What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Fitting O-360 scoop on a O-320 cowling

BJohnson

Well Known Member
During the initial build I modified my O-320 cowling in the scoop area and the FAB box fiberglass to fit within the existing cowling. Later I learned that I should have bought the O-360 cowling, but oh well. The mod has worked OK for the last 330 hours, but I annually need to replace a cracked FAB plate, and there are areas where contact with the cowl still occurs on occasion. I am getting ready for paint and have decided to modify the cowl and add the 0-360 scoop to the 0-320 cowling. There are two options, bond on the scoop and fair the fiberglass (the most cosmetic solution), or install with fasteners for easy removal and access to lower cowl area.

For those who have installed the scoop with fasteners, can you provide a PIREP on how that has worked out in service? Would you do it again or would you have bonded and glassed it on permanently?
 
I made the scoop removable on my RV-10 and loved it. Today I was fitting the cowl on my 9-A. I cut the scoop off on the -9 cowl and it will be removable as well. Have not decided on cam-locs or a hinge for the scoop. May end up with a combination of both. The removable scoop makes it a lot easier to get the lower cowling off and on, especially if you are doing it alone. I'll be putting a K&N air filter in the snorkel itself and feed the servo air through a hose.
 
Last edited:
How did you finish the edges

David, thanks for response. Did you fair the cowling so the edge of the scoop was flush to the cowling similar to the oil door?
 
My -6 had a removable scoop when I bought it. About 15 screws hold it on, with tinnerman washers and nutplates in the cowl. For access, I love it. I can do an oil change by just removing the top cowl (for access to the filter) and the scoop (for access to the drain). I have a quick-drain on the sump and that's enough.

In the 300 hours / 8 years I've had it, the paint around the tinnermans has started to crack, and it's not as pretty as it once was. I think having it as one piece it would have stayed nicer, longer, but that would have been balanced by greater wear-and-tear on the section behind the spinner, which gets beaten up over time removing the lower cowl.
 
I can do an oil change by just removing the top cowl (for access to the filter) and the scoop (for access to the drain). I have a quick-drain on the sump and that's enough.

I can see value in a removable induction scoop but using it as a shortcut for doing an oil change is not one of them.

The value of looking over the entire engine while the oil is draining can't be over emphasized. One of the most important areas is the exhaust system. It is doubtful it can be inspected in any level of detail with the bottom cowl in place.
 
David, thanks for response. Did you fair the cowling so the edge of the scoop was flush to the cowling similar to the oil door?

I first laid out a pleasing cutout line. Then made 4 relocation plates out on aluminum and used them to bridge the cut out lines. Numbered then and drilled 4 cleco holes in each plate,,,,2 on each side of the cut line. Carefully cut out the scoop. Prep the inside surface of the cowling for bonding with 36 grit about 2? around the cutout. Use packing tape to cover the inside edge of the cut out scoop and wrap it around the edge also. Cover about 2? of the inside edge with the tape for stray epoxy. Wax that tape up with Johnson paste wax or use mold release agent for an EZ release. Now lay up some 2-1/2? wide BID fiberglass tape, 4-6 layers depending on material, long enough to go around the cut line in one piece. Lay it out on some clear heavy plastic sheathing you marked with a magic marker. Cut out the fiberglass a little wider and you can then cut out perfect taping. Paint the prepped surface of the cowling with a light coat of pure epoxy. Re install the scoop using your relocation strips clecoed in place. Visually split the fiberglass taping as you lay it in place inside the cowling, 1/2 on the cowl And 1/2 on the scoop. Peel the plastic off the taping as you install. Nice,,,,,no sliding layers of glass and straight edges! Make sure it?s stippled down good for a good bond. Apply peel ply and let cure.. Pop off scoop after cure and clean up your nice flange. Now finish the edge of the cowling around the cut line with a micro/flox mix. Makes it really tough! Mark out where your cam locks will go on the scoop. Dig a small area of the honey comb out in those spots and fill with pure flox for hard points. Again,,,,makes for a camlock hole that is very durable. Now reinstall the scoop using the relocation strips clecoed in place and drill out for the camlocks. Install the receptacles on that nice flange you just made.:)
 
Back
Top