rtfm
Well-Known Member
Hi,
I guess we have all come across the accompanying diagram at some time or other. But it got me to thinking...
Typically, one tends to see air inlets in the front, and exits further back on the bottom of the fuse. But this pressure diagram seems to suggest other alternatives: For instance:
But as Orion has pointed out on a number of occasions, the volume of air passing through the cooling system is governed by the pressure difference between the exhaust and the inlet. And windshield/top-of-spinner would seem to offer by far the biggest differential. Even bottom-of-spinner/top-of-spinner would seem preferable as far as pressure differential is concerned. It would seem to be about twice as efficient as exhausting the hot air from the rear-bottom of the cowl.
In fact, the route taken by air in the windshield/top-of-spinner scenario would seem fairly similar to the more traditional bottom-of-spinner/rear-of-cowl route, except only for direction of travel. And the route taken by the bottom-to-top of the spinner would nicely encircle the cooling fins and not be quite as weird...
Bottom line is that it would appear that venting the air through a hole above the spinner would seem optimal.
Just a thought...
Duncan
I guess we have all come across the accompanying diagram at some time or other. But it got me to thinking...
Typically, one tends to see air inlets in the front, and exits further back on the bottom of the fuse. But this pressure diagram seems to suggest other alternatives: For instance:
- Air intake just in front of the windshield, but more significantly,
- Air exhaust in the FRONT of the cowl just above the spinner.
But as Orion has pointed out on a number of occasions, the volume of air passing through the cooling system is governed by the pressure difference between the exhaust and the inlet. And windshield/top-of-spinner would seem to offer by far the biggest differential. Even bottom-of-spinner/top-of-spinner would seem preferable as far as pressure differential is concerned. It would seem to be about twice as efficient as exhausting the hot air from the rear-bottom of the cowl.
In fact, the route taken by air in the windshield/top-of-spinner scenario would seem fairly similar to the more traditional bottom-of-spinner/rear-of-cowl route, except only for direction of travel. And the route taken by the bottom-to-top of the spinner would nicely encircle the cooling fins and not be quite as weird...
Bottom line is that it would appear that venting the air through a hole above the spinner would seem optimal.
Just a thought...
Duncan
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