Mike Parkin wrote:
> However, when airborne, the effect of the
> door is surprisingly minimal. In the cruise at 130kts, with the flap open
> the temperatures are as usual sub 100 degs - 60 to 70 degs maybe. With the
> duct closed, the temperatures (water, oil, CHT) are only raised by about 10
> degs. One advantage is it makes my cabin heater a little more effective.
Keep in mind that the maximum opening for optimal airflow is about 1/3rd
of the radiator surface. Air won't be able to rush with 100kts through
the radiators, so you need to compress the air after the radiators to
let it exit with the same speed as the surrounding air. Any opening more
than 1/3rd of the radiator surface is not going to have much effect at all.
When the flap is "closed", how much exit area do you still have? Mind
you that even small openings can have quite a large effect.
Although you have ram air cooling for the cylinders, I don't believe you
can cool the oil substantially without using the radiator. If your oil
temp doesn't increase when you have the flap closed, I suspect that
there is still plenty of air going through the radiator.
Frans
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