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You're welcome, Michael
Glad you found a source for the book. Like I say it takes a bit of digging
into, I had to re-read some sections several times to fully understand (I
think {:>)) the essence of their findings.
Ed
----- Original Message -----
From: "Michael Burke" <mburke@southernphone.com.au>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Tuesday, April 05, 2005 12:40 AM
Subject: [FlyRotary] Re: Cooling -Learned a lot
> Ed,
> Many thanks for your reply.
> I too have been searching the net for a definitive text on liquid cooled
> aircraft engine, theory and design but have not been able to find anything
> directly related to the subject of liquid cooled engines. Plenty of books
on
> Fluid Dynamics pertaining to jet engine design.
> Thanks for the link to the supplier in Asia, I found in other posts, as
I'm
> in Australia I'll buy direct from them.
>
> I'm not actually building anything yet (except confidence and knowledge).
> I'm at that stage of trying to reconcile what I can really like as opposed
> to what I can really afford. Short list is, RV8, Mustang II, Aerocad, or
> Team Tango, maybe Cozy IV if parts are available. Mazda Renesis will be
the
> power source for whichever kit I choose. I'm just so grateful there are so
> many guys working out all the problems with rotary engine installation who
> are willing to share their knowledge.
>
> Michael.
>
>
>
> ----- Original Message -----
> From: "Ed Anderson" <eanderson@carolina.rr.com>
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> Sent: Monday, April 04, 2005 10:36 PM
> Subject: [FlyRotary] Re: Cooling -Learned a lot
>
>
> > I have only read this one book (actually chapter 12) on liquid aircraft
> > cooling, its seems to be the ONE. It is not light reading, but
chapter
> 12
> > presents the liquid cooling challenge for aircraft in what appears to me
> to
> > be a fairly complete manner. You do have to did into it a bit. No, the
> book
> > has been out of print for decades. I finally got a bound Xerox copy
from
> a
> > foreign source with good legibility but that was about the best I could
> say.
> > Pages were out of order, upside down, etc. but like I said the
information
> > was legible.
> >
> > The book is "Aerodynamics of Propulsion" by Kuchemann and Weber better
> know
> > as "K&W"
> > published by McGraw-Hill in 1953. I searched long and hard for a copy
and
> I
> > found none in the typical out of print book sellers.
> >
> > There is one other book Hoerner Fluid Dynamics that is reported to be a
> > good one as well, but I have not acquired that one as yet.
> >
> >
> > I'll have to see if I can find my source for K&W, it was back a few
years
> > ago and I have had a couple of harddisk crashes since then.
> >
> > Ed
> > ----- Original Message -----
> > From: "Michael Burke" <mburke@southernphone.com.au>
> > To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> > Sent: Monday, April 04, 2005 2:47 AM
> > Subject: [FlyRotary] Re: Cooling -Learned a lot
> >
> >
> > > Ed is this book the"Holy Grail" on liquid cooled aircraft engines. Is
it
> > > still available from book stores, if not where can it be purchased.
> > > Many Thanks,
> > > Rotary Newbie,
> > > Michael.
> > >
> > > ----- Original Message -----
> > > From: "Ed Anderson" <eanderson@carolina.rr.com>
> > > To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> > > Sent: Monday, April 04, 2005 12:14 AM
> > > Subject: [FlyRotary] Cooling -Learned a lot
> > >
> > >
> > > > Too right, Jerry
> > > >
> > > > My first 40 hours or so were in the marginal cooling zone. {:>).
As
> > > other
> > > > things in this hobby, there are so many variables that interact,
that
> > what
> > > > may appear simply at first, is almost always a bit more complex. I
> > > > say(Cooling Axiom 1) if you have enough cooling surface area and air
> > mass
> > > > flow then it WILL cool. However, you may incur a high penalty in
> > > cooling
> > > > drag - which may not be as important for draggy airframes (such as
> > > biplanes)
> > > > as it is to sleeker airframes. Also a system that adequately cools
> an
> > > > engine producing 150 HP may not cool an engine producing 180 HP.
> > Picking
> > > > your cooling design point is important. Optimizing for cruise and
> your
> > > will
> > > > be less than optimum for take and climb. Optimize for climb and you
> > will
> > > > probably have more cooling drag than required at cruise.
Compromise,
> > > > compromise - cowl flaps are sometimes used to try to have the best
of
> > both
> > > > worlds.
> > > >
> > > > Some folks advocate a thinner, larger surface area core -which is
> great
> > > for
> > > > slow moving automobiles stuck in traffic with low dynamic pressure
> > > > potential, but I think is not the optimum for most aircraft. Once
you
> > > trip
> > > > the airflow and turn it turbulent you have incurred most of the drag
> > > > penalty. Larger surface area cores disrupt a larger airstream and
> incur
> > > > more drag. Yes, thicker cores produce a bit more drag than the SAME
> > > frontal
> > > > area thinner cores. But, with a thicker core you can use a core
with
> > > > smaller frontal area.
> > > >
> > > > The NASCAR radiator's average 3" thick and on the long tracks
where
> > > speeds
> > > > are higher some even go up to 7" thick. My contention is their
> > operating
> > > > environment is more akin to ours than regular automobiles moving at
> > slower
> > > > speeds. You know that the NASCAR folks will spend $$ for just a
tiny
> > > > advantage - so clearly they don't use thick cores because it is a
> > > > disadvantage. But, some folks will continue to point to the large
thin
> > > > radiators designed for environments with much lower dynamic pressure
> as
> > > > being the way to go. Will it cool? sure it will (Cooling axiom 1
> > above).
> > > > Is it the lowest drag option for an aircraft of the RV/TailWind
type,
> I
> > am
> > > > convinced it is not.
> > > >
> > > > The diffuser makes a considerable amount of difference and can made
> the
> > > > difference between a system that cools adequately and one which does
> > not.
> > > > The biggest culprit that lessens cooling effectiveness is turbulent
> > eddies
> > > > that form inside the duct due to flow detachment from the walls.
> These
> > > > eddies in effect act to block effective airflow through part of the
> > core.
> > > > So keeping the airflow attached to the sides of the diffusers is
> crucial
> > > for
> > > > good cooling from two standpoints. A good diffuser will reduce
airflow
> > > > velocity through the core which will reduces cooling drag. Pressure
> > > across
> > > > the core is increased which further enhances cooling.
> > > >
> > > > I have gone from a total of 48 sq inches opening (total) for my two
GM
> > > cores
> > > > and that provided marginal cooling - down to 28 sq inches (total)
with
> > > > adequate cooling with an engine now producing more HP.
Experimenting
> > with
> > > > the diffuser shape made the difference.
> > > >
> > > > The K&W book (Chapter 12) really provided the insight to how and
which
> > > > diffuser shapes provided the better dynamic recovery. The
Streamline
> > duct
> > > > was shown to be able to provide up to 82% recovery of the dynamic
> > > pressure.
> > > > Some folks reading the chapter misinterpreted the chart to show only
> 42%
> > > > recovery where there chart was actually only showing the pressure
> > recovery
> > > > contribution due to the duct walls and did not include the
> contribution
> > > due
> > > > to the core. On the same chart, an equation (which apparently gets
> > > ignored)
> > > > clearly shows that the TOTAL pressure recovery is 82%.
> > > >
> > > > I have taken the Streamline duct as a starting point, but since I do
> not
> > > > have the space to provide the 12-14" for a proper Streamline duct, I
> did
> > > > some "creative" things to try to insure that there was no separation
> > even
> > > > though my walls diverge more rapidly than the Streamline duct.
Won't
> > > claim
> > > > mine are as good as a Streamline, but they clearly are much better
> than
> > > the
> > > > previous design which basically just captured the air and forced it
> > > through
> > > > the cores.
> > > >
> > > > FWIW
> > > >
> > > > Ed Anderson
> > > > RV-6A N494BW 275 Rotary Hours (Plugs Up)
> > > > Matthews, NC
> > > > eanderson@carolina.rr.com
> > > >
> > > >
> > > > ----- Original Message -----
> > > > From: "Jerry Hey" <jerryhey@earthlink.net>
> > > > To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> > > > Sent: Sunday, April 03, 2005 9:27 AM
> > > > Subject: [FlyRotary] Re: phase I flight restrictions was:N19VX flys
> > > >
> > > >
> > > > > It was not long ago that "cooling" was the major issue. Now it
> seems
> > > > > that we have learned enough to make several different
configurations
> > > > > work. I can't lay my finger on what it is we have learned but my
> > > > > recommendation is to use smaller radiators and EWPs. Jerry
> > > > >
> > > > >
> > > > >
> > > >
> > > >
> > > >
> > > >
> > > > >> Homepage: http://www.flyrotary.com/
> > > > >> Archive: http://lancaironline.net/lists/flyrotary/List.html
> > > >
> > >
> > >
> > > >> Homepage: http://www.flyrotary.com/
> > > >> Archive: http://lancaironline.net/lists/flyrotary/List.html
> >
> >
> >
> > >> Homepage: http://www.flyrotary.com/
> > >> Archive: http://lancaironline.net/lists/flyrotary/List.html
> >
>
>
> >> Homepage: http://www.flyrotary.com/
> >> Archive: http://lancaironline.net/lists/flyrotary/List.html
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