TYPE: Medium bomber

ACCOMMODATION: Crew of four

POWER PLANT: Two Daimler-Benz DB 610A-1/B-1 liquid-cooled engines, rated at 2,950 hp each

PERFORMANCE: 407 mph at 22,300 ft

COMMENT: Prior to the receipt of RLM instructions to prepare for production of the Daimler-Benz DB 606-powered Junkers Ju 288, the Junkers construction bureau had introduced some major changes in the basic design of the bomber which had resulted in the Ju 288C intended specifically for the Daimler-Benz engines. One of the most noticeable external changes was the provision of a redesigned and elongated nose which increased overall length substantially. Defensive armament was supplemented by a ventral barbette aft of the bomb-bay, instrumentation was greatly improved and the structure was strengthened.
The first C-series prototype, the Ju 288 V101 with DB 606A/B engines, was completed in August 1942, this being followed within a few weeks by the similar Ju 288 V102.
The Ju 288C programme continued with high priority, production standards were finalized, and modifications dictated by flight test programme, together with production features, were embodied by the next prototype, the Ju 288C V103. Fitted with the more powerful DB 610 engines and introducing provision for underwing weapons racks, the Ju 288C V103 had the full complement of four remotely-controlled gun barbettes, and was flown for the first time in spring of 1943.
The Junkers Ju 288C V103 was intended as the first production prototype for the Ju 288C-1, and was rapidly followed by the Ju 288 V104 and V105 which were flown in May 1943, and the V106 which flew in June, these all being powered by DB 610A/B engines and differing only in minor items of equipment. At this time, it was proposed to manufacture the bomber in three versions which differed primarily in the defensive armament fitted. The Ju 288C-1 was to have a chin, dorsal and ventral barbettes each mounting twin MG 131 machine guns, and a tail barbette mounting a MG 151 cannon; the Ju 288C-2 was to have had twin MG 151 cannon in each chin, dorsal and ventral barbettes, and either two MG 131s in tail barbette or four MG 131 in a manned tail turret, and the Ju 288C-3 was to have been a night bomber with defensive armament restricted to twin MG 131s in a ventral barbette.
Suddenly, in June 1943, Junkers was informed by the Technische Amt that the entire “Bomber B” programme had been abandoned owing to increasing shortages of strategic materials and the effect that the launching of a major production program for a new bomber would have on existing production programmes at a critical phase in the conflict. However, despite the cancellation of the programme, Junkers completed two additional machines, the Ju 288 V107 and V 108, which were flown in July 1943, other airframes on the assembly line being scrapped. Some flight testing of the Ju 288 was continued until the summer of 1944, by which time a least 17 of the 22 prototypes had crashed while engaged in flight development. With the termination of the test programme, several of the surviving Ju 288B- and C-series prototypes were transferred to the Luftwaffe, and fitted with ventral gun pods similar to that fitted to the Junkers Ju 88P-4 and mounting a single 50 mm BK 5 (KwK 39) cannon, these saw limited operational use during the closing stages of the conflict (Ref.:7).

TYPE: Medium bomber

ACCOMMODATION: Crew of three

POWER PLANT: Two BMW 801MA radial engines, rated at 1,677 hp each

PERFORMANCE: 388 mph

COMMENT: The Junkers Ju 288, originally known within the Junkers Company as the EF 074, was a German bomber project designed during WW II, which only ever flew in prototype form. The first of an eventual 22 development aircraft flew on 29 November 1940.
The Ju 288 was the winner of the “Bomber B” contest, although the contest was started by Junker’s submission of the EF 074 and their selection was never really in doubt. “Bomber B” intended to replace the Junkers Ju 88 with a design that was larger, offer cabin pressurization for high altitude work, have longer range, a much greater war load, be even faster, and have improved defensive firepower. The design would replace all the bombers then in German Luftwaffe service.
Delivering all of these requirements in a single airframe demanded much more powerful engines, and all of the “Bomber B” concepts relied on the Junkers Jumo 222 engine to deliver this power. Ultimately, the Jumo 222 was a failure in spite of massive effort and several redesigns over a period of several years. No suitable replacement was ever forthcoming, dooming the Ju 288 program, and leaving the Luftwaffe with older bomber designs during the second half of World War II.
Junkers had been outlining a variety of improved models of the Ju 88 since 1937, powered by the planned Jumo 222 multibank engine, or Jumo 223 inline multibank diesel of greatly increased power of at 2,000 horsepower. The EF 074 was essentially a scaled-up Ju 88, sharing its general layout and most of its fuselage and wings with extensions in various places. The nose was redesigned with a more streamlined “stepless” cockpit, having no separate windscreen panels for the pilot and co-pilot. This layout allowed cabin pressurization to be more easily implemented. This design approach had been growing in favour, subsequently appearing in various German types, notably the Heinkel He 111P and H’s.
No serious work was undertaken on these versions, but after Heinrich Hertel left Heinkel and joined Junkers in 1939, the EF 074 design was submitted to the RLM in May 1939. Accordingly, the RLM sent out the specifications for the “Bomber B” design competition in July, the Ju 88 retroactively becoming the second aircraft to be designated “Bomber A”, as the June 1936 specification for the Heinkel He 177 also had that name. The “Bomber B” program aimed at replacing all of the medium bombers in the Luftwaffe inventory with a new design based on the EF.74 or something with equal performance. “Bomber B” was intended to have even better speed than the Ju 88, high-altitude cruising with a pressurized cockpit, heavier defensive armament, range allowing it to cover any point in the British Isles, and a 4,000 kg war load, double that of the earlier generation bombers. A number of companies returned proposals, but these were to some extent a formality, the EF.74 had already been selected as the winner, and of the rest of the designs submitted, only the Focke-Wulf Fw 191 and Dornier Do 317 progressed even as far as prototypes, and the Henschel Hs 130 coming under consideration as a late entrant.
Work began on building prototypes in early 1940, and the first example was completed by mid 1940. Power was supposed to be supplied by two Junkers Jumo 222 six-bank, four cylinders per bank, over 2.000 hp output class powerplants, but problems with the Jumo 222’s development — as with almost every new concept for over 2.000 hp output reciprocating aircrafts engienes then underway in the Third Reich — meant the first prototypes flew with BMW 801 radial engines, instead. The first flight-quality Jumo 222s did not arrive until October 1941, and even at this point it was clear they were nowhere near ready for full-scale production. When it became apparent the Jumo 222 was not likely to become a viable powerplant, in May 1942, Junkers proposed replacing them, for their projected Ju 288C version, with the much heavier Daimler Benz DB 606‘s instead; the same 1.5 tonne, twin-crankcase „weldet-together engines“ that Reichsmarschall Hermann Göring complained about some three months later, regarding the Heinkel He 177’s own endless powerplant troubles
Late in January 194, after protracted ground trials, the first prototype, the Ju 288 V1, was flown for the first time. It was powered by two BMW 801 MA engines, each rated at 1,600 hp. The defensive armament arrangement reverted to that of the original EF 074 proposal, dummy barbettes being mounted in forward dorsal and aft ventral positions.
During the early spring 1941, the first prototype was joined by the Ju 288 V2 which differed from its predecessor only in having spoiler-type dive brakes in place of slatted-type surfaces which were also featured by the Ju 288 V3, this third prototype commencing flight trials during the early summer, by which time work had begun on a further series of prototypes, the first of these being the Ju 288 V4.
The Ju 288’s intricate main landing gear system’s design proved to be troublesome. Such a complex main gear design, with only the single pivoting retraction point for its oleo struts taking the primary stress of touchdown, was likely only one of the many potential sources of trouble causing the Ju 288’s main gear units to repeatedly collapse on touchdown.
Although the Junkers Ju 288 never even reached production status, let alone official operational service, the aircraft did see limited combat duty. In 1944, following the cancellation of the Ju 288 programme, the surviving A and C series prototypes were hurriedly fitted with defensive armament and equipment and deployed as reconnaissance bombers on the Western Front. Very few missions were flown, owing to the scarcity of aviation fuel and spare parts, and the unresolved problems with the aircraft’s power plant and undercarriage. It is believed^] that the few Ju 288’s were attached to the same unit operating the small number of Junkers Ju 388 reconnaissance planes that saw service (Ref.: 7. 24).

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).

TYPE: Medium bomber

ACCOMMODATION: Crew of four

POWER PLANT: Two Daimler-Benz DB 603A liquid-cooled piston engines, rated at 1,750 hp each

PERFORMANCE: 348 mph at 19,685 ft

COMMENT: When the “Führungsstab der Luftwaffe” (Operations Staff of the Luftwaffe) drafted its so-called “Bomber B” requirement which was translated into a specification for issue to selected airframe manufactures in July 1939 by the “Technischen Amt des Reichluftfahrtministeriums” (RLM), (Technical Office of the RLM), its intention was nor merely the provision of successors for the Junkers Ju 88 and Heinkel He 111; its aim was also to carry the state of the art in medium bomber design a significant step forward.
The specification was noteworthy in the performance advances that it stipulated, and equally so in design innovations that it called for. The “Bomber B” had to possess a range of 2,237 miles do endow it with a radius of action sufficient to encompass the entire British Isles from bases that it was assumed would be available in France and Norway, a maximum speed of 373 mph at 19,685-22,965 ft., which compared favourably with the speeds of the best contemporary fighters, and a bomb load of 4,410 lb. It had to carry three or four crew members, possess a loaded weight of the order of 44,090 lb., and be of twin-engined configuration, utilizing the extremely advanced 24-cylinder liquid-cooled Daimler-Benz DB 604 or Junkers Jumo 222 engines then at an early stage in development, but the really radical demands of the specification were its insistence on pressurized accommodation for the crew, and the use of remotely-controlled barbettes to house defensive armament.
Initially, the specification was issued to four manufacturers: Arado, Dornier, Focke-Wulf and Junkers, although the scope of the contest was later to be broadened to include Henschel (Henschel Hs 130) when it was realized by the RLM that this company has more pressure cabin experience than any other contestants, with the possible exception of Junkers. The final proposals of the original four competing companies were submitted to the “Technisches Amt” in July 1940, and evaluation eliminated the Arado contender, the Ar 340, prototypes being ordered of each of the other contender, Dornier Do 317, Focke-Wulf Fw 191 and Junkers Ju 288.
Dornier’s proposal was based broadly on the design of the Dornier Do 217, the four crew members being housed ahead of the wing in a pressure cabin which, taking the form of a detachable compartment pressurized by tapping the superchargers of the Daimler-Benz DB 604 engines, was extensively glazed by a series of curved panels.
Two versions of the Do 317 were proposed: the simplified Do 317A, powered by two DB 603A engines (instead of the troublesome Daimler-Benz DB 604) and featuring conventional defensive armament, and the more advanced Do 317B with the heavy 1.5 tonnes apiece, counter-rotating DB 610A/B “power system” engines, remotely aimed “Fernbedienbare Drehlafette” (FDL)-style gun turrets (remotely-controlled turrets), heavier bombload, and an extended wing.
Six prototypes of the Dornier Do 317A were ordered, and the first of these, the Do 317 V1, commenced its flight test program on September 1943. The Do 317 V1 was very similar in appearance to the later Dornier Do 217K and -M subtypes, with a visually reframed slight variation of its multiple glazed-panel “stepless cockpit”, fully glazed nose design that accommodated a pressurized cabin provision, and triangular tailfins. Trials with the Do 317 V1 revealed no real performance advance over the Do 217. However, it was clear even at this point that the call for designs was to some extent a formality, as the Junkers Ju 288 design had already been selected for production. So it was decided to complete the remaining five prototypes without cabin pressurization equipment and fit them out with FuG 230 “Kehl-Straßburg” radio guidance transmitting gear to employ them as Henschel Hs 293 missile launchers. In this form, the prototypes were redesignated Dornier Do 217R. At this time, the Do 317B project was abandoned due to changing wartime conditions (Ref.: 7, 24).