Bruce A. Frank wrote:

I may not have the correct homebuilders spirit of desire to gather all
knowledge possible but it seems to me to be reinvention of the wheel to go
through all this testing of radiator air and coolant flow. If we were
starting from scratch and in a vacuum this might be necessary but we have
volumes of data from race car work over the last several decades. Race cars
are and have been operating in the same HP and speed ranges as the aircraft
we are building for a long time. The radiator sizes needed to provide proper
cooling for the horse power generated at the speeds we are flying are
readily  available from the racing radiator manufacturers. There is a
particular advantage working with them because they build specifically for
the automotive engines we convert for aviation. I can say that of the over
40 builders I have talked with who called the racing radiator manufacturers
for their Soob, Ford, Chevy, or Mazada engine radiator requirments none
missed the mark with the unit supplied by the manufacturer. Some have had to
adjust ducts, louvers or plenums but once airflow delivery and exhaust were
achieved the radiators supplied did the job with low drag (a concern of the
racer also) and excellent heat rejection in a unit sized to fit the
available space.

At one time there was fear that these manufacturers would not talk to
airplane builders and it may have been that way. I have found that the
people at both Griffin Racing and Ron Davis Racing will answer all my
questions including duct design with sizes, divergence and convergence
angles, intake lip design(including NACA inlets), and pressure differentials
through the cores and around the bodywork (cowling) to provide adequate
cooling air flow with proper re-acceleration for minimal losses.

Griffin for one would save themselves a lot of work on the phone if
they had a web site. I have been unable to find it so far. PL

One last thing, a few issues back Contact! magazine had an extensive article
on cooling ducts covering data compiled before and during WWII on the water
cooled warbirds. This same info was posted on the web site for the Canadian
Experimantal Aircraft Assoc. I don't know if it is still posted and I
apologize if this source has been mentioned before but all of the data and
necessary formulae were presented along with explanation for removing
dissolved gasses and bubbles circulating in the coolant system.

I think I have that link on the ACRE web site Bruce. If not could you
find 
the URL? PL

I did not intend to step on any toes here. I have not been a member of this
group for very long so I may have opened my mouth out of place. If I have
offended let me know but I thought it helpful to relate the experience and
other information we have obtained installing piston auto-conversions over
the last 15 years.

Bruce A. Frank

 
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