In this entry I ran into a major snag on the RV-12's left wing! While attaching the nose ribs to the left main spar, the 3rd and 4th ribs (from the inboard end) didn't fit the predrilled attachment angle holes (see picture below.) These two angles had been transposed during fabrication of the spar. Van's Aircraft was very helpful and after much discussion the final solution was to remove the rib assemblies (only took 90 minutes) and take the spar back to Van's for the angles to be removed and reattached. I will add this to the Gotcha list, however I think this just a one-up event.
Builder's Note: The picture below is of the repaired left spar. These attach angles can easily be inspected by laying a straight edge along them.
Builders note: Other possible Gotcha's: First, LP4-4 rivets must be used in when riveting the ribs directly to the main spar (pictures below.) This is noted next to one of the drawing but not directly in the instructions. Second, when riveting the ribs to the attach angles the factory head should be on the rib not the attach angle.
Enough fun and gotcha's! Lets cover what went well.
Reference page 15-05
With the bottom of the W-1210 Main Ribs resting on the work surface, a weight or clamp may be applied to the aft position of the wing assembly to hold it in position for attaching the W-1208 Nose Ribs. Take care not to bend the flanges of the W-1210 Main Ribs.
Step 1: Select five of the aft trimmed W-1208-R Nose Ribs and cleco then rivet to the W-1206-L Spar Assembly attach angles starting outboard and working inboard. Rivets should be installed with the manufactured head on the nose rib.
NOTE: LP4-3 rivets should be installed with the manufactured head on the rib(not on the attach angle). Use LP4-4 rivets to attach the W-1208 Nose Ribs aft flange to the W-1206-L Spar Assembly.
Step 2: Select two unmodified W-1208-R Nose Ribs, as well as the untrimmed nose rib that has the two nutplates to the spar assembly and attach angle. Cleco then rivet the last of the unmodified nose ribs to the spar assembly and attach angle.
Builders Note: Because of the challenge with the left spar I jumped over completing steps 3 through 7 and went on the the right wing.
Reference page 15-06:
Step 1: Lay the W-1206R Spar Assembly on the work surface with the flange facing up. Select one of the forward trimmed W-1210-L Main Ribs and cleco then rivet to the furthest outboard attach angle on the spar assembly.
Step 2: Cleco then rivet the forward trimmed W-1210-L Main rib which was match-drilled to the W-1216B-R Hinge Rib to the next inboard attach angle on the W-1206-R Spar Assembly.
Step 3: Select three of the forward trimmed W-1210-L Main RIbs and cleco then rivet to the next inboard attach angles on the W-1206-R.
NOTE: Use LP4-3 for attaching W-1210 Main Ribs to spar attachment angles. Use LP4-4 for attaching W-1210 Main Ribs to W-1206-R Main Spar Assembly
Step 4: Select one unmodified W-1210-L Main Rib and cleco then rivet to the next inboard attach angle and to the W-1206-R Assembly.
Step 5: Cleco then rivet the W-1210-L Main Rib which was natch-drilled to the W-1216B-R to the next inboard attach angle and to the W-1206-R Spar Assembly.
Step 6: Cleco then rivet the remaingin five W-1210-L Main Ribs to the next inboard attach angles and to the W-1206-R Spar Assembly.
Step 7: Cleco then rivet the forward trimmed W-1210-R Main Rib with the attached W-1210B-R RIb Doubler to the most inboard attach angle on the W-1206-R Spar Assembly.
That end this installment of the RV-12 aircraft build. Stay tuned as we cover more wind assembly on the E-LSA aircraft.
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