Cowling

 

3 Nov 2007 One thing that I haven't completed was blocking off the inlet ramps, which supposedly really help cooling. After a quick trip to the local TAP Plastics, I returned with a quart kit of expandable urethane foam. I really like this stuff! It's easy to use, and sands easy to any shape. Here's what it looks like after dribbling this on and allowing to expand.
  And here's what it looks like sanded to the desired shape. All I need to do is lay a couple like layups of glass over it and it's done.
15 Sept 2007 There hasn't been much in the way of exciting pictures lately, just a lot of sanding, and fussing with stuff. I gave the cowl one final sanding and then  shot a coat of rattle can primer on it so it's got a pretty lousy coat of paint, but it will fly like that for sure until final paint. Cam-locs are all installed but there's a couple I need to adjust, and there's a little edge sanding on the aft left top/bottom joint that needs a little care. Overall, I'm fairly pleased with the cowl.Oh, I did glass the marker beacon antenna into the lower cowl with the last 40 inches of coax stripped of its shielding.
  And here's what the oil access door looks like. I used the hidden hinge and I do like the way this worked.
27 Aug 2007 It's getting closer. All the cam-locs are installed and seem to fit OK. The top half looks funny with the cam-loc strip but there's a reason. Supposedly, once the c-locs are adjusted for the proper depth, you should be able to give a quick turn and they should unlock. I'm finding that isn't quite the case and they will allow the cam to turn in the housing. So.... I adjust the c-loc to the proper depth, then pull the locking pins and lock out the body. I had to adjust the top aft row with the c-loc strip off the plane as there's no way to pull the locking pins once it's set. About the only things left on the cowl are the oil door, and glassing the marker beacon antenna to the lower cowl. And more finishing...
19 Aug 2007 I was able to do a little more work on the cowl over the last couple days. The oil door still has a little work but overall, it's about 85% complete buit I'm trying to figure out when I bond/ rivet the latches and the hinge to the door. I'm using the hidden hinge and it looks like it should work well and the Hartwell latches are the 5000-2 models. I did find that if you don't bend the latch mount surfaces, the latch button/arm won't come close to being flush with the outside of the door.
  Was also able to install the cam-locs on the right side of the cowl to see how these were going to work. Some folks don't like these, but I kind of like the look.
  And from this view the nose of the cowl is coming along fairly well. I have just a little more work to even out some of the top/bottom mating lines but otherwise it's looking good. The big problem will be the gap between the spinner and the cowl. Right now, there's probably 1/4" difference from the top of the cowl to the bottom which makes for an inconsistent gap. I may wait to see if the engine sags on first run before I deal with that.
10 Aug 2007 Today was the day to start the oil access door. I thought this wouldn't be a big deal but it's going to take a little work. First, the indention in the cowl isn't near deep enough sooooo....  Trim the oil door to the right shape that you want, then outline the door on the cowl.
  Then cut out the oil door shape in the cowl. See where this is going? The idea is to make a nice, fairly close fit so the door can be inserted flush with the cowl. So far, so good.
  Take a little tape and wrap the edges of the door from the bottom and apply a bit of mold release. Make sure the area surrounding the door is sanded with some 80 grit to rough up the surface.
  Now comes the layup. I used three layers of 8oz tape which is probably overkill for the door lip, but it should make a nice door lip.
  After I got the oil door taken care of, I figured it was time to bond the inlet lips. There's a bit of trimming required here but it was easy. Eventually the inboard sides of the inlet lips get glassed for improved airflow, but this is going to wait until the baffeling is started. I also roughed up, then applied a coat of resin to the honeycomb areas. It seems to be really porous and I want to seal this.
7 Aug 2007 Time to see how well the Smooth Prime worked. After sanding down with 150 grit, I was really curious to see how this whole process worked so I sprayed a coat of rattle can primer on the cowl. To my surprise, the area covered in gray primer has no pin holes. Not one! Way too cool.
  Appears that the time spent prepping was well worth it.
6 Aug 2007 It dries quickly but I let it set overnight. Then applied 150 grit sandpaper to the primer. You would have thought it was Christmas as the white dust was everywhere! The good thing was that it was fairly easy to sand.
5 Aug 2007 After the thin coat of resin/ micro balloons, it was time for the Smooth Prime. This is really thick stuff but the word on the street is that it works. It's not really cheap either and at about $50 a quart, you don't waste any. Here's the lower cowl with a coat of Smooth Prime rolled on. I have no idea how you'd spray this stuff either.
29 Jul 2007 It was time to start filling the pin holes on this thing, so it's more sanding. The general process is to sand with 80 grit, then squeegee on a reduced coat of resin. Then sand with 80 and 150 grit, and do another coat of resin. The honeycomb areas seem to have a lot of pinhole potential so I finally squeegeed on a thin coat of resin/ micro balloons. I'll sand that down, then roll on a coat of super fill primer.
20 Jul 2007 The cowling seems to be coming along and it doesn't seem to be as bad as you'd think from reading the internet forums. I'm off to OSH in a couple days but hope to get back and make some good progress while the weather is still good around here. I'm also working along on the canopy, so while this dries, I do some canopy work.
  I've been working the join line around the spinner ring as this seems to be the worst part of the fit.
15 Jul 2007 Work continues to get in the way of meaningful progress on the RV and there was also a trip up to Arlington for the Fly-In which was good. I thought the RV turnout was a bit on the light side this year but the rumor is that it's so close to OSH, folks decided to wait for Oshkosh. Hopefully, next year I have this one on the flightline at AWO!

At least the crisis is coming close to an end for now. The next step was to bond the hinges and the cam-loc strip to the lower cowl. I used West System with some flox to bond the parts to the cowl half but used clecos to hold the parts while the epoxy cured. After the epoxy cured, I did some minor sanding, deburred, countersunk, and squeezed the rivets. Overall, I think this came out nice. In sanding the rivet lines a bit, I can see the issue with the pin holes and hopefully, they aren't too much of an issue to fill. I also need to do some work on the nose of the cowl which is next on the agenda.
8 Jul 2007 I think I'm pretty much there. There are a couple places along the sides where the gap may be just a bit too wide (around .040) but overall, it looks good. I think the next step is to bond the hinges and can-loc strip to the lower cowl. After that, the surface finishing starts. I think I'm going to try and do that in conjunction with the glass work on the canopy so I can knock this out at once. The plan is to hit this following Oshkosh and finish the glass work while it's still warm.
7 Jul 2007 There's been progress, just not a lot of update on the blog. Since 26 June, I managed to get the bottom cowl fitted pretty close. It's still not as bad as I thought it was going to be.
  Here's the cam-loc mount strips. The very forward tabs are a pain as you need to bend them inward just a bit, but this ends up being a concave curve at this point.
26 Jun 2007 Over the last day I trimmed up and drilled the top cowl. Just with clecos, it seems to be very steady. The cowl to boot cowl gap may be a little narrow right now but that's easy to fix. Otherwise, it seems like a decent fit.
  It was time to also start on the lower cowl. Tonight I was able to make the rough cutouts for the gear legs and that went well. I cut out a template out of some stiff paper which worked and kept me from sticking the cowl on and off a dozen times. The front matches up OK, but not great. I think I need to remove both halves, get the front mated, then mark out the rest of the trim lines. Hopefully, this goes quick. So far it's not too bad.
24 Jun 2007 It was really a chicken and the egg thing. I needed to work the baffling so I could fit a couple more hoses, but before that, I needed to start the cowling. So, it's time to start some cowling work. First on the agenda was the 2.25 spacers since I don't have my prop yet. It's on order, but it's going to be a while.
  Next, I needed to re-install the boot cowl. This hasn't been on for a really long time but it did fit OK.
  I'm doing the c-loc thing for the upper firewall and the sides, hinges for the bottom and lower sides. I got this nice c-loc mounting strip done, then realized it's not wide enough. Hummm, back to re-interpret the instructions. OK, it's supposed to be 1.125 to 1.25 overlap with the cowl allowing the recepticals to be mounted 5/8th from the cowl edge.
  Start messing with the cowl itself now. This is not going to be fun, I can already tell. For one, the face doesn't really match up well with the spinner plate. I need to figure out how that's going to work.
  I marked the 2" line aft of the boot cowl forward face and marked the line on the cowling. After cutting a little and sanding, it's pretty close. The downside it that everytime I put this on the airplane it move a bit. I need to figure out where the c-locs are going to go and drill a couple tooling pilot holes to keep this straight.