Prior to starting on riveting the fuselage understructure together, I had to finish riveting the previously modified fuel selector mount to the tunnel ribs, as I would soon lose easy access to the tunnel without climbing in to the fuselage.
The 3 rivets on each side of the tunnel had to be bucked, with the two forward most rivets being fairly easy. However, the aft most rivet close to the F-01043B forward fuselage bulkheads had limited space to fit a standard mushroom head rivet set. I instead had to carefully buck these using a flat offset suicide set.
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| Fuel selector mount riveted to the tunnel |
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| I was happy with how the shop heads came out, even on the aft most rivet where I had used a flat "suicide" set |
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| Offset "suicide" set wrapped in duct tape to prevent damage to adjacent parts while riveting |
Next, I was ready to start riveting the rest of the fuselage understructure together. This starts at the rear of the fuselage with the seat back brace, gussets and baggage door seal angle. Most rivets were easily set with the pneumatic squeezer, with only a couple having to be bucked close to the F-1034C bulkheads.
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| Seat back brace riveted to F-1034C-L bulkhead |
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| Shop heads uniformly squeezed |
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| Seat back brace riveted to F-1034C-R bulkhead |
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| Pneumatic squeezer made simple work of these |
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| Seat back brace ready for riveting to gussets and aft longerons |
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| Longeron rivets set into the left gusset and baggage door seal angles. Note the two holes left open for hinge frame attachment later |
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| One again the pneumatic squeezer made quick and easy work of the rivets along the longeron |
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| Right side longeron rivets set through the gusset and seat back brace. The rivet that lies close to the web of the F-1034C bulkheads had to be bucked |
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| Seat back brace and gusset fully riveted in |
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| Bucked shop head looking good on the left... |
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| ...and on the right |
I then riveted the aft longerons to the F-1005E gussets. All rivets were squeezed except for the forward most rivet, which once again was easily bucked.
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| Left longeron riveted to gusset |
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| All shop heads turned out well |
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Right longeron riveted to gusset
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| Aft longeron to gusset riveting complete |
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| Aft fuselage understructure riveting done |
Next it was time to start riveting the upper and lower fuse channels to the understructure, specifically the upper and lower firewall brackets. I had read that this can be somewhat difficult due to limited clearance and awkward angles in reaching some of the rivets.
I started by riveting the top flange of the upper firewall brackets to the top flanges of the F-1040 upper fuse channels. I was able to squeeze all of these fairly easily, but had to use the 4" no hole yoke to reach the four fwd most rivets due to the extended flange of the F-1001B firewall upper angle.
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| Riveting the forward most rivets on the upper flange of upper firewall brackets using a 4" no hole yoke |
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| Upper flange rivets all set... |
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| and shop heads turned out well on the left... |
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| ...including those aft of the firewall bracket |
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| Same riveting result on the right... |
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| ... with squeezed shop heads all looking even |
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| Clearer view of the firewall bracket shop heads on the upper right firewall bracket top flange |
I then worked on riveting the bottom flange of the upper firewall brackets. I was again able to use the pneumatic squeezer to set the aft most five rivets on each side, but then had to resort to bucking the remaining rivets due to the F-1001J longeron gussets getting in the way.
Riveting these upside down was hard, but with the cutouts I had previously made in the firewall side channels, I was able to use a long straight rivet set, rather than an offset rivet set, which provided for some additional stability while running the rivet gun.
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| Riveting the forward most rivets on the lower flange of the upper firewall brackets. I had to keep firm pressure while running the rivet gun to avoid it slipping off the rivet head due to the awkwardness of operating the rivet gun upside down |
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| Upper firewall bracket, lower flange rivets all set. There was one rivet head that received a couple of minor smilies due to the rivet gun slipping while riveting, but it was not worth replacing and I covered it later with primer |
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| Left side lower flange rivet shop heads all look great |
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| Right side upper bracket, lower flange rivets all set well... |
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| ...and shop heads all meet spec |
With the upper firewall bracket flanges riveted to the upper fuse channels, I then started on the top side of the lower firewall bracket flanges to lower fuse channels. I was again able to pneumatically squeeze the seven aft most rivets on each side easily, but then used the Main Squeeze to set the two forward most rivets on each side
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| Using the Main Squeeze to set the two forward most rivets on each side of the lower firewall bracket top flange. The squeezers narrow body allows it to fit right up agains the firewall. Both left and right sides turned out well |
Only the lower flanges on the lower firewall brackets remained to be riveted. I didn't want to buck any of these as I had done on the lower flanges of the upper firewall brackets, due to having to buck upside down close to the ground. Instead, I was able to use the Main Squeeze again with the 3" yoke to set all of these rivets with great success. I had initially tried using a 1" no hole yoke with the Main Squeeze for some, but had a couple of rivets start to lean slightly while squeezing (probably due to the throat of the 1" yoke contacting the lower fuse channel flange), but once I switched to the 3" yoke I no longer had any issues.
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| Using the Main Squeeze and a 3" yoke to set rivets along the lower flange of the lower firewall bracket |
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| Left side rivet heads all look good and tight |
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| ... and shop head came out great |
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| Right side rivet heads also sit well... |
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| ... and shop heads are all within spec (note the 3rd and 4th rivets from the front that leaned slightly, but shop head size and thickness is good) |
The last few remaining steps involved in riveting together the fuselage understructure include
- riveting the F-1013 longerons to the firewall gussets
- riveting the upper flange of the upper fuse channels to the F-1042 gussets and bulkhead side channels
- riveting the lower tab on the F-01002 bulkheads to the upper flange of the lower fuse channels
These were all handled with the pneumatic squeezer, except for
- the forward most rivet from the firewall gusset into the F-1013 longeron. This requires the shop head to be on the top, and the Main Squeeze manual squeezer made easy work of this
- the tab on the F-01002 bulkheads which were easily bucked using an offset rivet set
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| Fuse channel flange riveting complete... |
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| ...and F-1013 longerons inserted into the fuse structure |
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| A check of the fuselage understructure shape and it looks good as it curves aft |
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| Squeezing rivets from the F-1013 longeron into the firewall gusset. Here the Main Squuze was used to set the forward most rivet with the manufactured head at the bottom |
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| Longeron to firewall gusset rivets all set |
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| From below all shop heads and the lone manufactured head look good |
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| Longeron to firewall gusset rivets also set on the right side |
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| F-1042 gusset rivets set into the upper flange of the upper fuse channel |
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| From below, the aft most gusset rivet is close to the nutplate, but still far enough to comfortably rivet with the pneumatic squeezer |
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| Gusset to fuse channel rivets also set on the right side... |
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| ...and from below where shop heads for the 2 rivets from the F-1042 bulkhead side channel into the gussets can be seen. These were easily squeezed as well. |
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| Using an offset rivet set to buck the rivet from the F-01002 bulkhead tab into the lower fuse channel |
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| Tab rivet looking good |
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| While riveting these tabs, I made sure that the row of rivet holes along the outer flange of the F-01002 bulkhead were in a straight line to avoid any issues attaching the forward fuselage skin later. This sets the angle of the single tab flange on the lower fuse channel for riveting. |
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| Understructure riveting complete and ready for the skins |
Next up will be riveting the fuse side skins to the understructure.
Build Hints
- The following worked well for me to set firewall bracket flange to fuse channel rivets
- Upper firewall bracket, upper flange - all set with pneumatic squeezer with either 3", or 4" no hole yoke (with a 1/2" height 1/8" cup set)
- Upper firewall bracket, lower flange - 4 aft rivets set with pneumatic squeezer, middle rivet set with Main Squeeze, 4 fwd most rivets bucked using a long straight set
- Lower firewall bracket, upper flange - 7 aft rivets set with pneumatic squeezer, 2 fwd most rivets set with Main Squeeze
- Lower firewall bracket, lower flange - all rivets set with Main Squeeze and 3" yoke (with a 1/2" height 1/8" cup set)
- When riveting the single tab on the F-01002 bulkhead into the lower fuse channel, first make sure that the row of rivet holes in the F-01002 lies in a straight line. This will help avoid skin hole alignment issues later
Fuse Side Skins Time Taken: 7.6 hours
Dates: September 13 2025 - September 19 2025
Fuse Side Skins Total Time: 72.1 hours
RV-10 Build Total Time: 1158.6 hours
Priming Total Time: 142.6 hours (not included in build time totals)
