A True Dive-Bomber

Thursday, December 8th, 2011

The iconic German Stuka, with its wailing “Jericho trumpet” siren, was a true dive-bomber:

Flying at 4,600 m (15,000 ft), the pilot located his target through a bombsight window in the cockpit floor. The pilot moved the dive lever to the rear, limiting the “throw” of the control column. The dive brakes were activated automatically, the pilot set the trim tabs, retarded his throttle and closed the coolant flaps.

The aircraft then rolled 180°, automatically nosing the aircraft into a dive. Red tabs protruded from the upper surfaces of the wing as a visual indicator to the pilot that, in case of a g-induced black-out, the automatic dive recovery system would be activated. The Stuka dived at a 60-90° angle, holding a constant speed of 500–600 km/h (350-370 mph) due to dive-brake deployment, which increased the accuracy of the Ju 87′s aim.

When the aircraft was reasonably close to the target, a light on the contact altimeter came on to indicate the bomb-release point, usually at a minimum height of 450 m (1,500 ft). The pilot released the bomb and initiated the automatic pull-out mechanism by depressing a knob on the control column. An elongated U-shaped crutch located under the fuselage swung the bomb out of the way of the propeller, and the aircraft automatically began a 6 g pullout. Once the nose was above the horizon, dive brakes were retracted, the throttle was opened, and the propeller was set to climb. The pilot regained control and resumed normal flight. The coolant flaps had to be reopened quickly to prevent overheating.

Physical stress on the crew was severe. Human beings subjected to more than 5 g forces in a seated position will suffer vision impairment in the form of a grey veil known to Stuka pilots as “seeing stars”. They lose vision while remaining conscious; after five seconds, they black out. The Ju 87 pilots experienced the visual impairments most during “pull-up” from a dive.

Eric “Winkle” Brown, a British test pilot from the Royal Navy, and General Officer Commanding “Captured Enemy Aircraft Flight” section, tested the Ju 87 at RAE Farnborough. He remarked:

I had a high opinion of the Stuka because I had flown a lot of dive-bombers and it’s the only one that you can dive truly vertically. Sometimes with the dive-bombers, pilots claim that they did a vertical dive. What a load of rubbish. The maximum dive is usually in the order of 60 degrees. In a dive when flying the Stuka, because it’s all automatic, you are really flying vertically. You feel that you are over the top and feel you are going that a way! The Vengeance and Dauntless were both very good but could dive no more than 60 or 70 degrees. The Stuka was in a class of its own.

I can see why not every air force went with this idea.

Comments

  1. David Foster says:

    Wondering what a “contact altimeter” is? Obviously it would be best to use a radar altimeter, which measures true height above terrain, but that seems unlikely in 1939. Quick googling suggests that it was actually an ordinary barometric altimeter with a presetting feature. The pilot would have had to guess the ground height about sea level, or estimate it from a chart, and would also have had to have the altimeter set to the proper setting, which differs with weather conditions. I doubt that the opposition would have been providing altimeter settings, so they would have had to get it from their nearest friendly forces.

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