I'm sure that if Tracy were starting with a blank slate he might do
his cooling system differently. But, he's already racked up an
impressive number of hours with his evaporator cores. It would be a
major task to go back to a different design at this point.

I've had the benefit of watching this newsletter and I'll build a
cooling system the way that I think it ought to be done. Go ahead and
slag on Tracy's cooling system if you want, I'll see if I can build
one that I think will work better, but until I do, I'll sit on the
sidelines and try to learn from others.

If anyone is interested in what my cooling configuration will be, it's
a stock gen II oil cooler with a C&R radiator that's twice the size of
the oil cooler. They will be mounted next to each other underneath the
engine, with a scoop right underneath the spinner, which is(will be)
16" dia and 5 inches forward of the stock placement of the prop hub.
There will be a duct going from the scoop to the heat exchangers. I
hope to have the airplane done in 12-18 months.

I'm sure Tracy will be flying way before I am.

Brian Trubee

-> Gary Palmer wrote:

Hi Brian,
        The system you describe is almost exactly like Perry Casson's Glastar installation. He has had no cooling problems whatsoever. A beautiful job, but you better be prepared to do a lot of
custom cowl fibreglass work. Check it out at http://eaa154.dhs.org/perry/engine/index.shtml

        I agree with Monty's comments on engineering compromise. So often, these "critiques" and differences arise because there is a lack of clear statement of design objectives; I think Monty's
comments are bang on in this regard.

        If your objective is maximum power, and damn the noise, a peripheral port exhaust and intake make a lot of sense; on the other hand if a quieter, nice neighbor type of installation is your
objective, you will lean towards the Renesis because it is easier to keep the noise down.


        If you have a fixed pitch propellor, tuning an intake system for max torque at lower rpm's seen during takeoff seems appropriate, rather than at max rpm that would be appropriate for a
constant speed prop situation. Both are valid approaches depending on objectives.


        Different strokes for different folks and goals.

        Tracy's design objectives IMO have always leaned towards making the rotary installation affordable and reliable. I believe he has succeeded admirably in that regard with his redrive, and FI
computer. His cooling systems work at low cost, and avoid a lot of cowl modification, a not insignificant advantage for many builders. Arguably not the most efficient lowest drag solution, but
certainly good enough to win at Sun n Fun. Sounds like he met his primary design goals.


        Eaking out the last few percentage points of performance can be a consuming and expensive challenge, and for those inclined to chase that goal, go for it. There is lot's to be learned from
all points of view, and always room for improvement, that is what makes this hobby or disease, as a good friend once called it, so rewarding.

        Let's just keep the debate at a professional level so we can maximize the return on everyone's investment, and not lose valuable contributors. I notice after several years of mainly lurking,
that we are getting better & better in that regard.

        my 2 cents worth..........Gary

Gary Palmer
Lancair 235 C-GPLM
13B powered RV in the planning stage.
President EAA Chapter 245
http://eaa245.dhs.org/
gpalmer@NortelNetworks.com-

I had a lot of trouble with that web site with two different browser.

shtml gives the source on the html.

Can you capture the pictures of the left and right side of the engine
and up load them here Gary?

Paul Lamar
 
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