Conduit Routing - Baggage and Rear Seat area

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Prior to closing out the baggage and rear seat floors, I gave a lot of thought to routing of wiring and cables that would need to pass from the tail cone forward toward the firewall. 

As I don't currently have a full picture of the specific wiring that I will need to run, I decided to do what many other builders have done, and run several conduits under the floors through which I will later be able to fish wire bundles.

I started planning the conduit runs by first making sure that any potential obstacles were accounted for. I also wanted to avoid cutting additional holes through the bulkheads wherever possible, and luckily there are several existing lightning holes through which conduits can pass.

The storage bins I am installing in the baggage area make it difficult to run conduit down the central channels. There is, however, adequate space in the outboard channels

Initial plan is to run 3 3/4" conduits down each side of the cabin, with two coming up through each rear seat floor, and a single conduit exiting the rear spar bulkhead on each side. This will give me several options for wiring, and ensure that I can keep any data/signal wiring adequately separated from power wiring

At the rear of the cabin, the conduits will exit the F-1006B fuselage bulkhead through the outboard lightning holes, with 3 conduits passing through each hole. To support the conduits as they exit, I 3D printed brackets that are riveted to the bulkhead. Zip ties are then used to secure the conduits to the brackets.
Van's Conduit Lightening Hole Mount Extended - 1 conduit
Van's Conduit Lightening Hole Mount - 2 conduits


Conduit brackets riveted to the F-1006B fuselage bulkhead using LP4-3 blind rivets. These support 2 conduits at the bottom which run up through the rear seat floors, and 1 conduit at the top which runs forward through the F-1005A rear spar bulkhead

MS22529/2-1R grommet edging was placed around each lightning hole through which conduit, cable or wiring passes to prevent chafing

Grommet was secured with a dab of #732 RTV

Where the single conduit has to pass through the F-1034A fuselage bulkhead on its way to the rear spar bulkhead, I decided to use a bracket designed by Allen Glen to secure it. I 3D printed 4 of these (2 on each side) and secured it using LP4-3 blind rivets and backup washers.

Single conduit fed through 3D printed bracket

All conduits run under the steps and will be zip-tied to the steps to ensure they are secure

The conduits are supported under the baggage area floor with 3D printed brackets that are epoxied to the bottom skin.
Marking out the locations on the bottom skin where I will remove primer and epoxy the brackets

Primer removed and ready to bond the brackets

I applied 3M 2216 epoxy adhesive to the brackets and put them in place to cure for a few days

Conduit support brackets attached under the baggage floors. I also put self fusing silicone tape around the conduits where they passed through lightning holes and under the steps for additional protection from chafing

The two conduits coming up through the rear seat floors end just after passing through the F-1005C bulkhead side channels. I 3D printed additional support brackets to hold these conduits in place as they pass through lightning holes in the side channels.
Conduit brackets riveted to the F-1005C bulkhead side channels (2 on each side)

For the single conduit exiting through the rear spar bulkhead, I used 1/2" ENT threaded male adapters which fit over the conduit, and 3/4" threaded bushings that attach to those adapters to secure them to the rear spar bulkhead. 

I did also 3D print an insert that snaps into the ENT adapters which helps to secure the conduits even more firmly so there is no danger of the conduit sliding out over time.

I used a hole punch to make a 1" hole on each side of the rear spar bulkhead

Hole centered between rib and seatbelt attach point

Insert snapped into ENT adapter and conduit pushed in

Bushing threaded onto adapter from the front. I did have to cut away some threads from the ENT adapter to allow the threaded bushing to tighten up adequately

I blew nylon string (using a shop vac) through the conduit that can later be used to pull wires through. I also secured the adapter and bushing with some RTV and used torque seal to allow me to detect any unwanted rotation in the bushing in the future

I also put silicone tape around the ENT adapter behind the rear spar bulkhead. This also helps hold the conduit in place

With all the conduits in place, I finished up adding zip ties and silicone tape where needed and moved onto routing battery and coax cables which I will go over in subsequent posts.

Final conduit routing down the left side of the cabin. At this point I had already started working on battery cable and COM antenna coax routing

Final conduit routing down the right side of the cabin

Conduits zip tied to the brackets at the rear fuselage bulkhead as the wiring enters the tail cone. A pull string was blown through each conduit to facilitate pulling wires later

Conduits zip tied to the step, and self fusing silicone tape added under the step for additional protection

Conduits ending at the bulkhead side channel. These will be zip tied later so that I can move them out of the way in the meantime as needed

Conduits under the right rear seat floor as they exit the rib and pass up through the floor

With the rear seat floor in place, the conduits come up through the floor and will be hidden behind the side panel

A clearer view of the conduits running under the rear seat floor. With the floor pulled away, the conduits exit the F-1034A bulkhead, bend around through the rib and then up through the rear seat floor

Grip lock zip ties were used to secure conduits to the brackets at the rear fuselage bulkhead

Conduits under the left rear seat floor as they exit the rib and pass up through the floor. The cable running along the bottom is the 2AWG positive battery cable whose routing I will discuss in the next post


Dates:    February 23 - May 1 2026