It was actually controlled. This was discussed in these fourms before and I learned that the pilot could open and close the valve that made the sound. (it's somewhere near the wheel root I think, if I remember.) He could blast out patterns of sound so it could be a "Waaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa!" or a "Waaa-Waaaa-Waaa-Waaa" sound if he wanted.
Wasn't this produced by the wind that blew over the wheel skirts? And i also doubt they did this on purpose, i think it did that accidently and they kept it that way for the psycological effect.
No it was done on purpose, there's actually a little horn which the pilot can control.
and it was removed on later models.
oh sorry, i thought i read this somewhere a long time ago ,in a galaxy far far away...
Isn't that little yellow (on some schemes) underhang from the engine with the struts inside the "whistle?" It wasn't really a horn, just a giant whistle that could be closed and opened. I know it was terrifying to the people on the ground but I think it's a cool system.
The best MG34 sound is from the CoD and of the MG42 from MOHAA.