----- Original Message -----
Sent: Monday, May 07, 2007 3:47 PM
Subject: [FlyRotary] Re: Pinched
Duct
Ed, It
does really sound like you have a good handle on things. Truly for best
efficiency you want to run a bit hotter. Most of the cars now use 180°F
thermostat and many 190°! They are after mileage for the CAFE requirements
though. Lynn has mentioned several times that the best power range is around
170 for the rotary and that sounds about right. The interesting part is that
as you inprove your cooling your max power changes, usually towards more,
thank goodness. I intend to have my radiators in a "cheek" position so I can
run a longer wedge duct to them. Time will tell if this is any better than the
evap cores. At least on the rotary you don't have as much stuff blocking the
exit. We would all do well to consider that factor when designing our
setups.
I would really like to thank you Ed for your efforts to help all
of us who come later to the party. Your chronicles of both the good and
the bad will save many people from peril, THANKS AGAIN. Fly safe
and often!
Bill Jepson
-----Original Message-----
From:
eanderson@carolina.rr.com
To: flyrotary@lancaironline.net
Sent: Mon, 7
May 2007 11:19 AM
Subject: [FlyRotary] Re: Pinched Duct
Hi Bill,
My cooling system now seems well (if not
optimized) matched to my current installation. Full power take offs
on hot days see my cooling temps elevate to 200F for oil and 210-220F for
coolant. Once I hit 120 MPH IAS the cooling system catches up and starts
to eliminate the cooling deficit.
At my normal retired-man cruise of 7- 8 gph, my
coolant and oil range from 155-170F depending on OAT. When I push it to
my max fuel flow/power 10.5-12.5 gph at altitude the
temperatures of both increase until they are in the 190-195F range. This
gives me my maximum true airspeed. So it appears my cooling capacity is
about right where I need it. Certainly a surplus at low power
cruise, but just adequate on take/off climbout on hot days and adequate for
full boogie flight.
I really don't know how much drag (if any) I have
eliminated, but I am convinced that it is less than if I had more of the core
exposed to high velocity airflow.
Sorry, I can't be more definitive about it - I
would like to know as well, but only so much time to get all the wonderful
projects on my list done. Perhaps someone with the inclination and time
will someday put this idea in a wind tunnel and tell us {:>)
Ed