RE: Europa-List: Oil cooler thermostat

[nigel charles <nwcmc@tiscali.co.uk>]

>It is best to place a flap at the exit of the cowl/radiator duct.
Placing an obstruction in the front destroys dynamic pressure. An we 
need to recover as much pressure as we can to persuade the air to flow 
across the rad core.<

For what its worth I tried a cooler flap at the rear of the radiators.
With it fully closed it cut off nearly all the airflow and it made
little difference to the CHT and oil temperatures.

When I was at Vichy this year I met one of our French owners (sorry I
forgot his name). He has a very clever inlet cowl flap. It is part of
the lower cowl in front of the radiators and has a hinge at the rear of
it. In very hot weather it is lowered below the normal cowl allowing
more cooling air in. In cold weather it is raised impeding airflow to
the radiators. This is all controlled from the cockpit so that inflight
adjustments can be made. From what he told me it works very well. 

I appreciate that normally control of cooling air is best done at the
outlet but in this case it seems it is better to use the inlet.

Nigel Charles