Saturday, April 19, 2014

Installing WH-00046 Wiring Harnesses Begins

A productive day in the shop for a change … amazing how motivating good weather can be. The finishing touches were performed on the F-1202B instrument panel base. The remaining four nutplates were installed and the two WD-1204 engine mount brackets were match drilled then riveted in place.

I noticed a small issue with rivet holes used to attach the four nutplates onto the web of the F-1202B instrument panel base. The rivet holes for these nutplates are dimpled at the factory and in my opinion, not dimpled deep enough. Frequent readers may also remember this issue was also noticed on the firewall shelf. Fortunately, I still have the C-frame I borrowed from Pete after he finished building his RV-9A, so dimpling the holes again was an easy task. (Thanks again Pete … you will be getting it back real soon).
The CCR-264SS-3-2 pop rivets Vans would have the builder install is on the left and the AN426AD3-3.5 I’m using on the right. Note the existing dimples are so shallow even the CCR-264SS-3-2 rivet sits a little proud.
Using the C-frame outfitted with 3/32" 100 degree dimple dies to tweak the existing dimples in the nutplate rivet holes in the instrument panel base for a better fit.

Those builders building E-LSA will need to disregard this next step. Personally, I don’t like using the CCR-264SS-3-2 rivets unless there is no other way. The F-1202B lends itself well for back riveting the four nutplates … so that is what I did using a rivet gun, back riveting plate and AN426AD3-3.5 solid rivets. The back riveting plate was covered in shipping paper to prevent scratching the primer and riveting tape was used to hold the rivets in place when the panel base was flipped upside down. Turned out looking great!
Riveting one of the four nutplates that get installed on the web of the instrument panel base.
All four nutplates back riveted onto the F-1202B instrument panel base with AN426AD3-3.5 solid rivets.

The F-1202B instrument panel base is the attachment point for the two WD-1204 upper motor mounts. The motor mounts were secured onto the instrument panel base, all rivet holes match drilled, removed for deburring, and then riveted onto the F-1202B instrument panel base. Rivet holes on the forward edge are not riveted at this time.
Match drilling the F-1202B instrument panel base’s forward flange to one of the WD-1204 engine mounts.
Match drilling the F-1202B instrument panel base's web to one of the WD-1204 engine mount brackets.
Riveting the WD-1204 engine mounts onto the F-1202B instrument panel base with LP4-3 pop rivets.
WD-1204 engine mount brackets riveted in place on the F-1202B instrument panel base.

After studying the plans, decided I could hold off on riveting the F-1202B instrument panel base and move forward running the wiring harnesses. Just in case there is an issue, will not be placing the terminations or connectors on the wires at this time (just in case they need to be removed) until the rudder pedals are installed and the panel base has been successfully match drilled into the longerons.

One of the main reasons for holding off putting the side skins on and wanting to continue with running the wiring is because the plan is to install a backup airspeed indicator and altimeter so there is instrumentation to fall back on should the Dynon SkyView have a major malfunction. A static line will be required for the backup instruments, so I need to find a good routing location to run the static line from the tail cone up to the instrument panel. However, at this point not sure if there will be room in the existing wire grommets once all the wiring is in place ... so plan to fill them up now and determine if there is enough room left for a static line.

A while back, all the coax cables with BNC connectors were run through the grommets. The next item to be installed is the WH-00046 fuselage wiring harness. Following a builders tip from the forums, prior to installing the WH-00046 wiring harness, every location that has a lose wire or connector pins was wrapped with tape to prevent the lose wires from snagging while pulling the wires through the wire run grommets. A close look at the following photo one can see various locations on the wire harness have blue tape.
Slowly working the WH-00046 fuselage wiring harness through the wire run grommets in the RV-12’s center tunnel.