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.

RV-12 Stabilator (Part 2)

Reference: page 09-03, 09-04, 09-05; 8 hours

Continuing construction of a Vans Aircraft RV-12 stabilator.

Reference: Page 09-03

NOTE: The proper orientation of the spars (top, bottom, forward, aft) is critical throughout the Stabilator assembly. Make sure that all apar flange holes align with spar cap holes.

Step 1: Cleco the HS-1209 Spar Cap Spacers, the HS-1212 Inspar Ribs and the two HS-1211 Spar Caps together as shown in Figure 1. Orient the spar caps so that the closely spaced holes in the top spar cap align with the closely spaced holes in the bottom spar cap, and the machine countersunk holes face away from the inspar ribs. orient the inspar ribs with the tooling holes positioned as shown in figure 1. When all are oriented correctly, the lightening hole in the web of each inspar rib will align when sighting through all of the inspar ribs from the end.



Step 2: Rivet the HS-1211 Spar Caps. HS 1212 Inspar Ribs, and HS-1209 Spar Cap Spacers together using rivets called out in Figure 1.





Step 3: Cleco the HS-1202 Fwd and HS-1203 Aft Spar to the HS-1212 Inspar Ribs, as shown in Figure 2. Hereafter refer to this subassembly as the Spar Box Assembly.



Step 4: Cleco the WD-1207 Upper and WD-1208 Lower Horns to the HS-1202 Fwd and HS-1203 AftSpars. Identify the upper horn by the 3/15 inch indentifer hole. Point both of the horns forward as shown in Figure 2. Mark the top and bottom of the Spar Box Assembly for reference.

Builder's Note: My control horns didn't fit well and were loose on the spar as can be seen in the picture below. After checking with Vans Aircraft about the fit, I made a set of spacers (one for the front and one for the back of each bracket) out of aluminum sheet.







Step 5: Final-Drill #12 the fastener holes of the WD-1207 Upper and WD-1208 Lower Horns into the webs of both spars as called out in Figure 2. Insert an AN3 bolt into each hole before drilling the next.

Remove the upper and lower horn, deburr the holes and set the two horns aside.



Step 6: Final-Drill #30 all of the holes in the plate of both of the WD-1222.



Step 7: Align each WD-1222 Counterbalance Bracket to the corresponding holes in the HS-1202 Fwd and HS-1203 Aft Spat. Turn both brackets 90 degrees and cleco them in that position, as shown in Figure 3. Detail A-A.

Step 8: Insert the WD-1223 Counterbalance Arm into the forward WD-1222 Counterbalance Bracket (celecoed to the HS1202 Fwd Spar) through the Spar Box Assembly, then into the aft WD-1222 Counterbalance Bracket. Bring the aft end of the counterbalance arm flush with the aft edge of the aft counterbalance bracket, and orient the counterbalance arm as shown in Figure 3. Clamp the counterbalance arm to the counterbalance brackets.



Step 9: Match-Drill #30 the two holes from the neck of each WD-1222 Counterbalance Bracket into the WD-1223 Counter Balance Arm. Cleco as you go. then final-drill #12 per call-out in Figure 3, Detail B-B. Temporarily insert an AN3-14A bolt after final-drilling the first hole.





Step 10: Rotate the counterbalance arm and counterbalance brackets 90 degrees, make sure the top edge of the counterbalance arm (see call-out in Figure 3, Detail B_B) is oriented with the top side of the Spar Box Assembly. Mark the counterbalance brackets in relation to the Spar Box Assembly, and the counterbalance arm.

Remove the counterbalance arm and brackets, remove the HS-1202 Fwd and HS-1203 Aft Spar. Deburr holes, and clear away chips.



Builder's note: This completes page 09-03.

Reference page 09-04

Step 1: Cleco the HS-1224 Doublers to the inner surface of the HS-1202 Fwd Spar web. Final-Drill #12 the 3/16 inch holes.



Step 2: final-Drill #40 the 3/32 inch nutplate attach rivet holes in the HS-1224 Doublers.



Step 3: Bolt one of the called out nuplates through one of the #12 holes in the HS-1202 Fwd or HS-1203 Aft Spar for the WD-1207 Upper and WD-1208 Lower Horn. Using the nutplate as a guide, match-drill #40 the first nutplate attach rivet hole as called out in Figure1. Cleco the first #40 hole, then match-drill the other attach rivet hole. Repeat this step for all of the nutplates that are common to the upper and lower horns in the Fwd and Aft spar.



Step 4: Machine countersink the nutplate attach rivet holes flush on the outer surface of the HS-1202 Fwd and HS-1203 Aft Spar per call-out in Figure 1.

Mark the postions, remove the nutplates and doublers, deburr all drilled holes, clear away chips and re-cleco.



Builder's note: I prepped and primed parts before continuing.

Step 5: Rivet the HS-1224 Doublers, and the called out nutplates to the inner surface of the HS-1202 Fwd Spar web using rivets called out in figure 1.



Step 6: Rivet the nutplates for the WD-1207 Upper and WD-1208 Lower Horn to the HS-1203 Aft Spars using the rivets called out in Figure 1.



Step 7: Rivet a nutplate to both of the HS-1213B Outbd Hinge Brackets using hardware called out in Figure 2.



Step 8: Rivet the WD-1222 Counterbalance Brackets to the HS-1202 Fwd and HS-1203 Aft Spar in their previously marked postions per call-out Figure 3.



Builder's note: This completes page 09-04.

Reference: page 09-05

Step 1: Cut the 5/16 aluminum tube to make four HS-1210 Hinge Stops per dimensions in Figure 1. Deburr the hinge stops.



Step 2: Separate the HS-1214 Rib Clips by removing the material shown hatched in Figure 2.



Step 3: Cleco the Spar Box Assembly back together. Check alignment of HS-1202 Fwd and HS-1203 Aft Spar flange holes to the corresponding holes in both HS-1211 Spar Caps. All spar flange holes must align with spar cap holes.



Step 4: Rivet the previously countersunk holes in both flanges of the HS-1202 Fwd and HS-12-03 Aft Spar to the HS-1211 Spar Caps per call-out in Figure 3.



Step 5: Rivet the HS-1202 Fwd and HS-1203 Aft Spar to the inboard HS-1212 Inspar Ribs using rivets called out in Figure 3.



Builder's note: This completes page 09-05.

RV-12 Stabilator (Part 1)

Reference: page 09-02; 3.5 hours

Today we start in on the stabilator construction for the RV-12 airplane. Why a Stablator and not stabilizer? The elevator and horizontal stabilzer on the RV12 are one unit so it really is a stablator.

Step 1: Machine countersink the HS-1202 Fwd Spar for 1/8 inch rivets in the holes on both flanges as called out in Figure 1.


These holes are on both top and bottom flanges.

Step 2: Machine countersink the HS-1203 Aft Spar for 1/8 inch rivets in the holes on both of the flanges as called out in Figure 1.



Step 3: Machine countersink the HS-1202 Fwd Spar for 3/32 inch rivets in the nutplate attach rivet holes on the web as called out in Figure 1. (This figure is in Vans Aircraft's plan book)



Step 4: Machine countersink both of the HS-1211 Spar Caps for 3/32 inch rivets in the holes called out in Figure 1.



NOTE: It's not noted in the written instructions, however there are two holes refered to in figure 1 that need countersinking for 1/8 inch rivet. I'm pointing to one of them in the pictures below.





Step5: Machine countersink the HS-1213 Hinge brackets at the nutplate holes for 3/32 inch per call-out in Figure 2.



Step 6: Final-Drill #12 the HS-1213 Hinge Brackets through all of the 3/16/ inch as called out in Figure 2.



Step 7: Trim the HS-1213 Hinge Bracket to make the HS-1213A Inbd and HS-1213B Outbd Hinge Brackets by removing the material shown hatched in Figure 2.
Deburr all edge and drilled.





Step 8: Machine countersink the #40 holes in the HS-1209 Spar Cap Spacers for 3/32 inch rivets per call-out in Figure 3.



Step 9: Separate the HS-1209 Spar Cap Spacers by removing the material shown hatched in Figure 3.



Step 10: Separate the HS-1224 Doublers by removing the material shown hatched in Figure 4. Deburr the edge of the separated parts.



Note: Readied the parts for the next steps by alodining and priming. The gloves in the picture is just a reminder to wear protective gear (gloves and respirator) when working with zinc chromate primer.



This completes page 09-02.

RV-12 Anti-Servo Tabs (Finishing)

Reference: page 08-02, page 08-03, page 08-4; 2 hours

Today the Anti-servo Tabs will be completed.

Reference page 08-02

Step5: Rivet only the top flange of the four HS-1222 AST Ribs inside the top surface of the HS-1221-L AST Skin per rivet call-out in Figure 4.

NOTE: This completes page 08-02





Reference: page 08-03

Step 3: Orient the AST Control Horn to pass through the AST control horn cut-out. Rivet the HS-1220-L AST Control Horn to the inboard HS-1222 AST Rib as shown in Figure 2.



Step 4: The HS-1219-L AST spar must be installed on the inside surface of the HS-1221-L AST skin as shown in Figure 4. The reference hole oriented up and outboard. Rivet the AST Spar to the AST Skin per call-out in Figure 4. Omit the reference hole when riveting.

This completes page 08-03


Reference: page 08-04

Step 1: Rivet the bottom surface of the HS-1221-L AST Skin to the HS-1222 AST ribs per call-out in Figure 1. guide the lower flange of the AST skin to the outside surface of the HS-1219-L Spar as shown in Figure 2.



Step 2: Install the AST Hinge with eyelets outward, as shwon in Figure 2. Rivet the HS-1218B AST Hinge to the HS-1221-L AST Skin and the HS-1219-L AST Spar per call-outs in Figure 3. Begin at the hole farthest from the HS-1220-L AST Horn.

Hereafter refer to this as the AST Assembly Left and the opposite assembly as the AST Assembly Right.

The Anti-Servo Tabs for the RV-12 are now done as is section 08.