More fun with back-riveting…this time on the right elevator. I learned from the Sportair class that in order to avoid unsightly bends in thin control surfaces when back-riveting, you gotta have an extra pair of hands to open up the skins and at the same time keep the bottom skin flat against the work surface. So Ellen was once again co-opted to work on the plane. We also found out that small 2″x4″ blocks came in handy to press down and back along the skin bend.

Here’s the right side…

A stiff skin

…and the left.

The other stiff skin

Priming time again…ugh. I hate priming. But fortunately my friend and fellow RV-7 builder John was kind enough to lend me the use of his painting booth. So it was time to prepare the skins, stiffeners, and right elevator frame for priming. Everything but the skins was scuffed and alodined using the Touch-n-Prep pen. The skins were just scuffed.

Priming at Cap’n John’s place

Gotta have that mask on…

Cap’n John

Meanwhile, John relaxed and worked on the tiedown spacers for his wings.

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?