Since the premolded engine cooling NACA ducts don’t seem to be covered elsewhere in the manual, I’ll include them here. Much of the cutting was completed during Head Start, though I did cut the overheard fresh air duct at home. Then they’re all fitted up and held in place. The engine naca’s had been set with pop rivets for the trip to Ohio, which was sufficient. The fresh air naca was set with glass bubbles and held with tongue depressors. Then all three were given a radius underneath with the aforementioned glass bubbles, and then layed up with BID. Fairly straightforward, though somewhat time consuming, but I just love the more “visible” changes to the plane. Also note that all three got a fair amount of sanding once they were cured. The fresh air naca needed to have the premolded section sanded down to the roof line, which was fairly simple. The large engine naca’s, however, had a definite tilt to their flanges that made them visually pucker in comparison to the roof line. I filled the offending area with microballons and sanded, filled and sanded, and got to something I think is close. I will probably cover this area with Cabosil later for wear. Also note that the fresh air scoop needed to have it’s inlet ramped back into the fuselage roof for good flow, and this area was covered with microballons and BID.

Fresh Air Scoop Hole Cut	Tongue Depressors to Hold Pressure on NACA During Bonding
NACA Scoops with BID Layups	Covering the Ramp Foam with BID
Cutting the Foam Covering BID back after Cure

Posted By: Brett Ferrell
Sunday May 25th, 2003 at 10:56 PM

Categories: Cooling NACA and Cooling Plenum
Tags: Building Cooling Fuselage NACA