This is what I had hoped to do also except to have the front edge of the NACA moveable so that when I needed it I could drop it down and get a lot more air. This has already been proven to a limited extent by Vance Atkinson on his Cozy. He put a small linear actuator on the leading edge of his NACA and saw a noticable difference in cooling. Once the engine had cooled and stabilized after a climb he retrims it to the normal position. This way you don't have to stair step in a climb the way Tracy does. I will have to see if Vance has any hard data. In his configuration it has +/- 1" of travel, I am talking about dropping it down a whopping 3" with side seals to prevent loss of air. At that point it is no longer a NACA but a scoop. I am just waiting for John to fly his Cozy to confirm whether there is enough cooling in his design once he gets to altitude and things stabilize after climb.
...Chrissi

I assume Vance Atkinson has an air cooled air craft engine with less pressure
drop or resistance to air flow than a radiator.

Paul Lamar

Yes, he has a Lycoming. You might take a look at the airpath of a plans built Cozy. Not what I would call freeflowing by any means. Sure it is not as bad as a radiator but everything possible has been done to compartmentalize and baffle the engine. The cylinders are each wrapped with alumnimun sheet with an opening top and bottom, all the air has to flow up through those slots. The air also has to make several abrupt turns. I would guess that John's plenum with radiator, cooler and intercooler has more open area than a plans built Cozy and a much freeer exit path once past the coolers. Cozies are fraught with cooling issues because the air really does not want to go where they are putting it. The Long-EZ archives are full of schemes for trying to improve cooling no matter what kind of scoop.
...Chrissi

New to the list.  This pertains to carnard pushers.  Would vortex generators upstream help airflow into the intake ports?

Carl Murakami
Velocity 13B wannabe

I don't think so. Even with a zero boundary layer thickness a NACA duct
is not recommended for feeding heat exchangers. It is best suited for
things that suck like jet engines. Ironically it is not even used for
those.

Paul Lamar
 
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