On Wed, 29 Jun 2005 20:33:38 -0400, David Odum
MyFirstName@AirplaneZone wrote:

Lastly, as a Long EZ builder, owner, and flyer whose experience with
EZs dates back to the early Rutan days, my response to the scenario
and images depicted can be summed up in two words, Holy ****!

You weren't aware of why pusher props make more noise than tractor
props? See below for the scientific explanation.


http://www.pfa.org.uk/pdf_docs/engin..._driven_la.pdf.

The relevant part is quoted below:

Pusher propellers can be particularly noisy as the turbulence from
upstream structure, e.g. The wing, impinge on the outer portions of
the blade. The Cessna 337 is particular poor design in this respect.
This aeroplane has a tractor propeller in the front and a pusher
propeller and the rear of the fuselage. Consequently the turbulence
from the front, tractor propeller and the wing and fuselage pass
through the rear pusher propeller causing relatively high noise
levels.

The Long EZ's do not have a tractor prop making turbulence of course,
but the wing is generating lift and the exhaust pulses must pass
through the prop and this causes vibration. I'm positive I've read
other treatsies on the subject, and I'm reasonably sure some of it
came from Rutan himself.

It doesn't make sense to you that a prop spinning in turbulent air
will vibrate?

Corky Scott