emergency at high altitudes, the complete pressurized nose section (with all life support equipment attached) could be jettisoned by firing four explosive bolts, or it could take place automatically when the cockpit pressure dropped below a minimum level. An automatic parachute would then deploy to stabilize and slow the descent. When a safe altitude was reached, the pilot was ejected by compressed air, and would then descend to the ground using his personal parachute. This escape procedure was successfully tested by the Soviets after the war, with a captured DFS 346, which had a similar escape system.
DFS 228 V1 flight trials were made at Hörsching, southwest of Linz, by the DFS and also by Erprobungsstelle Rechlin in late 1944. Over 40 test flights were made, and although powered flight was to take place in February 1945, none were actually made using rocket power, and none exceeded 32.808 feet. It was in these tests that the upright pilot’s position was found to be unsuitable for proper cockpit pressurization. The decision was made to go with the prone position cockpit, and was included into the DFS 228 V2, which was built and also flight tested.
The main faults found with the 228 were that it suffered from poor aileron effectiveness at high altitudes and that the elevators were very sensitive. Other than the early pressurization problems, the general handling was satisfactory and the problems would not hamper the intended role of the aircraft. A potential problem could have arisen with the use of the Walter HWK 509A1 or A-2 rocket engines, due to the fact that the flight profile meant for the rocket engine to be intermittently operated, and the possibility existed of valves and pumps freezing up at the extreme altitudes and low temperatures in which the flight was to take place. Of course, newer rocket engines were continually being developed, and perhaps some sort of heating system or the possibility of using M-Stoff and A-Stoff (methanol and oxygen) for fuels, which could have operated at much lower temperatures, could have been developed.
Although powered flight had not been attempted at the time of Germany’s collapse, the construction of a pre-production batch of 10 DFS 228A-0 aircraft had begun at Griesheim, near Darmstadt.
The DFS 228 V2 was destroyed at Hörsching in May 1945, only the forward section had parts worth salvaging. The DFS 228 V1 survived the war, and was surrendered at Ainring in the US Zone of Occupation. On June 18, 1945, it was taken by road to the US Air Technical Intelligence Unit at Stuttgart. It was later sent to the RAE Farnborough in June 1946, and although allegedly was sent to the scrap pile in 1947, another report has the DFS 229 V1 being sent to Slingsby Sailplanes Ltd. at Kirkbymoorside in Yorkshire. Strangely enough, Slingsby offered a design for their T44, a stratospheric research sailplane which incorporated several DFS 228 features, including the detachable pressurized cockpit section (Ref.: 17).

Focke-Wulf Fw 186 (Planet Models, Resin)

TYPE: Autogiro, reconnaissance, observation

ACCOMMODATION: Pilot and observer

POWER PLANT: One Argus As 10c air-cooled inline piston engine, rated at 240 hp

PERFORMANCE: 103 mph

COMMENT: German helicopter development began with Focke-Wulf’s acquisition of the rights to manufacture Cierva autogyros during the 1920’s. Over 30 Cierva C.19 and C.30 autogyros were built during the late 1920’s and early 1930’s, and from this experience, Heinrich Focke, the engineering half of the Focke-Wulf company, decided to develop an original autogyro design to compete in the Luftwaffe’s contest to provide a utility-liaison aircraft. The Focke-Wulf entry, designated Fw 186, was essentially a Focke-Wulf Fw 56 “Stösser” (Goshawk) parasol wing advanced trainer, with wings removed, tail unit and landing gear redesigned, and configured for two seats in tandem. The engine remained unchanged, with a clutch arrangement installed to start the blades rotating for takeoff. An autogyro, similar in principle to today’s gyrocopters, uses the main power plant for forward thrust, while the rotors freewheel in flight. The aircraft could take off and land in very short distances, but it could not hover or take off and land vertically.
The first flight of the Focke-Wulf  Fw 186 was on July 1939 and although very successful, it was beaten out by the Fieseler Fi 156 “Storch” (Stork) for the Luftwaffe contract, and disappeared from the scene afterward. Only two examples were built (Ref.: Planet Models).

Focke-Wulf Fw 191 V1 (Airmodel, Vacu-formed)

TYPE: Medium bomber

ACCOMMODATION: Crew of seven

POWER PLANT: Two BMW 801A radial engines, rated at 1,539 hp each

PERFORMANCE: 385 mph at 20,800 ft

COMMENT: The Focke-Wulf Fw 191 was a prototype German bomber of WW II, as the Focke-Wulf firm’s entry for the Bomber B advanced medium bomber design competition. Two versions were intended to be produced, a twin-engine version using the Junkers Jumo 222 engine and a four-engine variant which was to have used the smaller Daimler-Benz DB 605 engine. The project was eventually abandoned due to technical difficulties with the engines
In July 1939, the RLM issued a specification for a high-performance medium bomber (the “Bomber B” program). It was to have a maximum speed of 370 mph and be able to carry a bomb load of 4,000 kg to any part of Britain from bases in France or Norway. Furthermore, the new bomber was to have a pressurized crew compartment, of the then-generalized “stepless cockpit” design (with no separate windscreen for the pilot) pioneered by the Heinkel He 111P shortly before the war and used on most German bombers during the war, remotely controlled armament, and was to utilize two of the new 2,466 hp class of engines then being developed (Jumo 222 or DB 604), with the Jumo 222 being specified for the great majority of such twin-engined designs, that Arado, Dornier, Focke-Wulf and Junkers had created airframe designs to use. The Arado Ar E340 was eliminated. The Dornier Do 317 was put on a low-priority development contract; and the Junkers Ju 288 and Focke-Wulf Fw 191 were chosen for full development.
Overall, the Fw 191 was a clean, all-metal aircraft that featured a shoulder-mounted wing. Two 24-cylinder Junkers Jumo 222 engines (which showed more promise than the DB 604 engines) were mounted in nacelles on the wings. An interesting feature was the inclusion of the Multhopp-Klappe, an ingenious form of combined landing flap and dive brake fitted in four sections to the wing trailing edges, which was developed by engineer H. Multhopp. The entire fuel supply was carried in five tanks located above the internal bomb bay, and in two tanks in the wing between the engine nacelles and fuselage.
The tail section was of a twin fins and rudders design, with the tailplane having a small amount of dihedral. The main landing gear legs retracted to the rear and rotated 90° to lie flat in each engine nacelle with the mainwheels resting atop the lower ends of the gear struts when fully retracted, much like the main gear on the production versions of the Junkers Ju 88 already did. Also, the tailwheel retracted forwards into the fuselage. A crew of four sat in the pressurized cockpit, and a large Plexiglas dome was provided for the navigator; the radio operator could also use this dome to aim the remotely controlled rear guns.
The Fw 191 followed established Luftwaffe practice in concentrating the crew in the nose compartment, also including the nearly ubiquitous “Bola”, inverted-casemate undernose gondola for defensive weapons mounts first used on the Junkers Ju 88A before the war, and in the use of a “stepless cockpit”, having no separate windscreen for the pilot, as the later -P and -H versions of the Heinkel He 111 already did. This was pressurised for high-altitude operations. The proposed operational armament consisted of one 20 mm MG 151 cannon in a chin turret, twin 20 mm MG 151 in a remotely controlled dorsal turret, twin 20 mm MG 151 in a remotely controlled ventral turret, a tail turret with one or two machine guns and remotely controlled weapons in the rear of the engine nacelles. However, different combinations were mounted in the prototype aircraft. Sighting stations were provided above the crew compartment, as well as at the ends of the aforementioned “Bola” beneath the nose.
The aircraft had an internal bomb bay. In addition, bombs or torpedoes could be carried on external racks between the fuselage and the engine nacelles. The design was to have had a maximum speed of 370 mph, a bomb load of 4,000 kg, and a range allowing it to bomb any target in Britain from bases in France and Norway.
It is said that the intention to use electric power for almost all of the aircraft’s auxiliary systems (also a fact for the successful Focke-Wulf Fw 190 fighter), requiring the installation of a large number of electric motors and wiring led to the nickname for the Fw 191 of “Das fliegende Kraftwerk” (the flying power station). This also had the detrimental effect of adding even more weight to the overburdened airframe, plus there was also the danger of a single enemy bullet putting every system out of action if the generator was hit. On its maiden flight early in 1942, the Focke-Wulf Fw 191 V1 showed immediate problems arising from the lower rated engines not providing enough power, as was anticipated. Additional problems occurred with the Multhopp-Klappe, which presented severe flutter problems when extended, and pointed to the need for a redesign. At this point, only dummy gun installations were fitted and no bomb load was carried. After completing ten test flights, the Fw 191 V1 was joined by the similar V2, but only a total of ten hours of test flight time was logged. The 2,466 hp Junkers Jumo 222 engines which would have powered the Fw 191 proved troublesome. In total only three prototype aircraft, V1, V2 and V6, were built. The project was crippled by engine problems and an extensive use of electrical motor-driven systems. Problems arose almost immediately when the Junkers Jumo 222 engines were not ready in time for the first flight tests, so a pair of 1,539 hp BMW 801A radial engines was fitted. This made the Fw 191 V1 seriously underpowered. Another problem arose with the RLM’s insistence that all systems that would normally be hydraulic or mechanically activated should be operated by electric motors.
At this point, the RLM allowed the redesign and removal of the electric motors (to be replaced by the standard hydraulics), so the Fw 191 V3, V4 and V5 were abandoned. The Fw 191 V6 was then modified to the new design, and also a pair of specially prepared Junkers Jumo 222 engines were fitted that developed 2,170 hp for takeoff. The first flight of the new Fw 191 took place in December 1942. Although the V6 flew better, the Junkers Jumo 222 was still not producing their design power, and the whole Jumo 222 development prospect was looking bad due to the shortage of special metals for it. The Fw 191 V6 was to have been the production prototype for the Fw 191A series.
Due to the German aviation engine industry having ongoing problems in producing power plant designs capable of output levels matching or exceeding the 2,100 hp figure throughout the entirety of the war years, that had any demonstrable level of combat-ready reliability, the Jumo 222 engines were having a lot of teething problems, and the Daimler Benz DB 604 had already been abandoned, a new proposal was put forth for the Fw 191B series.
The Fw 191 V7 through V12 machines were abandoned in favor of using the Fw 191 V13 to install a pair of Daimler Benz DB 606 or 610 “power system” engines, which were basically coupled pairs of either DB 601 or 605 12-cylinder engines. Their lower power-to-weight ratio, however, from their 1.500 kg weight apiece for each “power system”, meant that the armament and payload would have to be reduced. It had already been decided to delete the engine nacelle gun turrets, and to make the rest manually operated. Five more prototypes were planned with the new engine arrangement, V14 through V18, but none were ever built, possibly from the August 1942 condemnation by Reichsmarschall H. Göring of the coupled “power system” DB 606 and 610 power plants as “welded-together engines, in regards to their being the primary cause of the unending series of power plant problems in their primary use, as the engines on Heinkel’s He 177A “Greif”, Germany’s only production heavy bomber of World War II.
One final attempt was made to save the Focke-Wulf Fw 191 program, this time the Fw 191C was proposed as a four engined aircraft, using either the 1,322 hp Junkers  Jumo 211F, the 1,332 hp Daimler-Benz DB 601E, the 1,455 hp Daimler-Benz DB 605A or similar rated DB 628 engines. Also, the cabin would be unpressurized and the guns manually operated, with a rear step in the bottom of the deepened fuselage — in the manner of the near-ubiquitous “Bola” gondola used by the majority of German bombers for ventral defense under the nose — being provided for the gunner.
However, at this time, the whole “Bomber B” program had been canceled, due mainly to no engines of the 2,500 hp class being available, which was one of the primary requirements in the “Bomber B” program. Although the Fw 191 will be remembered as a failure, the air frame and overall design eventually proved themselves to be sound; only the underpowered engines and insistence on electric motors to operate all the systems eventually doomed the aircraft. All in all, there were only three Focke-Wulf Fw 191s ever built (V1, V2 and V6), and no examples of the Fw 191B or C ever advanced past the design stage. The RLM kept in reserve for Focke-Wulf the future number: Fw 391 for follow-up designs, but nothing ever developed. The project was eventually scrapped (Ref.: 24).

Arado Ar 234B-2 “Blitz” (“Lightning”), (9/KG 76), (Dragon)

TYPE: Fast medium bomber

ACCOMMODATION: Pilot only

POWER PLANT: Two Junkers Jumo 004B-1 turbojet engines, rated at 900 kp each

PERFORMANCE: 461 mph at 20,000 ft

COMMENT: In late 1940, the Reichsluftfahrtministerium (RLM, Reich Air Ministry), offered a tender for a jet-powered high-speed reconnaissance aircraft with a range of 1,340 mi. Arado was the only company to respond, offering their E.370 project, a high-wing conventional-looking design with a Junkers Jumo 004 tubojet engine under each wing.
Arado estimated a maximum speed of 480 mph at 20,000 ft, an operating altitude of 36,000 ft and a range of 1,240 mi. The range was short of the RLM request, but they liked the design and ordered two prototypes as the Arado Ar 234. These were largely complete before the end of 1941, but the Jumo 004 engines were not ready, and would not be ready until February 1943. When they did arrive they were considered unreliable by Junkers for in-flight use and were cleared for static and taxi tests only. Flight-qualified engines were finally delivered, and the first prototype, the Ar 234 V1 made its first flight on July 1943 at Rheine Airfield.
By September 1943, four prototypes were flying and four more prototypes under construction. The sixth and eighth aircraft of the series were powered with four BMW 003 turbojet engines instead of two Jumo 004s, the sixth having four engines housed in individual nacelles and the eighth flown with two pairs of BMW 003s installed within “twinned” nacelles underneath either wing. These were the first four-engine jet aircraft to fly.
The projected weight for the aircraft was approximately 8 tonnes. To reduce the weight of the aircraft and maximize the internal fuel the eight prototype aircraft were fitted with the original arrangement of trolley-and-skid landing gear, intended for the planned operational, but never-produced Arado Ar 234A version.
Arado did not use the typical retractable landing gear. Instead, the aircraft was to take off from a jettisonable three-wheeled, tricycle gear-style trolley and land on three retractable skids, one under the central section of the fuselage, and one under each engine nacelle.
The RLM had already seen the promise of the design and in July 1943 had asked Arado to supply two prototypes of a “Schnellbomber” (“Fast bomber”) version as the Arado Ar 234B. Since the original skid-equipped Ar 234A’s fuselage design was very slender and filled with fuel tanks, there was no room for an internal bomb bay and the bombload had to be carried on external racks.
Since the cockpit was directly in front of the fuselage, the pilot had no direct view to the rear, so the guns were aimed through a periscope, derived from the type used on German World War II tanks, mounted on the cockpit roof. The Ar 234B version was modified to have fully retractable tricycle landing gear, with the mid-fuselage very slightly widened to accommodate the forward-retracting main gear units, the nose gear retracting rearwards. The first twin-Jumo 004 powered prototype Ar 234B (V 7) flew on 10 March 1944 for the first time and made history on 2 August 1944 as the first jet aircraft ever to fly a reconnaissance mission.
Production B-series aircraft  were slightly wider at mid-fuselage to house the main landing gear, with a central fuel tank present (the middle one of a trio of fuel tanks) in the mid-fuselage location forward tank, central and an aft. Under tests with maximum bombload consisting of three SC 500 bomb, the Ar 234 V9 aircraft could reach 418 mph at 16,000 ft. This was still better than any bomber the Luftwaffe had at the time, and made it the only bomber with any hope of surviving the massive Allied air forces. The normal bombload consisted of two 500 kg bombs suspended from the engines or one large 1,000 kg bomb semi-recessed in the underside of the fuselage with maximum bombload being 1,500 kg. In case the full bomb load was to be deployed on an Ar 234B for an operational sortie, fuel had to be reduced and two Walter HWK 109-500A-1 “Starthilfe” (Take-off assistance) liquid fuel jettisonable JATO rocket pods delivering 500kp thrust each were fixed under each wing.
Production lines were already being set up, and 20 Arado Ar 234B-0 pre-production aircraft were delivered by the end of June 1943. Later production was slow, as the Arado plants were given the simultaneous tasks of producing aircraft from other bombed-out factories hit during the USAAF’s “Big Week”, and the ongoing license-building and nascent phasing-out of Heinkel’s heavy He 177A bomber, even as the Arado firm was intended to be the sole subcontractor for the Heinkel He 177B (He 277) series strategic bomber, meant to start construction at Arado as early as October 1944. Meanwhile, several of the Ar 234 prototypes – including a few of the surviving six twin-engine Jumo 004-powered “trolley-and-skids” Ar 234A-series prototypes – were sent forward in the reconnaissance role. In most cases, it appears they were never even detected, cruising at about 460 mph at over 29,900 ft, with the seventh prototype achieving the first-ever wartime reconnaissance mission over the United Kingdom by a Luftwaffe-used jet aircraft.
The few 234Bs entered service in autumn and impressed their pilots. They were fairly fast and completely aerobatic. The long takeoff runs led to several accidents; a search for a solution led to improved training as well as the use of two jettisonable RATO units. The Jumo 004 engines were always the real problem; they suffered constant flameouts and required overhaul or replacement after about 10 hours of operation.
The most notable use of the Arado Ar 234 in the bomber role was the attempt to destroy the Ludendorff Bridge at Remagen. The aircraft continued to fight in a scattered fashion until Germany surrendered on 8 May 1945. Some were shot down in air combat, destroyed by flak, or “bounced” by Allied fighters during takeoff or on the landing approach, as was already happening to Messerschmitt Me 262 jet fighters. Mostly the remaining aircraft sat on the airfields awaiting fuel that never arrived.
Overall from mid-1944 until the end of the war a total of 210 aircraft were built. In February 1945, production was switched to the Arado Ar 234C variant. It was hoped that by November 1945 production would reach 500 per month. Only a few of this four engine aircraft were built before Germany finally collapsed (Ref.: 24).

Messerschmitt Me 262 HG III/ Concept 3 (Unicraft Models, Resin)

TYPE: High-speed test aircraft. Project

ACCOMMODATION: Pilot only

POWER PLANT: Two Heinkel-Hirth HeS 011 turbojet engines, rated at 1,300 kp thrust each

PERFORMANCE: High subsonic speed, estimated

COMMENT: In early 1941 several high speed versions of the basic Messerschmitt Me 262 were designed on the drawing board. The first of these “Hochgeschwindigkeitsjäger” (HG), (High-speed fighter) was the Messerschmitt Me 262 V9, unofficially called HG I. This aircraft featured modified wing leading edges of the inner wing section, swept angles of stabilizers, and a “Rennkabine” (Racing canopy), shallow, low-drag cockpit canopy and windscreen with low profile.
Other two projects were created following this way: The Me 262 HG II called for an outboard wing of increased chord and an improved air intake and engine installation, and finally  the Me 262 HG III, which was the final stage of development. It required more radical modifications, as a new 45 degree swept wing with engines housed in the wing roots. Three variants of the Me 262 HG III are known correspond to the original layout.
Entwurf 1” (Concept 1) had a the original tail plane of the Me 262, “Entwurf 2” (Concept 2) had a butterfly-type tail plane, and “Entwurf 3” (Concept 3) together with various subtypes was considerably altered in the fuselage area, where the cockpit was relocated at the rear and formed a part of the empennage group. The swept back stabilizers were located behind the cockpit. This Messerschmitt Me 262 HG III/ Concept 3 attained a very high state of fighter technology, which in the post-war period was the only realized abroad after a passage of several years.

Messerschmitt Me P. 1110/II “Tunnel-Einlauf”, (“Tunnel-air-intake”) with Kramer X-4, (Planet Models, Resin)

TYPE: High altitude fighter

ACCOMMODATION: Pilot only

POWER PLANT: One Heinkel-Hirth HeS 011 turbojet engine, rated at 1,300 kp

PERFORMANCE: 630 mph

COMMENT: In Autumn 1944, in the context of the “Jägernotprogramm” (“Emergency Fighter Program”) the Oberkommando der Luftwaffe (OKL, Luftwaffe High Command) requested for proposals for a new generation of fighter/interceptor aircraft in order to replace the Heinkel He 162 “Salamander” or “Volksjäger” (“Peoples fighter”).
Besides designs such as Blohm & Voss Bv P.212, Focke-Wulf Ta 183, Heinkel He P. 1078, and Junkers EF 128 Messerschmitt proposed its project Me P. 1110 with three different variants.
First of the designs was the Messerschmitt Me P.1110/I, a turbo-jet powered interceptor with a conventional-looking design with the air intakes located in the middle part of fuselage sides above the wing the inlet not protruding the cross section (“Rampen-Einlauf”, “Ramp-air-intake”). The wing was of wooden construction and was swept back to 60 degree at the wing root and 40 degree at the leading edge. The tail plane was conventional with elevators and a vertical fin and swept back. Power was provided by a Heinkel/Hirth HeS 011 turbojet engine. A pressurized cockpit with streamlined fairing,  tricycle landing gear and three MK 108 30mm cannon in the nose with a provision for two more in the wing roots was envisaged.
The second design was the Messerschmitt Me P.1110/II that differed from the Me P.1110/I mainly in a V-tail unit and a divided annular air intake behind the cockpit. The advantage of this unusual arrangement was that it would reduce drag by fifteen percent compared to a single nose air intake at the cost of four percent air flow reduction to the jet engines. To increase the air flow a supercharger was provided that additionally withdraw the boundary layer.
Like the Me P.1110/I, the Me P.1110/II had 40 degree swept-back wings, an HeS 011 jet engine and was armed with three MK 108 30mm cannon in the nose with a provision for two more in the wing roots.
The third design the Messerschmitt Me P.1110 “Ente” was of canard configuration with small wings in the front and larger wings in the rear part of the fuselage.
All projects would be soon dropped in favor of the Junkers EF 128 and none of the Messerschmitt designs made it to the prototype stage. (Ref.: 20, 22).

Arado Ar. 340 (Anigrand Models, Resin)

TYPE: Medium bomber

ACCOMMODATION: Crew of four

POWER PLANT: Two Junkers Jumo 222 or Daimler-Benz DB 604 (both liquid-cooled) or BMW 802 (radial) piston engines
PERFORMANCE: 360 mph

COMMENT: In 1939, the “Technisches Amt des Reichluftfahrtministeriums” (RLM); (Technical Office of the Reich Air Ministry) issued specification for a “Bomber B” requirement.
The Reich Air Ministry ordered the aircraft to replace the Junkers Ju 88 and Dornier Do 217 bombers by 1943. At first four manufacturers submitted plans to the Air Ministry: Arado project E.340, Dornier Do 317, Focke-Wulf Fw 191, and Junkers Ju 288. Later, Henschel was asked to submit its Henschel Hs 130 design due to the expertise of this company with its experiments with pressurized cockpits. Meanwhile, Project “Bomber B” contest winner was the Arado design, officially named Ar 340.
While the designs of all other contenders were of more conventional layout the Arado Ar 340 was designed with a central fuselage containing all four crew members. The cockpit and rear compartment were glazed and pressurized. The projected Junkers Jumo 222 engines were positioned in a unique twin-boom arrangement connected only through the wing assembly, a configuration which offered the crew better visibility. The landing gear was mounted to the load-bearing wing center-section. The tail of the aircraft was a unique design, where the tail plane did not connect the two booms but was cantilevered outwards instead, each similar to the asymmetric Blohm & Voss Bv 141B booms and tail arrangement. Also similarly, this would have provided the rear gunner with a clear range of fire directly behind. The fuselage extended forwards beyond the engines, with the gunners situated behind the cockpit, ahead of the bomb bay and wing spars. The MG 151 cannon in the tail of the central fuselage would have been controlled with remote aiming through periscopes. There were also two remote-controlled “Fernbedienbare Drehlafette FDL 131” 13mm (remotely-controlled gun turrets) to be placed above and below the fuselage.
The Ar 340 was one of the steadily growing numbers of later-war military airframe designs designed to use the troublesome Junkers Jumo 222 engine. Otherwise an innovative design, these powerful engines were selected because they would have allowed the Arado Ar 340 to carry the required payload of 5,900 kg within a relatively compact airframe, despite their still-strictly developmental nature. As the development of the Junkers Jumo 222 engines were cancelled, plans were discussed to power the Arado Ar 340 with Daimler-Benz DB 605 liquid-cooled engines or BMW 802 radial engines. Meanwhile the RLM favoured the Junkers Ju 288 and the Arado project was not pursued.
Ultimately, the entire “Bomber B project” was cancelled, primarily as a result of the failure to develop the required engines (Ref.: 24).

Dornier Do 335A-0 “Pfeil” (Arrow”), (Dragon Models)

TYPE: Heavy Fighter

ACCOMMODATION: Pilot only

POWER PLANT: Two Daimler-Benz DB 603A liquid-cooled engines, rated at 1,725 hp each

PERFORMANCE: 475 mph

COMMENT: The Dornier Do 335 “Pfeil” (“Arrow”) was a WW II heavy fighter built by the Dornier Company. It’s performance was much better than any other twin-engine designs due to its unique push-pull configuration and the lower aerodynamic drag of the in-line alignment of the two engines. It was Luftwaffe’s fastest piston-engine aircraft of World War II. The Luftwaffe was desperate to get the design into operational use, but delays in engine deliveries meant that only a handful were delivered before the war ended.
The origins of the Dornier Do 335 trace back to WW I when Claude Dornier designed a number of flying boats featuring remotely driven propellers and later, due to problems with the drive shafts, tandem engines. Tandem engines were used on most of the multi-engine Dornier flying boats that followed, including the highly successful Dornier Do J “Wal” (“Whale”) and the gigantic Donier Do X. The remote propeller drive, intended to eliminate parasitic drag from the engine entirely, was tried in the innovative but unsuccessful Dornier Do 14, and elongated, tubular drive shafts as later used in the Do 335 saw use in the rear engines of the four-engine, twinned tandem-layout Dornier Do 26 flying boat.
There are many advantages to this design over the more traditional system of placing one engine on each wing, the most important being power from two engines with the frontal area (and thus drag) of a single-engine design, allowing for higher performance. It also keeps the weight of the twin power plants near, or on, the aircraft centerline, increasing the roll rate compared to a traditional twin. In addition, a single engine failure does not lead to asymmetric thrust, and in normal flight there is no net torque, so the plane is easy to handle. The choice of a full “four-surface” set of cruciformly tail surfaces in the Do 335’s rear fuselage design, included a ventral vertical fin-rudder assembly to project downwards from the extreme rear of the fuselage, in order to protect the rear propeller from an accidental ground strike on takeoff. The presence of the rear pusher propeller also mandated the provision for an ejection seat for safe escape from a damaged aircraft, and designing the rear propeller and dorsal fin mounts to use explosive bolts to jettison them before an ejection was attempted — as well as twin canopy jettison levers, one per side located to either side of the forward cockpit interior just below the sills of the five-panel windscreen’s sides, to jettison the canopy from atop the cockpit before ejection.
In 1939, Dornier was busy working on the P.59 high-speed bomber project, which featured the tandem engine layout. In 1940, he commissioned a flying test bed, closely modeled on the airframe of the early versions of the twin engine Dornier Do 17 bomber but only 40% of the size of the larger bomber, with no aerodynamic bodies of any sort on the wing panels and fitted with a retractable tricycle landing gear to validate his concept for turning the rear pusher propeller with an engine located far away from it and using a long tubular driveshaft. This aircraft, the Göppingen Gö 9, built by , Schrempp-Hirth, a small sailplane company, showed no unforeseen difficulties with this arrangement, but work on the Dornier P.59 was stopped in early 1940 when the RLM ordered the cancellation of all projects that would not be completed within a year or so.
In May 1942, Dornier submitted an updated version his design as the Dornier P.231, in response to a requirement for a single seat, “Schnellbomber” -like high-speed bomber/intruder. P.231 was selected as the winner after beating rival designs from Arado, Blohm & Voss and Junkers, development contract was awarded as the Dornier Do 335. In autumn 1942, Dornier was told that the Do 335 was no longer required as a “Schnellbomber”, and instead a multi-role fighter based on the same general layout would be accepted. This delayed the prototype delivery as it was modified for the new role.
The Dornier Do 335 V1 first prototype flew in October 1943 and initial trials revealed essentially good handling characteristics. Acceleration was particularly favourable and the turning circle was rather better than had been anticipated. The use of a nose-mount annular radiator for the forward engine (much like a Junkers Jumo 211-powered Junkers Ju 88, or Jumo 213-powered Focke-Wulf Fw 190D-9) and a ventral-fuselage mount air-scooped radiator installation for cooling the rear engine (appearing like that on a North American P-51 “Mustang”) was distinctive.
However, several problems during the initial flight of the Do 335 would continue to plague the aircraft through most of its short history. Issues were found with the weak landing gear and with the main gear’s wheel well doors, resulting in them being removed for the remainder of the V1’s test flights. The Do 335 V1 made 27 flights, flown by three different pilots.
During these test flights the second Do 335 V2 was completed and made its first flight on December 1943, followed by the third Do 335 V3 on January 1944. In mid January 1944, RLM ordered five more prototypes, one to be built as Do 335A-6 night fighter. By this time, more than 60 hours of flight time had been put on the Do 335 and reports showed it to be good handling characteristics, but more importantly, it was a very fast aircraft. Even with one engine out, it reached about 350 mph.
Thus the Do 335 was scheduled to begin mass construction, with the initial order of 120 preproduction aircraft to be manufactured by DWF (Dornier-Werke Friedrichshafen) to be completed no later than March 1946. This number included a number of bombers, destroyers (heavy fighters), and several yet to be developed variants. At the same time, DWM (Dornier-Werke München) was scheduled to build over 2000 Do 335s in various models, due for delivery in March 1946 as well.
On 23 May 1944, as part of the developing “Jägernotprogramm” (“Emergency Fighter Program”) directive, maximum priority was given to Do 335 production. Furthermore, the decision was made, along with the rapid shut-down of many other military aircraft development programs, to cancel the Heinkel He 219 night fighter, which also used the DB 603 engines, and use its production facilities for the Do 335 as well. However, Ernst Heinkel managed to delay, and eventually ignore, its implementation, continuing to produce examples of the He 219A.
At least 16 prototype Do 335s were known to have flown as well as Muster-series prototypes on a number of DB603 engine subtypes. The first preproduction Do 335A-0s were delivered in July 1944 to the “Erprobungskommando 335” (“Proving detachment 335”) formed for service evaluation purposes. Approximately 22 preproduction aircraft were thought to have been completed and flown before the end of WW II including approximately 11 Do 335A-1 single-seat fighters of which two examples had been converted to a trainer version Do 335A-12 for training purposes (Ref.: 7., 24).