Jerry Hey wrote:

Air cooled engines have generous clearances in order to survive temp
fluctuations.  Still, they get too hot on hot days and too cold on
long power off decents.   The only thing I have seen pilots do is
either open the cowl flaps all the way or close them all the way.
Not much real temp. controlling.   I would still like to  hear from
the guys who have no thermostats.   Is there a problem with
over-cooling on cold days?   It seems unavoidable to me.    Jerry

There is absolutely no doubt in my mind a Mazda engine would over cool
with out cowl flaps and a thermostat. Since nobody is running cowl flaps
very few are flying with out thermostats. Perry Mick tried no thermostat
and sure enough the engine gets cold on long decents. I also think
Tracy flies with out one or has flown without one. Tracy?

Paul Lamar

Well, it depends on what you define as over-cooling.  I still have no cowl
flap (just lazy) and no thermostat.  On a long decent my water temp goes
down to around 150 F (typical summer flying conditions).  Oil temps are
about the same. This is way cooler than optimum (efficiency) but not cold
enough to be a mechanical problem.  In the winter (below 50 F) I simply
stuff a rag in the right side rad diffuser and get the same temps as in
summer.  I'll get around to installing a cowl flap someday but in the mean
time, it just isn't a real world problem.

Tracy Crook
tcrook@rotaryaviation.com
www.rotaryaviation.com

 
The AirCraft Rotary Engine NewsLetter.              Powered by Linux.
ACRE NL web site.
http://home.earthlink.net/~rotaryeng/            http://www.linux.org