Flyin' Bryan's RV-8 Adventure: Left Wing Leading Edge Assembly

Some of my followers have mentioned to me that they are "concerned" that have not shown much actual airplane assembly progress of late, so this post is for them. After widening out the support brackets for my LE cradle, I decided I wanted to check the clearance to determine if it was wide enough to allow the assembly of the leading edge ribs and skins. I got down the left wing LE from the shelf, made sure my door seal material was in place, and fit the LE wing skin into the cradle. It took a fair amount of sqeezing the skin together to make it skinny enough to fit between the brackets, but it seemed to go on without too much fuss. It is a stressed skin similar to the skins on the empennage, so it requires compression to fit around the ribs.

As shown below, even though there are several voids in the brackets, the skins seemed to fit just fine, and the 1/8 inch rubber door seal material I found seemed to work perfectly as an anti-scratch lining for each bracket.It also grabs the skin to keepit from slipping a whole bunch, so I really like that solution.

After the skin was in place, I took the LE ribs and decided to doa trial fit.I was not really following directions in the plans - I just wanted to see things would fit together OK or not.My overall concern is that many builders have difficulty clecoeing the ribs in place, even with the help of the cradle. I think Vans recommends a procedure of starting at the trailing edge and moving forward on one side, and continuing from the front to the back on the other side. Another instruction is to remove all the vinyl to ensure that the rib holes line up with the skin holes correctly, but I think this may be more critical for the fuel tanks. I decided not to go to all that trouble adn just wanted to see how easily or difficult it would be to fit the ribs to the LE skin with the vinyl still in place.

I started attaching ribs to the skin from the outboard end, and I did start from the aft end on the bottom, which of course tends to be a bit flatter than the top side of the wing which is curved more than the bottom. As I got to the nose of each rib I would put clecoes in every hole, and would space them out by every other hole as I moved further aft on either side. I did have problems trying to wrap around to the other side after reaching the nose of each rib, and I found that if I clecoed the third or fourth hole aft of the tip on the top side, that allowed me to go back and cleco the remaining holes near the tip of the LE fairly easily. I was also quite pleased about the alignment of the holes in each rib and the skin, which means that all that time I spent straightening the ribs and ensuring that the rivet holes were aligned really paid off.

Here is the final nose rib on the outboard end. The overhang on the skin and additional holes are fot the Wing tip, which is basically the final step in the entire wing assembly process.

Next are a couple of shots of the most inboard rib of the LE, which I think is designated part number 408 L. This rib is unique from all the others because it is slightly thicker, is not predrilled with rivet holes, and is also about .032 inches smaller in circumferance than the others because there is an additional .032 inch thick joiner strip that is inserted between this rib and the skin. This joiner strip is then drilled for screws and nut plates that will attach the outboard end of the fuel tank to the inboard end of the wing LE.

Because the inboard rib is not predrilled with any holes, this is also the only rib that I have not straightened or fluted yet. I needed to clamp the rib onto the skin first to see where the holes generally line up, and the sharpee marks that you see in the folliwing pics on the side of the rib are the locations between the holes in the skin where I can sfely fulte the rib to straighten it.

Here is shot of rib flange from the inside of the LE skin - nice and square. Stupid digital picture won't flip the pic the right way, but you get the idea.

Here is the entire left wing LE all clecoed up and in the cradle. I have to admit that my next real construction step is to prep and prime all the main ribs and then rivet them to the front and rear spar. This LE assembly, however, was a nice departure, and something that also needed to be done sooner or later.