> Jerry Hey wrote:
> >
> > >  > Paul,
> > >>  Has there been any reference data to calculate the necessary

of the
> > >>  swirl tank? How do you decide if you need one? It looks like some
> > >>have them and
> > >>  some don't.
> > >>  Thanks
> > >>  Dean
> > >
> > >Most automotive systems don't use swirl tanks and they work quite

> > >I am going to try it with out and just copy an automotive system
exactly.
> > >After all, billions of dollars have gone into developing automotive
> > >cooling systems. If it will work for a 6000 pound truck pulling a
> > >7000 pound load up an 8% grade in So Cal at 65 MPH  on a 100 F
> > >day it will work for an airplane.
> > >
> > >People flying use all sorts of different plumbing systems. I cannot

this
> > >time identify why some plumbing systems work well and others don't.
> > >It is buried in too many other factors.
> > >
> > >I CAN see why some cooling system don't work for aerodynamic reasons
> > >and that problem  appears to be at the top of the list. In that
> > >category having the back side of the rad too close to an object
> > >seems to be the main reason. Second is not having enough
> > >air outlet area for the cowl. Third is having a poorly shaped
> > >inlet duct. Having a radiator that is too small is way down
> > >the reason list. Most are too large given all the other mistakes.
> > >The exact plumbing system used is probably at the bottom
> > >of the reason list.
> > >
> > >We still have not got to the point where we are considering cooling
> > >drag as nobody is yet using cowl flaps to my knowledge.
> > >
> > >This is the way I see it now.
> > >
> > >Paul Lamar
> >
> > I think the difference is that automobiles universally have radiators
> > with one of the tanks above the engine.  If the rad is below the
> > engine you will need a swirl pot.    Race cars with low radiators
> > have swirl pots.  Jerry

I have a large radiator lying flat in the bottom of the aft fuselage, well
below and far from the engine. I have a simple small overflow tank and no
swirl pot. The rear housing heater outlet and smaller top outlet are both
connected back to the coolant pump.
I flew again yesterday. The weather was cool, (about 15C-60F)  dry and
windy. Coolant and oil temperatures went to 200-210F on climb out as they
usually do. Cruising at 3-4000 ft after a few minutes (after some time)

temps stabilized at coolant 160 and oil 180-5.
My coolant temp sensor is in the rear housing in the standard Mazda
location. My oil temp sensor is in the oil pan in the standard Mazda
location.

Paul, I have never seen the coolant at 160 in flight before. After I
mentionned high temperatures in cabin compounded by hot air trapped in

fuselage, you suggested hot air exits under the stabilator. I tried that

it appears to be quite efficient, for the engine cooling as well. Thanks

the
tip.
Yvon Cournoyer