In Search of ... Symmetrical Fins

[GregGleason]

I thought you might just use the hollow mold to make cast epoxy fins.

Cast fins would be easier and would work, but epoxy by itself is quite brittle. In addition to being brittle, they would also be heavier and more difficult to repair. Any crack would render the fin suspect for the next flight and would put it in the "repair hangar".

While the vac-bagging method takes longer (and I don't like that aspect at all), all things being equal it will yield a lighter, more robust fin that should take the somewhat harsh, landing environment where I fly.

Greg

 

[GregGleason]

I made progress on the other fin half. Half of the battle is just trying to get the procedures and processes down. Doing airframe layups used to be hard and now it's fairly routine, so I hope vac-bagging will get to that point.

Here is mold "A" (I make a distinction between the halves, it's either "A" or "B") under vacuum.



Under the takeoff fitting, I placed cardboard to protect the vacuum system from epoxy intrusion. It was a marvel to see how flat the cardboard was crushed while under vacuum.


And after taking it out of the ZipLoc bag, which was the same bag I used on the "B" mold.



It looks pretty good, but I'm looking at the side that doesn't count. But it looks like the composite structure is in pretty good shape.

Greg