Section 38, Cowling

I was casting around for something to do while waiting for my back ordered parts to arrive. I thought I'd trim down the cowling halves to the trim line - it had to be done sometime, why not now. As I was looking through section 38 I was surprised that there wasn't a "pause until the engine is mounted" step.

Can I really get through all of section 38 (which goes all the up through attaching the piano hinge to attach it to the fuse) without the engine being mounted without problems later? I've assumed all along that I'd need the engine mounted before attaching those piano hinges that attach it to the fuse. If not, how far can I safely go? Is there a way to adjust later for final fit?

I waited until the engine was mounted, but if I had just cut to the scribe lines I would have been OK. I seem to recall a thread on this about a year ago.

Cowl attachment

I suggest that you wait until the engine is hung.

There is lots of discussion of this issue here and waiting for the engine is advised.

Waiting for the engine is the best way to make sure it fits, but like I said my scribe lines were dead on. Still, better safe than sorry!

Yeah, I guess I'll wait. Just trying to find something to do while waiting for parts. You're right, though, better safe than sorry ...

When I built my first homebuilt (a plans built) I transferred the spar cut lines to the wood using tracing paper that was not rigid. I unknowing cut in a curve. I spent 10 minutes trying to figure out a way I could use it without ordering and waiting for more spruce. I picked up my circular saw and cut it in half so I wouldn't be tempted! Sometimes patience IS a virtue!

Optimum time to fit RV-12 cowlings?

As many have suggested, I have put off fitting the cowlings until the Rotax engine as been installed. At this point in time, the engine is hung, fuel lines installed and quite a bit of the wiring has been completed.

After the prop & S-1202 spinner plate is installed, should I proceed to fit the cowlings ? or install the exhaust system then fit the cowlings?

I would assume that installing the oil and cooling systems prior to fitting the cowlings would only complicate matters.

Any guidance would be appreciated.

I fitted the cowls at the point you are at now. The cowl edges needed quite a bit of trimming to fit properly, so much that I wondered if I'd mounted the engine correctly. Later after fitting the exhaust, I ended up fibreglassing and re-shaping the exhaust opening to make the lower cowl easier to remove. I also moved the oil cooler duct opening forward as per the mods sticky to give greater clearance to the muffler.