Lower Cowl Drilled

I didn't expect to happen today but then it just looked too nicely trimmed after a few hours of sanding that I could not resist.
But I am getting ahead of myself. First there was another slap on, adjust, mark, sand, session.

That turned out to be pretty good, needing only a few spots with further trimming. Finally, the lower half came on and cleared the skin while maintaining the clearance to the backplate of the spinner.
I taped the lower half in place as I had to remove the upper cowl to clamp the lower one in place. Then the drill went in, followed by the obligatory cleco.

That went well and, deviating from the instructions, I then prepared to trim the upper half as well. First I had to put the cover on the avionics deck so I had the correct reference edge.

And on came the upper cowl.

Another long strip of blue tape marked the edge to trim the fiberglass back to. In some spots it's about a 1/4".

It was late in the afternoon and I was not up for this sanding marathon, so this will follow on another day. The next step should be to trim this cowl back, so I can see how the sides fit. Once they have been matched, I can then install the side hinges and catch up with the instructions again.

Getting Ready To Trim

I've spent quite some time today to adjust the cowl and determine what and where it needs to be trimmed more. For that purpose I let the cowl halves overlap the skin. That way you can see the edge of the skin and mark it with blue tape on the fiberglass. Just keep in mind that this gets you only close but not perfect as the halves are at a small angel to each other.

I used the spinner backplate as another reference and small wedges to secure the cowl halves in the right position.

First I was concerned about the gap between the halves but I believe it to disappear when both are clearing the skins after they have been trimmed.

What does still concern me is the clearance of the oil cap. It appears that it sits awfully close to the edge of the cutout as well as high enough to maybe interfere with the yet to be installed access door.

This will be the place for the oil cooler...

.. and this will have the channel to get air to the water cooler. You can also see the nice fit of the curve to the skin and the hinge on that side.

Before the final masking I decided to reduce the gap to the spinner backplate a bit and reposition the cowl slightly to get a symmetric fit around the backplate.

Then I put the trim tape on, only on the rear end of the lower cowl. The horizontal edge will change when the cowl eventually clears the skin.

Tomorrow morning I will take the assembly off and start trimming. I just hope I can get them back in the same position.

First Cowl Fitting

I finally got around to install the spinner back plate and the propeller hub so I would have a reference point for the upcoming cowl trimming.

I used cheap bolts and nuts just to hold the backplate in place. This will all have to get removed and reinstalled with the real hardware before going live.

Then I put the lower cowl on, just for a trial fitting. I knew I wouldn't have enough time to start working on the cowl but I just wanted to see how much work I had to face.

I don't know about you, but to me this looks pretty close to being done. The clearance to the backplate is certainly a bit too tight for now but the rest looks promising.
I guess, I know what I am going to do on the weekend ...

Hinges Installed

I continued the cowl work by marking all the about-to-be-drilled holes on the back of the hinges that I had cut yesterday. I suppose that the cowl will get drilled using these aim points, but I am not there yet.

For now the hinges got installed on their counterparts on the airframe.

I also gave the top cowl a trial fit of which I have no picture. All I can tell you is that it appears that there is more fiberglass dust in my near future.

I think before I continue with the cowl, I will install the spinner backplate to have a reference point for fitting.

Cowl Hinges

I was so happy yesterday as I thought the cowl trimming might pretty much be done...
In the morning I discovered that I forgot to trim back the recessed flange of the lower cowl. So back to dusty trimming work again it was!
Then the halves were matched together and the front screw holes were marked.

Drill and cleco, was the next step.

The fiberglass was put aside and the hinges had to be cut.

At noon, I had a nice interruption from tedious work by a visit from Chet and Barry. Two great guys from Oro Valley who are thinking about building a -12 and putting a Viking engine on. They have built a -6 and a -9 and know what they are doing. I bet they wouldn't need more than maybe 6-9 months to put the baby together.

When they left I went back to work and cut the hinge pins to length, bent and pointed them.

I've also adjusted the hinge loops on the installed hinges on the upper firewall. They needed to get filed a bit wider as the bent narrows the gap on the inside of the curve. It's hard to take a photo of this, so I skipped it.

Next steps are marking the drill holes on the hinges and more cowl work.

Down to the Scribe Line

I finally picked up on building again. It was chilly 68 degrees this morning and I felt this was the change I had been waiting for.
Unfortunately, the work that was waiting for me was not very enjoyable. Sanding fiberglass!
It was time to trim the cowling down to its scribe lines, which required quite some manual labor and created a lot of unhealthy dust.
After 3 hours all the edges had been trimmed down.

Next step will be to match the two halves together and test for a tight fit.
I am also anticipating some nasty brake line work as the fittings on the pedals will have to get removed, cleaned and reinstalled.