SECTION 28: FWD FUSE RIBS, BHDS & BOTTOM SKIN
Build Instruction Updates
Page 28-2
Step 2 requires "Final-Drill #19, #30, and #40 all holes in the flanges of the attach angles that mate to the fwd fuselage ribs." and show the image of a nut plate on the flange that mates to the fwd fuselage rib. However, the kit does not have any provision for this nut plate in the attach angle, nor in the fwd fuselage rib (see photo)
Further searching on Vansairforce (link) indicates that this nut plate was previously used to hold adel clamps for the fuel lines, but are not required in the newer kits.
Check for more recent updates here
Page 28-3
Step 3: In section 29, page 29-14, step 9, you will be instructed to machine countersink the outboard #40 holes on the flanges of the F-01042-L-1 and F-01042-R-1 Bulkhead Side Channels. If your kit is newer and has final-sized holes, you will not need to final-drill these holes between now and then. Consider countersinking these #40 holes now as it is somewhat easier than doing it after it has been riveted to the fuselage. They should be flush on the outside and should accommodate an AN3 rivet with a 0.032 skin.
Page 28-5
Plans call for installation of the VA-188 Flo-Scan Mount Bracket to be installed in the tunnel location. This bracket is to be used for the Flo-Scan as well as for the FT-60 'Red Cube' fuel flow transducer. The positioning in the tunnel (between the electrical fuel pump and the engine-driven pump on the engine side of the firewall) is contrary to the installation instructions for the FT-60. See Vansairforce threads on this topic for alternative locations (link and link).
Page 28-8
Step 1: In section 29, page 29-14, step 9, you will be instructed to machine countersink all the #40 holes in the F-01004K-L-1 and F-01004K-R-1 Center Section Side Plates. If your kit is newer and has final-sized holes you will not need to final-drill any of these holes later, so consider countersinking now.
It's definitely more difficult to do that once it is partially riveted in place and the main spar and temporary wing bolts are in the way. Consider machine countersinking all of the #40 holes now. They should be flush on the outside and should accommodate an AN3 rivet with a 0.032 skin. Do not countersink the #30 holes, however.
Page 28-10
Step 6: On the version of the plans published 01/07/21 figure 1, there are three rivets called out to be countersunk for an AN426AD4 rivet - the top row of rivets attaching the forward seat supports to the fwd fuselage bulkhead. In fact, all four of the top row of rivets holding the forward seat supports should be countersunk. The F-01043D cover panel lays across all of those rivets and a universal head would cause a bulge. Verified w/ Vans Support 2/14/2023.
Note: I managed to miss the fact that the K1000-3 nutplate is on the opposite side of the F-1043A bulkheads than all of the other nutplates. It's obvious in Figure 1 but just double-check when doing the countersinking.
Step 10: The plans omit telling you to dimple the bottom flanges of the F-1048-L/R forward fuse ribs. Consider doing it at this step.
Page 28-11
Step 5: On the version of the plans dated 01/07/21, the rivet callouts in figure 2 to attach the inboard and outboard forward seat supports to the fwd fuselage bulkhead don't add up to equal the number of holes joining the parts. The top row should be AN426AD4-5 qty 4 (NOT 6 + 6), and the bottom two rows should be AN470AD4-5 qty 8 (this is correct, albeit labelled poorly). The third row is left open to attach the fwd floor in a later chapter. Verified w/ Vans Support 2/14/2023.
Page 28-12
Figure 2: Note that the 7 rivets on each side of the bottom skin must be double flush. This means you have to countersink the shop head side of the main spar so that when they are driven, the shop head sits flush into the spar. The landing gear steel piece sits on top of this area, and the shop head of the rivet will interfere with it if it's not flush.
Page 28-13
Step 2: I can't find any reference to it in this section or Section 27, but you'll want to dimple the #40 holes on the bottom flange of the firewall since the skin is also dimpled and the instructions call out for countersunk rivets. Step 2: Before riveting the F-1048 L and R Fwd Fuselage Ribs to the bottom skin, you need to ensure you've dimpled the 8 holes (4L and 4R) for the Vent DL-10 2.4 Flanged Ducts. These are installed on as per page 36-4 using CS4-4 rivets, but the plans omit instructions to create the dimples until too late. Ref on VAF here
Page 28-14
Step 7: Check the threads shown. The 3 upper AN3-6A bolts might need two washers to show 3 threads out the nut.