On 06/12/2010 12:30 AM, JEFF ROBERTS wrote:
> On the figures below I would like to see pictures of the opening if
> possible. When I take Goldrush down for the winter annual I was going to
> start cutting on the dog box to reduce it and fix a flap. I would like
> to see what others have done to reduce the box size and opening if
> possible. I now have much lower temps. I can't get the CHT's to break
> 250 F even on a hot day climb.
Reducing the inlet opening doesn't imply higher temperatures. The
standard inlet is way to large: that area of air can never go through
the radiator at the speed it enters. So a lot of turbulence is the
result. A smaller opening with a properly designed diffuser will give
more efficient cooling, with less drag.
To reduce cooling, you can use a cowl flap. In cruise, where you spend
most of the time, you need less cooling than during take off. You can
use the cowl flap to direct the air parallel to the aircraft while
cruising, and releasing it with the same speed as the air around it.
This is a further reduction of cooling drag and turbulence.
The standard exit is angled too steep, so the air curves around the
outlet and produces turbulence. Also the exit is too large, larger than
the void can be filled with air entering the cowl, or passing through
the dual radiators.
It all adds up.
If you want to clean up the airplane, on the Europa the cowling is the
place where you can gain the most.
If I'm back from Popham, I will see if I can post some pictures.
Frans
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