The Stuka is the sound of the first year of the war. In Poland, Norway and France it flew ahead of the tanks as artillery that could be anywhere in minutes: it rolled over, pointed its nose almost straight down at a bridge or a gun position, and released its bomb from a few hundred metres up. It was slow, and once the fighters it needed were gone it was shot out of the sky over England — but it fought to the last day in the East, and for one year it changed how wars were fought.
~383 km/hTop speed (B-2)500 kgBomb load (B-2)
2· WHY IT MATTERED
Accuracy from a dive, not a bombsight
Level bombers of 1939 missed by hundreds of metres. A Stuka pilot lined the target up through red lines painted on his canopy at 60°, 75° and 80°, and dived at it: the bomb left the aircraft already pointed at the target, so most of the range error of level bombing disappeared. A good crew could put a bomb within tens of metres; in combat, with flak, cloud, a moving target and a hurried release, the misses were wider. It was still why a squadron of them could take out a bridge the whole artillery had missed.
Pulling out of a 550 km/h vertical dive takes about 6 g, enough to grey a pilot out. So the Stuka did it itself: pressing the bomb release also triggered an automatic pull-out through the elevator trim. A contact altimeter lit a lamp at the preset release height — around 450 metres at the lowest — because below that there was no room left to recover.
4· WHY IT MATTERED
Only as good as the air around it
At 400 km/h with a fixed undercarriage the Stuka was easy meat for a Spitfire or a Hurricane, and the Battle of Britain stopped its daylight career in the West within weeks. In the East, where the Luftwaffe kept air superiority longer, it went on, and from 1943 the cannon-armed Ju 87 G became a dangerous specialist tank hunter in expert hands, though how many tanks it really killed is hard to pin down: wartime claims ran far ahead of what the ground confirmed.
5· THE ENGINE
An inverted V-12 that could fly upside down
The Jumo 211 hangs its twelve cylinders below the crankshaft — an inverted V — which gave the pilot a better view over the nose and made the guns and exhausts easier to package. More important for a dive-bomber, it was fuel-injected from the start: a carburettor engine coughs or cuts when the aircraft rolls inverted and the float chamber empties, and the Stuka rolled inverted into every attack. A two-speed supercharger gave it one gear for low altitude and one for high, the simplest way of matching an engine to the thin air it breathes higher up.
Ju 87 B (1939): Junkers Jumo 211D · inverted V-12 · 35.0 L · direct injection · two-speed supercharger · 1,200 PS · Ju 87 D (1941): Jumo 211J, 1,400 PS
The Stuka B carried one 250 kg bomb under the fuselage and four 50 kg bombs under the wings; the later D took a single 1,000 kg bomb. Its two forward machine guns fired about 0.5 kg of bullets a second between them, nothing by fighter standards, and the gunner behind had a single MG 15 for the fighters that would come, a twin MG 81Z from the D model on. The famous siren, a small propeller-driven whistle on each leg, cost 20 to 25 km/h and crews often took it off. The Ju 87 G swapped the bombs for two 37 mm cannon with tungsten-cored shells, six rounds each side, and went hunting tanks.
7· TRY IT
The dive, live: angle, speed, g and the pull-out
Choose the dive angle, the speed the brakes hold, the pull-out g and the release height. The lab draws where the bomb goes and how much sky the recovery eats, and shows why the contact altimeter was never set below about 450 m.
Readout
Pull-out radius476 m
Height lost levelling off393 m
Lowest point57 m
Bomb’s fall2.7 s, 73 m forward
Above about 5 g the pilot greys out — which is why pressing the release button started the pull-out automatically. No drag on the bomb; real ones fell a little shorter.
8· THE LAB
Power, guns and range: the same three models for all ten
Power against altitude from the type of supercharger, weight of fire against the other nine, and Breguet range with the armour and drop-tank trades. Simplified models, each scaled to this aircraft’s published figures, so the shapes are honest and the third decimal is not.
At 4,000 m: 1,074 hp in total, true airspeed 383 km/h.
Readout
Power1,074 hp
Per engine1,074 hp
True airspeed383 km/h
Service ceiling8,000 m
A simplified model calibrated to the published rating and top speed — the shape of the curve is the point, not the third decimal.
Junkers Ju 87 Stuka, 1 of 10
Deep dive · How dive-bombing works· opened from Junkers Ju 87 Stuka
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How dive-bombing works1939
Point the whole aircraft at the target, let go, and survive the pull-out — the machine did the last part for you.
500–600 km/h·60–90°·6 g, automatic·~450 m
01The idea
An 80° dive from 4,000 m, release at 450 m, a 6 g pull-out that eats 400 m of sky
A bomb dropped from level flight keeps the aircraft’s forward speed and falls in a long curve; a small error in speed or timing is a big error on the ground. A bomb released in a steep dive is already travelling towards the target, so most of the error disappears. The price is the pull-out: the aircraft must turn from pointing down to pointing along the ground, and that turn costs height, g and, if the pilot has misjudged it, the aircraft.
02Why it matters
The geometry of the dive
Dive brakes under the wing held the Stuka at 500–600 km/h so that it did not accelerate past the speed the wings could stand. The pilot lined up red lines on his canopy — 60°, 75°, 80° — with the horizon to read his dive angle, and the bomb, swung out on a crutch so it cleared the propeller, left along the line he was looking down.
03Why it matters
The pull-out costs 400 metres
A turn at speed v pulling n times gravity has a radius r = v²/(g(n−1)). At 550 km/h and 6 g that is about 480 metres, and turning from an 80° dive to level loses roughly 400 metres of height. So the contact altimeter was set to light at about 450 metres: any lower and the arithmetic said the aircraft would meet the ground before it was level.
04Why it matters
The pilot was not trusted with it
At 6 g a seated pilot’s vision greys and then goes; some blacked out completely. So pressing the bomb release also triggered an automatic pull-out through the elevator trim, and the aircraft recovered on its own while the pilot came round. It is one of the first examples of a machine flying the manoeuvre because the human could not.
05Try it
The dive, live
Choose the dive angle, speed and pull-out g and see where the bomb goes and how much sky the recovery needs.
Readout
Pull-out radius476 m
Height lost levelling off393 m
Lowest point57 m
Bomb’s fall2.7 s, 73 m forward
Above about 5 g the pilot greys out — which is why pressing the release button started the pull-out automatically. No drag on the bomb; real ones fell a little shorter.