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Old 08-24-2010, 08:37 AM
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DanH DanH is offline
Join Date: Oct 2005
Location: 08A
Posts: 10,452

Says in part: "Fit the cowl halves together at the front."
Next paragraph says: "Mark the screw pattern for joining the top & bottom behind the spinner. Clamp top and bottom together at the spinner and drill the screw locations . . ."

I will be doing that on the floor and will probably put a 2 by cut the height of the firewall as a sort of spacer to hold the top and bottom halves (that attach to the firewall) the proper distance apart.
Exactly right.

Overlap the sides. Don't trim the top to the bottom or vice-versa.....trim either or both to an imaginary line which exactly bisects a 13" circle. The small white tabs set equal inlet size, ie a level split line. When trimmed install a single cleco as far back inside the inlet as possible. Doesn't matter if it is in a screw location; you can fill any extra hole later.

Move to your engine. Attach a steel or aluminum tab to the forward baffle attach points (1/4" screw) above each front cylinder. These support the nose of the upper cowl. The rear is supported by overlapping the boot cowl. Draw a centerline on the top rear center of the cowl. Draw a matching centerline on the top of the boot cowl. Adjust the length of the front supports so the cowl nose is dead behind the spinner and perfectly level. Install a block to set the spinner gap. Align the centerlines at the rear of the cowl. Now trim the rear edge of the cowl so it sits on your hinge line or camloc tabs. The upper cowl is now where it belongs.

Raise the lower cowl into position, again overlapping the sides. Install the two front clecos, and run a strap around the halves. Mark and trim the rear edge of the lower cowl. This may require a few on-and-off cycles.

Now trim the sides. Start by drawing a level line back from the front of the cowl where you had already established a bisect line in the very beginnning. Trim both halves to this line.

From here it's fine tuning and fasteners. Works for any cowl; did a Rans S7 with the same proceedure a few months back.
Dan Horton
Barrett IO-390

Last edited by DanH : 10-26-2018 at 07:56 AM.
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