Paul and Group,

Thank you very much for you book, /"How to Cool Your Wankel". /It was
invaluable to me with my cooling design. You will certainly see that I
tried to apply the concepts shown in the book.

I'm writing to solicit critiques on my cooling design. I'm building a
Glass Goose...a composite, two place, pusher, seaplane (see Glass Goose
(Small).jpg). I'm installing a Mazda Renesis four port rotary.
I'm locating the stock RX8 oil cooler five inches in front of the engine
directly behind the intake (see Oil cooler location (Small).jpg).

Water cooling will be accomplished via two 16" x 12" x 2" heat
exchangers located inside the pylon below the engine. I've built same
dimension cardboard boxes and place them outside of the pylons just to
show you where they will be located when installed on the inside on the
pylon (see Heat exchanger location (Small).jpg, Heat exchanger location
rear view (Small).jpg, and Heat exchanger located inside the pylon
(Small).jpg).

Here is my cooling design using the principles of your book (Engine
Cooling Glass Goose.jpg). I'll be flying in Texas so since my main
objective is to not overheat I tended to design toward the more generous
side of any envelopes....intake sizes (30% of core face), core sizes
(600 to 800 ci. My design has 768 ci), etc.

And, here are my questions:

1. Have I done it right? Too much? Not enough? I'm hoping you'll be able
to tell me I can use less (the intake area (see Intake area.jpg) is
about 4 inches too wide for my cowling. However, proper cooling in all
operations in the most important issue.

2. Seems like I've read on the site that if two heat exchangers are used
they should be in series rather than parallel. Is that correct?

3. If parallel is the answer, I would like to route water hoses to the
top of the right heat exchanger, out the bottom of the right heat
exchanger, to the bottom of the left heat exchanger, then out the top of
the left heat exchanger back to the engine. Will that work? Does a heat
exchanger care which way water runs through it?

4. One of the aerodynamic issues the Glass Goose has is maintaining air
flow down the side of the pylon. Current airplanes use VGs and/or
turning vanes to control the air down the side of pylon. As a byproduct
or advantage of this cooling design, I'm hoping that the turbulent air
coming out of the cores along the pylon may help hold the air to the
pylon. What do you think?

5. Do you think the prop may pull some air through the heat exchangers
to help cooling on the ground? Do I need a fan in this design? Where
would it go?

Do you know where I can get custom louvered grills?

Thank you very much for your consideration and comments,

Sandy McNabb


I like your drawings Sandy. Very well done.

Q2 should be in parallel.

Q4 since the top speed is  low the best idea IMHO is to position
two 19 by 16 by 3/4 inch thick cores on the outside of the pylon and tilt them
out to form scoops.  Real quick and easy to do. Use a boundary layer splitter
plate about 1 inch out from the pylon surface.

I know this is a radical idea but it will work and has worked
for other people when mounted on the bottom of the fuselage.
Check it out in my book.

Your picture of the rads mounted on the outside triggered this
idea in my feeble brain :) We have gone around and around on cooling
the Goose and this is the best idea anybody has come up with so far IMHO.
The drag on the aft pylon is high anyway so this will not add much more.

Q5 yes the prop will help.

I'll send some more ideas in the next message as there is no room
in this one left.

We will discuss plumbing details when we come up with an acceptable
solution for you.

Paul Lamar

Sorry. I made a word error in my previous posting. In question #3, it should be
"If series is the answer,....."

Sandy.

No problem Sandy. Here are the best of the old ideas.
The main objection was loss of cargo room.

I'll do a 3D of the latest idea I mentioned in the message above.


Paul Lamar

Paul,
I can't remember seeing these integral oil pan engine mount designs before.
I have been agonizing over a simple design for and integral mount pan design
for the single and one of these will fit the bill nicely.

To my mind the integral approach if far better than the 2 piece approach, in
that it would be easier to fit.
Thanks
George (down under)


Sandy, The problem using the front cowl scoop is there is not enough
room along side the engine when the exhaust system, motor mounts
and alternator are mounted to get the cooling air down and back to the internally mounted rads. Make sure you mock up the exhaust system, motor
mounts and alternator before you cast the installation in concrete.

I am still working on the new Goose 3D.

Paul Lamar