SECTION 25: MID FUSE BULKHEADS

Build Instruction Updates

• 01/07/21 25_10.pdf

Check for more recent updates here

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F-1004C-L and F1004C-R

Conduit Summary

The holes in the bulkheads are only big enough to have cables run directly through them using snap bushings (vs. in a conduit). Also, there are only two holes on each side and depending on your needs, you need more.
You do need conduits for sure but only to tunnel underneath the baggage compartment. You can go back to snap bushings forward of the baggage compartment if you like. Some people though like to just run at least some of the conduits all the way from the tailcone to the front. Now that is where the diameter needs to increase from .75 to at least .77 for Van's Nylon conduits. It is a pain to enlarge those holes afterwards since they are tucked in underneath horizontally-running structures. Adding more holes can be done later but is also a bit easer if the bulkheads aren't in the plane yet. If you run conduits all the way from the back to the front, it will be easy to route the static pitot tube, the pitch and yaw servo cabling, the pitch trim servo cable, the battery cables etc. Also makes cabling for later add-ons easy.

Hints

Step 8 details the assembly of the bulkheads to the center section prior to deburring and priming these parts. Now is a very good time to consider whether you will need additional pass-through holes in the bulkheads for items like conduit, pitot, static, and AoA sensor tubing, air conditioning lines, and other electrical circuits. Many builders find that the two holes referenced here and on #PAGE 25-4 are insufficient for all of the required lines and circuits for an RV-10, especially if it is going to have a full glass panel and backup/redundant electrical systems.

Do yourself a favor and read forward in the plans to Sections 29 and OP-37 (even if you do not use the Van's provided wiring harness, OP-37 is very useful in understanding the options for routing electrical circuits).

Later in the build, especially after the side skins are installed, it is quite difficult and awkward to cut new holes for conduit or other pass-throughs. Installing caterpillar or snap bushings can be awkward later, too. You will save considerable time later by thinking ahead at this point.

See also Section 26 where the F-1017 under-seat ribs can be much more easily modified before installation to allow conduit and antenna installation, which might not be done until Section 35 or later.

ENSURE that any additional holes you cut in the bulkheads are properly spaced and, if needed, reinforced per the guidelines in AC43.13.

See also this FB thread on the subject.
See also this FB thread on the subject.

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• Step 6
  Step 6 requires you to 'Rivet the Mid Seat Rail Support Subassemblies, F-1004C-L and -R Center Section Bulkheads and F-1004N Stiffener Angles to the F-1004A Center Section Bulkhead per the callouts in Figure 2.' Figure 2 in the plans (Rev 1 Date 1/7/21) omits the quantity and rivets to be used. The older plans (Rev 0 Date 7/24/14) shows the rivets and places.
• Step 7
  Don't insert the snap bushings instead widen the two holes to a bit larger than .75 inches (.77) so they can pass through Van's conduit later. Also drill a third / forth hole with same diameter underneath the two holes for a more conduits if desired.

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• Step 7: Check that F-1004J has the correct length and is not pushing the spar caps out of their proper position where the wing attach bolt holes no longer line up through all layers. See also this FB Post 2/2024.

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• Step 4
  Don't insert the snap bushings instead widen the two holes to a bit larger than .75 inches (.77) so they can pass through Van's conduit later. Also drill a third and forth hole with same diameter underneath the two holes for more conduits.

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• Enlarge the two holes at the lower corners of F-1005A to a bit larger than .75 inches (.77) so they can pass through Van's conduit later

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• Enlarge the two holes at the lower corners of F-1034A to a bit larger than .75 inches (.77) so they can pass through Van's conduit later