Ernest,

RV10. Skinny front tapered to the firewall. The sides are lower pressure
than the nose on a conventional cowl. In this arrangement I think NACA's
may work well.

Bobby

Bobby, Before going side INLET I suggest that you go to Peter Garrison's site and check out his plot for his Melmoth 2 CFD. The plots won't be identical to an RV-10 but are made on an aircraft of similar size and configuration. (4 seater standard Lyc engine etc.) We usually want our intakes in a HIGH pressure area and exits in a low pressure area. You are correct that the sides of the cowling are usually LOWER pressure than the front. Go to

www.melmoth2.com click on the topics subhead and then CFD. He has had a close association with some really hot designers like Rutan and John Roncz. Roncz ran his design through a high-end CFD program in the design stages and this led to his unusual updraft cooling design. Noting his cowl shape is fairly standard. Checking the pressure plots shows that the sides might not be a good spot for the radiator intakes. Your radiator locations aren't bad. This is the location I have considered for my rads as well. but angling the "noses" in and applying duct work from a front inlet would be a good idea. As Tracy says YMMV, but checking these pressure plots is a good idea. I like the idea of side EXITS similar to the Thorp 18 since the area at the rear of the cowling at the firewall is starting to go low pressure. Carefull contour of the exit to place the exit air close to freestream angle would be necessary as well. Of course the typical botton exit is also OK. Good luck.

Bill Jepson