6/6/2006
I decided to go with another method of installing and sealing these ribs on the right tank. This way is quite a bit less messy, but there are those who argue that the rivet won't be set to proper Mil spec, and that it invites leaky tanks. I have talked to several builders who have done it this way, and they report no problems, and one airplane has over 400 leak free hours on it. Tonight I did what's called fay sealing the ribs to the skins. This is done by putting a thin layer of sealant on each rib flange, then installing them with a clecos in EVERY hole.
The sealant is allowed to cure to a tack dry state, then the rivets will be wet installed with a dab of sealant in each dimple within the next 24 hours. After the rivets are set, sealant is applied in the same way it was using the other method, which is to cover each shop head, and fillet the edges of the ribs. There's a great write up on this method in this thread at the Vans Air Force Forums.
Here's the inside of the tank with all clecos in place.
In order to get a better "grip" with the clecos to hold the ribs as tight as possible to the skins, I used a 6-32 nut between each cleco and the skin. This restricts the spring inside the cleco from opening up to put out just a little more force or pulling power.
1.5 hours