Cooling Flap

Posted on by Neal

With the oil cooler in place, and the cowling holes drilled, I was able to final install the cooling flap, and hook up the control cable.

I found the screws and mounted the cooling flap assembly to the bottom of the fuselage. In the process I noticed a series of 4 pre-drilled holes in the bottom of the fuselage that I’ll need to investigate and probably fill. Two of them look like a spare antenna mount, and the other two could be drain holes.

Once the flap was in position I hooked up the control. It was a little fiddly to get it just right, but in the end it worked out ok. The flap closes and leaves a small cushion gap per the plans, and it operates very smoothly.

After I finished I noticed that the plans call for washes under the screws that hold the cooling flap in position. They aren’t mentioned earlier in the plans when initially test fitting the cooling flap assembly, so I hadn’t noticed them at first. I’ll have to find the washes and install them later.

Cooling flap assembly installed and taped down at the back end
Threading the control cable through the drilled bolt that acts as the pivot point for the flap door control
Cushion gap on the control
Control fully retarded to open the flap
Flap fully deployed
End of the cable after setting the length and bending and trimming the control cable
Safety wire over this clamp

Oil Cooler Install

Posted on by Neal

Today I worked on installing the oil cooler. I was able to get it done, but I did run into some problems. The biggest issue was that the plans called for a 60 degree clocking of one of the fluid fittings on the oil cooler. But this angle had it pointed directly at the scat tubing for the cabin heat. There was no way the oil line would have fit, and access to the fitting was limited. Unfortunately I didn’t realize this issue until I had already set the RTV and installed the air inlet. My choices were to either remove the oil cooler and the fluid fitting then reinstall at a different angle, or move the scat hose out of the way. I decided to try to move the scat hose and the related assembly to make room for the oil line. This seemed less disruptive than removing the oil cooler and redoing the RTV.

In the end I was able to move the scat hose just a little, and while it was disconnected I hooked up the oil line. Once the oil line was routed to the engine, it bent away from the scat hose just enough to make it work out.

Torquing the b-nuts on the fluid fittings was challenging, as I had to use a crow foot to apply torque. I used a wrench to hold the fluid fittings while torquing the b-nuts to avoid applying excessive torque to the oil cooler.

In the end I’m pretty happy with how it turned out.

The air inlet. The large bead of red RTV in the foreground squeezed out once I torqued the bolts. It was subsequently removed leaving that row of veins unobstructed.
The fluid fitting in the top of the picture is oriented to be pointed directly at the scat tube. I had to move the scat tube out of the way to allow the oil line to fit
Looking up after moving the scat tube. The fluid fitting is visible in the background, just to the right of the scat tube. This was enough to allow the oil line to sneak past the scat tube.
The oil line connected and torqued
The other oil line connected and torqued
One of the oil lines where it connects to the engine. In the background is a rats nest of wiring, something I’m looking forward to tidying up soon.
Looking down, both oil lines are visible, either side of the oil filter. The red cap in the foreground is the last port that needs a fitting. This is an unused tach port, and I need to order a cap to go over it.

Oil Cooler Fittings and Seals

Posted on by Neal

Tonight I installed the two fluid fittings on the oil cooler, and the two rubber seals which will sit between the oil cooler and the air inlet.

The fluid fittings were easy enough. Vans published a video of this procedure, highlighting the need to use two wrenches to avoid torquing (and cracking) the oil cooler. The cooler is made of fairly soft aluminum, and cannot handle the torque needed to seat the fluid fittings. There have been cases of oil coolers failing in flight, and even a recall on a batch of coolers (mine is not affected).

I followed the video, measured the clocking angle, and installed the two fittings.

Then I proceeded to apply silicone adhesive to the sides of the top of the cooler, and followed the instructions to glue down the two seals.

I also spent time filling in the remaining gaps on the inlet where I missed a spot or two when applying RTV last night.

Oil cooler
Installing the first fluid fittings
Both fittings installed. Note the two wrenches used, one to hold the nut on the cooler, and one to torque the fitting
Beds of silicone adhesive applied
Seals glued down
Close up of the left hand seal

Bottom Cowl Screws

Posted on by Neal

Tonight I finished a job on the cowling, locating and drilling the screw attach points on the trailing edge. There are a total of 8 holes, 4 in the middle section, and two more on each side. There’s a template supplied for the outboard holes, so I made the template and drilled those outboard holes, then attached the heat flap to locate the 4 center holes.

I was careful to not drill into the nut plates, which would cause them to lose their ability to hold the screws.

Making the template. Simple cutting a part into two and using one half
Template taped into position.
Template taped into position
Heat flap temporarily installed overlapping the cowling. This gave me the locations for the 4 holes in the cowling. When finally installed, the heat flap goes under the cowling.

Dip stick

Posted on by Neal

Tonight I installed the dipstick on the engine. Just a few minutes of work to screw it into place, I still need to torque this and safety wire it, but I don’t have a big enough crow foot to complete the task.

Plastic cap removed
I used food grade anti seize per the engine manual
Screwed into position

Control cables

Posted on by Neal

Today I was able to spend a few hours working on the airplane. I managed to get all of the control cables installed and routed. I appear to have a control interference issue between the pilot stick and the throttle, and looks like I need to remove half an inch off of the left control stick. However, I need to measure the amount of throw in the aileron pushrods, because it might be that the stick can’t actually move that far horizontally before the bell crank hits its limit.

I was able to connect the prop and alternate air controls, and the mixture and throttle connected. I can’t connect the heat flap actuator until I finish drilling some holes in the bottom cowling.

The routing through the wiring under the panel worked out ok. The prop control was just barely long enough, but I think it’ll work ok. I have loosely connected it for now to ensure I have the right length and throw on the lever. The alt air works great, and the mod from aircraft specialties, allowing the door to open and close, is a nice upgrade.

Controls
Controls
Throttle cushion gap. This is a larger gap than is called for, but I can’t get anything less than this without it being too small of a gap
Behind the control bracket
Under the panel. In the top right you can see the somewhat messy routing of control cables through (actually above) the wiring bundles
Heat flap control
Throttle cable attach. Blue tape indicating this is not final torqued
Mixture control
Throttle and mixture controls

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