446 hours - Let the rolling begin

There is nothing like a complete computer melt down due to a virus and tax season to put a damper on your efforts to build an airplane. It's been a rough week all around, but I am back in the saddle and have a few pics from last weekend to get caught up on. I basically started rolling the leading edge of the right elevator and also did some prep work for drilling the center bearing bolt holes in the control horns once the leading edge work is done.

First thing is first - I needed to kerf the leading edges of the top skin on both elevators by using the edge roller tool. Same process as when I did it for the rudder. If you can look past all the smudged finger prints, you can see the small crease in the leading edge where the tool did its job. This is important for ensuring that the overlapped skins will rivet together cleanly, without curling up at the edges when the rivets are squeezed.

The idea is that you want to kerf the top skin so that when it compresses down on the bottom skin underneath the two edges will mate together nice and flat. The top needs to go on the outside to help shed water that may accumulate on the leading edges from rain or slush on those less than perfect weather days or when you need to wash the airplane.

the bottom skin needs to be primed where the skins will overlap. In the event that any moisture does penetrate this area you want to do your best to prevent sources for corrosion. Since this is a common area where corrosion can occur iit is in your best interest to apply some form of protection here. My advice is to wait untl after you bend the leading edge, because when I put duct tape over the leading edge with the primer to roll the edge, most of the primer got lifted off by the tape when I removed it. I need to go back adn see how I did this for the rudder because I don't remember having this problem when I worked on it.

Oh, well,  just have to respray it this weekend adn close everything up.

Now, in this next pic, can you tell if it is cold outside or not? I'm sure the hat and heavy coat don't give it away at all! BtW, this was in the garage with the heater cranked up full blast and the insulated garage door closed. Yup, it was cold. Wasn't goin to let that stop me though. I am taping up the bar on the mid section of the elevator in this next pic. Those that follow show the end result:

I decided to try some different techiques this time from the way that the rudder was done. Namely they were:
- I did not use the fancy bend table or the U bolts to hold down the bar on the table while I cranked on the bar to roll the skin. I ahve seen too many pics where everyone just tapes it up adn starts cranking, adn it all seems to turn out fine, so I thought I would try that approach. What I found is that you still have to be very conscious about pushing down and rolling at the same time so that you do not crease the skin where it joins the flanges of the forward spar.
- I did NOT want to roll it so far that the edges of the skins were already perpendicular to the spar before I even start closing them together. This got me into serious trouble with the rudder, because the inside skin ended up being rolled too far, aand I may still decide to open it up adn try to correct it a bit. But for now I will try to get the elevator skins right on the first attempt.

In fact, it turned out that even though I thought I had only rolled them just far enough, the inside skin still ended up being a bit over rolled. Personally I would say that you only need to roll the leading edge so tyhat it sits about 30-35 degrees up when you remove the bar and the tape. Don't even take it to 45 degrees or you will ahve the same problem I do. It really takes a lot of hand contouring the skins to get them to close up adn to ensure that the edges are laying flat against each other.  SO less is more for this part of the operation.

- I did find as others had told me that the elevator skins a re a bit easier to work with than the rudder. The technique to finish the rolling by hand is still an art form, however, and I can't even really describe how you need to do this very well. It is a combination of using the upper pad of the palm of your hand and the bottom portion of your fingers to gently and slowly push the initial bend of the skin closed until you finally reach the mid point where the top and bottom skins will overlap. The rest of the technique is figuring out how to push UP AND AWAY on the skin to keep it from forming a crease where the spar flange edge is located under the skin. Best way to describe this is to take it slow, and work up and down the entire section of the rolled skin. Then, when you think you have it just about right, keep bending it and rolling it with your hand some more so that the skins overlap each other, and only mnimal pressure is required to push the two skins together so that the rivet holes line up. I think that the whole trick to this is finding the sweet spot on the skin where you can apply pressure to keep bending it closer toward the mid section without risking
creasing the skin where it joins the spar flange.

Other than that, you pretty much just have to do it to understand how it needs to work.

-Roll only one section at a time. Yes it takes a bit longer to do this, but it is easier to roll smaller sections at a time.

-  I decided to use a smaller diameter piece of water pipe for the bottom skin, adn a larger diameter bar for the outer skin. I do like how this worked out. My outside diamters were 3/4 " for the inside skin (bottom), and 1 1/8 " for the top or outside skin. This seemed to position the top and bottom skins in such a way that allowed them to form better as you close each one up by hand.

-  I used gorilla tape to roll the edges. Be warned - it will remove the primer on your leading edge - very strong stuff that gorilla tape.

Next pic is about ready to flip the skin over adn roll the bottom mid section of the right elevator.

 The bar gets positioned against the skin so that the skin overlaps the bar by about half the diameter of the bar, or a bout half way across the bar for short :) Then you flip it over so the bar is on the bottom, attach some locking pliers to both ends, and crank away formly and consistently.

The only other thing to comment about is the length of the bars to use. This will be different for the rudder and the elevators, but about 20-22 inches seems plenty long enough to handle any of the control surfaces that need to be rolled. You need to have just enough bar hanging over the exposed cutouts where the rod end bearings are installed, but not so much that it extends beyond the other side of the cutout.

Here is the top section, which is the easiest to put together. I recommend doing this section first to give you an idea of what it will take to do the other sections.

And another important pic to illustrate the fact that the more help you have to perform this step, the easier it is to get it done. You mainly need at least one peson to hold down the skin on the back side becaue you need to move the taped bar assembly far enough forward to be able to attach the locking pliers to the bar to get a good roll. I found that I needed to start the roll, and then reposition the pliers again to roll it just a bit more. If nobody is holding the part down, the heavy bar will flip the whole thing right of the table and you will calling Vans to order more parts. My son Adam was gracious enough to help me with this.

And after both sides are rolled - the center and bottom sections are almost together. The remaining hand forming will close the gaps that you see and align the rivet holes so they can be clecoed together.

This next pic shows what happened to my primer when the tape was removed. Also shows that the edges were still a bit over rolled.