| Table of contents |
|
2 Prototypes 3 Ju 188A & E 4 Ju 188D & F 5 Ju 188C 6 Ju 188G & H 7 High-altitude versions |
In 1939 the Luftwaffe was already planning to replace their first series of aircraft, which had resulted in such famous aircraft as the Junkers Ju 87 Stuka and Ju 88, and the Messerschmitt Bf 109 and Messerschmitt Bf 110. All of these designs were state of the art when first designed, but were now five years old and becoming somewhat out of date.
For their tactical bomber role, currently filled by the Ju 88, the RLM introduced a new contest for a design concept they called Bomber B. Bomber B designs needed to be powered by one of the new 2,500hp class engines, fly at 600km/h (375mph) fully loaded, have a pressurized cockpit for high altitude work, use remote control armament, and carry a 4000 kg load to any point in England. The winner of the contest would replace all of the bombers then in service, or even on the drawing board.
Of the four designs submitted, only the Focke-Wulf FW 191 and Junkers Ju 288 were seen as promising, and both were told to go ahead with advanced design and prototype construction. Both designs were the leap forward that the Luftwaffe hoped for. They had the load and range to replace the medium and heavy bombers like the Heinkel He 111 and He 117, but they also had the speed and dive bombing ability to replace the lighter planes like the Dornier Do 17 and Ju 88. The Ju 288 quickly came out ahead in the competition, largely due to less interference from the RLM who interferred constantly with the FW 191. But like most of the German projects from the early 1940's, the Ju 288 project fizzled out when one engine after another failed to materialize.
By 1942 it was becoming clear that the plane wasn't going to be ready any time soon, and at the same time the Ju 88's were increasingly at the mercy of a rapidly improving RAF and Soviet VVS. Luckily Junkers had been working in private on a more modest upgrade to the Ju 88, the Ju 88B, which had already flown in early 1940 and showed some improvement over the basic versions.
The modifications were slight. They included a redesigned cabin with a much more streamlined layout. The wing was widened by 2 m for additional high-altitude performance, but a new "pointy" design resulted in roughly the same drag as the earlier version. The larger elevator and rudder units from the Ju 88G were used to give the plane better control at altitude. The defensive armament was also redesigned; the dorsal and ventral positions retained their MG131's, but the nose gun was upgraded to the MG151/20 cannon, and a well-streamlined turret with a MG131 was added on top.
The Ju 188 was designed to be fitted with either the 1,775hp Junkers Jumo 213E or 1,700hp BMW 801G engines without any changes to the airframe. Engines were delivered as a power-egg complete with all needed plumbing and engine mounts. It was originally intended that both would be known as A models, but the naming was later changed: the Ju 188A model powered by the Jumo, and the Ju 188E with the 801.
A prototype with the Jumo, the Ju 188V-1 was flying as early as December 1941, and was quickly followed by another nine to complete the pre-production run. Although the improvements over the existing Ju 88 was modest at best, the new designs were ordered into production.
So limited were the changes that E-1 models were rolling off the line by early 1943, and 283 had entered service by the end of the year. A modified version mounting a small sea-search radar set under the nose and shackles for a torpedo for naval strike missions was delivered as the E-2.
Although the A and E models were to have been delivered at the same time, the Jumo engine was having difficulties getting into production. The first A models delivered included a new "boosted" Jumo that delivered 2,240hp for takeoff, and were known as the A-2. A version modified like the E-2 was delivered as the A-3.
For all its good points, the Ju 188 was only a small improvement over the Ju 88 it was supposed to replace. The bombload and bomb-bay was no larger than the earlier plane, so although it could handle a larger load by mounting externally, doing so hurt performance. Even then the performance was rather poor considering all the effort – only 325mph or less. One has to wonder about the German armament designers as well, the fancy dorsal turret had only one gun in it, yet they retained the single-gun flexible position only inches away from it. In the meantime the various projects to finally provide the plane with real tail armament were all adbandoned.
Delivery problems of the Jumo were never entirely sorted out, and the only model to be built in large numbers were the E series with the 801. Even then so few were available that they were generally given out to Ju 88 units, who flew them on "special" missions where the longer range or better performance would be helpful.
Reconnaissance versions of the A and E models were produced. The airframe was modified with the removal of the bomb aimer and the forward gun, and additional fuel cells were added to extend the range to 2,110 miles (3,400 km). The D-1 was otherwise similar to the A-1, and the D-2 fitted nose radar for naval reconnaissance. Similar conversions of the E models were the F-1 and F-2.
It was planned to skip over a "B model" to avoid confusion with the original Ju 88B, but in the original planning the A and E models would both be called A's. The Ju 188C would thus be the next model in line, equipped with a new tail-mounted remotely-controlled turret with two 13mm MG 131 machine guns. This modification would have greatly improved defensive firepower, always lacking on German designs, but never entered service.
One problem with the Ju 88 that carried into the 188 was the lack of internal room for bomb storage. Both carried the majority of their bombload on the outside of the plane on racks under the wing, where it greatly effected performance. This was to have been addressed in the G and H models, which extended the fuselage downward for more room. This left enough room at the tail to fit a manned turret in place of the C model's remote-control one. Oddly, the designs still had the nose area extended under the plane for a rear gunner, when this would no longer be needed and its removal would have greatly cleaned up the lines of the plane. Neither version was ever produced.
In 1943 it was planned to upgrade the entire lineup with even more wing area and a pressurized cockpit for high-altitude work. A single basic airframe would be offered in three versions, the Ju 188J heavy fighter, Ju 188K bomber, and the Ju 188L reconnaissance version. All three did away with the under-slung gunner's compartment, leading to a cleaner nose profile, and the bomber and recce versions mounted their loads in a long pannier under the middle of the plane instead of the deeper fuselage of the G and H models.
Simpler versions of these with no defensive armament and even longer wings became the Ju 188S fighter and Ju 188T intruder. With Jumo 213E-1 engines 2,168 hp at take-off and 1,690 hp at 31,400 ft, the Ju I88T could reach 435 mph (700 km/h). Operating at this altitude, the Ju 188S could carry only 800 kg of bombs.
Before any of these could start production, the entire lineup was renamed the Ju 388, the vastly improved performance warrenting this change in name.Background
Prototypes
Ju 188A & E
Ju 188D & F
Ju 188C
Ju 188G & H
High-altitude versions