Fuel tank sealing

[markejackson02]

I am building a Van RV-8.  Working on the tanks right now.  The Van's tanks are build by inserting sealant (Proseal, same as the Mooney) under the ribs, then riveting them to the skin.  As each rivet is driven in place, the rivet hole is filled with sealant to form a seal so that there is no leaking around the factory rivet head.  Once everything is riveted, sealant is applied to the inside of the tank along the rivet heads (the shop heads).

 

In looking at the Mooney tanks, it appears to me that the whole thing is built and riveted, then they brush a coat of sealant along the seams of the tanks.  Re-sealing looks like the same exercise, applying sealant to the seams/rivets (after removing the old sealant).  Does anyone know if Mooney wet drove the rivets when originally constructing the tanks?

 

 

[M20F-1968]

They did not wet rivet the legacy aircraft in the 1960's.  I believe thay have been doing that in the most recent models (Ovations and later) but I am not sure when they started the wet riveting.  Also, confusing the issue is that the wing is made on a jig by it self.  I do not remember seeing any visible PRC on that assembly, which would be the case if the tanks were wet riveted.

[moodychief]