Control Cable Bracket

Posted on by Neal

Tonight I started working on the control cables. Vans sent me the correct control cable bracket, which has an extra hole for the cooling flap, and a redesigned layout. It’s made from slightly thicker material and feels solid. I was able to prime it yesterday, so I mounted it tonight. I also trimmed the alt air cable and the cooling flap cable. The cooling flap cable has a push-button release mechanism, which uses a small ball bearing to create the friction necessary to hold the cable in whatever position it’s set. The instructions have you pull the knob out 6 inches, then cut the end of the cable. At about 5 inches, the ball bearing is exposed and falls out if you aren’t careful. I noticed this and put the parts into a zip lock bag while I trimmed the cable, then reinstalled it. It would be a major pain in the butt if the ball bearing fell out onto the floor, I would never find it!

The cabling under the panel is going to present a challenge for routing these control cables, but I plan to pass each cable between the cable bundles and the mounting frame I built forward of the sub panel. It should work ok, although I’m sure I’ll run into some kind of challenge.

Original bracket on the left, new one on the right
The cooling flap control. Barely visible is the small hole where the ball bearing sits, just above the “2” on the ruler.
The ball bearing, spring, and button which forms the grip mechanism inside the cooling flap control cable handle.

Engine Sensor Wiring

Posted on by Neal

Tonight I wired up the Manifold Pressure, engine oil temperature, and fuel pressure sensors. I wanted to finish the job and wire up the oil pressure sensor, but I ran out of butt splices. I tested the sensors by powering up the instrument panel and looking for signals. I was happy to see all of the gauges reporting data correctly.

I also took the opportunity to test and adjust the canopy unsafe warning. At first the canopy pins weren’t contacting the micro switch, but after a quick adjustment it now works great.

Oil temperature sensor wiring
Typical connection between sensor and wiring harness. I used butt splices because I don’t want these to come apart in-flight, and I have plenty of wire length to allow cutting and re-doing this if I even need to replace the sensor

Heat vent controls

Posted on by Neal

Tonight I installed the two heat vent cockpit controls. These are push/pull controls that are mounted on the instrument panel and open the heat vents, one pilot side, and one passenger side.

No real challenges installing these controls. I was careful to ensure I had a 1/16 cushion gap when the vents are fully closed. This will be more critical on the other controls, but it was good practice.

In the process of reading through the plans I made a couple of realizations. One is that I have the wrong version of the control mounting bracket. The version I have is labeled as the updated part number with a -1 at the end, but it’s actually the old version. I emailed Vans to confirm, hopefully I can get a new one quickly. I could just make a new one, but locating the holes would be time consuming. Unfortunately I’m blocked on the rest of the control cable install steps until I have that bracket in-hand.

The other realization is that my panel wiring harnesses are going to be interfering with the control cables. I can probably make it work, but will need to look out for chaffing problems in places where the wiring bundles and control cables are touching.

The control cable collection
Pilot side cabin heat control
Passenger side heat control
The mechanism to open and close the heat vent. These are on the firewall.
Routing of the control cable

Oil cooler

Posted on by Neal

After a 10 day work trip to India I was able to accomplish one small task tonight. I cut and deburred these spacers for the oil cooler. Right now this is about all I’m going to do with the oil cooler. I’m hoping to pick up a 3D printed oil cooler plenum to replace the standard Vans model. The 3D printed plenum will be circular to match the circular scat tube, vs. the square cornered Vans model. Based on what I’ve read and been told, there should be some improvement in oil cooling efficiency using this modified plenum. It’s currently in testing and not ready for production, but hopefully will be ready near the end of the year.

I also took a few minutes to confirm that my oil cooler serial number is not in the range impacted by the service bulletin issued earlier this year. https://www.vansaircraft.com/service-information-and-revisions/sb-00080-rev-2/

Oil cooler spacers

Manifold pressure line

Posted on by Neal

Tonight I installed the cushion clamps to secure the manifold pressure line, and the rubber hoses to route pressure to the e-mags.

I found I had to make an adjustment to the routing of the line, so I removed the engine-side connector, rerouted, then reconnected the line. That also led to moving some clamps around, but I think I have a good routing now. Once the oil cooler scat tubing is installed I may have some interference, but I’ll deal with that later.

Installing the rubber tubes was kind of a pain, as access to the mags is somewhat restricted. But I get the feeling it will be even worse when I have to do some wiring back there.

Rerouted line to work around the engine mount
The rubber hoses installed
Final routing on the left hand side

Oil Pressure and Manifold Pressure

Posted on by Neal

Tonight I installed the oil pressure sensor line, and started on another modification to move the manifold pressure sensor. This modification is courtesy of Steve at Aircraft Specialties and makes use of the unused port on the Vans bracket. It’s a more elegant solution for providing manifold pressure to the two E-mags, in my opinion.

The oil pressure line was straight forward, just connecting two fittings with a hose, and torquing the b-nuts.

The manifold pressure line was slightly more involved. First uninstalled the pressure sensor from its original location on the right side of the firewall, and reinstalled it on the left side, using the spare port. I hunted around and found a spare plug, and then installed that along with the Aircraft Specialties supplied fluid fitting. I made up the rest of the fittings, routed the lines across the engine compartment and installed the line at both ends. Now I just have to locate and install the cushion clamps to secure it in place.

Oil pressure line connected and torqued
Manifold pressure line routed across the top of the engine compartment. The two needle fittings will connect to the two e-mags using lengths of rubber hose
The lines routing to the Vans bracket
Top-down view of the Vans bracket. The fitting on the right is a straight fluid fitting, despite looking like it’s 45 degrees in this picture. Sensors from left to right: oil pressure, fuel pressure, manifold pressure

Fuel lines

Posted on by Neal

Tonight I finished installed the remaining fuel lines, torquing them and marking with torque seal. With that, the fuel system is plumbed from the wing root, through the fuselage, firewall, engine-driven fuel pump, fuel transducer, fuel control, fuel spider, and out to each injector. Once the wings are installed, the final piece is the short connection from the wing root to the fuel tank.

This felt like a bit of a milestone, so I took a selfie from under the engine.

Firewall exit. After fretting about clocking this fitting to 5 degrees, I have no idea why that clocking is even necessary. Perhaps it’s related to the EXP engine changes
Fuel pump connection
Fuel controller connection
Looking up from under the engine

CHT and EGT wiring

Posted on by Neal

Tonight I cut the EGT and CHT wiring to length and installed ring terminals on each wire. Then using the hardware from the CHT and EGT kits I connected all the wires and covered with the provided fiberglass sleeves.