X-Mozilla-Keys:                                                                                 
Fred wrote:

Dear Paul:

    Related: through a bit of searching and referrals by some technical
associates in past lives, I found a highly experienced and capable heat
exchanger design engineer who spent 20 years at Garrett in this specialized
field.  He has developed several heat transfer programs, has banks of data,
and is now working as a consulting engineer for Garrett (now Allied signal)
and others including various race car teams.  He has designed the radiators
on Kenworth trucks among other items.

We had a long chat this morning including a discussion of the benefits of
various radiator designs.  I am sending him the data I collected for louvered
fin radiators which I found to be inferior to staggered offset fins for
aircraft use.  He confirmed this to be the case for very high face velocities
which are required in aircraft.  (A typical figure for a Lancair IV is 3500
feet per minute while a Kenworth truck is perhaps 2000.)  The louvered fins
are easier to produce in high production, and have a slight performance
advantage over a range of velocities typical of trucks and autos.  However,
the drag is very sensitive to the fin angle on the louvers, and the core I
tested may have been far from optimal.

    In any event, here is the information to contact him you can add to your
data base.  As noted above, he does not work for free (only I do that!) but
if a group of rotary engine enthusiasts with similar needs were to team up to
fund the design and analysis of a common radiator package usable on a range
of aircraft, I could help with the preliminaries, he could do the
verification and/or modification work using the latest up to date whiz bang
stuff, and then a group of builders could build a test rig for diffuser and
flow distribution design.  He noted that in some cases on aircraft, they have
used oblique diffuser plates in the flow duct to get good distribution across
the face of heat exchangers.  I need to explore this a bit more.

Fred Faulkner
Thermodynamic Analysis
2458 Lomita
Suite 215
Lomita, CA  90717
310-530-6991
Nfaulkn@IBM.net

Fred works with Bob Greenwood who runs TEMP inc. (www.tempinc.com) which
manufacturers high performance heat exchangers including radiators.  I spoke
with Bob and confirmed that he can also build units like the Fluidyne designs
with the oil cooler integral in the radiator frame so one can handle the
requirements of both with only one inlet and heat exchanger.  Given the oil
flow rates and thermal load, they can size the combined radiator and oil
cooler.

With a good team effort, we may be able to get more rotary engine planes
flying by helping what appears to be a major problem: cooling.

Fred

 
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