Dave’s RV-7A Building Log

Did more countersinking and installed more nut plates. I also riveted the back plates to the spinner after checking the clearance one more time. The spinner is now complete and looks excellent.

Now for the moment of truth. I’ve had the spinner on for a while but have been afraid to install the cowl. I fitted the cowl without installing the prop or spinner, so it was a bit of a guessing game. Well, it turned out much better than I expected–maybe even perfect.

Even the gap looks really good.

This thing is really starting to look like a plane.

From there I started working on installing the camlocs, primarily on cutting the backing strip.

Countersunk the spinner and started installing nut plates.

Lots of drilling and deburring. I riveted the nut plates to the tabs and the tabs to the filler plates. I just need to rivet these to the spinner back plate.

I then drilled all of the holes in the back plate out to #19 for #8 screws. I was in the middle of using the nut plate jig on the back plate when I realized I made a mistake. Instead of drilling for 14 screws around the whole spinner, I drilled for 14 on each side. I guess I just zoned out when I was measuring out the holes. I knew things were going too smoothly. Frustrated is a huge understatement for my mood. I don’t want to re-fabricate that stupid back plate and remove & re-install the prop. I’ll call up Vans and see what they say about it. I know it looks obvious in the picture, but it wasn’t so obvious before I drilled for the nut plates.

I took a break for a while and thought through the issue. I was thinking of just leaving out every other screw, but that wouldn’t work. I’d end up with a big gap at one end or the other. The only fix is to re-drill, which means a new back plate.
[5/26/2006: Miles at Vans confirmed the extra screws aren’t a problem. I’ll just have a very unique (and secure) spinner.]

I moved on to something else. I drilled the holes for the front plate. That went pretty smoothly. I laid out the holes on the plate, drilled them, and then using a flashlight drilled through the spinner into those holes. Worked well.

I worked on the spinner filler plates some more until the prop had 1/8″ clearance at coarse pitch. I made two small pieces of Al sheet to hold the filler plates in place per the plans, although I used .032 instead of .064. The thinner sheet is plenty sturdy enough.

I sanded the inside of the spinner a bit more where the front plate hits. The spinner is not absolutely perfect but it’s within 1/32″ of where I want it to be. I don’t want to reduce the structural integrity of the spinner by sanding it too much.

I carefully measured and marked the pattern for the screws and rivets on both the spinner and filler plates and drilled all the holes to #40 to start.

With everything clecos in place, I checked the coarse pitch one more time. I’m glad I did. There were a couple spots that were still a bit tight. Once I rivet on the filler plates, it’ll be much harder to tweak the gap.

I tweaked the cutouts in the spinner a bit more with some sand paper and got them right where I want them. I then turned to the plates that go behind the prop to fill in the gap. The fiberglass I cut out will work nicely. I cut them down to size with the die grinder and belt sander. I didn’t think twisting the prop would affect them, but it does. Julie helped me mark how much to remove. Just a tad bit more sanding.

I used the plexiglass disc in the die grinder and made the cutout in the spinner. I finished it up on the belt sander. The end of the belt sander worked perfectly for cleaning up the curve of the cutout. From there it was several iterations of enlarging the cutout with a half-round file and sand paper in order to give the prop 1/8″ clearance all the way around. I used the strap wrench to rotate the prop to high pitch to check that clearance. It ended up being a bit more than I wanted, but it’ll be fine.

I found that the spinner wouldn’t go far enough back, because of the front plate. I sanded the inside of the spinner a bit and got it fitting pretty well.

The instructions mention it’s important to make sure the spinner is concentric with the engine shaft. It says to identify a point at the tip of the spinner and make sure it’s stationary as the prop is turned. However, since the engine is preserved, I shouldn’t spin the prop. Instead I measured from the point at the tip to back edge at several locations. It’s pretty close, but one side is a tiny bit longer. I’ll do some sanding to correct that and straighten the back edge as well.

The first task of the day was to figure out how high on the panel the audio panel could be placed. I made a template showing the depth of each avionics box. The left edge represents the panel, and the jagged right edge is the back of each component.

I then backed the plane into the driveway, opened the canopy, and hopped in. Well, it wasn’t exactly that easy. I decided to cleco the forward skin back in place in order to make sure everything was lined up correctly. I installed some of the clecos from underneath (not an easy task) to avoid interference with the canopy. The canopy and forward skins are really battling each other. I had to use putty knives to pry the skins apart while Julie slowly lifted the canopy. I have some bending/beveling to do on those skins.

Once inside with the canopy closed, I determined that the audio panel needs to be at least 1.5″ from the top of the panel. Otherwise the rear of the PMA8000B will hit the tip-up canopy reinforcement. I’ll have to ask Ross to move the avionics stack down a tiny bit. I had to crawl out via the baggage comparment due to the canopy opening issues. The plane looks great with the prop installed, though.

The next step in getting the spinner fitted is to make a template for the cutout for the prop blades. I used a piece of cardboard, trimming it until there was just a tiny bit of clearance. I then muscled the prop to coarse pitch with a strap wrench while Julie marked the enlarged cutout on the cardboard.

I then traced this carefully onto the spinner exactly 180 degrees apart. I’m hoping to save the fiberglass cutout in order to use it for the filler plate.

Today was broken into so many small work sessions that it’s hard to say how long I worked on it. Felt like all day, but was probably around 2 hours.

I worked on the rear bulkhead for the spinner. This part is one of the most frustrating I’ve run across yet. The whole part is pre-punched except for the middle that has to be cut out. They probably didn’t cut it out to avoid stocking two parts for fixed-pitch and constant-speed props. That would fit in the penny-wise/pound-foolish category. I would have happily paid an extra $20 to avoid this stupid task. I used a hole saw, a jig saw, a Dremel cutter, a Dremel sanding drum, a vixen file, and various sand paper to get this done. I nearly ruined the whole part at one point when the jig saw grabbed the part.

I primed the bulkhead and reinforcement ring, riveted them together, and installed it on the back of the prop hub.

“Honey, would you mind helping me for a ‘minute?’” The prop isn’t super heavy, but it’s certainly awkward. And you have to hold pressure off of the bolts in order for them to turn easily.

It takes a long time to get the bolts threaded into the crank flange. I did a couple twists on each bolt in succession going around and around and around.

Eventually, it snugged up very nicely. I don’t have the extension needed to properly torque the bolts. I’ll leave that for later.

It sure looks sweet with the prop on.

The prop arrived via FedEx Freight.

I unpacked it and started getting it ready for mounting. I read the included manual cover to cover.

I also got a hold of Ross and had him make the changes I requested and return the drawing file. It’s getting close at this point. I’ve got a few minor tweaks, but the only major thing I’m worried about is possible interference between the audio panel and the tip-up canopy reinforcement.