Jan 16 2004 - I am starting on the cowl mounting next. My plan is to use Skybolt camloc fasteners along the firewall perimeter and leave the AN257 hinge on the horizontal cowl seam.

First I will fabricate the mounting strips for the Skybolt camlocs. In preparation, I made three .063 angles and made the length of each to just fit in the door recess at the very top of the opening. I then placed them equally to support the thin strip while fitting the mounting plates. This keeps from introducing a weave in the firewall since this point is pretty flexible.

Here the LH mounting strip is in place. I'll make relief cuts to lighten the strip and allow for bending the tabs to match the skin surface, but it is very close as is with no bending. I'll show the camloc spacing I'm going to use shortly. I am also going to add a .020 strip down the sides and on the bottom strips and then shim the fiberglass back up to the skin surface.

Since I dimpled the skins and the firewall, I drill three or so holes, then remove the strip and machine countersink. Repeat for the remaining holes to get a good fit.

Jan 17 2004 - I made the remaining strips along the firewall perimeter. The long red line on the side skin is where the top/bottom cowl split line is located roughly in the center of the 4th and 5th rivets below the overlap. I'm using 4" spacing on the fasteners centered around the seam. From the seam down, the first one is 2" and then 4" thereafter. From the seam up, the first spacing is 2", then 4", then 3-15/16" thereafter with a fastener in the top center. All these measurements are made on the outer skins then transferred to the strips later.

The relief cuts in the strips I'll make later will allow the hinge to come back almost flush with the firewall.

Here is the top center. The red lines are the center location and the seam between LH and RH strips is toward the LH side since the longer strip will help support the flimsy RH side.

Here the plates are trimmed. I think maybe 1-1/8" width ahead of the skin might be marginal. I followed the Skybolt instructions, but another 1/8" might have been better. We'll see when the hardware gets here early next week. I'll hold off riveting these on until then just in case. See last picture for further comments.

I'll also trim the area where the hinge goes with additional clearance rather than leave the radiused edge.

The bottom plates are complete as well. The total count of fasteners is 25. The kit comes with 26 so I have one spare.

The fit of all the parts came out really good. I just need to make the .020 shim for the lower parts before everything gets a final cleanup and they get riveted on. The tabs are 3/4" each side from center and the radius of the cutout is 1". The radius is 1/4" ahead of the skins.

Jan 18 2004 - I decided to proceed with mounting the plates after doing more research - I easily meet the the 1-1/8" minimum. Here is the fuselage with the all the skins finally riveted on.

I tweaked the plates several times until I was satisfied that each tab was parallel to the skin profile. I masked the exposed tab and primed the remainder of the plates and the shim strips prior to riveting. All firewall rivets can be installed with the engine mount in place, but a no-hole yoke is required near each attach point.

01/19/2004 Update - The Skybolt fasteners arrived and will fit fine on the tabs I made. If done over however, 1-1/4" in front of the firewall probably would have been optimal. You might use that dimension if starting from scratch.

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