Junkers Ju 87 Stuka
German Dive Bomber of WWII
By Stephen Sherman, Apr. 2007. Updated July 7, 2011.
Whistling as it dived to bomb Polish and French targets, the Ju 87 Stuka dive bomber epitomized the savage technological terror of the Blitzkreig early in World War Two. While other advances quickly rendered the Stuka (Sturzkampfbomber, or dive bomber) obsolete, it remained in service throughout the war, with over 5,700 built.
On the Eastern Front in particular, the Ju 87 continued attacking Russian tanks for years.
One Stuka pilot, the famed Hans-Ulrich Rudel, claimed destruction of a battleship (!), 519 tanks, and over 2,000 other vehicles.
The principles of dive bombing are simple enough -- put the airplane into a near-vertical dive and drop the bombs close to the target, thus simplifying the complex problem of aiming a bomb from altitude, while moving forward, through windy or turbulent air.
But it's not quite so simple to do it. As dive bombing was not a kamikaze tactic, the pilot must pull the aircraft out of the dive just after release. To prevent the airplane from building up too much speed, dive brakes (large perforated flaps) are needed. To endure the gee forces of the pullout, the airframe must be very sturdy. And to learn the proper release and pull-out techniques, the pilot must be highly trained and motivated.
Some daring pilots had tried the concept of dive bombing in WWI and the US Marines used it between the wars in Central America.
In the early 1930's, as the Luftwaffe secretly rebuilt German air power, the Henschel Hs 123 biplane served as a dive bomber. In 1936, the Luftwaffe decided to replace the Hs 123. Junkers Ju 87 defeated the Arado Ar 81 biplane, the Blohm & Voss Ha 137, and the Heinkel He 118 in the competition.
The Ju 87 prototype was an ugly inverted gull wing monoplane. Slotted flaps and ailerons gave good control at low speeds, but produced a lot of drag. The fixed landing gear struts were encased in aerodynamic fairings, "pants," A big radiator bulged below the nose. The fuselage tapered down from the cockpit, offering the pilot a good view. The greenhouse-style canopy housed two - the pilot and rear gunner. Dive brakes extended beyond the trailing edge of the wings.
The 640 horsepower Jumo 210 engine (not used in the prototypes) powered the first production variant, the Ju 87A. About 200 of the A-1, A-2, and A-3 were built from early 1937 through late 1938. Three of these saw service in Spain, the Luftwaffe's dress rehearsal for WWII.
The Ju 87A carried two forward-firing machine guns, and a flexible machine gun for the rear gunner. Normally it carried a single 250 kg bomb, on a swing-down rack, so that when released it cleared the propeller arc.
An automatic bombing system (which linked the autopilot, gunsight, bomb release gear, dive brakes, and elevators) simplified the pilot's actions. The pilot set his chosen altitude for bomb release/pull-out, normally 900 meters. Then, when he opened the dive brakes, the automatic system adjusted the elevator trim tabs and started the dive. The pilot then manually fined-tuned the dive angle (often 90 degrees!) by reference to the visual horizon. At release, the automatic controls adjusted the elevator trim tabs and the aircraft pulled out, usually getting no lower than 450 meters.
In 1939, all "A" variants were retired from front-line units and assigned to training.
Visibly different from the Ju 87A with its neater, less bulky "pants," the B variant was almost twice as powerful, with its 1200 horsepower Jumo 211Da engine. The engine's fuel injection system let the Stuka to fly inverted and to perform negative gee maneuvers without the fuel cutting out.
The more powerful engine permitted the Ju 87B's bombload to double, the normal load for a "B" was a 500 kg bomb. For short-range missions, it could also carry four 50 kg bombs in the outer wings. Dive speed approached 550 KPH (324 MPH). To augment the Ju 87's well-known whistling, the crews attached sirens, "Trumpets of Jericho," to the landing gear, as an added psychological weapon. The Ju 87B retained the A's three rifle-caliber machine guns.
Starting with the "B," production moved to Weser Flugzeugbau at Berlin's Templehof airport.
A variant of the "B," the Ju 87C was navalized version, designed for use on the carrier Graf Zepplin; it featured folding wings, hooks, and other changes.
The Ju 87R, was also based on the "B," it being a long range fighter, equipped with extra tanks in the outer wings and attachment points for underwing drop tanks. In the profile view above, an extra is shown. The "R" version did see service in Norway, the Balkans, Greece, and the Mediterranean.
The "D" featured an all-new engine installation, the Jumo 211J or 211P, which had more radiators, an oil cooler, and new paddle-bladed propeller. In the most visible external change, the canopy tapered back more smoothly. In the rear, twin belt-fed machine guns replaced the single drum-fed weapon. With a more powerful engine, the Ju 87D could carry an 1800 kg bombload, with the capability for a single 1400kg armor-piercing bomb. Despite a sturdier landing gear, the "D" Stuka continued to suffer collapses.
Later D's added more armor because of its increasing use in ground-attack against armed troops. These also substituted 20mm cannon for the 7.9mm wing machine guns.
This was two-seater training version of the "D" model, with weapons removed.
The definitive Stuka, the Ju 87G, was designed for ground attack missions, carrying two 37mm Rheinmetall-Borsig BK3,7 anti-tank cannon. These guns, located in distinctive pods in the outer wings, used tungsten-core armor-piercing rounds, fired at a muzzle velocity of 850 meters per second. Burdened with the heavy anti-tank gun, the "G" Stuka was no longer a dive bomber; the dive brakes were omitted; the 20mm cannon were (of course) removed.
Stukas undertook the first bombing raid of World War Two, against cables near the Dirschau railroad bridge.
One Stuka Group participated in the invasion of Norway on May, 1940, hitting Norwegian forts and, in a spectacular success, sinking HMS Afridi, a Tribal-class destroyer.
The Battle of Britain
Here their weakness showed; the Stukas lacked the range and payload capability needed to inflict real damage on the British air defenses. Slow as they were, they wer no match for the RAF fighters.
Stukas enjoyed great success on the Russian Front, especially the "G" model, fitted with anti-tank guns. The Ju-87 served through 1944 as an effective ground-attack platform.
Great Aircraft of the World, Len Cacutt (editor), 1986