Junkers Ju 87

The Junkers Ju 87 or Stuka (from the German Sturzkampfflugzeug, "dive bomber") was a German two-seat bomber and ground attack aircraft—pilot and gunner/radio operator—from World War II. Designed by Hermann Pohlmann, the Stuka first flew in 1935 and debuted in combat in 1936 during the Spanish Civil War as part of the Condor Legion sent by the German Luftwaffe.

The plane was easily recognizable by its inverted gull wings, its faired and fixed landing gear, and the bellowing of its Jericho-Trompete siren ("trumpet of Jericho"), becoming the symbol of German air power propaganda and Blitzkrieg victories between 1939 and 1942. The Ju 87 design included several innovative features, such as automatic raising of the wings' dive brakes to ensuring that the aircraft recovered from a dive attack even if the pilot fainted due to high acceleration. Although tough, precise and very effective in its attacks, the Ju 87 was vulnerable to then modern fighter aircraft, as were many other dive bombers of the war. His flaws became evident during the Battle of Britain; Its poor maneuverability, low speed and little defensive armament meant that the Stuka needed a strong fighter escort to operate efficiently.

The Stuka operated with greater success after the Battle of Britain, and was used in Africa in 1940 and Its power as a precision attack aircraft was very valuable to German forces in the Balkan Campaign, in the North African and Mediterranean theaters and in the early stages of the Eastern Front, campaigns where Allied fighter resistance was scarce and disorganized. Later, once the Luftwaffe lost air superiority on all fronts, the Ju 87 once again became an easy target for enemy fighters. Despite this, because it had no better substitute, the model continued in production until 1944. By the end of the conflict, the Stuka had largely been replaced by ground attack versions. of the Focke-Wulf Fw 190, but was still used until the last days of the war. It is estimated that around 6,500 Ju 87s in all versions were produced between 1936 and August 1944.

The German pilot, Colonel Hans-Ulrich Rudel was the most outstanding Stuka ace and was the most highly decorated German soldier of the Second World War. He was the only one to receive the highest German military decoration, the "Knight's Cross of the Iron Cross with Oak Leaves in Gold, Swords and Diamonds", on December 29, 1944.

Development

Its design and construction began during the period of reactivation of the German armed forces after their dismantling after the defeat of the First World War.

The technique of dive bombing was already familiar in the First World War, but no aircraft specifically designed for this mission existed until the 1920s. One of the first was the Junkers K 47, of which two examples flew in 1928 with Bristol Jupiter engines, and another twelve with a Pratt & Whitney R-1690 Hornet were sold to China. Intense experiments were carried out with them, demonstrating that the 90° dive was the most precise, although the idea required a robust aircraft and a determined pilot, plus a dive angle indicator.

Many of those who would later become leaders of Hitler's Luftwaffe became convinced that dive bombing should be the main weapon of an air force dedicated to close support of ground troops. When the new Luftwaffe fighter aircraft were planned in 1933, an elegant biplane, the Henschel Hs 123, was provisionally adopted for this role, while Junkers worked hard to develop the final Stuka.

The design team, led by Hermann Pohlmann, initially adopted the same configuration as the K 47: a single-engine, low-wing monoplane with fixed landing gear and double drift. The Ju 87 differed in its all-metal construction with a strong skin structure, without the corrugated exterior previously used on Junkers metal aircraft, and in its broken "inverted gull" or W wing. As on the K 47 the entire trailing edge It was occupied by the flaps and ailerons in a "double wing", a Junkers patent, and the crew was accommodated back to back under a large glass cover.

The prototype flew in the spring of 1935 with a 480 kW (640 HP) Rolls-Royce Kestrel engine.

Despite the installation of aerodynamic dive brakes on the intrados, in one of the first recoveries from the dive maneuver, a failure occurred in the tail structure and the plane crashed.

After a long development, in the course of which the engine was changed by another German Junkers Jumo 210 Ca of 640 HP, which drove a three-blade variable pitch propeller; and a new simple drift was adopted, the Ju 87A-1 entered serial production at the beginning of 1937. Approximately 200 examples were manufactured between A-0, A-1 and A-2 in series, all with large trouser fairings on the landing gear, and the A-2 with the most powerful 680 HP Jumo 210Da engine and improved VDM propeller.

In 1939 all A-series aircraft were transferred to training units, and the growing ranks of the Stukageschwader (dive bombing squadrons) were equipped with the much more capable Ju 87B. Visually the biggest difference was the train fairings, smaller and more aerodynamic, but the key difference lay in the power, doubled thanks to the new Jumo 211 A engine, which moved a wide constant speed propeller. The first serial subtype, Ju 87 B-1, carried the 1200 HP Jumo 211Da, with direct fuel injection that immunized it against icing and against sudden stops in inverted flight or in maneuvers with negative g, giving him full acrobatic capacity.

Manufacturing was transferred from Dessau to the Weser Flugzeugbau installed in the large oval building at the Berlin Tempelhof airport terminal, where up to 60 were built per month towards mid-1939.

Design

Basic design (based on B series)

The Ju 87 was a single-engine, cantilever-wing monoplane aircraft of all-metal construction. It had fixed landing gear and could carry two crew members. The main material of its construction was duralumin, the external covers were made of duralumin sheets as well. The parts that had to be of solid construction, such as the wing flaps, were made of an aluminum and titanium alloy called "Pantal" and its components made of a very light magnesium alloy known as Elektron. The bolts and parts that had to withstand high tensions were made of steel.

The Ju 87 had removable hatches and covers to facilitate maintenance operations and inspections. Designers avoided welded parts where possible, preferring instead parts created by casting and mold. It was possible to interchange large segments of the structure as a complete unit, increasing the speed of repair. The structure is also subdivided into sections that allowed it to be transported by road or rail.

According to the Aircraft Certification Center, the Ju 87 had achieved structural strength requirements suitable for a dive bomber. It was capable of diving speeds of 600 km/h and a maximum horizontal speed of 340 km/h near ground level, and a flying weight of 4,300 kg. Performance in dive attacks was improved with the introduction of underwing dive brakes, which consisted of long rectangular slats under the trailing edge, which, when rotating perpendicular to the air flow, allowed the Ju 87 to maintain a constant speed. and a stable position to help the pilot aim. They also prevented the crew from suffering high accelerations and extreme G-forces during dive recovery.

The fuselage had an oval cross section and housed a water-cooled V12 Junkers Jumo 211 engine in its front part. The flight deck was protected from the engine by a firewall before the center section of the wing where the fuel tanks were located. At the rear of the cabin the bulkhead was covered by a canvas cover that could be torn by the crew in an emergency, allowing them to escape through the main fuselage. The cabin was divided into two sections joined by a strong welded steel frame. The cockpit was made of Plexiglas and each of the two crew compartments had its own sliding opening.

The engine was mounted on two triangulated main support structures that came out of the fuselage and were supported by two tubular uprights. The engine was bolted to them at the highest part of it. The firewall, made of asbestos mesh with duralumin sheets on both sides, was joined by universal joints. All ducts passing through it had to be arranged so that harmful gases could not penetrate the cabin.

The fuel system was made up of two tanks located in the central section of both wings, each with a capacity of 250 liters. These tanks had a predetermined limit that, if exceeded, would alert the pilot by means of a red warning light in the cockpit. Fuel was injected into the engine from the tanks by means of a hydraulic pump. In case this failed, the fuel could be pumped manually using a hand pump.

The engine cooling system had two water containers made of aluminum, a 10-liter ring-shaped one located between the propeller and the engine, and another 20-liter one under the engine.

The control surfaces were largely similar to those of other aircraft, with the exception of the innovative automatic dive recovery system. This began the recovery and climb after the dive brakes were deactivated. The pilot could override the system by exerting significant force on the control stick to take manual control. The wing of the Ju 87 was the most unusual feature. It was made up of a central section and two external sections installed using four universal joints. The central section had a large negative dihedral and the outer surfaces a positive dihedral. This created the folded W-shaped wing, or inverted “gullwing,” along the leading edge. The shape of the wing improved the pilot's visibility to the ground and also allowed for shorter landing gear.

The offensive armament consisted of two MG 17 cal machine guns. 7.92 mm mounted on the wings, which were powered by a mechanical pneumatic system from the pilot's control stick. On the other hand, the gunner and radio operator operated an MG 15 machine gun, also of 7.92 mm, mounted on a mobile mount for defensive tasks. The usual war load was a 500 kg SC 500 bomb mounted on a fork that extracted it from its position under the fuselage to drop it out of the reach of the propeller.

Dive procedure

	Ju 87 Stuka in battle Junkers Ju 87 attacking a ship. You can appreciate the sound of the Jericho-Trompete mermaid.
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The automatic dive control was set by the pilot at the desired recovery altitude using a contact altimeter. After performing a list of ten vital actions, the pilot opened the underside dive brakes, which immediately put the plane into a dive, and adjusted the angle manually by aligning the red lines at 60°, 75° or 80° in the side window. of the cabin with the horizon. The pilot then aimed the machine gun sights at the target as in a fighter, using the rudders to achieve the correct alignment with the target. When the altimeter warning light came on, the pilot pressed a button on the joystick for automatic recovery, usually at an altitude of 450 m above ground. If this did not occur, the pilot had to pull the lever back with all his strength, aided by careful use of the elevator compensator. Speed reached 550 km/h, and it was common practice to install sirens – known as “Jericho trumpets” – on the upper covers of the landing gear legs to terrorize those in the vicinity of the target. On close missions, four 50 kg SC50 bombs could also be carried under the wings. The pilot could fire two 7.92 mm MG 17 machine guns mounted on the wings, next to the angle of the dihedral, while the radio operator had an MG 15 of the same caliber in a rear mobile mount for defense up and behind.

Variants

Together with the Ju 87B-2 variant, which as a single seat could carry an SC100 bomb, Weser built a batch of Ju 87C-0 with folding wings, tail and other changes to adapt it to its use aboard the aircraft carrier Graf Zeppelin, which would never be finished. Another model was the long-range Ju 87R, with extra tanks in the external section of the planes and equipment for launchable underwing tanks. It entered service in time for the Norwegian campaign - where one of them disabled a radio station by deliberately colliding with the antennas - and proved particularly suitable in the Balkan, Greek and Mediterranean theaters of operations. The Ju 87R saw a large container suspended from the main pump fork to transport spare parts and miscellaneous loads.

The Ju 87B and its derivatives caused widespread devastation in Europe in the early years of World War II, where they encountered only one serious obstacle. Over England their losses were unacceptably high, with 41 shot downs in the days of August 13 to 18, 1940, so from the 19th, the Stukas were withdrawn from attacks against British targets.

Already at the beginning of the war the Ju 87 design could be considered somewhat outdated, but this fact was hidden by its fantastic success. As happened with other types of the Luftwaffe, the lack of an effective substitute determined the excessive prolongation of its mass production; and like the Messerschmitt Bf 110 and Heinkel He 111, its production increased from 1941 to 1944.

The standard basic type during this period was the Ju 87D, designed in 1940, first flown in early 1941 and used in combat on the Eastern Front and North Africa. It was powered by a 1400 HP Jumo 211 J-1 engine that moved a VD-11 propeller with very wide blades, providing better flight performance, translated into greater offensive loads. The maximum bomb load reached 1,800 kg; It could carry a 1,400 kg PC1400 armor-piercing bomb on the central support, and on the underwings it could carry SC500 or a wide range of loads, including containers with six 7.92 mm MG 81 machine guns or two 20 mm cannons. The rear defensive armament was replaced by a double-mounted MG 81 Z, exceptionally light weapons with a high rate of fire with belt feed instead of the 75-shot combs. Additionally, the plane's lines were refined to reduce drag; The most notable improvement corresponded to the hood and cabin cover. The landing gear was also redesigned, and from 1942 onwards, the wheel and leg fairings were progressively discarded.

The most numerous variant was the Ju 87D-3, which incorporated better protection for the crew and the vital parts of the aircraft as a result of its increasing use as Schlachtflugzeug (assault or close support aircraft). Since 1942 all versions began to carry out missions other than dive bombing, such as towing gliders, attacking partisan guerrillas and small transport with a great variety of loads. A few Ju 87D-4s were equipped as torpedo boats, and the next major variant was the Ju 87D-5, with a larger wingspan to counteract the increased weight of the Dora series. The Ju 87D-7 was a night variant motivated by heavy losses in daytime assault missions, with a more powerful Jumo 211P engine and long flame arresters in the exhausts that exceeded the wing trailing edge. As in the D-8 variant, the fixed machine guns were replaced by 20mm MG 151 cannons and the dive brakes disappeared. The Ju 87D-8 was the last production version; The total number of examples built at the end of September 1944—when aircraft production practically ceased, with the exception of fighters—reached the generally accepted figure of 5,709.

There were plans for other successors, such as the Ju 87F and Ju 187, but only conversions of the ubiquitous D model were built. The most important of these was the Ju 87G subtype, of which only the Ju 87G became operational. 1. It was a specialized anti-tank version, equipped with two BK 3.7 cannons suspended under the wings just next to the landing gear. This 37mm cannon was a formidable weapon, weighing 363kg and had been widely used as anti-aircraft. However, the cannon had a serious drawback: despite the high initial speed (850 m/s) of its armor-piercing projectile, it had only six cartridges per metal comb weapon, and a rate of fire of 160 rounds per minute, which which meant a total duration of the burst of 2.25 s or barely two projectiles per second.

The most important user of the Ju 87G-1, Hans Ulrich Rudel, is credited with 519 destroyed Soviet armored vehicles (a verified figure). This pilot, who continued flying after losing a leg in 1944, flew 2,530 combat missions and continued to command Stuka formations on daytime missions, long after the remaining Stukagruppen had replaced their vulnerable aircraft by the safer Focke-Wulf Fw 190 F and G.

Another variant produced by conversion of existing Ju 87D series airframes was the Ju 87H two-seat dual-control trainer. A trainer for the Ju 87 had not initially been considered necessary, but by 1943 the art of surviving with such an aircraft had become such a specialized and important task on the Eastern Front that even highly experienced veteran fighter and bomber pilots had to fly with Ju 87 instructors before taking up their new positions in the depleted ranks of the Stukagruppen. Of almost all Dora variants there were H conversions, which maintained the same suffix number.

There were some experimental variants, mainly dedicated to weapons testing of other aircraft. One of the most surprising test programs was that of a Ju 87D-3 equipped with large fuselated cockpits on the planes. The idea was to convert the Ju 87 into a vehicle for the infiltration of agents into the enemy rearguard. The final cockpit design provided space for two men seated in tandem, with wide windows to provide the pilot with side vision; In a gentle dive, the two nacelles could detach from the wings and descend with parachutes. There is no evidence that the system was used.

The Ju 87 was widely used by all Axis air forces, including those of Italy, Hungary, Slovakia, Romania and Bulgaria. When a Ju 87 with Italian insignia was discovered, it was mistakenly believed that it was manufactured in Italy; The United Kingdom even invented the designation Breda 201 Picchiatelli. In fact, since 1939 all Ju 87s were built by Weser in the same Tempelhof building.

Operators

Germany

• Luftwaffe

Bulgaria

• Bulgarian Air Force

Croatia

• Croatian Independent State Air Force

Czechoslovakia

• The Czechoslovak Air Force operated aircraft captured in the post-war period.

Slovakia

• Slovak Air Force

United States

• USAAF used a plane captured in the 1943 Tunis Campaign for a short period of time before it crashed.

Hungary

• Royal Hungarian Army Air Force

Italy

• Aeronautical Regia

Japan

• Japanese Imperial Army Air Service

United Kingdom

• The British Royal Air Force tested several specimens captured during and after the war.

Romania

• Royal Romanian Air Force

Yugoslavia

• The Air Force of the RFS of Yugoslavia used aircraft captured after the war.

Operational history

Tests in Spain

Up to 12 examples of different variants were evaluated in operational conditions by the Condor Legion during the Spanish Civil War; probably the V4 prototype was the first to be shipped in late 1936.

Gruppen VB/88, an experimental unit of the Condor Legion, received a total of six Ju 87A for combat evaluation. Apparently used in action in the breach of the Iron Belt of Bilbao and in Teruel, the "Anton" were replaced in the third quarter of 1938 by as many Ju 87B-1s, which were used mainly in the national advance on the Mediterranean coast. and Catalonia.

All the Stukas of the VB/88 returned to Germany at the end of the Civil War, including the remains of one that was shot down over Bujaraloz. In Spain, the Stuka demonstrated its excellent qualities as a dive bomber, achieving an accuracy of less than five meters on point targets.

World War II

At the beginning of World War II, the Luftwaffe had 336 Ju 87Bs. The first combat mission in this conflict was carried out by three Ju 87B-1s, which took off from Elbing at 4:26 on 1 September 1939 to destroy the Polish blasting device on the Dirschau bridge over the Vistula River, which They complied at 4:34, that is, about 11 minutes before the declaration of war on Poland.

It was widely used in the first German campaigns in Poland, France, in the invasion of Russia, in North Africa and in the Mediterranean, with good results especially in attacks on ships and mobile units. By the end of World War II, 5,709 units had been built in multiple variants (this is the generally accepted figure), being used in almost all European and North African theaters.

It was a stable, precise and very effective aircraft, although due to its age it was also slow, poorly maneuverable, poorly armed and very vulnerable to enemy fighters. The Germans learned in the Battle of Britain that air superiority had to be obtained before undertaking effective ground attacks, a superiority they had always had in previous campaigns.

The Stuka is always associated with the most decorated German soldier, Hans-Ulrich Rudel, pilot of a Stuka anti-tank version Ju-87G-1.

Survivors

Specifications

(The list does not include the Ju 87C, a naval adaptation derived from the Ju 87B, created for use on the German aircraft carrier Graf Zeppelin; nor the naval Ju 87E derived from the Ju 87D; nor the Ju 87R long-range; nor the Ju 87H unarmed for use in formation and training)

• Ju 87A was able to transport a 500 kg but no rear machine gun and for short flights
• Ju 87B was able to transport a 1,000 kg but no rear machine gun and for short flights
• The Ju 87D could transport a heavy bomb only for short flights
• Ju 87D-5 could increase the size to 15,00 m and replace MG 17 with two MG 151/20 cannons to increase its ground attack capacity.

Specifications (Ju 87B-2)

Data reference: Ju 87 B-2 Betriebsanleitung, Juni 1940 (D.(Luft) T.2335/1)

General characteristics

• Triple: 2 (pilot and radio/artillery operator)
• Length: 11 m
• Scope: 13.8 m
• Height: 4,23 m
• Elong surface: 31.9 m2
• Empty weight: 3205 kg
• Weight loaded: 4320 kg
• Maximum weight at takeoff: 5000 kg
• Motriz plant: 1× Junkers Jumo 211D, liquid-cooled V12.
  • Power: 883 kW (1184 HP; 1200 CV)
• Propellers: 1× Junkers VS 5 per motor.
• Propeller diameter: 3.4 m

Performance

• Speed never exceeded (Vne): 600 km/h (373 MPH; 324 kt)
• Maximum operating speed (Vno): 390 km/h (242 MPH; 211 kt) at 4000 m altitude
• Cruise speed (Vc): 209 km/h (130 MPH; 113 kt) at 4500 m altitude
• Scope: 789 km without bombs
• Scope in combat: 500 km with a load of 500 kg in pumps

Weapons