Match-drilling the elevator counterweight
The next step is match-drilling the counterweight skin and ribs to the lead counterweight itself. Vans recommends using a drill lubricant, which seemed to help when cutting through the lead. I also pilot-drilled the holes to #30 before final drilling them to #12.
Match-drilling the elevator counterweight
The final result…the assembly looks good. Can’t do much more until I prime the skins and stiffeners.
Right elevator counterweight ribs
Over the last few days I tweaked the right elevator’s counterweight ribs to adjust their alignment. These ribs are match drilled back-to-back, then fitted to the counterweight skin which encloses the lead counterweight itself. In this picture, you’ll see the ribs clecoed to the right elevator spar. There were a couple of problems with this assembly. First, the small tabs on the inside rib don’t quite align with the prepunched holes in the spar (the circled area in the above picture). Actually, the holes weren’t even close. I called Van’s, and was told to leave the holes as-is, and just match drill as required when fitting this assembly to the skin. That will mean a couple of ‘figure eight’ holes in the tabs, but apparently that’s ok. Problem solved.
The other problem is that the ribs must lie flat together for their flange rivet holes to align with the counterweight skin. I had to spend extra time adjusting the flutes on these ribs to get the rivet holes as straight as possible. I also received some good suggestions from Roberta Hegy on re-radiusing the flange bends; doing this helps snug up the ribs together and reduces the distance between the two lines of rivet holes. Thanks Roberta!
Scuffed and alodined all stiffeners. The Touch-n-Prep pen worked great! I also realized that I’d neglected to match-drill the trim servo mounting plate to the left elevator skin, so that got done today. I then deburred, dimpled, scuffed and alodined it. I also forgot to take any pictures. Even if I had, they would be pretty boring…you’ve seen one stiffener, you’ve seen ’em all.
Not much visual progress through today, so again no pictures. After edge-finishing the elevator skins and deburring stiffener mounting holes, Ellen and I dimpled them with the DRDT-2. The -2 worked great, as usual.
Match-drilled stiffeners to the right elevator skin today. No issues here. Also no pictures, so use your imagination.
Cougar 52 on approach to the Henry Goodrich
January 10-13: No airplane building work this week, but some very cool flying. We traveled to St. John’s, Newfoundland (that’s in Canada, for all you geography majors) to fly with a helicopter company providing support to oil rigs on the Grand Banks. It was quite an eye-opening experience…the company’s crews routinely land their heavy twin-engine Super Puma helos, stuffed with people and equipment, on pitching oil rig helidecks, at night, in the weather, with winds approaching 60 kts.
Stiffeners drilled to left elevators.
With the stiffeners fabricated, it was time to match drill them to the skins. Got the left side done today. The Rockwell angle drill I found on eBay came in handy when drilling those stiffener holes close to the skin bend.
Elevator stiffeners
Over the last three days I completed a majority of the elevator stiffeners. Unlike the rudder, elevator stiffeners aren’t all pre-marked to their finished length; some must be fabricated from longer lengths of stiffener angle. Also during this process, I found another discrepancy in Vans’ plans. Rudder plans don’t call for removal of all reference holes from each stiffener, but the elevator plans do. Which one is correct? I asked Van’s this question during rudder construction and got the following response… “You don’t need to remove all of the holes, but if you have it won’t significantly affect the strength of the stiffeners.” So why require it on the elevators?
Got bent!
And the leading edge is finished. Closing the middle and lower sections was a four-handed operation; I squeezed the leading edges together while Ellen inserted clecos. The process was repeated after final-drilling the holes to #30 and deburring them.
Done!
And with the leading edge finished, the rudder is finished. After all the hassle with rivet guns and the tedium of setting trailing edge rivets, I’m pretty happy with the results.
Done!
Gotta have at least one picture of me and a finished product. Look close and you’ll see Ellen in a reflection from the rudder skin.
Get bent!
The next adventure in learning was how to roll and close the rudder leading edge. I bought both 7/8″ and 1″ dowels from Home Depot, not knowing which one would work better. As it turns out, the 1″ dowel is a better choice; following Van’s directions with a smaller diameter dowel leads to a rolled edge that has a lot of curvature toward the front edge, but not enough at the rear edge (next to the spar) to make closing a little easier. I tried moving the dowel a little closer to the spar, but it was tough to get it to stay there. Generally after a couple of bends on each side, the edge was ready for closure.