Nazi Germany (1943)

Medium Bomber, Pathfinder: 362 Built

The Junkers Ju 88 was among the most versatile and longest serving aircraft of the Second World War, and can be counted among the very few that weren’t completely obsolete at the end of hostilities. A modern design in the days preceding the war, it was intended to become the primary medium bomber in Luftwaffe service. In the following years, it to was to be replaced by the more modern Ju 288. However, production shortfalls made phasing out the dated Heinkel 111 unfeasible, and the Ju 288 would never see service, for a multitude of technical reasons. It thus fell on Junkers to keep the Ju 88 updated through the end of the war, producing a number of bombers, fighters, night fighters, and reconnaissance aircraft to service in whatever roles were needed. Among the last of these variants was the Ju 88S, which sought to produce the fastest bomber variant of the aircraft possible.

The Secret Airforce

The rearmament of the German air forces began as a covert program, with the government  hiding its efforts in both accumulating a pool of experienced airmen, and producing capable combat airplanes. The foundations of a new air force were laid during the Weimar period, where all of the existing civil airlines were merged into the state owned Deutsche Lufthansa enterprise under the directorship of Erhard Milch. Milch was a former Junkers employee, and future Inspector General of the Luftwaffe during the Second World War. In running Lufthansa, he created a pool of experienced pilots, aircrew, and maintainers under a single state enterprise, one which could provide the necessary expertise for providing the human resources necessary for any new military organization.

The task of arming this air force had to be achieved more covertly, and was pursued through two means. The first was simply to continue the production of civilian aircraft in order to maintain technical competence and an industrial base for building aircraft, and secondly, to design military equipment in secret abroad. The largest of these efforts was in the Soviet Union where several firms, the first being Junkers, built facilities supplied with shadow funding from the Weimar government. The Junkers plant at Fili, near Moscow, would sell military aircraft to the nascent USSR while gaining invaluable design and production expertise for facilities back in Germany.

In the years to follow, German aircraft firms would go on to produce a number of dual-use civilian aircraft. Even before the rise of the Nazi party in Germany, this secret rearmament program was producing designs like the Junkers K-37 high speed mail plane, which was developed into a bomber in Japan as the Mitsubishi K-1 and 2. The designs of new military aircraft accelerated under the Nazi regime, who unlike their predecessors, were not simply interested in keeping pace in military aviation, but were now looking for weapons to defeat the United Kingdom, France, and the Soviet Union.

The new Luftwaffe was to have a very strong striking arm, and thus needed a bomber fleet. To meet this need, the government requested designs for high speed airliners and mail delivery aircraft that could double as light and medium bombers. By the end of 1935, this contest produced the Heinkel He 111, the Dornier Do 17, and the Junkers Ju 86. They were all capable, and very modern for their day, but with the expectation of conflict by around 1940 it was clear a second generation of aircraft would be needed to phase out these models once they began to show their age. The resources for this effort were in a competition between a large, four engine Uralbomber to strike at targets deep within the Soviet Union, and a smaller twin-engined Schnellbomber, a shorter ranged, more flexible medium bomber. The death of the Uralbomber’s strongest supporter, General Wever, and the more practical concerns of being able to support a fleet of heavy bombers, ensured the Schnellbomber’s ascendancy. Beyond this, the range of medium bombers was judged sufficient for war against France and Britain, who were seen as the primary opponents to the regime in the short term, and thus Germany would have the time to develop a heavy bomber later on for war against the Soviet Union.

This Schnellbomber was to be a fast medium bomber capable of engaging distant targets without need for an escort or heavy defensive armament. The requirements were listed as needing a top speed of 500 km/h, a 1000 kg bomb load, a range of 2500 km, and of course it needed to have a modest production impact, taking no more than 30,000 man hours to build. Junkers, and Willi Messerschmitt at the Bayerisch Flugzeugwerke, were the only major competitors, and though Messerschmitt’s Bf 162 was the simpler of the two, the design was not altogether finished at the time of its submission, and thus the Junkers Ju 88 was the clear front runner.

The Junkers Ju 88 was a modern, but not revolutionary design, it represented the most up to date concepts in airplane design, did but not incorporate any cutting edge technology. It was originally developed as a high speed level-bomber, but after the death of General Weaver, Ernst Udet was made the general Flugzeugmeister, the general inspector for the Luftwaffe. This change would result in severe complications to its, and other aircraft’s, development. A fervent advocate of the newly refined techniques of dive bombing, he made it a requirement that new bombers be made able to perform these attacks, which would require a substantial number of modifications to the design. Udet was a famed Great War aviator, but had very little in the way of engineering knowledge, and this decision slowed the development of the Ju 88, and largely doomed the later heavy bomber projects.

This requirement saw the program shift from the aircraft being a Schnellbomber to the multipurpose ‘Wunderbomber’, which required significant structural strengthening and the installation of dive breaks with an automatic recovery system. This added drag, weight, and delays in prototyping, but in the end, the design changes were worked into the aircraft satisfactorily. Production however was not forthcoming, as the German aviation industry would struggle to shift a massive proportion of capacity to building the new plane at an overly optimistic, and unreachable, rate of 300 per month. The plans for the plane were delivered in 1934, and the first prototype flew in 1936, but serial production only began in 1939. It wasn’t until 1940 that the Ju 88A-1 medium bomber was being produced at about ⅔’s of the desired 300 planes per month. It was the massive number of design changes resulting from the typical industrial corrections, the mission changes from the Luftwaffe, and simply basic design tweaks, that caused delay after delay.

Teething issues notwithstanding, the Luftwaffe had its most advanced bomber in the form of the Ju 88A. While it wasn’t the supposedly untouchable high speed bomber it was originally supposed to be, it was a multipurpose aircraft capable of carrying out a much wider number of missions. While it was slower than the original concept, it traded that speed for being able to engage large, mobile targets such as trains, columns of vehicles on roads, ships, and static point targets too small to be hit with level bombing.

The Early Years

Following its slow production during 1939, the Ju 88A was not employed widely until 1940, during the invasion of Norway. Its pilots were immediately appreciative of the plane’s superior handling and speed over the older bombers in service, and its dive attack capabilities were soon put to use. Equipped with the new aircraft, elements of Kampfgruppe 30 engaged a number of Allied ships during Operation Weserubung, badly damaging the cruiser HMS Suffolk, the French cruiser Emile, and sinking the destroyer HMS Gurkha.

It was during the invasion of Belgium and France that some of the design’s shortcomings became apparent, chief of which was its poor defensive armament and the limited fields of fire from the forward and top-rear machine gun positions. Not yet employed in significant numbers, the Ju 88 units on this front participated mostly in attacks against the French air force in suppressing their bases and attacking aircraft production. Beyond this they attacked port facilities and shipping to complicate the transportation of forces between Britain and the continent.

The attacks on the UK, culminating in the weeks that have come to be known as the Battle of Britain, would further demonstrate the destructive capabilities of the Ju 88, but also its vulnerability to fighters. In the end, bomber losses were high among all Luftwaffe units involved, with Ju 88 units specifically having trouble maintaining serviceability rates with their new aircraft. In short, both the RAF and Luftwaffe were pulverized and great damage was rained across much of Southern England, but in the end the defenders prevailed, and the Luftwaffe was forced to retreat and regroup.

Returning that fall, the Luftwaffe began the Blitz, nightly attacks against British cities conducted in the hope of breaking the resolve of the civilian populace. For the Germans, these raids would be less costly, but unlike earlier attacks on British production and shipping, there was little they could point to as a success beyond the acreage of burned out homes. The performance of the Ju 88 over the He 111 and Do 17 on these missions was largely a non-issue given the inaccuracy of nightly air defenses, and the small, but growing, RAF night fighter force. The true battle was being fought over the airwaves with the Luftwaffe using radio navigation aids to guide bombers to their targets, and the British sending out their own signals to disrupt them.

Adaptation

As with all military aircraft, design improvements were constantly being worked in via small changes, or different design variants. While there are few aircraft with as many variant designs as the Ju 88, these started simple. Initially there was a basic heavy fighter conversion of the Ju 88A-1, the Ju 88C-1 and 2. The glass ‘beetle’s eye’ nose glaze was replaced with a metal nose with fittings for 7.92mm machine guns, and 15 mm and 20 mm autocannons. These were built by modifying completed bombers, and in the earliest models, these fighters still had bombing gear and dive brakes. Beyond these easy converts, it was clear the basic bomber design itself could be significantly improved. The first major revision was in installing a set of long span wings and replacing the 1200hp Junker Jumo 111B’s for newer, more powerful models. While the more powerful Jumo 111J would not be produced in the numbers needed until 1941, implementing a new, longer span wing proved easy enough thanks to the modular construction of the aircraft. The revised design was the Ju 88A-5, which would go on to see service during the Blitz and the campaigns to follow.

The first thorough improvement to the design was the Ju 88A-4, which incorporated the long span wings, a redesigned rear canopy equipped with a second gun to improve firing arcs, better radio equipment, and the new Jumo 211J engines which each produced 200 PS more than the older Jumo 211B. This new design would prove to be the foundation for many more variants of the aircraft, all made to pursue different missions.

By the end of the Blitz, the Luftwaffe was having to contend with the nightly bombing of Germany by the RAF’s Bomber Command, and the Mediterranean theater, which featured action at very long ranges against maritime and ground targets alike. To suit these disparate needs, several new variant designs of the Ju 88A-4 were created. Mass produced heavy fighters were built to service long range day and night fighter squadrons, torpedo computers and shackles were added for anti-shipping units, and streamlined recon planes were built. Once the Jumo 211J was available in large numbers in 1942, Ju 88A-4 production would surge after pre-built airframes were finally receiving their new engines, and thus the number of Ju 88’s variants was expanded upon as well.

Mid War Service

By the end of 1942, the war had grown to four major fronts and the Ju 88 was used extensively on all of them. Over the Bay of Biscay Ju 88C-6 long range fighters flew cover for U-Boats, over Western Europe they served as night fighters, and across the Mediterranean and Eastern Fronts there were a great number of bomber, torpedo bomber, and photo reconnaissance units. However, near the end of 1942, the Ju 88A-4 derived models were starting to grow more vulnerable as the Luftwaffe’s fighter forces saw continued attrition. The Allied fighter forces were also growing considerably in strength, especially those of the UK and US who were building a considerable technological edge over their German opponents. With the Ju 288 having failed to materialize, Junkers would have to return to the drawing board with their old design.

With the wings already having been modified, further performance improvements were to come through streamlining and new engines. In 1942, a proposed major redesign of the aircraft with a new, streamlined canopy was proposed and prototyped, but it was clear that the production delays in adopting this new Ju 88B would be unacceptable. The new design would be included in the later Ju 188, but no major fuselage changes would be made on the Ju 88 for the rest of the war. Instead, a streamlined nose glazing would be considered, as would a new rear streamlined canopy with a defensive 13mm Mg 131 gun mount.

The only new major change in equipment was the introduction of the BMW 801 engine, which was now available in greater numbers, no longer reserved for Fw 190 fighter production. The Jumo 111J, even in its improved form, was growing increasingly obsolete as it had reached its operational limits. A successor design, the Jumo 213 with an improved pressurized cooling system, and designed to operate at much higher RPMs, was in development, but Germany’s reliance on second rate ‘economy alloys’, and resources being spread thin across several competing engine designs had caused long, painful delays. Once Germany’s access to molybdenum, tungsten, cobalt, and nickel were restricted by the Allied blockade, engine development ran into significant barriers. Thus, modified versions of older designs presented some of the few ways forward.

The BMW 801 promised a power increase of over 300 PS per engine, and beyond that it featured a highly advanced engine control system that meant the pilot only needed to adjust the throttle, and the system would adjust the RPM, boost, and mixture as needed. It’s only major drawback was its relatively dated single stage supercharger. Regardless, it represented the way forward for the Ju 88, and several new designs were drafted using this engine. The first of these were heavy fighters, which were much improved thanks to this massive increase in horsepower. The Ju 88R series would be the first mass produced variants to use this engine, but it still used an otherwise unmodified bomber airframe. There was much to be improved in regards to aerodynamics, especially in the case of the lower underslung ‘gondola’ which carried a pair of autocannons and a position for a ventral gunner on the Ju 88R. Further developments would see the removal of this feature, and net a massive reduction in drag, which would lead to the development of the final series of production Ju 88s.

These new models would be the Ju 88G, a night fighter, the Ju 88T, a reconnaissance aircraft, and the Ju 88S, a high speed level bomber and pathfinding aircraft. Apart from a few pieces of specialized equipment, and the larger vertical stabilizer on the Ju 88G, these aircraft shared the same supply chain, and the technical differences between them were so minor that they shared basic manuals. This would prove vital, as during this period, Inspector General Erhard Milch was attempting to rationalize all aircraft production into as few airframes as possible in order to increase overall production, and to ease the requirements of servicing aircraft. As part of this scheme, the Ju 88 would prove essential, with its single airframe fulfilling many of the most essential roles in the Luftwaffe.

The new Ju 88S, would resemble the recon plane almost entirely save for its lack of camera mounts. It was fitted with the low drag nose cone first installed aboard the earlier recon models, BMW 801D engines, and the dive brakes were removed. Compared to the Ju 88A-4, the top speed in a clean configuration was increased from 470 km/h to 588 km/h, at 6 km. At its maximum cruise speed of 460km/h, the plane nearly reached the maximum speed of the previous model. Performance could be improved further at high altitudes using the GM-1 nitrous boost system. The system was simple, it used the nitrous as an oxygen carrier to increase the oxygen content of the air entering the manifold at altitudes where the supercharger’s effectiveness fell off, and recovered engine performance otherwise lost to the thinner air. Using this system saw these planes reach a top speed of 610 km/h at 8km. Of course, carrying an external bomb load would seriously affect these speeds, but this boost in performance was remarkable. While the Ju 88S had sacrificed its dive bombing capability, it more than made up for it in sheer speed, which put it in the same league as the otherwise incomparable DeHavilland Mosquito Bomber.

The first of these planes was the prototype Ju 88V-56, which was followed by 24 production aircraft delivered up until June of 1943. These were not new airframes, however, but rebuilt Ju 88A-4’s, converted at Junkers Flugzeugwerk Magdeburg. Few major changes to this design were made until later, though the engines were soon changed to BMW 801G-2s, which was geared specifically for use in bombers.

Schnellbomber Once More

The first unit to receive these aircraft was Gruppe I of Kampfgruppe 66, this being a specialized pathfinding unit whose task was to lead bombers to their targets at night. They received the first of the aircraft of May of 1943, and were employed in small raids and reconnaissance operations over Southern England from their base in Chartres, France. One of the first losses came on the 30th, when one plane was shot down by a Mosquito night fighter, who pursued and intercepted them at 30,000ft. The crew bailed out, and the plane went down over England, its wreckage carefully picked over once the empty canisters of the GM-1 system were identified.

The unit trained for raids conducted with conventional beam navigation systems, but also the newer EGON method. This system operated using one or more Freya radars which tracked the path of an aircraft by its Identify Friend-or-Foe transponder signal and guided it along its course toward the target via radio transmission. Such a system would require a well trained crew as the Freya’s lack of a height finding capability meant that careful attention would be needed to maintain the plane’s altitude while receiving directions from the ground controller. This system would be less vulnerable to jamming than the radio beam direction types that the British were already familiar with, but it still relied on the typical Luftwaffe communications systems, which they were also familiar with.

It wasn’t until 1944 that they were used for their intended purpose, during the revenge motivated Operation Steinbock, or ‘Baby Blitz’ as it came to be known. The previous year had seen an intensification of the Allied Bombing of Germany, especially with the highly destructive raids against the city of Hamburg, and the disastrous Bomber Command offensive against Berlin in the Winter. In the span of those six grueling months, Bomber Command went from its highest capability for destruction, to its worst blunder of the war so far. Despite the apparent futility of the assault on their own capital, Hitler wished to exact a cost on the British people, and Reichsmarshal Goering felt it was an opportunity to show the lethality of his air force. The Luftwaffe had seen some improvements, and the addition of the massive, if troubled He 177 heavy bombers, gave the force a destructive new weapon. In contrast to the highest echelons of leadership, Colonel Dietrich Peltz, who was to direct the operation, wished to use this concentration of bombers against Allied shipping, which he believed could damage their oceanic supply lines before an anticipated cross-channel invasion. He failed to convince either of his superiors, and thus proceeded with Operation Steinbock.

KG 66 was effectively the leading edge of the force which peaked at 524 planes, supplying a total 42 bombers, 23 being Ju 88S-1s. The general level of night flying proficiency among the raiders was poor, and thus the pathfinders were essential in leading the raiding force to their targets. The attack was to mirror the tactics of RAF’s Bomber Command, with light, specialized pathfinders plotting a route for heavy bombers carrying the heaviest types of bombs available, intermixed with smaller incendiaries, and fragmentation bombs on timers set to explode well after the raid ended. The assault began on the night of January 21/22, and it immediately became apparent that all of the existing guidance systems in use were compromised, even EGON to an extent. In spite of this, EGON was the primary system in use on these raids, and was capable of high accuracy on nights without interference. Early in the campaign, on a night of poor visibility, the pathfinders failed to illuminate London, and only some 30 of 500 tons of bombs fell on the city that night. The RAF and the city’s Flak batteries would claim 20 planes, with 15 being lost to accidents.

However, the Luftwaffe was committed to the offensive, and launched another attack at the end of the month, and they returned to the city 7 more times in February, when the pathfinders had shown serious improvement. In March, they shifted their attention somewhat to Hull, and Bristol, but London remained their primary target, attacked five more times in March before the last major raid on the city in mid April. The Germans had little to show for their attacks, as while they had done a great deal of damage to the city, the worst since the Blitz, they found the Londoners as immovable as they had been near the start of the war. For their efforts, the Luftwaffe had largely expended their bomber forces, with Luftflotte 3’s Fliegerkorps IX now being left with 130 serviceable bombers. Reserves were drawn upon for replacements, and forces were redeployed from the Mediterranean, but there was nothing that could hope to challenge the 7000 planes of the Allied Air Forces across the channel. What might have been a potent strike force against the invasion was blunted in a shortsighted disaster that not only failed to take into account the lessons from Blitz, but what they themselves faced from Allies only weeks ago.

The Last Effort

I./KG 66 did not escape Steinbock untouched, losing about half of their aircraft, with only their Ju 88S and Ju 188 bombers remaining. However, as a specialized unit, and one of the only users of the Ju 88S, they were soon supplied with fresh aircraft and set to a new mission. Steinbock had largely destroyed the Luftwaffe’s bomber forces, and thus there was little use for a pathfinder force tasked with directing large formations of bombers. The Luftwaffe’s fortunes had also declined since the futile offensive, as the American 8th and 15th air forces were employing long range escorts which now contested the airspace over all of Western Europe. When the Allies returned to France, they did so under the protective canopy of their fighter forces. To strike at the American and British armies now deployed to France, one of the few options available was to attack at night. With the bomber force having been depleted, it would thus fall to what remained, with assistance from night fighter squadrons, to carry out attacks against the Allied beachhead, supply lines, and frontline positions.

In this, I./KG 66 was perhaps the best equipped squadron for the task, having superior navigational training, and better aircraft than the typical raiders. Their operations were infrequent through the Autumn of 1944, while they rebased several times to keep ahead of the advancing Allied armies. Beyond this, there was a lull in night operations across the Western Front from roughly September to December. Their situation had deteriorated significantly, with chronic fuel shortages now being universal, and the Western Allies having succeeded in blinding German early warning systems by deploying ground based jammers to the continent.

It was during the last month of 1944 that Germany’s remaining resources in the west were to be placed on an all-or-nothing offensive to stall the advance of the Allied armies. Operation Wacht Am Rhein would involve throwing what remained of the Heer’s offensive capabilities at the Allies at a moment where they had outpaced their supply lines. One of the major factors for the operation was the need for poor weather, to eliminate the Allied advantage in the air. For both sides of the coming battle, the only air units that could take part were those capable of instrument flying. For the Germans, this eliminated the use of all but the scarce remaining bombers, and their night fighters, which had become a second line night attack force since the Normandy landings. Against them were handful of American P-61 night fighters, with most of the RAF’s Mosquito squadrons having been transferred to the UK to refit to the new Mk XXX.

KG 66 was to take a vital and early lead in the air operations during the offensive, where it would again act as a pathfinder force. They now also operated the Ju 88S-3 from their base in Dedelsdorf, Germany, this being a new subtype that used the more reliable Jumo 213A engines. Operations began on the night of December 17/18, with the Luftwaffe mounting some 243 night attack sorties. KG 66’s role was to aid in the navigation of night fighters, and to illuminate targets along the roads between Sittard, Maastricht, and Liege. Given the Allied supply situation, and the chaotic road traffic experienced across the front, these strafing and cluster bomb attacks would inflict considerable losses and sow confusion along the roads. Losses among the night fighters themselves were steep, as despite the minor presence of allied night fighters, the use of proximity, radar-fused shells among Allied flak units proved lethal.

The night attack force would fly out the next night, with only limited success, but no losses. These attacks would continue throughout the offensive against rear line supply convoys, trains, and troop concentrations. They had some notable success, but at a very high cost to the night fighter force at a time when experienced aircrews could not be replaced. KG 66 would fare somewhat better given their less direct role in the assault, and would have an active strength of 29 Ju 88S-3s by January 10th, 1945. By this time, the S-3 was also found in the inventories of a number of standard bomber units. Outside of KG 66, the largest numbers of the aircraft were found in the first and second Gruppe of LG 1, a training unit now serving in combat, having been issued the aircraft the previous July.

For the next few weeks, what remained of the German bomber and night fighter forces of the Western front would be used as night harassment forces. Morale plummeted as there was little hope of anything being achieved in these costly actions, and the best of the RAF’s night fighter forces were again on the continent. During these night raids, crews felt a constant anxiety over the presence of the dreaded Mosquito, which possessed both incredible speed and an endurance that allowed it to pursue targets on long chases. When these planes were found to be operating in a certain region, night attack sorties for the night were called off. Such notices came at a great relief to the dwindling number of bomber and night fighter crews who were called upon to support the army as it retreated ever deeper into Germany itself. In the final weeks of the war, KG 66 was merged with KG 200 and participated in night harassment sorties until the capitulation of the German armed forces.

Handling and Use Characteristics

The Ju 88S retained the good flying characteristics the series was known for. It featured well harmonized, responsive controls that remained light at higher speeds, and possessed excellent take off and landing characteristics. The use of the highly automated BMW 801 and Jumo 213 engines also removed a substantial amount of workload for the pilot, who only needed to adjust the throttle to bring the aircraft to its various power settings. Combined with the level, azimuth only autopilot, the Ju 88 was an aircraft many Luftwaffe crews felt confident in flying hands off for extended periods of time. This would prove essential considering the mostly nocturnal use of the plane, where pilots flew by instruments and needed to pay close attention to the various navigational signals guiding them to their targets. Overall, the Ju 88 has been described as a viceless aircraft with very forgiving handling.

It would also prove to be incredibly fast, with a clean configuration allowing the Ju 88S-1 to reach 588 km/h at 6 km. Using various boost systems allowed the aircraft to reach higher speeds. GM-1 nitrous boosting allowed the S-1 to reach 610 km/h at 8 km, with the S-3 being able to reach 615 km/h. At lower altitudes, the S-3 could make use of methanol-water injection to allow the engine to produce considerably more power. While no data is extant on performance of the aircraft with this system, crew testimonies claim the heavier Ju 88G-6 night fighters were capable of exceeding 600 km/h at lower altitudes using MW50.

Famed Royal Navy pilot Capt. Erik ‘Winkle’ Brown would also be among the few allied pilots to have had the opportunity to fly many models of the Ju 88, from bombers to night fighters. Capt. Brown felt the aircraft possessed largely the same excellent handling characteristics from the Ju 88A-5 medium bomber to the Ju 88G-6 nightfighter. He praised it for its easy ground handling, thanks to its excellent brakes, it’s good handling during climbs, and light controls at cruising speed.

Capt. Brown would spend more time with the G-6, a variant very similar in construction to the Ju 88S-3, and was able to put one through more demanding tests. Having previously flown several versions of the Ju 88, Brown was particularly impressed by the high speeds he reached in a Ju 88G-6 (Werk-nr 621965). The aircraft remained in line with his general, glowing remarks over the Ju 88. “It was a pilot’s airplane, first and last, it demanded a reasonable degree of skill in handling and it responded splendidly when such skill was applied. There was a number of very good German aircraft but, with the exception of the Fw 190, none aroused my profound admiration as did the Junkers ‘eighty-eight’.”

Perhaps the simplest, but greatest, advantage the aircraft had was in the close proximity of the crewmembers, which allowed them easy communication in the event of intercom failure or emergency. It also allowed the pilot to be seated beside the gunner and flight engineer, an ideal arrangement providing both easy communication and good situational awareness. This arrangement also provided good protection from rearward attacks, with the armored gunner’s position and the bulkhead armor between the crew and any attacker. Should all else fail, the bail out procedure was as simple as it could have been. The entire rear of the canopy detached, allowing for all of the crew to bail out from the shared compartment.

The general design of the aircraft was modular, with the wings, stabilizers, and engine units being attached to the aircraft by very robust, but easily removable connectors. Thus, the maintenance, replacement, or adjustment of any one of these components was made far easier. This lent to an overall ease of maintainability for the ground crews who could perform dreaded tasks like engine replacements rapidly, and without much exertion. The unified engine units could simply be disconnected and pulled away from the mount.

While it inherited the benefits of the original design, it also had its flaws. The most obvious of which was the poor visibility due to the bars of the reinforced cockpit frame, which reduced visibility, and the troublesome landing gear which had a tendency to buckle if the aircraft was brought down too hard. The landing gear was a hydraulically actuated set that rotated 90 degrees so that the wheels would lie flat within their nacelles. This greatly reduced drag, as the shallower landing gear bays contributed far less to the frontal area of the plane, but they could be broken in hard landings or harsh ground maneuvers while carrying a heavy payload. These types of accidents were typically handled by the local repair staff, but greater levels of damage often called for an aircraft to be disassembled and sent to repair depots, or factories, for restoration.

The most common accidents with the plane were landing accidents involving flipping the plane over onto its nose. Due to the forward placement of the engines, it wasn’t uncommon for the plane to flip over forward while landing, when less experienced pilots were too heavy on the brakes. These typically resulted in little more than damaged propellers and smashed nose cones, and thus didn’t remove an aircraft from service for very long. In more dramatic cases the plane could be flipped onto its back and injuring the crew.

Production

As one of the more minor variants of the Ju 88, the S was manufactured across several facilities, with both new built, and modified production models. The Ju 88S-1 was entirely an Umbau series, a modified production aircraft built from new Ju 88A-4 airframes. These were produced at the Junkers plant in Magdeburg, with the first deliveries arriving in the Spring. At Magdeburg, a total of 57 planes were manufactured in 1943, with 14 more being built the following year, with production being terminated in May.

The Ju 88S-3 was built as both new airframes, and modified production aircraft. All of the new production aircraft were built at the Henschel Aircraft Factory in 1944, beginning in June. Here, they replaced the production of the Ju 88A-4, with a total of 264 rolling off the line in 1944, and 12 more the following year. The Henschel plant built another 15 from Ju 88A-4s. The Ju 88S-3 was by far the more prolific of the two and wasn’t just regarded as a specialized aircraft, with deliveries being made to standard bomber squadrons. Apart from these bombers, Deutsche Lufthansa at Berlin-Staaken converted 3 Ju 88S-3’s to high speed couriers and transports.

The production of the Ju 88S itself continued at a fairly high pace for a specialized design well into 1944, when bomber production was drastically cut in favor of fighters. There was also a declining interest in piston engine bombers, as the German aviation industry began to produce a growing number of jet aircraft. The Arado 234 was seen as an obvious successor, being the only reconnaissance plane that was truly non interceptable.

The build conditions of these aircraft declined precipitously between 1943 and 1944 as the German war effort ran short on key materials, and an ever growing number of factory workers were drafted. This hit a critical level in 1943, where the mass use of forced labor became the standard across most wartime German industries. In aviation, it had become an accepted practice the previous year, with concentration camp inmates being made to work at a number of plants. As the German labor pool continued to be drained, an even larger proportion of forced laborers were used, now drawing large numbers from the concentration camp system, and forcefully deported workers from Eastern Europe. This change saw a vast drop in working conditions and a large increase in sabotage; production quantities surged while quality backslid considerably. This process was overseen by Erhard Milch, inspector general for the air force, and armaments minister Albert Speer. They expanded upon the use of forced labor drastically in early 1944, following the American Air Forces targeting of German fighter production. This enabled them to build more aircraft than ever before, but saw a sharp increase in rates of sabotage and an overall decline in quality.

Much of this production strategy also relied on corner cutting and the implementation of extremely long work hours, with a 72 hour work week eventually becoming the standard. In terms of materials, they cut back the production of spare parts, began to accept well-used parts in new production aircraft, and recycled refurbished equipment from written-off planes. The production of all but a small, crucial number of fighter, night fighter, and reconnaissance models were cut drastically or eliminated. Overall, this strategy allowed them to drastically boost fighter production in the short term, but the rate could not be maintained and declined in the fall of 1944, only a few weeks after its peak.

Construction

Fuselage

The Ju 88A-4 was the most widely produced bomber variant and formed the basis of the Ju 88S’s design. This was also true in a literal sense, with many of the new models being built from existing A-4s. It was conventional all metal aircraft in its construction, and, while it pushed few technical boundaries, it was state of the art and versatile. It was primarily made of aluminum alloys, with cast parts used for load bearing elements. Some use of Elektron magnesium alloy was made to further reduce weight, but later in the war this had been replaced by steel, which was primarily used in the landing gear fittings. The fuselage cross section was rectangular with rounded corners and clad in large sheet aluminum stampings. It used a semi-monocoque structure made up of formers and bulkheads joined by connectors that ran front to aft, with the outer aluminum skin riveted to both elements, which allowed it to bear some of the structural load. Its structural load factor was 4.5 with a 1.1 multiplier for the first wrinkle, 1.3 for yield, and 1.8 for failure. In service, it proved very sturdy, with Junkers engineers claiming after the war that there had been no reported major structural failures over the service life of the airframe.

By the time of the Ju 88S, the construction process had been improved to the point where the fuselage was built from sub-assemblies that would become the upper and bottom halves of the fuselage. These would then be joined together after wiring and internal components were fitted. Wing construction followed a similar process, making heavy use of sub assemblies, followed by equipment installation, skinning, and painting.

Wings

The Ju 88’s wings were the heaviest part of the aircraft, comprising much of its total structural weight at over 1200 kg. A pair of massive main spars ran from the root to the wing tip, a rear spar ran across the entire span of the wing to support the flaps and aileron. One forward spar ran from the engine nacelles to the fuselage to transfer thrust from the engines and support loads from the landing gear. These spars were joined by relatively few airfoil shaped ribs and stiffened with corrugated aluminum. The wings were joined to the fuselage by means of four large ball-screw connectors, which made for easy assembly and alignment.

The vertical stabilizer was fixed to the fuselage by means of the same ball-screw connectors as the wings. Installing it was simple, with the rudderless stabilizer being fitted to the fuselage, and the rudder fin being affixed afterwards. The horizontal stabilizers did not use the same fitting system. Instead, they were each inserted into the fuselage by two spars which were then bolted together.

As previously stated, the landing gear could prove troublesome due compromises in its design. During early prototyping, the landing gear was redesigned to use a single strut that would rotate so that it would lie flat beneath the wing when retracted. While this did remove frontal area that would have seriously impacted the aircraft’s high speed performance, it came at the cost of added complexity, and made for a far less robust landing gear arrangement. Differing from earlier series, the Ju 88S’s landing gear frames made use of welded cast steel instead of light weight alloys.

The wings were also equipped with an excellent de-icing system which took in air, ran it through a heat exchanger around the exhaust ejector stacks, drove it through channels in the wings, and then out over the ailerons. As the BMW 801 had no exhaust stacks compatible with this system, they made use of a petrol-fired heater to supply air to the de-icing system on the Ju 88S-1.

Engines

Apart from the initial use of BMW 801D’s, the Ju 88S used two engines in service, the BMW 801G-2 and the Junkers Jumo 213A-1. The BMW 801G-2 was a 14 cylinder, 41.8 liter radial engine which produced a maximum of 1715 PS at 2700 rpm. It had a bore and stroke of 156 mm by 156 mm, weighed 1210 kg, had a compression ratio of 7.22:1, and ran on C3 95 octane aviation gasoline. It was equipped with a single stage, two speed supercharger that gave the engine a full throttle height of 6 km. Despite its lackluster high altitude performance, the engine had a massive advantage in its high level of automation. Designed with an mechanical-hydraulic computer, called the Kommandogerät, the pilot needed only to adjust the throttle to bring the engines to a higher or lower power setting. RPM, mixture, and boost were all managed by this system, and massively reduced the pilot’s workload. The BMW 801G-2 would be installed aboard the Ju 88S-1 before later being replaced with the Jumo 213A-1 on the S-3.

The Jumo 213A was a 35 liter, inverted V-12 that was derived from the earlier Jumo 211. The new engine was designed to work at significantly higher RPMs and featured a new pressurized cooling system, which kept the internal pressure stable regardless of altitude. The engine ran on B4 gasoline, which was approximately 89 to 91 octane by the stage of the war this aircraft was used. The primary issue with the older Jumo 211 was its open cooling system which left it open to the effects of external air pressure. At higher altitudes, the lower boiling point of water severely its performance. The new engine possessed a smaller block, a more powerful supercharger, and an automated control device, like that on the BMW 801, called the Bediengerat. The A, being a low altitude model of the engine, had a single stage, two speed supercharger.  This gave the engine a full throttle height of around 6 km, roughly the same as the BMW 801. The engine had a bore and stroke of 150mm by 165mm, a weight of 940 kg, a compression ratio of 6.5:1, and it produced 1775 PS at 3250 RPM. A large annular radiator provided cooling for the engine’s pressurized cooling system, and oil.

Both engines were installed in ‘Kraftei’ units which placed the engine and its associated cooling systems within a single, unified arrangement. These allowed for a great ease of maintenance, as the entire engine could be easily removed and replaced. These engines were fitted with VDM and VS-111 propellers on the BMW 801G and Jumo 213A respectively. Both engines employed direct fuel injection.

Fuel System

Fuel capacity varied dramatically depending on the mission loadout, as the rear fuselage tank would be removed in order to carry the GM-1 or MW 50 bottles. Fuel tankage consisted of multiple wing tanks contributing 1680 liters, a forward fuselage fuel tank of 1220 liters, a rear fuselage tank of 680 liters, and up to two external fuel tanks of 900 liters. At the lowest fuel capacity of 1680 liters, the Ju 88S-1 could fly a maximum of 1130 km at a cruise speed of 420 km/h, or 750 km at a maximum cruise speed of 460 km/h. At a maximum fuel capacity of 3580 liters, this was increased to 2415 km at low cruise, and 1590 km at high cruise.

Endurance with the Jumo 213A-1 powered Ju 88S-3 was somewhat lower, with a reduced fuel capacity of 1680 liters giving the aircraft a range of 1000 km at cruising speed of 410 km/h, and a range of 900 km at a maximum cruise speed of 450 km/h. The maximum operational fuel load was reduced to 2900 liters, which permitted a range of 2050 km at low cruise, and 1570 km at high.

Engine Boost Systems

The Ju 88S-1 could carry the GM1 high altitude boost system, and its successor, the S-3 could carry this system and the low altitude MW 50 low altitude boost system. The GM1 system was a nitrous boost system which provided high oxygen content to the engine at altitudes where the super charger failed to provide a boost with enough oxygen content to run the engine at its higher power settings. The mixture was delivered into the supercharger intake by means of compressed air. Activating the system was done by flipping the activation switch in the cockpit, which was accompanied by gauges showing the pressure remaining in the system. The activation time was approximately five minutes.

The chilled liquid nitrous was stored in insulated bottles, in either a three bottle arrangement, where each held approximately 90 liters, or a single large container containing approximately 284 liters. The flow of nitrous was either 3.26 kg per engine, per minute, or when set to the emergency setting, 5.98 kg per engine per minute. The emergency setting was typically ignored, as it was seen to cause engine trouble. In the three bottle version, the boost could be sustained for a non-consecutive 45 minutes, or 27 at the emergency setting. The chilled nitrous also aided in reducing knock via charge cooling. It should be understood that this system does not boost the maximum power output of the engine, but is rather a method of recovering power lost due to the thinner air at high altitudes. The activation height for the BMW 801 was 7 km, below which it offered no benefit.

MW 50 was a low altitude boost system to increase the maximum power output of the engine. This is done by reducing knock and allowing the engine to run at manifold pressures far higher than normal. This is achieved by increasing the overall octane rating of the fuel by adding methanol, rated at approximately 115, and water, which allows for a denser airflow at the manifold via charge cooling. This allowed the Jumo 213A to run at 2100 PS, roughly a 325 PS increase. Use of the system was rare on the Ju 88S.

It was not without its drawbacks. Firstly, the mixture was highly corrosive, and even with its anti-corrosion additive, it markedly shortened the lifespan of the engine. Second, was that it was restricted to use at lower altitudes. Unlike GM1 which delivered using pressurized air bottles, MW 50 was supplied into the supercharger via a pump. After rising above the supercharger’s maximum effective height, pressure in the system would fall until it offered no benefit to performance.

Crew Accommodations

The crew arrangement on all Ju 88 models would set the entire crew within the canopy and in close contact with one another. The bombardier sat to the pilot’s right, a flight engineer/gunner at the pilot’s back, and a ventral gunner sat beside the flight engineer or in a prone position inside the “gondola”, where his weapon was located. Aboard the Ju 88S, the ventral gunner’s position had been omitted with the removal of the gondola, however the positions of the other crew members remained largely unchanged. While these close quarters arrangements were somewhat claustrophobic, they ensured easy communication between the pilot and the rest of the crew at all times. It also made for a much simpler bail out procedure, as half the canopy would detach and allow for a quick escape for all aboard. In the Ju 88S, the crew entered the aircraft through a hatch below the cockpit.

Armament

The aircraft came equipped with a pair of ETC 500 underwing racks which could support a payload of up to 1800kg per shackle. These two pylon positions were plumbed to allow them to mount a pair of 900 liter external fuel tanks. It was possible to mount a second pair of ETC 500 racks could be added beside the standard two, though this does not seem to have been carried out in the field. The Ju 88S retained the internal bomb stowage, and could be used to carry small diameter bombs or extra fuel. Apart from flares and small incendiaries that could be accommodated by this bomb bay, most of the weapons used were larger diameter bombs mounted to the external shackles, being either conventional high explosive or anti-personnel cluster bombs.

The single 13 mm MG 131 was placed at the rear of the canopy within an armored glass mount and supplied with 500 rounds of armor piercing and high explosive shells in equal proportion.

Avionics

The Ju 88S was typically equipped with the following devices: FuB1 2 (Blind approach receiver), Fug 10P (radio set), FuG 25 (IFF), FuG 101 (Radio altimeter), and in rare cases the FuG 136 (pathfinder command receiver).

The FuB1 2 was a blind landing system that guided the aircraft onto a runway by way of two radio beacons placed at 300 m and 3000 m away from one end of the airstrip. It was a tunable device so that airfields could possess separate frequencies between 30 and 33.3 mHz. The aircraft itself carried the Eb1 2 beacon receiver, the Eb1 3F beam receiver, the FBG 2 remote tuner, the AFN 2 approach indicator, the U8 power supply unit, and either a mast or flush antenna.

FuG 10P was a radio developed by Telefunken and was coupled with the Pielgeräte 6 radio direction finder. The device consisted of numerous transmitters and receivers capable of operating at various ranges. Each component was fitted in a modular box which was connected to a wall rack to allow for the quick replacement of damaged components. One pair, E10 L and EZ 6, operated at between 150-1200kHz, and another, S10 K and E10 K, between 3-6mHz. Other components included the U10/S and U10/E power supply units, and the fixed antenna loading unit AAC 2. Numerous versions existed and made use of various other components.

FuG 25 “Erstling” was an IFF system manufactured by GEMA that would respond with coded impulses to the ground-based Wurzburg, Freya, and Gemse radar systems up to a range of 100 km. The receiver operated on a frequency of 125 mHz and the transmitter at 160 mHz. The entire unit was contained within the SE 25A unit, with the BG 25A control box in the radio operator’s station. This unit was used to facilitate the use of the EGON navigation system wherein a pair of Freya, or Wasserman, radar stations would ping the IFF. Finding its direction, gauging the signal strength, and triangulating its angle between the radar stations allowed the ground controllers to accurately set the position of the aircraft against a plotting table. Navigational commands were issued over wireless telegraph or a specialized device, the FuG 136 Nachtfee.

FuG 101 was a radio altimeter designed by Siemens/LGW with a maximum range of 150-170 m and operated on a frequency of 375 mHz at 1.5 kW. Accuracy was within 2 m and the entire system weighed 16 kg. It consisted of the S 101A transmitter, E 101A receiver, U 101 power supply unit, and the pilot’s panel indicator.

FuG 136 Nachtfee

This communication device consisted of a CRT indicator aboard the plane which received commands from a ground based control console, using the EGON navigation system. These commands were represented by a 12 position, clock-like display, where each position represented a different navigational command. These were sent to an aircraft’s onboard FuG 25 IFF system via transmission pulses from the ground based radar. In addition to the 12 commands, based on the position of the pulse, an additional 4 commands could be given with a double pulse. For example, a transmission of position 1 followed by position 2 would be an entirely different command than simply just one on position 1. The device required constant monitoring by a specialized crew member.

Conclusion

The Ju 88S would prove a tremendous improvement to Junker’s ever versatile bomber, achieving extremely high speeds and proving a difficult target to intercept. In terms of its sheer performance, Junkers was successful both in keeping their bomber from falling obsolescence, developing an airframe which was very successful both as a medium bomber and night fighter. However, nothing could prevent the eventual undoing of the Luftwaffe, from both the British and American Air Forces, and the terrible, short sighted decision making that dominated the upper echelons of power in the Third Reich.

Variants

Ju 88S-1: Bomber-Pathfinder equipped with BMW 801G-2 engines. 71 Built.

Ju 88S-2: Bomber-Pathfinder equipped with BMW 801T turbocharged engines. Experimental, none built.

Ju 88S-3:Bomber-Pathfinder equipped with Junkers Jumo 213A-1 engines. 291 Built.

Ju 88S-3 Highspeed Courier: Deutsche Lufthansa fast transport and mail carrier. 3 converted.

Ju 88S-4: Bomber-Pathfinder equipped with Junkers Jumo 213A-1 engines and vertical stabilizer from Ju 188. None built.

Specifications

Combat range varied dramatically depending on the fuel, weapon, and boost system arrangement. A Ju 88S-1 carrying pair of 250 kg bombs, and equipped with GM-1, had a combat radius of 330km. Without GM 1, its combat range was otherwise comparable to the Ju 88A-4.

Illustration

Credits

Written and Edited by Henry H.

Illustration by Arte Bellico

Sources

Primary:

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Ju 88S-1 Flugzeug Handbuch Teil 12 G Rüstsätze (Stand Marz 1944). Der Reichsminister der Luftfahrt und Oberbefehlshaber der Luftwaffe, Berlin. 1944.

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