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Why did the Ju-87 Stuka have a siren? Was this for purely psychological reasons or did it help the pilot in some way?

Vikki
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flyingfisch
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3 Answers3

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Wikipedia:

The B-1 [variant] was also fitted with "Jericho trumpets", essentially propeller-driven sirens with a diameter of 0.7 m (2.3 ft) mounted on the wing's leading edge directly forward of the landing gear, or on the front edge of the fixed main gear fairing. This was used to weaken enemy morale and enhance the intimidation of dive-bombing. After the enemy became used to it, however, they were withdrawn. The devices caused a loss of some 20–25 km/h (10-20 mph) through drag. Instead, some bombs were fitted with whistles on the fin to produce the noise after release.

So, yes, it was purely psychological and actually hindered the pilot by reducing air speed in ordinary flight and they were removed when they stopped having the psychological effect.

David Richerby
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    Reducing airspeed is actually kind of helpful in a dive - when you're heading for the ground, even a few km/h can be the difference between pulling up and wiping out. Note that some aircraft of the time had dive brakes to slow them down when dive-bombing. – anaximander Nov 06 '14 at 16:43
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    @anaximander: The Ju-87 have massive air brakes that control airspeed during dives. Compared to the airbrakes the effect of the siren was insignificant. But the siren did have noticeable effect on level flight. – slebetman Nov 06 '14 at 16:50
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    Given the way the StuKa was employed, close to the front lines from forward bases, the impact on level flight wasn't really relevant. Adding 1-2 minutes to the time to get to target isn't bad. And they weren't going to have to dogfight, they were never designed for that. Saving resources for use elsewhere was probably a bigger factor in not fitting them on later models. – jwenting Nov 06 '14 at 18:18
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    @jwenting: While they were not designed to dogfight, they still had to evade enemy fighters and being slower makes them more vulneareable. And they were slow and thus vulnereable even without the sirens. – Jan Hudec Nov 06 '14 at 19:24
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    @jwenting: A drag effect taking 5% off your top speed makes it easier for the enemy to intercept you, or aim at you with flak. It lengthens the time you have to spend over enemy territory. It increases fuel consumption. It decreases your climb rate, both after take-off and when coming out of a dive (when you really want to get back to altitude quickly, after all you just dived on a military target, and small-caliber flak usually takes a dim view on that). Quite significant points, and obviously, the Luftwaffe thought so as well. – DevSolar Nov 07 '14 at 08:38
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    @DevSolar as the Germans at the time the sirens were removed were operating under air superiority, I seriously doubt a negative effect on their ability to evade enemy fighters was much of a factor. Neither the Poles, the Dutch, the Belgians, or the French or Danes had air forces that could threaten the Germans over the battlefield. – jwenting Nov 07 '14 at 09:06
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    @jwenting: While that statement is correct on the strategic level, it doesn't help the individual Ju-87 that encounters an enemy fighter. Even a biplane would be a threat to the basically helpless Ju-87. Also note that air superiority doesn't help (much) against AAA, while speed does. "Once the enemy became used to it", the siren was no longer effective, significantly reduced combat performance, and gave the enemy additional warning, so it was removed. You don't put on aerobatic smoke trails just because you have air superiority either (unless you're playing War Thunder)... – DevSolar Nov 07 '14 at 09:44
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    @DevSolar of course, but such decisions as to change the design of an aircraft are made at higher than tactical levels. Of course it's quite feasible that units in the field removed the sirens of their own accord when they found them a hindrance, and reporting that back up the chain eventually led to their removal from new production aircraft. – jwenting Nov 07 '14 at 09:46
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The psychology behind it helped the pilot ... panicking enemies doesn't make for very good shots, they're more likely to miss you. They're also more likely to just drop flat on the ground rather than dive into cover or try to shoot back at you.

And that was pretty much the idea. Get the enemies to become disoriented, panicky, so they're less efficient fighters and easier to defeat by both you and the ground forces you're supporting.

Farhan
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jwenting
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    Funny enough, I remember a quote from a British artillery soldier serving in North Africa, on whom the Ju-87 had the opposite effect. "You just ran a couple of meters away from your gun emplacement, and you were safe. They never missed." ;-) – DevSolar Apr 14 '16 at 14:33
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Another reason for the siren is that during the first years of WWII most army's ground transportation was horse drawn. You freak the horses and the unit does not move. The French, Polish, and Russian armies used primarily horse drawn transport. The British and American armies used trucks. A truck can't freak out like a horse.

FreeMan
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Steven Van Helten
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    Excellent point, I hadn't even thought of that. – flyingfisch Jun 24 '15 at 14:29
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    Horses were actually used in greater amount by the German themselves. Confirmed here. – mins Apr 29 '16 at 11:05
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    Actually Germany (2.75 mil) and the Soviet Union (3.5 Mil) used more horses. France was the only other army that had a sizable amount (500K) and only used them until about 1939. The siren was never meant to "freak out" any horses. It was simply a attempt at intimidation. And was removed after a short time. –  Apr 29 '16 at 10:28