rstieg wrote:
>
> The post about air whistling through air cleaners sounding like a turbo got
> me to thinking:
> what pitch would approximate a Merlin engine at about 25 inches boost?
Hmmm... lessee. About 175-200 db at 2 ft from the exhaust, overall
primary frequency of about 6000 Hz at speed, strong secondary frequency
from the straight-cut gears in the prop drive of about 8000 Hz. Lots of
lower harmonics... a _great_ deal of noise up close. <g>
> how 'bout the siren used by the Stuka?
About 10000 Hz. But I don't think it was a siren in the conventional
sense... the sound only occurred in steep dives, and was some sort of
aerodynamic device, rather than a motored siren, I think.
> Tape of a Ferrari in fourth gear??
As loud as your speakers can stand, and the frequency is dependent upon
the fidelity of the speakers. [Ferrari owners will say, no matter how
loud, "louder!, it's not faithful to the original."]
> Will probably settle for a playing card up against the cooling fan.
About 85 db (frequency dependent upon the number of blades and the speed
of the fan), until the card wears out, 65-70 db thereafter. <smile>
> rick stieg 75 spit (noisy enough)
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