Cooling Flap

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

Dip stick

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

Shortening control sticks

Over the last two days, my dad and I worked on solving two problems with the control sticks. 1. shortening the control sticks to prevent contact with the panel when full forward, and 2. modifying the passenger-side wiring to avoid interference with the structure around the stick.

When I first installed the sticks I didn’t have the panel installed, and wasn’t sure how much clearance they would have. With the panel installed, the stick grips were hitting the bevel on the bottom edge of the screens, and the flap switch. We took the sticks out, removed the grips, cut away the sleeve, shortened the stick about 1.5 inches, installed a new sleeve, then reinstalled the sticks. Of course we started with just the passenger side, got the dimensions just right, then copied for the pilot side.

On the passenger side wiring, we removed the bulky connector I had fabricated, and just went with d-sub pins isolated with heat-shrink tubing. This is the same approach as the pilot side. There is a risk of the connectors pulling apart over time, but the multiple layers of tubing will help. I’ll also be zip-tying each side of the connectors to the stick to reduce strain.

Removing the stick will still be possible, but not recommended except for maintenance.

I plan to install a switch on the passenger side ground wire so I can deactivate the stick buttons and switches as needed.

Passenger side showing the new wiring configuration.
Full forward stick position clears the panel
Full forward stick clearance

Seat ramps

Tonight I torqued up 4 bolts that had been installed as part of the quick build but not torqued. This had been on the to-do list for a while, but I decided to do it now so I could install the seat ramps.

Bigger picture, I’m gearing up for a first power-up of the instrument panel. For the next few tasks I’ll be in and out of the cockpit, so I want the seat ramps installed to reduce risk of bending or dinging any of the internal structure.

Once the bolts were torqued I installed the seat ramps. There’s a slight alignment issue with one of the screw holes near the seatbelt, so I’ll have to look at that at some point. These ramps will be coming out again at least a few more times, to install the seatbelts, to connect wing systems, and to troubleshoot problems.

Bolt torqued, but not yet torque sealed
Second bolt torqued and waiting torque seal
Seat ramps installed
Pilot side seat ramp showing the alignment issue

Shoulder harness cables and engine unboxing

Tonight I spent a few minutes installing the seatbelt shoulder harness cables. These mount to the seatbelt lugs, which are located at the baggage area rear bulkhead. The cables protrude forward and allow a seatbelt shoulder harness to attach at a location just behind the seats. Small job, but needs to be done.

Then I decided to finally open up the engine box. This has been sitting unopened since the engine arrived in January. It was exciting to see the engine, if only the top portion. I took out the documentation and spent time reading through it.

Top of the engine. It’s wrapped in plastic and encased in foam to keep to protected. inside, it has preservative oil to prevent corrosion while it sits waiting to be run.
The seat belt shoulder cables
Selfie, for fun

Cowl flap assembly

Tonight I only had a few minutes to work on the plane, so I bolted the flap door assembly to the tunnel cover. It was fun to play with the flap door mechanism, and once again admire the precision of these pre-punched parts.

Flap door sitting inside the tunnel cover. This whole assembly is screwed onto the bottom of the fuselage immediately behind the cowling

Cowl flap

With guidance from Vans, I trimmed about 1/16th off the leading edge of the cable clamp bracket, then primed it., match drilled it, and riveted into place.

A small notch was needed to obtain sufficient clearance
Bracket riveted into place

Cowl flap

Tonight I fixed the two challenging nut plates, and then cleaned and installed tape on the sides of the exit door. I tried to install the cable support assembly, but ran into an interference issue with the engine mount.

I ended up not replacing the nut plates. I was able to eventually work a screw into one hole, which seemed to clear it, and subsequent screw installations were fine. In the other hole I used a tap to just start a thread, maybe 2-3 rotations, and that was sufficient to allow the screw to go in.

The tape on the exit door was trivial to install, although I found it harder to cut cleanly than I would have liked. I may have to finesse it a little when the time comes to install it for the final time.

The problem that stumped me was the interference between the engine mount and the cable support assembly. I emailed Vans to see if I can safely trim the support to create some clearance between the two. The holes are pre-punched, and the parts are all pre-formed at the factory, so it’s weird that they don’t fit well together. I would need to remove about 1/32 or 1/16 to allow the cable support bracket to clear the engine mount.

UHMW tape installed on one side of the exit door assembly
In the bottom center of this image, you can see the cable support bracket contacting the edge of the engine mount.

Cowl flap

Today I installed the panel that covers the exhaust channel, and match drilled the 4 holes along the forward edge.

I was able to easily install screws in 8 of the 10 nut plates, but 2 of them are refusing to accept screws. The 2 nut plates are slightly misaligned, so I’ll need to remove them and re-install them. The aft-most nut plate will be the hardest to remove as it’s underneath the seat and the seat ribs will make access particularly challenging. Just one more job for the to-do list.

Offending nut plate holes circled in red. Match-drilled holes visible along the forward edge.

In other news, the firewall forward kit arrived today. The only thing missing is the exhaust, which is on backorder with a 4-6 week delivery estimate. That’s fine, as I have everything I need to get the engine ready to be hung.

Cowl flap

Today I countersunk the cowl flap and riveted together the flap unit. Everything was straightforward except one rivet that was repeatedly problematic. The rivet tipped 3 times, and each time I removed it, before I was finally able to set it. Even the last time I set the rivet it tipped over, but I decided it was good enough.

Countersinking the flap