Another Seaplane Question

Date:         17 Dec 99 01:57:35 
From:         "P. Wezeman" <pwezeman@blue.weeg.uiowa.edu>
Organization: The University of Iowa
Followups:    1 2 3 4
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	What was the cabin noise level like in cruising flight
in one of the pre-war Boeing 314 or Short Empire trans-Atlantic
flying boats? Was it too loud to carry on a conversation easily?
If information on noise is not available, how much
sound insulation (if any) did the planes have and how did it compare
to that on the later piston airliners? I have flown on a Lockheed
Constellation and a Douglas DC-7 and as I recall these were
reasonably quiet. Of course these planes needed thermal insulation
at high altitudes and this would have damped the noise even if
there was no soundproofing as such. Has anyone ridden on one of
the surviving Martin Mars water bombers or on Kermit Week's Short
Sunderland?
	I came across some information about my earlier seaplane
question: why did some seaplanes like the Short Empire, Sunderland,
and Martin Mars use wingtip floats for stability on the water
while others such as the Dornier DO-X, Martin China Clipper, and
Boeing 314 used sponsons for the same purpose? In reading about
the 314 I found that the sponsons on that aircraft just did not work
all that well; they did not provide enough righting moment to keep
the wing tips out of the water under all circumstances. This is not
surprising when you consider how short their moment arm was compared
to tip floats. So it seems that floats are the better solution, at
least for aircraft with longer wing spans. Floats can also be
retractable as on the Saunders-Roe Princess and some others. I
believe there was a small amphibian, similar to the Republic SeaBee,
where the end of the wing folded down so the wing tip was the float.
I would be interested to know if float pylons can act as winglets
to improve the efficiency of the wing.

                        Peter Wezeman, anti-social Darwinist

                             "Carpe Cyprinidae"