Following Dan Horton’s recommendations, I set the engine advance to a range of 19.6-28 degrees…
The process is very easy, just power up the electrical system, set the prop to the appropriate position, and blow a puff of air into the Manifold Pressure port on the mag. Conveniently I already have flexible rubber tubes connected to these ports, so it was a trivial task.
Last night I drained the engine preservation oil and added 6 quarts of mineral oil. I ran out of time to set the engine timing, but that is a quick job I can accomplish next time I’m at the hangar.
While I was changing the oil, I took the time to replace the oil drain plug with a quick drain fitting, and put some RTV between the starter solenoid and the snorkel.
I started by removing the snorkle and inspecting the fuel servo. Sure enough, some preservative oil had drained down the intake pipes and collected in the bottom of the servo. Rather than removing the servo, I was able to suck the oil out using a small piece of flexible plastic hose, and the wiping up the residue. There’s still a film of oil, but no pooling of oil at all.
Then I removed the bottom set of spark plugs, and rotated the prop a few times to push out the remaining oil. A lot of oil came out of cylinder 2, and just a small amount from the other cylinders. I leveled the airplane to help drain as much as possible. I also used a borescope to check the cylinders and take a few pictures, just because.
With that done, I removed the oil drain plug and let the rest of the oil drain out the bottom.
After consulting a number of threads from Vansairforce, I left the oil filter alone. This is a new filter added by Lycoming, so I’ll just keep it on for the first 10 hours of engine time. At $40 per filter, no need to waste a new one.
Once all the oil was out, I cleaned and installed the quick drain fitting. I used some loctite to seal the threads, and torqued it to 14 foot pounds, per the table of limits for a 1/2-14 pipe fitting. The quick drain should make future oil changes a lot easier – just push on a drain hose, and push the fitting up and rotate to release all of the engine oil.
I then cleaned and reinstalled the spark plugs. After wiping off all the oil, I used some acetone to clean the threads and carefully wiped the spark plugs down. I added some copper based anti-seize and reinstalled, torquing to 35 foot pounds per Lycoming’s spec.
Then I put the snorkle back on, adding a bead of RTV to help protect it from the starter. There’s plenty of clearance, but the RTV will help reduce any chance of rubbing and damage as things heat up, shift around and vibrate etc.
With that done, I poured in 6 quarts of straight mineral oil.
Tonight I finished safety wiring the prop attach bolts. I had previously wired two of the 6 bolts, but had left the others so I could move on with other tasks. At the time I was working towards a deadline – moving the fuselage to the airport – and didn’t want to spend more time on the task. The first two bolts had been a real pain, and I had redone the wiring several times before I was satisfied that it didn’t suck too badly.
For the remaining four bolts, I started by practicing with the thinnest safety wire I have, which is much easier to work with. After figuring out the routing, the length required, and any other relevant details, I switched to the large diameter wire and completed the task. The bolts are wired in pairs, and each bolt has a hole through the center where the wire passes. Because of the varied orientation of the bolts, each one presents a unique challenge in getting the wire through the hole. I was lucky that only one bolt needed loosening and reorienting, and I was able to get all the others to work without adjustment.
In the end I was quite happy with how it turned out, and found that a little practice and lots of patience definitely helps.
Before completing the aircraft wiring, I decided to switch to a Lithium battery, and EarthX seems to be the most popular brand for RV builders. The difference in weight between the original lead acid battery and the Lithium battery is substantial. I didn’t have the original battery specs, but it must be 3-4 times heavier than the Lithium battery. There are some other benefits too, such as a longer period of output, longer store of charge, and a battery health indicator output wire.
The EarthX 1200 series is an almost exact match in size. It’s slightly deeper, slightly narrower, and the top is shaped differently. The battery came with some foam to help make up for the narrower shape. I added a washer on each side to account for the wider shape, and added some aluminum strips with foam to the hold-down bar to ensure a snug and secure fit.
The battery terminals are basically the same, so once I had modified the hold down bar and charged the battery, it was ready to go.
I took the time to address a minor issue with the tail fairing, where it was trimmed a little too much. Right under the leading edge of the horizontal stabilizer the fairing is designed to cover the gap between two sections of aluminum. I had trimmed it slightly too much and a small 1/8 gap had been created.
I took the fairing home and added some fiberglass and micro-balloons to build up the edge about 1/4 inch. A quick sand and spray with primer and I reinstalled the fairing. I used some more micro balloons behind the fairing, using tape to prevent it sticking to the fuse, and it came out with a perfect fit on the aluminum.
My original plans with the control sticks was to use Infinity Aerospace stick grips. Unfortunately, no amount of trimming of the stick base was enough to create clearance from the throttle and mixture controls with these stick grips. If I had installed a throttle quadrant instead of the standard vernier controls, they would have worked out.
So I went with plan B and bought the standard Vans stick grips. These provide *just* enough clearance from the throttle and mixture controls, and they clear the bottom of the panel. There is still interference if the cabin heat vent is on and the stick is in the full forward and left/right positions, but there really isn’t anything I can do to avoid that.
The sticks just needed to have their base holes drilled, and the wire harness connectors replaced with my setup, and they were ready to install.
This morning I finished out chapter 41 (wing attach) by installing the fuel vent lines. I opted for Aircraft Specialty vent lines, just to save some time and effort, and I also installed the JD Air fuel vents.
The standard Vans fuel vent design has a fuel line passing from the tank down through the wing fairing, where it’s chamfered at 45 degrees. I’m sure this works great, but there are a couple of downsides. The line has no screen, so there’s a risk of insects or dirt making its way into the fuel line, or even the tank, and causing an obstruction. There’s also a chance I’ll snag the vent on something and damage it. JD Air makes a streamlined vent with a built in screen, so I installed these instead. Aircraft Specialty makes a fuel line that fits the JD Air vent, so that was very convenient.
The vent itself attaches to the bottom wing root fairing using a bulk-head fluid fitting, so it simply screws into position. I was then able to loosely install the fairing, position the fuel line, final torque the fairing screws, then torque the b-nuts on the fuel line to secure it in place.
Everything went well, the only bummer is the gap at the aft end of the fuel vent, caused by the curvature of the fairing. It’s no big deal, it’s just cosmetic, and no one will see it unless they look for it specifically.
I also installed fuel placards and some grip tape on the pilot side of the wing walk area.
After a weeks off for the holidays, I was able to make some more progress this week.
I finished the wing root fairings, and installed the wing root fuel lines. These are the lines that connect the fuel tanks in the wings to the fuselage.
The wing root fairings were fairly straight forward. Getting the right shape on the bottom fairing was probably the biggest challenge.
Soon after getting the shape right I realized that I needed to countersinking the holes on the tank attach bracket. And then I noticed I had more containing to do on the wing top skin, so that the top fairing could be installed.
I brought all my countersinking, drilling, dimpling and riveting equipment to the hangar today and knocked it out. The countersinks are a little tricky because the nut plates are already installed, so a #8 countersink (the correct size) doesn’t work because the pilot interferes with the nut plate threads. I used a #21 count sink bit which seemed to be just the right size to fit into the nut plates. The countersinks are fairly deep because the fairing has #8 dimples that need to nestle down into the countersinks. The aluminum stack up is several layers deep, so there is plenty of material to support the counting depth. The only tricky part was the top, inboard countersink on the tank attach bracket. This was too close to the fuselage to get the counting cage to sit vertical, let alone the drill. I rigged up a long extension, about 18 inches long, a drilled those countersinks without a cage. It was quite easy to see the depth and I just went little by little until it was done.
There are some holes that need to be match drilled, and then 3 nutplates installed on each size. I drilled, dimpled and riveted these.
I found some proseal and used it to glue down the wing spar spacers, after giving them a little shape to conform to the wing skin.
The fuel lines were next on the list. These were pre-bent by Aircraft Specialty, and they fit exactly right. The time consuming challenge was finding a way to get them into position. The line is short and quite inflexible, and the flared ends, which are easily damaged, mate to the aluminum fittings on each side.
I loosened up the fuselage side fitting so I could flex it inboard and create enough space to insert the fuel line. I had to use a wedge to push and hold the fuselage fuel line out of the way enough to insert the new line. Once the line was in position, I torqued everything up and it all looked good.
Not much progress this week. I focused on switching out the connectors for the landing lights, and then installing the landing light lenses.
The original landing light wiring setup used molex connectors for the three wires providing power and ground to the Landing and Taxi lights. I was never very happy with the crimps on the wires, the poor connection, and the awkward angle of the wiring entering the molex connector.
I decided to replace them with DTM connectors, and re-route the wiring. DTM connectors provide better wire support, are water resistant, and have a much more positive connection and locking mechanism.
I removed the landing light clusters from both wings, brought them home and switched to DTM 3-wire connectors. Once I had them re-installed in the wings, I tested the lights and then installed the landing light lenses. The wiring setup is much more robust now, and I’m sure it will work out well.
I spent some time on the wing root fairings. Each fairing consist of two parts, an upper and a lower fairing. The upper is thicker and covers the area from the flap to just forward of the main wing spar. This is designed to be walked on when entering and existing the cabin. The lower fairing is thinner and longer, and covers the bottom of the wing, and wraps around the leading edge. Forming the curve around the leading edge was a bit time consuming. The plans explain the initial bend, which is easy enough, but then some careful manipulation by hand is needed to get the final shape. It took an hour or so to get the curve right on both sides.
There are a few more steps to finish these fairings, including riveting on a series of stiffeners.
I didn’t have much time this week, but I was able to get the trim system working correctly.
Using the laptop and a long Ethernet cable I was able to use the VPX configurator tool on my laptop to send power to the trim motors. I was pleasantly surprised that both the roll and pitch servos worked correctly. I carefully verified that the orientation was correct. It would be easy to reverse either one. For example, the elevator trim tab moves up and down just like the elevator, but it has the opposite effect from the elevator itself. Pitching “up” causes the elevator trailing edge to move up. Trimming “up” causes the elevator trim tab to move down, not up. It moves opposite the elevator, providing a force that moves the elevator to change the aircraft’s pitch.
After confirming the motors were working, I was able to set the correct max, min, and midpoint settings for both servos.
I then worked on mounting the aileron trim brackets on the right wing aileron pushrod. These connect the springs from the servo control arm to the pushrod, actuating the aileron.
