I opted NOT to have the pre-built spars that Van's offers. Mostly from a cost perspective. It's another $500.00 to have this done. And besides, I'm supposed to be building this myself. So lets go into the spars themselves.
The spars are the single most important structural component in the airframe. All wing loading is supported from this component. It is really just a bunch of laminated pieces of aluminum. The pieces are laid on one another and rivet together. The riveting is the important part. These are large rivets, the largest on the plane in fact, and the normal riveting tools are not strong enough to pound the larger rivets. Here is the spar root. Notice all pieces temporarily together, checking alignment and fit.
Below is a side view of the same section. You'll notice bolts, and tape on the rivet heads. There are some pieces in the middle that must be in perfect alignment, and if during riveting they fall out, god help you. You can never get into this section again. So tape those rivets. You'll thanks me later.
Below is the same spar, a little further down. Notice the "lightning holes. These are to save weight and are not material to the strength of the component. (And yes there are leaves on the floor. Its fall here and very windy. Part of working in a garage with the door open. A leaf blower cleans the floor in seconds)
The real complication comes in setting the large 3/16 rivets in the spar. I did quite a bit of research on this. There are several methods. The easiest, and most costly of course, is to buy or rent a pneumatic squeezer from a tool vendor. An alternative is to use your existing "C-frame" dimpler and a good heavy 3 pound hammer. (btw, the hammer used here was found in the breakdown lane of hwy 316 locally. Julie doesn't understand why I pulled over when I saw this in the breakdown lane. See Julie, now you know. hehehe)
Alignment is critical, but this rigging with various pieces of wood for support of the long span worked very well. I would recommend this method as it worked well for me.
A close up shot below shows you the business end of the c-frame
Last Updated 11/05/02