Junkers Ju 87 Stuka

Introduction

On 27 September 1937, the commander of the French airforce, General Vuillemin, sent the Prime Minister, Edouard Daladier, a very pessimistic report about the relative strength of the German and French airforces. In it he claimed that if war broke out, the German Luftwaffe would become master of the air quickly, and:
Thus the concentration of French land forces can be gravely troubled and subjected to very important delays. It will be the same for its transport.

Also, land operations will be rendered very difficult as the result of the power and frequency of enemy air intervention at the rear of the Armies and on the field of battle itself.

As a realistic evaluation of the strategic situation at the eve of the Sudeten crisis, which would find its end in the ignominious agreement of Munich, this lacked accuracy. Vuillemin and the other French generals enormously overestimated the strength of the German forces. After the end of World War II, at the Nuremberg trial, the German generals admitted that in 1938 their army would have been completely outnumbered by the combined forces of France, Great Britain and Czechoslovakia.

But as a prophecy of the things to come in 1940, Vuillemin's pessimistic assessment was remarkably accurate. It was probably not the opinion of the majority of French generals -- Vuillemin did not even bother to send a copy of his report to the Chief of the General Staff, general Gamelin. Nor was this wisdom going to help the French in any way, for the French air force completely failed to prevent this announced disaster. The weapon that would turn pessimistic prophecy into painful reality was the Junkers Ju 87, universally known as the Stuka. That was actually a generic term, shorthand for Sturzkampfflugzeug, to describe all dive bombers. The Stuka would become the symbol of the Luftwaffe, of its efficiency in ground support operations, of the terror that is spread, but also of its weakness as a strategic force. The success of the Ju 87 also contained the seeds of a disaster for the Luftwaffe, because it began to require that all its new bombers would be able to execute dive bombing attacks, including heavy mediums such as the Do 217 and heavy bombers such as the He 177. This policy was to be highly detrimental for the Luftwaffe.

The Origins of Dive Bombing

The concept of dive bombing was certainly not unique to the German Luftwaffe. The theoretical basis for it is simple enough, that it would come to different minds in different places and at different times. It would probably be unjustified to look for the "inventor" of dive bombing.

In normal (horizontal) bombing the released bomb has a horizontal, forward speed vector given to it by the movement of the aircraft. To this a vertical acceleration is added, caused by the pull of gravity, which causes to bomb to fall. The combination of the two results in a parabolic curve, which is distorted by the drag of the bomb and the wind. The basic idea of dive bombing is to make the speed vector of the aircraft coincide with the direction of gravity -- vertical -- so that the trajectory of the bomb becomes a straight line instead of a complicated curve. This greatly reduces the problems of bomb aiming. Because the bomb is usually released from lower altitude and at higher speeds, the effects of the wind are also minimised.

There are of course also disadvantages. A vertical or near-vertical dive results in a rapid build-up of speed, and airbrakes are needed to reduce the terminal dive velocity of the aircraft to acceptable limits. At the end of the dive, after the release of bombs, a sharp pull-out is necessary to keep the aircraft in the air, and this puts considerable stress on the aircraft. These requirements usually meant that dive-bombers had to be heavy, robust aircraft, with an unimpressive performance in level flight. Dive bombing also required highly specialised, intensively trained crews. These pilots not only had the technical problems of judging the diving angle correctly -- the natural tendency is to overestimate it -- aiming their bombs correctly, dropping them and then pulling out at the correct time. They also had to resist the mental and physical stress of a fast dive and a sharp pull-out manoeuvre.

The technique was first used during Word War I. The first officially acknowledged dive bombing attack seems to have been made by Lieutenant Harry Brown of the RFC (Royal Flying Corps) who sank a munitions barge in 1917. After the end of the war the RAF (Royal Air Force) conducted research and experiments, but finally decided that the method was too dangerous and halted its development. Instead, the British chose to concentrate their efforts on the creation of a strategic bombardment force. The FAA (Fleet Air Arm) kept the idea alive, but the development on its aircraft was seriously hampered by the RAF control over all aircraft, including shipboard aircraft.

The development of dive bombing continued in the USA. The USMC (US Marine Corps) practised dive bombing, although seldom at angles of more than 45 degrees, during operations in Haiti in 1919. A more refined form of the technique, influenced strongly by aviators who had flown in Europe during W.W.I, was used by them during the US intervention in Nicaragua in 1927. During these years, the USMC pilots also included spectacular dive bombing demonstrations in their air show routines. The USN (US Navy) adopted dive bombing as doctrine, not to provide ground units with tactical air support (as had been the goal of the USMC) but as an effective method to hit enemy ships - relatively small, moving targets. The aircraft used during these years were developments of the Curtiss Hawk family of fighter biplanes, the F6C and BF2C. The name of `Helldiver' was attached to these aircraft, although this would not become officially the name of an American aircraft until the Curtiss SB2C was introduced, during W.W.II.

In Germany, forbidden by the treaty of Versailles to develop military aircraft (a regulation which was often infringed upon, with the occasional help of the Russia, Japan, Sweden, the USA and other countries), the military leadership had to concentrate more on the theory of their application. Theorists developed the concept of a new style of mobile warfare, fought by Panzer divisions which combined tanks with motorized infantry and artillery, and intensively supported by attack aircraft. After Hitler came to power in 1933, work began to convert the theoretical concept into a real force. Ernst Udet, the head of the aircraft development programme of the Reichsluftwaffe, was very impressed with the demonstrations he saw in the USA in 1933. (Not because the concept of dive bombing was new to Udet, for the development of German dive bombers was already underway.) After he had flown the Curtiss Hawk, he bought two, which he demonstrated in Germany. This helped to advance the case of the dive bomber in Germany.

Birth of the Ju 87

In Germany the development of dive bombers was set up in October 1933, as part of the secret rearmament programme. (Which in its origins dated back to 1921, long before Hitler came to power.) The first dive bombing unit was equipped with the Heinkel He 50, a sturdy biplane that had originated from a Japanese requirement for such an aircraft. Later the Henschel Hs 123, also a biplane, replaced the He 50. The Hs 123 was, like many early aircraft of the Luftwaffe, seen as an interim type, but it would actually give excellent service during most of World War II.

In 1934 the Luftwaffe tested a modified Junkers K 47, an all-metal, low-wing monoplane with twin tail fins. The K 47 was originally designed as a two-seat fighter, and the diving tests were purely experimental. There was also an exchange of ideas with the Swedish airforce, which was also interested in dive bombing - and would, after the end of W.W.II, produce one of the most advanced dive bombers ever flown, the Saab 18. Then in 1936 the Luftwaffe selected a new dive bomber to replace the Hs 123. The contenders were the Arado Ar 81, the Blohm & Voss Ha 137, the Heinkel He 118 and the Junkers Ju 87.

Arado Ar 81

The Ar 81 seemed an anachronism compared to the other contenders, because it was a biplane. It had a fuselage with nice, clean lines, and a fully covered cockpit for the two crew members. The fixed landing gear was covered with spats. The biplane wings were of single-bay configuration (with a single pair of outboard wing struts). The installation of the Jumo 210C engine was similar to that later adopted by the Ju 87, with a rectangular `beard' radiator. The performance of the Ar 81 was good, it was faster than the prototypes of the Ju 87 and Ha 137. But its biplane configuration doomed it.

Blohm & Voss Ha 137

The Ha 137 -- the Ha designator was used instead of the Bv designator connected with Blohm & Voss, because the manufacturer had been known earlier as Hamburger Flugzeugbau -- was an all-metal, single-seat monoplane. It had a deep fuselage of rectangular cross-section, and an inverted gull wing with trousered undercarriage legs. The installation of the Jumo 210C engine was neater than designed by the other contenders, with a close-fitting cowling and a small radiator set under the wing centre section. Nevertheless the type exuded a ponderous uglyness. The Ha 137 could carry one 250kg bomb and four 50kg bombs, with a fixed armament of one 20mm cannon and two 7.9mm machine guns. Five were built. The performance of handling of the Ha 137 were good, and Wolfram von Richthofen (a nephew of the W.W.I 'ace' Manfred von Richthofen) recommended its production. But nothing came of this, because Udet preferred the Ju 87.

Heinkel He 118

The Heinkel He 118 was designed by the brothers Günter, and had the smooth elliptical wing and fuselage contours typical of their designs -- such as the He 70 and He 111. It was the aesthetically most appealing of the contenders. The He 118 too had an inverted gull wing, but this was set higher on the fuselage. The He 118 was also the only contender with retractable landing gear. It was powered by the Daimler-Benz DB 600 engine. Although the He 118 was without doubt the most advanced of the contenders, it was not satisfactory, mainly because it failed to reach a diving angle of more than 50 degrees. When Udet impulsively flew the He 118 outside its limits, the propeller was torn away. Udet escaped by parachute. The He 118 later did provide inspiration for the Japanese Yokosuka D4Y Judy dive bomber.

Junkers Ju 87

The Ju 87V1, which made its first flight on 17 September 1935, was again a monoplane with an inverted gull wing, but it was by far the ugliest of all. The wing had no taper on the leading edge of the anhedralled center section; on the dihedralled outboard section the leading edge tapered gently backwards. The trailing edge tapered more sharply. In line with earlier Junkers practice -- also seen on the Ju 52, Ju 86 and the K 47 -- the entire trailing edge of the wing was fitted with slotted flaps; the ailerons too were slotted. This gave the Ju 87 fine low-speed handling, but of course also generated a lot of drag.

The undercarriage was fixed and covered with ugly 'trousers'. The blunt-edged nose had a deep radiator, with entrance louvers, for its Rolls-Royce Kestrel engine. This was replaced in later prototypes and the Ju 87A series by the Jumo 210 engine, and a smaller, rectangular radiator bath. The fuselage itself had fairly gracious lines. It tapered upwards from the nose to the cockpit, so that the pilot had a good forward view. The view all around was excellent, thanks to a roomy greenhouse canopy for the two crew members. The slender tail structure is alleged to have been quite vulnerable to enemy fire, because the control lines were grouped close together.

Initially the rectangular, strut-braced tailplane had two small, rectangular endplate fins, but after the crash of the Ju 87V1, that was attributed to weakness of the tail, this was replaced by a large single tail fin.

The dive brakes consisted of a pair of long, rectangular strips attached to stubs under the wing leading edges. They were rotated perpendicular to the airstream to reduce the speed of the aircraft. Initially the brakes were not fitted to the first prototype, and after they were fitted the tail of the Ju 87V1 broke up during a dive test. But the third prototype (Ju 87V3) demonstrated its ability to dive at 90 degrees, and to resist a force of 6G during the pull-out. It was primarily this ability that made it win the competition.

Here are specifications for the Ar 81 and Ha 137. I did not find data for the He 118. Maybe someone can fill in the gap?

Type: Ar 81 V3 Ha 137 V4
Crew: 2 1
Engine: 640hp Junkers Jumo 210Ca 610hp Junkers Jumo 210Aa
Wing Span: 11.00m 11.15m
Length: 11.51m 9.47m
Height: 3.61m 2.79m
Wing Area: 35.60m2 23.50m2
Empty Weight: 1925kg 1810kg
Maximum weight: 3070kg 2411kg
Maximum Speed: 345km/h at 4000m,
300km/h at SL
300km/h
Ceiling: 7700m 7000m
Climb: 4000m in 11min 2000m in 4min
Fixed Armament: one 7.9mm MG17 two 7.9mm MG17 and
one 20mm MG FF
Rear Armament: 7.9mm MG15 none
Bomb Load: 250kg one 250kg and four 50kg

Development History

There were three major versions of the Ju 87: The A-series, the B-series (including the R and C) and the D-series (including the G and H). Every step in this series involved an engine change, a redesign of the engine installation, a refinement of the cockpit canopy, and a modification of the undercarriage. They can be easily recognised.

Ju 87A

The production Ju 87A featured the revised tail with a single fin, but the heavy `trousers' on the fixed undercarriage of the prototype were retained, making it easy to distinguish this version from later models of the Ju 87. The radiator intake was (relatively) small and rectangular, and is another easy recognition feature. If that is not enough, the cockpit of the A-model featured two small angled out antenna masts, that were later replaced by a single, vertical one. The canopy had hinged panels instead of the sliding sections featured by later models.

The Ju 87A-0 pre-production model entered service in the spring of 1937. The engine was the Jumo 210, which was to be retained in different versions by the production A-series: the Jumo 210Ca for the A-1, and the Jumo 210Da for the A-2. Production of the A-series ended after 262 aircraft, at the end of 1938.

The Junkers Ju 87A had two fixed, forward-firing MG 17 guns, installed in the wing outboard of the undercarriage attachment points. There was a flexible MG 15 in the rear cockpit. The Ju 87A could carry a 250kg bomb, or a 500kg bomb if the rear gunner was left home. The bomb was carried on a swing-down rack, a tubular structure of which the front end was attached under the engine. On release, the bomb was swung forward and downward, so that it was free of the propeller disc. (The swinging bomb crutch seems to have been an American invention. The USN considered it important enough that they refused, in 1939, to allow export of such bomb racks to France! The logic behind that decision is difficult to explain.) There were also two small racks for SC50 bombs under each outboard wing panel.

The Ju 87A did not see combat, with the exception of three aircraft which were sent to Spain during the civil war, but it was important in the development of the automatic bombing system of the Ju 87. This consisted of an Askania autopilot, which was used together with a Revi gunsight. The bomb release gear, elevator controls, and dive brakes were linked to this system. Before attacking the pilot would set the bomb release height. The deployment of the dive brakes automatically adjusted the elevator trim tab, and put the aircraft into a dive. When the bomb release height was reached and the bombs were dropped the autopilot adjusted the elevator trim tab again, so that the aircraft became tail heavy and pulled itself out of the dive. The use of the elevator was forbidden, except in case of emergency.

The pilot thus needed not to be concerned too much with the pull-out. This was just as well, because the pull-out put a an acceleration of 6G on aircraft and pilot. Under such conditions one could not expect the pilot to perform complicated control sequences. Normal procedures called for a bombr release at an altitude of about 900m, which brought the Stuka down to about 400m before it started to regain altitude.

Ju 87B

The Ju 87B was to be the standard model during the early years of World War II. It was powered by the much more powerful Jumo 211 engine. This engine had fuel injection, an important feature for an aircraft which had to be subjected to heavy G-forces and acrobatic manoeuvres. A new engine cowling was designed, with a new air intake on top of the cowling, and a deep half-circular radiator under it. The radiator was larger for the B-2 model than for the B-1, because the B-2 had an even more powerful engine, and it can only be described as a deliberate insult to the aerodynamicists.

The trousered undercarriage of the A-model was replaced by a `spatted' one, with closer-fitting leg covers and better streamlined wheel spats. The change was more than cosmetic, for the undercarriage was also redesigned and considerably strengthened. The mainwheels were also moved slighlty backwards. If the Ju 87 had to operate from poor airfields, such as found at the Eastern front, the spats were often removed because they tended to get clogged with mud. It was not even uncommon for Ju 87s to have their undercarriage ripped off when operating from such airfields. On the undercarriage legs a fitting was installed for a siren, a so called `Jericho Trumpet', to enhance the effect on morale of the Ju 87's attacks. This was driven by a small propeller on the left undercarriage leg. When the siren was not installed the mount was faired over, leaving a protrusion on the undercarriage. The sirens were mostly discarded during the Battle of Britain, because they reduced the performance of the already slow and vulnerable Ju 87.

The greenhouse canopy of the Ju 87B was also different of that of the Ju 87A, with sliding sections for the pilot and the gunner, which replaced the earlier hinged entry panels. The twin radio masts of the JU 87A were replaced by a single, tall, vertical mast.

Ju 87C

The Ju 87C-1 was a shipboard development of the Ju 87B, intended for use on Germany's -- never completed -- aircraft carrier Graf Zeppelin. The carrier was launched at the end of 1938, but work was halted in 1940. It was resumed in 1942 but abandoned again the next year. The Graf Zeppelin was intended to carry 40 aircraft, of which 28 were planned to be Ju 87Cs.

The wings of the Ju 87C had a smaller span and folded outboard of the undercarriage attachment points. The folding was similar to that used by the Grumman F4F Wildcat: the wings folded backwards with the leading edges turning down, so that they could be stored flat against the sides of the fuselage. The Ju 87C of course also had attachment points for catapult launch and a tailhook for arrested landings. The landing gear was made jettisonnable for a ditching, and flotation bags were fitted.

The Ju 87C also had the capability to carry underwing fuel tanks, extending its range from 800km to 1600km. This was to be retained for another (land-based) production model, the Ju 87R.

Because the Graf Zeppelin was never completed, the Ju 87C only operated from land bases.

Ju 87R

The Ju 87R was a long-range version of the Ju 87B, with design features of the Ju 87C. The out-of-sequence R-designation stood for `Reichweite', range. They were intended for anti-ship attacks, and proved very effective during the fights in Scandinavia.

An additional fuel transfer system was fitted, new fuel tanks installed in the wing, and the outer wing attachment points were modified so that 300l fuel tanks could be carried instead of bombs. The R-1 and R-2 were equivalent to the B-1 and B-2, but the R-1 had a longer range, because the B-2 model was heavier than the B-1.

Ju 87D

The Ju 87D had a completely redesigned engine installation. The engine was still a derivative of the Jumo 211, but the more powerful J or P model was used. The main coolant radiator was removed from under the engine cowling, and two radiators were installed under the wing centre section instead. A shallow oil cooler was retained under the engine cowling. A new VS11 propeller with paddle blades was used.

There were also other aerodynamic refinements. The greenhouse canopy now tapered aft, instead of having a nearly constant cross-section as had that of the B-model. The aft gunners exchanged the single drum-fed MG15 gun for twin belt-fed MG81 guns.

The bomb release gear was better faired in, and the maximal bomb load was increased to 1800kg. This could include a 1400kg armour-piercing bomb on the centreline rack. The landing gear was again strengthened, but nevertheless the Ju 87D retained a reputation for landing gear collapses on rough runways. The wheel covers were again changed, and the fitting for sirens were eliminated.

The D-3 introduced additional armour, because the Ju 87 now more often had to dodge the fire of the troops it attacked. From the D-4 model onwards the 7.9mm win guns were replaced by the 20mm MG151/20 cannon. The D-5 model had a longer wing span, with pointed wing tip extensions. An interesting development was the D-7, which had night flight equipment and radar.

Ju 87E

Like the Ju 87C had been the navalised derivative of the Ju 87B, the Ju 87E was the navalised version of the Ju 87D. But it was never built.

Ju 87G

The Ju 87G was the final version of the Stuka. It abandoned the dive attack in favour of an armament of two 37mm Rheinmetall-Borsig BK3,7 anti-tank cannon. These weapons fired special armour-piercing ammunition, with tungsten cores, at a muzzle velocity of 850m/sec. They were installed in gun pods fitted outboard of the landing gear legs. The ammunition was in six-round clips. The first operational trials were made in March 1943. The normal 7.9mm or 20mm wing guns were deleted. Dive bombing was not possible with the additional weight of the guns, so the dive brakes were also deleted -- the Ju 87G could still drop bombs, but not in a dive.

Initially, the Ju 87G was seen as quite dangerous to its crews. The additional weight and drag of the wing guns adversely affected performance and handling, and low-level attacks in the face of the Russian AAA and fighters seemed suicidal. But true as that was, it remained that the Ju 87G was extremely effective. The 37mm gun was in 1943 considered obsolete as an anti-tank gun on the ground, but from the air it was still effective, because the Ju 87G could attack tanks from the rear or from above, were their armour was much thinner. Not that the Germans refrained from trying out bigger cannon on anti-tank aircraft, but the Ju 87 could not possibly carry these, and larger aircraft such as the Ju 88 were not agile enough to operate successfully against tanks.

There were two versions, the G-1 and the G-2, with short and long wing spans, respectively -- the G-2 was based on the long-wing D-5 model. Production of the Ju 87 was halted definitively in October 1944.

Ju 87H

The Ju 87H models (H-1, H-3, H-5, H-7 and H-8) were disarmed versions of the equivalent D-models, equipped with dual controls, for use as trainers. The rear cockpit design was again modified, with bulging windows to give the instructor a reasonable view forward.

Ju 87K

The Ju 87K designation was used for export models. The K-1 was equivalent to the A-1 and intended for export to Japan. The K-2 and K-4, equivalent to the B-1 and A-1, were exported to Hungary.

Specifications:

Type: Ju 87A-1 Ju 87B-1 Ju 87D-1 Ju 87G-1
Engine: 640hp Junkers Jumo 210D 1200hp Junkers Jumo 211A 1300hp Junkers Jumo 211J 1300hp Junkers Jumo 211J
Wing Span: 13.00m 13.20m 13.80m 13.80m
Length: 10.80m 11.00m 11.00m 11.00m
Height: 3.90m 3.77m 3.77m 3.77m
Wing Area: 30.00m2 31.90m2 31.90m2 31.90m2
Empty Weight: 2273kg 2760kg 2810kg 3600kg
Maximum weight: 3324kg 4400kg 5720kg 5100kg
Maximum Speed: 320km/h 350km/h 354km/h 344km/h
Dive Speed: 550km/h 600km/h 600km/h
Ceiling: 9430m 8100m 9000m 7500m
Climb:
3000m in 8.8min 3000m in 14min 3000m in 13.6min
Range: 995kg 800km 1165km 1000km
Fixed Armament: 1*mg7.9mm MG17 2*mg7.9mm MG17 2*mg7.9mm MG17 2*g37mm BK3,7
Rear Armament: 1*mg7.9mm MG15 1*mg7.9mmMG15 2*mg7.9mm MG81Z 2*mg7.9mm MG81Z
Bomb Load: 500kg 1000kg 1600kg

Combat History

Evaluation in Spain

In late 1936 three Ju 87A-1s were sent to Spain for operational evaluation. They were followed in 1938 by three Ju 87B-1s. More would arrive later. The A-models had not been very successful in combat, mainly because of technical shortcomings, but the Ju 87B proved to be effective. They were used to attack bridges, command posts, artillery positions, and ships in harbour.

The war in Spain was more important for the Ju 87 than the other way around, for it was in Spain that the Germans developed their air-ground cooperation doctrine.

Poland

On 1 September 1939, at 04:26 hours, three Ju 87Bs took off for the very first bombing attack of World War II -- before the official declaration of war. Their targets were cables near two railway bridges at Dirschau. The cables had to be cut to prevent the destruction of the bridges; it was a partial success, because the Poles managed to blow up one bridge.

That first day of the war was not an overall success for the Luftwaffe and the Ju 87. Most of the strength of the Luftwaffe was sent far behind the lines to destroy the Polish air force on the ground, but without conclusive results -- it was estimated that the Poles lost about 30 aircraft by it. But during the next days the co-operation between the armed force and the Stukas proved to be excellent. Every time the Polish army tried to organise resistance to the rapid advance of the tanks, Stukas were called in to destroy it. The largest Polish counter-attack, when 170,000 men attacked the rear of the 10th Army in the battle of the Bzura, was brought to a halt under the relentless air attacks, before the Polish were surrounded at Kutno.

If the quick German success in Poland was watched with admiration as well as concern in some other countries, the fate of Warsaw was a warning of the barbarism that the war would bring. Technically, the attacks of German bombers on the fiercely defended Polish capital may have been allowed by the rules of warfare. Nevertheless, the destruction of the city caused great anger. It also had a strong effect on the minds of other allied leaders, who would during 1940 being reluctant to defend cities against the advancing German army, if this meant that they would be mercilessly destroyed from the air.

The Germans indeed made a propaganda movie about the Ju 87, and the devastation it had caused in Poland. Allegedly, the Germans bombarded parts of Warsaw after the end of the fighting, to get more impressive footage for this production... It ended with a threat against England, if it did not seek peace. As far as England and the Ju 87 were concerned, it was a hollow threat.

Denmark and Norway

There was little reason for the Stukas to intervene in the land battle during these fights in the Scandinavian countries. Instead, the Ju 87 was used extensively for attacks against allied ships, which tried to supply their own expeditionary force in Norway and to prevent the Germans from reinforcing theirs.

The attacks of the Stukas concentrated mainly on the allied attacks to recapture Narvik and Trondheim by landings at Harstad, Namson and Andalsnes. They did inflict considerable losses on the attackers, although they did probably not change the outcome of this operation, which was doomed from the start by the stupidity of allied planners and the events in France. At Narvik the Luftwaffe sank a cruiser, and damaged two others and the old battleship Resolution. For the Royal Navy this was a serious lesson about operating under enemy air superiority -- a lesson that some people refused to listen to, and others would quickly forget. But the commander of the French troops in Norway, a man with the confusing name of Mittelhauser, admitted later:

At any rate, when the Stuka was revealed to us, when we saw the British fleet giving up before Trondheim (because of it), we had the feeling that we were face to face with something quite new, and of a technical surprise whose employment to be decisive.

We can only assume that the general didn't know that dive bombers were not a new invention. Even the French navy had some. The French airforce held the view that they were of no use over land.

France and the Low Countries

Poland not being much of an opponent for Germany, it was in May 1940 that the Stukas really proved their effectiveness. There it was not only its accuracy as a dive bomber, but also the fear that it spread -- among combatants and civilians alike -- that was decisive. Of course it did not help that the French Army had two commanders and three headquarters, none of which actually knew what was going on at the front. Nor did it improve things that French generals had been too complacent to properly train their soldiers. The French had expected that after any serious move made by the Germans, they would have days or weeks to react, while reinforcements and artillery were laboriously moved to the frontline. Now they experienced that their own old-fashioned army, based on the tactical principles of W.W.I, was completely unable to defend itself against this kind of attack.

The fatal breakthrough on 13 May near Sedan was preceded by an attack of the Ju 87s on the positions of the French defenders. Small groups of Stukas methodically attacked the villages in front line, road crossings and artillery positions. Even the Germans, moving forward under protection of these attacks, were frightened -- perhaps understandably, because there had been a few "friendly fire" incidents during the campaign in Poland. The French general Ruby reported:

The infantry, cowering and immobile in their trenches, dazed by the crash of the bombs and the shriek of the dive bombers, were too stunned to use their anti-aircraft guns and fire. Their only concern was to keep their heads down and not move. Five hours of this punishment shattered their nerves. They became incapable of reacting to the approaching enemy infantry.

It is unbelievable, but the French general Huntziger refused to call in fighters to chase the attackers away, because of the attrition that such operations would cause! The prevailing view was that air force was a vulnerable weapon, that would soon be lost if it were used. General Gamelin is alleged to have predicted that "It will burn itself in a flash." (In fairness to Gamelin: I heard a Belgian reserve officer express the same opinion ten years ago!)

When the French commanders saw their mistake, they began to ask for British fighter aircraft to protect their troops. They were unaware that because of monumental incompetence, most of the French air force had remained inactive. Three quarters of the French fighters were never committed to the battle. The Luftwaffe was free to attack anything that moved. Most of that movement was to the rear. The Ju 87s, sometimes flying nine missions per day, cleared the road for the German forces which brushed irresistably through France. Some French units launched limited counter-attacks, such as General de Gaulle's 4th armoured division, but they were immediately attacked by the Ju 87s, and forced to retreat:

Until sunset they continued to bomb us, and the consequences were wrecking for our vehicles, which could not leave the road, and our artillery, which could find no cover.

The tanks, its seems, were more difficult targets; but they could do little without their support vehicles and the divisional artillery.

The Luftwaffe's attack on Dunkirk, however, showed the limitations of both the Luftwaffe and the Ju 87. The French and British soldiers, finally accustomed to the screaming attacks of the dive bombers, resisted admirably, defending the city until almost all the British and many of the French soldiers could be evacuated over sea. At the same time, the operations of the RAF to protect the evacuation caused heavy losses for the attackers, although a large number of ships was sunk or damaged. It was the first sign of the vulnerability of the Ju 87.

The Battle of Britain

For the battle of Britain, the Luftwaffe amassed a force that included 336 Ju 87s, of which about 280 were operational. But the contribution of the Ju 87 to the attack on Britain was brief, and in fact mainly limited to the attacks on shipping in the channel, during the initial stages. Here the Ju 87 was effective enough, and the Royal Navy was forced to remove a destroyer flotilla from Dover and give orders that destroyers would only pass the Straits of Dover during the night. There were also a number of attacks on convoys off the British coast. The best known of these was the fight off Eastbourne, which was reported `live' by the BBC. In this battle three ships were damaged, but seven Stukas were shot down for the loss of one Hurricane.

Then the Stukas turned their attention to the British airfields. Attacks on Detling, Lympne, Hawkinge and Tangmere followed. But by now the Fighter Command and taken measure of the Stuka, and the attacks of the next days would make it clear that the Ju 87 was a sitting duck for the Spitfires and Hurricanes of the RAF. On 18 August the so-called "Stuka-slaughter of Thorney Island", when a large formation was caught without fighter cover, cost the Luftwaffe 30 Stukas -- shot down, crash-landed, or damaged beyond repair. This forced the Luftwaffe to pull back the Stukas from the offensive against Britain. They continued operating against shipping in the channel, also at night, but no longer participated in the main effort. The Ju 87s were conserved for the actual invasion.

Ju 87 in Italy

One of the weaknesses of the Italian Regia Aeronautica was its lack of dive bombers. The Italian attempts to develop such an aircraft had ended in a complete and ridiculous failure: The SM85 was abandoned after the type flew a single mission.

Yet it was clear that dive bombers were a very effective weapon against British ships in the Mediterranean. As was proven by the Germans when sent Stukageschwader I and II to the help the Italians. The Stukas badly damaged the carrier Illustrious, sank the cruiser Southampton, damaged several other ships, and nearly cut off the supply line to the besieged Tobruk.

So by 1941 the Italians received 46 B-1s, 50 B-2s, 59 R-2s. In 1943 they received an additional 46 aircraft, D-2s and D-3s. The Italians gave the aircraft the nickname Picchiatelli, which means "Striker". Although the Italians were trained initially to use the same tactics as the Germans, who did dive vertically on their targets in small groups, they soon developed their own methods. Rather oddly, the Italians also used the Ju 87 for the method which later became known as skip bombing -- horizontal attacks at very low level, dropping their bombs in such way that they would bounce of the water and hit the attacked ship on the waterline. The advantage of this method of attacking was that the target was hit on the waterline, and a dive directly into the defensive fire was avoided.

The Eastern Front

At the Eastern front, air support was not as adequate as it had been in France. This was because the Luftwaffe was so enormously overstretched: Too many aircraft had too stay in the West and the Mediterranean.

The task that would come to the Ju 87 on the Eastern front was the destruction of enemy tanks. One of the things that the Germans had not accounted for in their war plans was the enormous number of tanks the Red Army had, and their qualities had escaped the observation of most. Confronted with the presence at the of large numbers of excellent T-34 tanks, and the disappointing production of their own industry, the Germans sought to compensate their numerical inferiority in other ways. For the Ju 87 it was a "target-rich environment". The giant tank battle of Kursk, the largest ever, saw the participation of large numbers of Ju 87s.

But the Ju 87s now had to operate from often very primitive airfields, at the end of long supply lines, and in a harsh climate. Aircraft had usually to be maintained in the open air, and hangars or shelters for parked aircraft were non-existent. Equipment broke down in the Russian winter. Rudel wrote:

The engines no longer start, everything is frozen; it is suicide to trust the instruments.

Stuka units also often had to improvise the transport of their own supplies and ground crews. In Germany, enormous overwing pods were developed for this, which allowed the Ju 87 to carry four people. But they remained experimental, and a common solution was too load everything in a DFS 230 glider and tow it behind a Ju 87. For use during the winter, optional ski landing gear was developed, although it was not widely used because it reduced performance. The removal of wheel spats was also common.

Tactics changed from dive-bombing to low-level attacks, and finally the use of dive bombing was abandoned entirely by the Ju 87G versions. Because of the dangerous nature of such operations, the armour of the Stuka was substantially increased. Of course it became even more dangerous when the Soviet air force gained the upper hand, because it first and foremost wanted to achieve tactical air superiority over the battlefield, where the Ju 87s flew. The obsolescence of the Ju 87 was now seriously felt, and the type was increasingly replaced by the fighter-bomber versions of the Fw 190.

If the Ju 87 continued to be effective, it was mostly because of the very experienced crews. The most successful Stuka pilot was Hans-Ulrich Rudel, who was to become the most decorated German pilot of W.W.II. He was also the pilot who flew the most combat missions -- a staggering 2530. He was credited with the destruction of the battleship Marat, 519 tanks, and over 2000 other vehicles. According to one rumour, Hitler was so impressed by Rudel's actions that he contemplated naming him as his successor!

Evaluation

During W.W.II, several Ju 87s fell into allied hands, but not until at the end of the war the famous British test pilot Eric Brown had the opportunity to fly an Ju 87D-3. He had flown numerous allied dive bombers, such as the Blackburn Skua, the Vultee A-35 Vengeance, the Vought SB2U, the Douglas SBD Dauntless and the Curtiss SB2C Helldiver. Therefore he was in an excellent position to compare these aircraft.

To him the Ju 87D-3 - then completely obsolete - imparted an "almost oppressive" sense of vulnerability. The pilot sat high a the greenhouse company, with an excellent view all around, but also terribly exposed. The Ju 87D-3 accelerated well on take-off, but climbed slowly, and was both too slow to escape from fighter attack and too stable to evade it. Briefly, the Ju 87 was an "ideal target", even for the most inexperienced fighter pilot.

On the other hand Brown confirmed that the Ju 87 was ideal for dive bombing, "a genuine 90 deg screamer", in which it felt quite natural to be in a vertical dive. Dive bombing practice in the Ju 87 he found "more enjoyable... than I had ever experienced with any other aircraft of this specialist type."

Before the dive, the aircraft had to be trimmed for cruise conditions, the bomb release altitude was be set, and the cooler flaps closed. Deploying the dive brakes automatically put the Ju 87 into a dive, and engaged a security device which limited the control column movement to 5 degrees from neutral -- enough to give effective control for bomb-aiming, but preventing manoeuvres which could overstress the aircraft. After bomb release the Ju 87 pulled itself out of the dive. The pilot then closed the dive brakes, and climbed away.

Compared with other dive bombers, the Ju 87 left a favourable impression. If it was vulnerable, it was not more so than the Douglas SBD Dauntless, the Aichi D3A Val, or the Blackburn Skua. And it was more accurate than any of those.

Comparison

Here is a comparison of the Junkers Ju 87B-1 with some other dive bombers of World War II. They are all naval types.

The Blackburn Skua was a British dive bomber and two-seat fighter. It was rather too slow and cumbersome to be an effective fighter, and was rapidly replaced by the Fulmar. As a consequence, the FAA did no longer have a dive bomber after the Spring of 1941. The Skua eyed a bit more modern than the Ju 87, because it had retractable landing gear, but it was quite ugly. Its diving characteristics were good. The usual dive angle was 70 degrees, and its dive brakes were modified 'Zap' type trailing-edge flaps.

The Douglas SBD Dauntless was the standard dive bomber of the USN for a good part of the war, and continued in service until the end. It played a very important role in several battles in the Pacific -- the most famous that of Midway, where SBDs sunk four Japanese carriers. The SBD too had retractable landing gear, and it had better streamlining than most contemporary dive bombers. Thus it had a relatively good performance. It also had good diving characteristics, and diving angles between 70 and 75 degrees could be achieved. The dive brakes were large trailing edge flaps which were perforated to reduce the buffet. Nevertheless, it was admitted to be an obsolescent and vulnerable aircraft. It just happened to be still better than its intended replacement, the Curtiss SB2C Helldiver.

The Aichi D3A Val was the most important Japanese dive bomber of the war, which was produced until January 1944. The more modern Yokosuka D4Y appeared only when the war was already lost for Japan. The D3A shared the fixed landing gear of the Ju 87 and had similar dive brakes: rotating strips attached under the wing leading edges. But its other features, such as the elliptical wing, showed mostly Heinkel influence. During the first year of the war, with very highly trained and experienced crews, the D3As achieved a hitting rate of about 80%. They were agile enough to be used as dogfighters after they dropped their bombs, but when the USN pilots improved their tactics the D3A became very vulnerable.

Type: Junkers
Ju 87B-1
Blackburn
Skua
Douglas SBD-5
Dauntless
Aichi
D3A2
Engine: 1200hp
Junkers
Jumo 211A
830hp
Bristol
Perseus XII
1200hp
Wright
R-1820-60 Cyclone
1075hp
Mitsubishi
Kinsei 44
Crew: 2 2 2 2
Wing Span: 13.20m 14.07m 12.66m 14.53m
Length: 11.00m 10.84m 9.91m 10.25m
Height: 3.77m 4.32m 3.94m 3.35m
Wing Area: 31.90m2 28.98m2 30.19m2
Empty Weight: 2760kg 2493kg 3028kg 2618kg
Maximum weight: 4400kg 3733kg 4322kg
Maximum Speed: 350km/h
362km/h
at 2040m
407km/h
at 5060m
450km/h
Dive Speed: 600km/h 407km/h 445km/h
Ceiling: 8100m 5820m 8075m 10880m
Climb: 3000m
in 8.8min
5820m
in 43min
3050m
in 8min

Range: 800km
2084km 1560km
Fixed Armament: 2*mg7.9mm MG17 4*mg7.7mm 2*mg12.7mm 2*mg7.7mm
Rear Armament: 1*mg7.9mmMG15 1*mg7.7mm 2*mg7.62mm 1*mg7.7mm
Bomb Load: 1000kg 227kg 815kg 370kg

Sources:


Emmanuel Gustin
mailto:gustin@uia.ua.ac.be