RV-12 Stabilator (Part 4)

Reference: page 09-06; 4 hours

Received the replacement ribs from Vans Aircraft and am ready to continue building the Stabilator for the RV-12. Still ended up with very small cracks in two of the ribs. These were reworked per Vans technical help line.

Up to this time I have been referring to the figures in the plans (i.e "... as shown in Figure 2.) just as the written instructions in the plans do. As this blog is not a replacement for the plans, I'm going to drop the reference to the figures in the plans, unless I'm referring to something specific in the plans.

Reference: page 09-06

Step 2: Radius the edges at the narrow end of the HS-1204 Fwd Inbd Ribs and HS-1205 Fwd Outbd ribs. A great way to form the radius is with a fine file. Deburr all of the ribs.





NOTE: Step 3, 4, and 5 describe installation for the ribs o the right side of the stabilizer. Installation for the ribs on the left side of the stabilator is a mirror of the right Perform the remaining steps on this page on both sides of the stabilator. Flute ribs as necessary per Section 5N.

Step 3: Rivet the HS-1216 Aft Main Ribs and the HS-1206 Inbd Main Rib to the HS-1214 Rib Clips per call-out.



Step 4: Rivet the HS-1204 Fwd Inbd Ribs to the HS1202 Fwd Spar per call-out. Include the forward flange of the HS-1206 Inbd Main Rib when installing the outer most fwd inbd rib. Orient all the rib flanges as shown in plans.

Builder's note: I used a hand riveter for the center rivet on each rib as it has better clearance. Then used the pneumatic riveted for the other two rivets per rib. Note for these hard to reach spots the rivet mandrels are prebent to increase clearance. This is a technique taught by one of the EAA Homebuilt aircraft videos. Here is a link to the video: http://bcove.me/gysro9tr





Step 5: Rivet the HS-1205 Fwd Outbd Rib To the HS-1207 Outbd Main Rib through the HS-1202 Fwd Spar. Orient the flanges of the fwd outbd main rib so that they point inboard.

hereafter refer to the Spar Box Assembly with all of the ribs attached as the Stabilator Skeleton Assembly.





This completes page 09-06.

RV-12 Stabilator (Part 3)

Reference: page 09-06; 1.5 hours

Step 1: Rivet the HS-1214 Rib Clips to the HS-1203 Aft Spar per call-outs. Note the orientation of each rib clip, and be sure that all three holes of each rib clip align to all three holes of the aft spar before riveting.



Builder's Note: In preparing for the next few steps I discovered cracks in the stabilator ribs (see pictures below.) They could not be seen until after the blue plastic was removed. In talking this over with Vans, the options are to repair or replace depending on the size of the cracks. Because of the length of the cracks and the heavy scoring on one rib, replacement was the best option in this case. An excellent source of information on crack repair and inspection is the book AC 43.13-1B - Acceptable Methods, Techniques, and Practices - Aircraft Inspection and Repair. I'm adding this to the Gothcha list, because if these cracks weren't caught before assemble it would be bad.





The above rib was not a typical stress crack.

While I am waiting for the replacement ribs, I will be working on deburring parts. Until next time.