[MrNomad]

Building an RV9A, Superior O-360, which means 7A cowl.

The plan calls for a hole in the firewall to accomodate the front main gear leg bolt where it attaches to the engine mount. Thanks to the engine mount shims I can slip a castle nut & cotter pin on the end of the AN5 bolt and prefer not to make another hole in the firewall. The castle and the end of the AN5 bolt rubs (just a bit) against the firewall.

Comments please?

Second, hole # C is dreadfully close to the fuel pump mount and the cable will surely rub up against the fuel line. Why not place hole #C 3/4" to the left?

What are the ramifications of such relocation?

Third, I plan to paint the plane before first flight using the engine mount as part of the rotisserie. For rotisserie purposes, the engine will be off and we'll weld up a jig that fits the dynafocal array.

Before I add carb & exhaust to the 360, I plan to bolt the engine to the mount, fit the cowl, stripe for paint, then remove cowl & engine, and then paint.

Question: Will the later addition of carb and exhaust necessitate additional cuts to the cowl, thereby screwing up my paint?

Last: What methods have others used to compensate for engine sag and therefore, cowl misalignment after 10-15 hours of flight?

Thanks. We started on June 1, hope to be done by Dec, work on it every day, and have a helper 4 hours per day.

 

[N523RV]

** If you really don't want to drill the hole, mark the location where the bolt rubs and use a ball-peen hammer to put a dent in the firewall at that location. You definitely don't want it to rub.

** The stock hole locations worked out very well for my O-320 Fixed Pitch setup. As I recall, that hole actually does intersect somewhat on the doubler.

** Leaving off the carb/exhaust should not pose an issue later on. Just make sure the gear leg slot is sufficient. (3-blade prop requires longer slot)

** I made no adjustments for engine sag on mine and after 118 hours I can't see that it has sagged any.

 

[kentb]

Just paint the cowl latter

I used the same cowl on my IO-320 with CS prop. I fit everything and then painted it before flight. After my first flight I could see that the mixture linkage on the side of the throutle body was rubbing on the cowl. I cut a hole around the close area and then build a bubble over it. Now I will repaint the cowl when I do the fairings.

Keep in mind that the engine moves a lot during startup and shutdown. Things may need to be adjusted.

Kent