Dave’s RV-7A Building Log

I spent the evening undoing the work from yesterday and redoing it at the front of the baffles. I made a patch for the hole in the back of the baffles. It’s not a structural area, so the patch will be fine. I really don’t want to redo the baffles at this point. Riveting in there would have been nearly impossible, so I used (gasp) blind rivets. I used some of the sealed rivets that I had left over from the fuel tank. I also put some RTV under the patch to help seal it.

I cut a new hole in the right baffle floor and clecoed the flange in place with some RTV. I’ll let that set up before I rivet.

I moved the cabin heat muff back to the #1 exhaust pipe again. It’s going to be a tight fit to get all of the hose routed through there.

I bought a 2″ hole saw a while back, but it has the “quick release” style mandrel. I finally picked one of those up on the way home. I used the hole saw to cut a hole in the back right baffle wall. I then used the flange as a template to drill the holes. It’s going to be tricky doing the riveting in there. I’d prefer not to remove the baffles, but I might have to.

After deburring everything, I then used some high-temp RTV to seal the flange to the baffle. At this point I looked at the plans and realized I was supposed to put the screen in there as well. I took off the flange, re-applied more RTV, and clecoed it back on with the screen in place. I decided to wait on riveting until the RTV set up.

I then worked on getting the cabin heat muff secured. I tightened down the nuts that hold the end caps in place and put the band clamps around the whole thing. It’s definitely cramped on this section of exhaust pipe and the end caps aren’t straight, but it works.

It was around this point that I started to think about this location more. Having the slip joint inside the heat muff is not a good thing. If for some reason the exhaust gases were to leak out of the joint, they’d go right into the cabin. Not good. I posted a message on the VAF forum to confirm that it could be a concern. Since I didn’t want the flange permanently installed to the baffle if I decide to move it, I unclecoed it from the baffle. I set the flange down on some wax paper so the RTV could still hold the screen in place. Looks like I’ll be making a patch for the rear baffle wall. Oh well.

For lack of something better to do, I messed around with the control cable linkages. Whoever put the throttle/mixture cable kit together at Vans was asleep on the job. The plans call for different hardware than what is included in the kit. I ended up ordering some extra large area washers. They arrived a while ago, but I hadn’t installed them yet. I looked over the prop, throttle, and mixture links and installed the proper washers. I tightened down the nuts and added cotters pins. On second thought, I’ll probably have to remove the pins. I’ll need to be able to install the link onto the end of the control cable. These pictures are prop, mixture, and throttle, in that order.

I also messed around with some possible configurations of the breather tube. With the oil filter adapter in the way, I can’t install the breather tube per the plans. I’ll have to develop a different routing.

I have several tasks that are waiting on various parts. I’ll place some orders so I can move forward on the rest of the engine stuff.

I stopped my Sears earlier in the day and picked up a few socket wrench gizmos that I thought would work on the hard to reach exhaust pipe nuts. I ended up using a 1/2″ 6-point swivel socket and 6″ extension bar. I used the one for a 1/4″ socket wrench (and then a 3/8-1/4″ adapter since the torque wrench is 3/8″) only because Sears didn’t have the 3/8″ in stock. It probably would have worked as well. I tightened up all the exhaust pipe nuts to 120 in-lb.

I dinked around a little bit with the cabin heat muff and looked at a few web sites to see where people tap off the aft right baffle wall. I also had trouble tracking down my 2″ hole saw. At that point I wasn’t feeling so hot for some reason, so I worked on the computer for a while.

I used Excel to make a list of everything that’s left to do on the plane. I’m sure I left out 1/4 of the tasks, but I’ll keep adding to it as necessary and crossing things off as I get them done. I thought it would be depressing to see how long the list is, but it’s not bad. It helps to condense some items like “Wiring”. I’ll expand those once I start working on them.

Today was an absolutely stellar day, sunny and 70 degrees. It felt like summer. Consequently, I spent most of the day outside washing the cars, hanging out in the back yard, and riding bikes with Adele and the dog.

I did find time to work on the exhaust hangers. Those things are a pain, mainly because of the limited access behind the engine and the funky spring clamps that go around the exhaust pipes. I positioned the pipes where I wanted them. I then used some cleco side clamps and/or needle nose vise grips to hold the two clamps around the pipes. From there I measured distances, cut the little pipe thingys, and cut the rubber hose. I also flared the ends of the tubes as Dan showed on his site to hopefully keep them from slipping off. Installing everything took quite a while, because a few of the bolts I could only turn one flat at a time.

The hangers attach to the sump. These pictures show which bolt I used on the left and right sides, respectively.

There was one spot I had to do a little filing on the sump in order for the hanger tab to have a flat spot to sit on.

I’ve noticed that almost everyone puts the cabin heat muff on the back exhaust pipe rather than the front, and pulls the air off the back baffle wall. This also makes a lot of sense to me. The routing of the SCAT tubing is much, much easier. I had previously partially installed the muff on the front exhaust pipe, so I removed that and started installing it on the rear pipe.

Last night was the 4th grade competition for the math team. They did great. My duties as Math Team coach are almost done.

I didn’t get too much done on the plane today. Instead I took my first RV ride with John Adams. His plane looks great. I especially like the simple but noticeable paint scheme.

We flew up to Arlington and grabbed a bite at the Taildragger. Jim Piavis met us up there in his Boredom Fighter.
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The Black Jack Squandron was practicing, and I got to see them land in formation. Pictures cannot capture how cool it is to see 9 planes break from the overhead one after another. And yet I keep trying to photograph it.

After lunch, we hung around Jim for a little bit. It was challenging for John to slow down to Jim’s speed. It’s tough taking shots in the tight confines of an RV, especially when the plane is bouncing all over the place. I have a new appreciation of Ed Hicks pictures. Here’s a couple that turned out pretty good.

The RV is a great flying machine. It’s fast and incredibly responsive like a sports car. I definitely made the right choice of plane to build. Thanks John for the ride!!

After I got home, I decided to pull the plane out into the driveway and do a thorough sweeping of the garage. Plenty of neighbors slowed down and gawked at the odd sight.

Jeff Harrang and his wife Carol, potential RV builders, emailed me earlier in the week and dropped by to check out the project.

After all of that, I spent a little bit of time verifying the lengths of the throttle, mixture, and prop cables. I have the regular venier controls that came with the firewall forward kit. I’m going to return them to Vans and order throttle quadrant-compatible cables, but I wanted to double check the lengths first. They all look good.

Took a night off for the Seattle Eastside EAA 1440 (provisional) Chapter meeting. And another night off to drink beer and celebrate my birthday.

Tonight I installed the alternator belt. I grabbed a 7355 and 7360 from Carquest. Their belts are actually made by Gates. The 7355 ended up working out well. It’s a tight fit, but the belt might stretch a bit after the engine is run. There’s about 1/4″ between the alternator and prop oil line. If the belt is too long the alternator will rub against the FAB. There’s not much leeway on either side.

Another thing that took some time was fixing one of the mounting bolts. There weren’t any threads showing above the lock nut. I removed the alternator and grinded down the mounting bushing. That plus using a thin washer did the trick.

I tensioned the belt so that about 12 ft-lbs of torque applied to the alternator pulley stud caused the belt to just slip while the starter ring gear was held in place. I read on the forum that’s the best way to set the tension.

Saftey wiring the alternator bolts was a pain. I did the inboard bolt with the starter ring gear off, but then screwed up the outboard bolt. I wrapped the wire the wrong way. I didn’t want to remove the perfectly tensioned bolt, so I re-did the safety wire with the ring gear in place. It’s much more difficult, but doable. The second time looked much better anyway.

I also sanded down the filler I put on the ramps on the top cowl. The filler is really easy to sand. It turned out good enough. I’ll perfect my filling skills around the inlets of the cowl where it will be more noticeable.

I also installed a few various things around the engine, the fuel pressure line, and the plugs for the extra holes on the sender manifold. It’s cool installing all of these various gizmos. There are fewer and fewer parts on the shelves.

I’ve been waiting to install a few things on the back of the engine until the P-mags were installed. I was waiting to install them until I could time them. In order to time them, I need to turn the crank to top dead center #1. However, I asked Mahlon at Mattituck if it’s OK to turn the crank. He said it’s better to wait until just before firing up the engine. I think moving the cylinders will displace the preservative oil that they’ve sprayed inside each of the cylinders.

I decided to temporarily install the P-mags and then I can time them later when I’m closer to first engine start. The first thing I had to do was remove the long mounting studs that were on the left side. When using old-fashioned magnetos, my understanding is that an “impulse” magneto is installed on the left side. This is the only magneto used for starting and can retard the timing so that it fires after TDC. For some reason, that magneto needs a spacer and thus longer mounting studs. The P-mag doesn’t need them and they actually get in the way. Reading Walter’s tribulations with removing the long studs, I went right for the vice grips. I got them to turn about one revolution and then used the double nut technique to remove them and trash them. Mattituck nicely provided two short studs, which I installed instead.

With that done, I installed the P-mags. Adele was hanging in the garage with me, so I had her help in a few of the really tight spots. Her small hands were able to reach in among the engine mount and various stuff much easier.

Adele installed the oil pressure line on the engine and I installed the oil cooler. There’s one spot on the cooler flange I might trim a little bit so it doesn’t hit the engine mount. It fits great other than that. I installed the fittings in the oil cooler and turned them to an optimum angle in order to install the oil cooler lines.

I took another look at the fuel line to the mechanical pump. It’s simply too long. Ordering a custom length hose is expensive, but the standard hose is kinked way too much for my comfort. I removed that hose and added it to the pile of stuff to return to Vans.

I started looking at my options for manifold pressure. I need to route that to the two 1/8″ barbs on the P-mags and to the sender for the engine monitor. Vans provides a kit for routing the MAP behind the firewall, but I don’t see any reason to do that. It would be much easier to put the sender in the engine compartment and route a wire through the firewall. It would be one less hole in the firewall, too. There’s an extra port on the manifold used for oil and fuel pressure, so I’m hoping to use that. Connecting all the various different sized stuff together is going to take some creativity.

I’ve read in a few places that it’s a good idea to put a restrictor on the MAP line so that oil and debris don’t get in and to prevent total loss of pressure in the cylinder if something happens to the line. The restrictor also helps to even out the pulses, although hopefully the P-mags and EMS will even out the pulses. The easiest method of making a restrictor seems to be to epoxy an AD5-4 rivet into the fitting in the engine and then drill a small hole in it. I’ll investigate a bit more to make sure that’s the best option.

I was poking around and found an alternator belt that Mattituck included in the goodies box, probably because they mistakingly thought I ordered an alternator. I knew it would be too long as it was a 7365, but I thought I’d see how much too big. It was about an inch too long.

I started out by mixing up some epoxy with the West Systems Microlight filler. I wanted to smooth out a few spots on the cowl ramps and fill in the holes I had to drill. Making the ramps perfectly smooth isn’t really necessary, but I might as well practice on an area that won’t be seen. As it turns out, I mixed up the goop a bit to runny. It filled in fine, but sagged a little before setting up. It’ll still be good enough for the ramps.

The next logical step after installing the baffles was to install the Filtered Airbox (FAB) air intake plenum. I’ve been contemplating laying up an extra layer of fiberglass on a few areas that have some cracking, but then figured I could always fix it later if it falls apart. After installing all of the screws, it’s on there very solid and clears the starter just fine.

There was still one clip I needed to make on the right side baffles. It’s not clearly depicted on the plans, but the instructions mention it. It’s fairly obvious that something is needed otherwise the aft baffle side will push outboard too much.

Next up was the oil cooler. I made the spacers for mounting the oil cooler to the baffles. As Dan points out on his log, it’s a good idea to place washers on both sides of the spacer tube. It’s not in the plans, so you have to subtract 3 to 4/32″ from the dimensions.

I decided to wait to install the oil cooler until I have the P-mags installed. However, I did install the fitting for the manifold pressure. I need to figure out how to hook this thing up to both P-mags and the transducer for the engine monitor. (top blue fitting in the picture)

Time for Easter dinner!!

I started off my mixing another batch of epoxy. I decided to reinforce the ramp extensions I made previously. Before I laid up just 2 layers of fiberglass and it seemed a bit flimsy, especially since the baffle seal will be pushing against it. I laid up 3 strips on each side to reinforce the forward edge.

I then moved on to finishing up the riveting on the baffles. There were several rivets that I had to buck. A few aren’t very pretty, but they’ll hold just fine. I also drilled the holes in the bottom flanges that are safety wired together to wrap around the bottom of the cylinders. I also reamed all of the holes for screws 1/64″ larger per the instructions to allow for movement.

I then decided to mount the alternator. I’m not sure why I put this off so long. The parts have been sitting primed on my bench for weeks. I guess I was just concentrating on the baffles. Anyway I installed it.

I mounted the starter ring gear and estimated that I need an alternator belt 33″ inches long. Van’s suggests starting with a Gates 7350. I looked up that belt on www.rockauto.com, which states it is 35-5/8″ long. I’m not sure if that’s an inside or outside diameter, but I’m guessing it’s a bit too long. I’ll stop by the local auto parts store and see what’s available.

From there I figured it was time to install the baffles for the last time. It all went very smoothly, although I did manage to scrap a bit more paint off the rocker covers. I was hoping to be able to install the screw behind the dipstick, but I just couldn’t contort my fingers to get back there. I snapped a picture of the safety wire, cut it, removed the dip stick tube, installed the screw, and re-installed the dip stick tube.

Big day with some big accomplishments (as long as those stupid baffles don’t need to come off again).