[NSRCA-discussion] Cooling/spinners

[Koenig, Tom]

Matt and all,

"On the other hand, with so many of us having stopped building, where's the creativity and innovation going to come from? It saddens me to see a whole new generation of "modellers" who only want to fly, using ready made everything."


I couldn't agree more!!!!! A sign of the times we live in.

Tom
-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of Rcmaster199 at aol.com
Sent: Tuesday, 21 February 2006 9:26 AM
To: nsrca-discussion at lists.nsrca.org
Subject: Re: [NSRCA-discussion] Cooling/spinners


In a message dated 2/20/2006 2:04:45 PM Eastern Standard Time, simestd at netexpress.com writes:

If you've ever taken a close look at the
engine installation on a high performance piston aircraft, the cowling
is typically very tight by pattern standards and they have nowhere near
our 3:1 outlet:intake rule of thumb for cooling.  Instead they make
extensive use of baffling and ducting to control the air path and make
it work for them.

It's "elementary" Thermo 101 kind of stuff with a little fluid dynamics thrown in for good measure. Keep the air in the turbulent regime around the engine to maximize cooling effectivess. To some degree, we did that in our earlier designs by maintaining a slender fuse and cowling in tighter by necessisity.

With the advent of the Pachyderm fuses, we copied full scale size-wise but with little forethought about cooling. Having a large bucket of dead air up front in our fatso fuses does nothing for the engine/motor. Slows the plane down tho.

And BTW, the exit really doesn't need to have 3X the entry area to be effective if properly designed to draw the air out. Remember Bernoulli??

On the other hand, with so many of us having stopped building, where's the creativity and innovation going to come from? It saddens me to see a whole new generation of "modelers" who only want to fly, using ready made everything. It does produce wonderful piloting skill tho.

Matt


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