Rudder 7-9-2 to 7-11-1
It is time to start closing up the rudder. This involves applying tank sealant along the trailing edge while working in a 2-hour window to get the two rudder halves riveted together.
I didn't get many pictures during the sealing process (due to having to handle the tank sealant and work efficiently), however the full process is documented in the video below. Here are the highlights
- I put paper underneath the trailing edge while applying tank sealant, but should have put a little more as I still managed to get some sealant in a few spots on the work bench. I also used wood blocks to rest the trailing edge on, and threw those away after the tank sealant was applied.
- I applied as thin a coat of tank sealant to the trailing edge as I could. Just enough to adhere to the skin with minimal squeeze out.
- I used paper towel rolls to keep the skins apart while blind riveting the rudder stiffeners and shear clips together. These worked really well. One roll at the end of the skin, and another roll placed between stiffeners and moved as needed.
- Blind riveting the stiffeners and shear clips was easy. I just had to pay attention to keep the rivet puller perpendicular to the rivet head while pulling, while at the same time making sure not to let the puller hit the skins as the rivet mandrel snapped.
- I riveted most of the bottom rib with the Cleaveland Main Squeeze, but clecoed the two holes closest to the trailing edge for riveting later when I was not time crunched.
- I used the aluminum angle, match-drilled to the trailing edge a few days earlier, to cleco the trailing edge to. I was very happy with how straight the trailing edge appears.
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| Ready to seal the trailing edge and join the rudder halves |
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| Stiffeners and shear clips riveted together using blind rivets |
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| Trailing edge clecoed to the aluminum angle and weighed down |
I left the rudder for a few days to allow the tank sealant to cure completely before continuing.
On a side note, I noticed a couple of small dimples in the right rudder skin when I flipped over the rudder after sealing. I can only assume these were formed by the manual pull riveter when I was riveting the shear clips to the right skin stiffeners. I didn't realize it at the time but the riveter must have hit the skin as the mandrel snapped causing the dimples. This is a cosmetic defect that I'll have to live with for now, but I'm pretty sure the dimples can be hidden when I eventually have my finished RV-10 painted.
After about 4 days of curing I removed the weights and aluminum angle from the trailing edge. I was very happy with how straight the edge looked, and there was minimal tank sealant squeeze out through the holes and along the edge.
I spent a little time with the deburring bit and a #40 reamer just making sure the holes and countersinks were clear of tank sealant, and a quick wipe with acetone along the surface easily removed any sealant on the skins.
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| Skins and holes clean of excess tank sealant |
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| Straight trailing edge! |
I then proceeded to rivet the two remaining holes in the bottom rib nearest to the trailing edge that I had only clecoed while applying tank sealant. These holes were pretty tight, but I was able to put a solid rivet in the second hole nearest the edge using the Cleaveland Main Squeeze and the 4" thin nose yoke. I still had to start squeezing with the manufactured head slightly proud of the countersink, and I then pushed it flush and finished setting it without any issues.
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| Blind rivet (the one with the hole through the middle) placed at end of bottom rib in left skin |
For the bottom rib rivet closest to the trailing edge, I used a pull rivet as recommended in the plans. Again I had to squeeze a little and then push the rivet flush to the skin before completely setting it. This worked and I got the rivet in there, but the shop head is literally up against the opposite solid rivet shop head. I don't think that is an issue, but I'll get some builder advice on that.
Next I riveted the spar to the shear clips using LP4-3 blind rivets. I opted to do this with the manual rivet puller just to get more feel for pulling rivets with it, however I used the pneumatic puller to set the final 2 rivets in the top shear clip as there was very little room up there between the skins to feel comfortable with the manual puller. The pneumatic puller is so easy to use as it pulls the rivet in one stroke!
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| Rudder spar riveted to the shear clips |
With the spar riveted to the shear clips, I moved on to riveting the rudder horn to the spar and striker plates. This requires a combination of different blind and solid rivets. The rivets all went in easily using the pneumatic puller and squeezer.
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| Striker plates and rudder horn riveted together with the spar |
The next step involved riveting the top rib halves together using the rivet gun and bucking bar. Prior to riveting these, I practiced setting AN470 4-4 rivets into the practice kit that I had previously disassembled just to get a better feel for using the cup set. That went well, so I started riveting the rudder top rib together and to the spar. Space was a little tight getting the tungsten bar in place near the spar, but I was very happy with how all the rivets came out. I used the Cleaveland Main Squeeze on the final rivet at the end of the top rib.
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| Shop heads set to the correct diameter and depth |
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| Manufactured heads with virtually no scuffing of the primer. Two innermost rivets were LP4-3 blind rivets. |
I completed riveting the skins to the spar using the pneumatic squeezer and a 4-inch thin nose yoke as I had to reach past the leading edges to get to the rivets. For the 6 rivets (3 each side) nearest the top rib I decided to use the Main Squeeze as these were a stretch even for the 4-in yoke and I wanted to have a bit more control over the squeezing. All rivets went in nicely though.
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| Main Squeeze was used to set the skin/spar rivets closest to the top rib |
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| All other skin/spar rivets were squeezed |
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| Counterbalance rib riveted into place |
Next I moved on to riveting the trailing edge, setting double flush rivets. I decided to alternate the shop head side (as other builders have done) to give a more symmetrical look to the rudder.
I used the rivet gun and a narrow straight flush rivet set to initially set the rivets. Starting from the middle of the trailing edge and partially setting every 9th rivet, I then partially set every rivet in between those, and kept splitting the difference until every other rivet was partially set. I then finished setting the rivets using the Cleaveland AEX trailing edge flat set in the pneumatic squeezer.
With alternating rivets done on one side, I flipped the rudder over and set all the rivets on the other side, again working outwards from the middle of the trailing edge. I was very happy with the overall results, as the edge was very straight and no significant pillowing of the skins between rivets.
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| Trailing edge riveted with double flush rivets |
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| Happy with the straight trailing edge on the rudder! |
Build Hints
- When pull riveting close to a skin manual rivet puller, put some foam padding around the head of the rivet puller to protect the skin due to the recoil of the puller when the rivet mandrel snaps.
Time Taken: 10.6 hours
Dates: August 19 - August 28 2022
Rudder Total Time: 33.6 hours
RV-10 Build Total Time: 81.3 hours
Priming Total Time: 8.8 hours (not included in build time totals)