Max Richter wrote:

Hallo,

i am wondering why American aircraftradialengines have no aerodynamical
spinners.Airplanes with inlineengines like P51;P40;P38 and so on have
aerodynamical optimized spinners.
And German radialengines had spinners like the FW190.Zero´s and other
Japanese aircraft had them.
What is the reason why the wellbuild American aircraft had just a little
hup on their propellers.
Thank You and greetings
Max

I think that the reason is that because of the comparatively
large frontal area of most radial engines that a spinner is sort
of superfluous...IOW. the airstream is backed up well in front of
the prop hub therefore it 'makes it's own cone' in front of the
prop hub therefore a spinner on the prop hub would serve little
or no useful purpose...besides, you don't want the air to be
scooted outside the cylinders so what purpose could a spinner
provide? I'm open to other opinions...what say?...


(The small hub is necessary to contain the prop pitch change
mechanisms BTW...)

And on second thought the Beechcraft C-45 (Expeditor) does have
small spinners on their props...FWIW
--

-Gord.
(use gordon in email)