Cmd Buzz Corey wrote:
wrote:
Found this:
"The engines and propellers produced an unforgettable throbbing sound
when the B-36 flew overhead. A friend of mine remembers the sound from
his boyhood as a "captivating drone. The noise went down to your heels,
it was so resonant. It just stopped you in your tracks. You looked up
into the sky to try to find this thing, and it was just a tiny cross,
it was so high." Others remember that it rattled windows on the ground
from 40,000 feet."
w3rv
Thats about how high they would be when they came over our house some
200 miles west of Ft. Worth and the windows would rattle. It was an
unmistakeable sound.
One of the unique features of the B-36 is it's geared-down props, i.e.,
the props turn much slower than it's six big Wasps. The rotational
speed reduction was necessary because given the 19 foot diameter prop
disk the tips of the blades would go supersonic and all hell would
break if loose if they turned at engine RPMs. I don't know of any other
reciprocating engine powered fixed-wing military A/C which had
geared-down props like the B-36 had.
Seems reasonable to me to wonder if the B-36 also churned out an
acoustic signature which was also quite unique in that from the ground
they apparently sounded something like six "down to your heels"
thumping overpowered military helicopters which I'm sure we've all
heard in our neighborhoods. The little speck in the sky does thumps
galore on the ground from miles away. With it's six big, unusually
slow-turning props the B-36 it might very well be that it's acoustics
were helicopter-like. Except a whole lot more so. Acoustics is radio in
a different medium and frequency range. The results of resonance apply
to both. The B-36 probably had an acoustic SWR of 1:1 at ground level.
I never saw a B-36 in flight but I was there when Bell-Boeing V-22
Osprey airframe No. 8 arrived in the pattern over Brandywine airport in
West Chester PA and flew it's last flight before being turned over to
the American Helicopter Museum which is on the airport property. The
V-22 also has monster slow-turning props and can fly like a fixed-wing
A/C at speeds not too disimilar from B-36 speeds. I'm here to tell you
the thing damned near drove all of us who were there that day thru the
tarmac during it's high-speed demo passes. The Apache did not.
w3rv