Re: REFLECTOR: duct installation

[Jerry_Brainard@AICI.COM (Jerry Brainard)]

In considering a water cooled engine solution for the XL, I
have been thinking about the cooling problem.  I have seen
examples of counter-flow cooling that are very efficient.  This
approach theorectically would result in lower volume of cooling
air and a smaller radiator.  I am not an engineer so I have no
hard data on how this approach would change sizing of anything
or how it would be designed.  I just thought that it might work
for this application.

My assumption is that better minds than mine have examined this
question and there are major flaws in this solution.  I am
seeking those flaws so I can put this into the "nice in theory,
but won't work here" bucket.

Jerry Brainard




From: reflector@awpi.com AT SMTP on 01/11/99 10:24 AM

To:   reflector@awpi.com AT SMTP@ANTHEMCC
cc:    (bcc: Jerry Brainard/OH/AICI/US)
Subject:  Re: REFLECTOR: duct installation


From:            "R. Wayne Owens" <wamowens@bellsouth.net>

> sizing the radiator. The most practical way is to use a large
truck radiator > and run the engine full power on a test stand,
cover more and more of the

How much area did you end up with? Did the truck radiator have
a fin density close to radiators commonly used in conversions?
(The VW Rabbit diesel radiator is a common one.)

> and take a measurement. of volume and square area. I now have
some > interesting ratios of power Vs volume of radiator to
work with. I compared

Definitely would like to see your ratios.

> My conclusion was there may not be enough room in the front
for
> the required
> radiator volume  and especially the 7 to 11 degree tapered
duct work

I can't see any way there's enough room in the front of a
Velocity for a water cooled engine's radiator. On the AirSIG
list serve, we've been working on a cooling system workbook,
and our resident aerodynamist, Steve Crow, sez a good rule of
thumb is a square foot of radiator face per 100HP. (The
radiator the Swing's used had about a square foot of area, but
their cooling problems weren't as great as the rule of thumb
would indicate.)

If you use a streamline diffuser, the leading diffuser length
is only about 3X the height of the radiator, but for the
radiator area needed, I have a feeling a P51 style scoop is the
only option. (Since water cooled engines run at lower
temperatures, they need more airflow for cooling than an equal
HP Lycosaurus.)

For those that are planning on a SVX in your Velocity, send a
message to AirSIG@cyberlynk.com (Garfield Willis) about joining
AirSIG. We've been working a lot on cooling system problems and
have an extensive set of information on using Soobs in
aircraft.

---
David Parrish