Trent's RV14 Build: 7-12: Rolling rudder leading edges / test fitting rudder

Spent around 3 hours today rolling the rudder leading edges.

I decided from reading the forums to roll the top (left) skin first, as this allows the lower skin to be bent more easily underneath the top skin. I began by using Van's recommended method on the lower left section first, and tried using 1.25" PVC pipe, 1" wooden rod and finally 3/4" wooden rod.

The trouble on the -14 (it may be other types as well, i think this is a RV9 rudder) is that in actuality, the section of the leading edge that rivets together is actually basically flat. The apex of the curve occurs around 1/2" from the spar flange (the flange is indicated by the red arrow). As such, when you tape the rod to the end of the skin as per van's instructions, you end up curving the section of skin where it will be riveted, and the section where the curve needs to be (closer to the spar flange) remains less curved! It can be hand massaged back to shape and the curve in the end of the skin bent out, but this results in a curvy top skin and takes AGES!

So i decided to try another method i found on the forums. This involved the used of 2 rods held together at the ends by cable ties. I had good results by using the 3/4" rod on the inside up against the spar flange, and the 1" rod on the outside. The procedure involves standing the rudder up on the trailing edge, and using your fingers to keep the smaller rod down toward the bottom of the curve near the flange, while simultaneously pulling toward yourself to ensure you don't bend the skin at the spar flange. At the same time, you push the larger rod forward in a rolling motion - imagine the lower rod staying stationary near the spar flange at the point you want the apex of the curve to be, and the larger rod rolling around the smaller rod, effectively shaping the skin around the lower rod.

In these images, the rod on the inside is the same size as the outer rod (1") - but i found a 3/4" rod inside gave a better result.

This effectively creates the curve you want at the right place, and keeps the ends of the skin flat where they rivet together. I was able to complete each section in one motion and almost set the curve where it needed to be. It needed a little massaging and tightening of the curve near the spar to make it sit correctly. I was pretty happy with the result.

Pretty close

All the upper skins done

The lower skins are done in the same manner, you just need to roll the larger rod under the top skin as you go - and sacrifice some skin off your hands in the process! The top skin is slightly curved at the rivet hole end, so that it sits nicely on the lower skin to get a good seam.

Upper section showing how the skins sit once rolled. There is some pressure on the rivets, but not much. The upper skin here us being held up by the lower skin a little, so that there is some pressure by the upper skin on the lower, to ensure a good seam.

Rolled but not clecod

Rolled and clecod - i used tape to ensure no sideways pulling pressure was on the clecos when they were installed / removed as i didn't want to damage or elongate the holes.

Middle section seam

Lower Section seam

Upper section seam

It also needs some evening up of the curves - it is easy to have one curve a bit tighter than the other, which results in a non-symmetrical shape once they are riveted together. I just clecod and taped them and had a look, and massaged as required.

Not quite symmetrical, but close. Test fitting showed no binding or rubbing on the VS at all.

The project is no longer rudderless!

Test fitting the rudder

At this point, how can one not attach the rudder to the VS!!! I just needed to see this thing swing.

To attach the rudder, first i had to screw in the eye-bolts. This was done by adding some boelube to the threads, and screwing them in using my homemade PVC tool (plans for this available everywhere). The plans give measurements for the length from the spar web to the centre of the eye-bolt. I marked each measurement on the ruler with tape, and placed a short AN3 bolt in the hole (so i could find the centre), rotating the eye-bolt by half turns until the centre of the AN3 bolt aligned with my tape.

Lube us used to assist the bolt installation as the nutplates are very tight.

homemade tool

measuring the distance from the spar to the centre of the eye-bolt

Once this was done, i very very carefully mounted the VS on the workbench, and secured to the bench with a strap and pipe hangers screwed to the bench. I was then able to mount the rudder and check it went past 35 degrees with no binding (which it did!). I also checked it was on straight by measuring the gap between the upper skin and the the counterbalance skin at each end - it was exactly 5/32" at both ends, so the given eye-bolt lengths were perfect. Happy with the result.

Of all the three eye-bolts, the upper and lower were a push in fit into the VS brackets, whereas the centre had a bit of space between the bearing and the bracket (perhaps one bracket was not 90 degrees exactly). This is ok, as it will pull tight when i bolt the brackets to the bearing later on.