Fiberglass canopy skirt - composite engineering question

[lostpilot28]

I'm at the point of attaching the canopy skirt to the RV, but I've decided to go with a big-ole one-piece fiberglass skirt. I was thinking of making it with 3 layers of 8oz E-glass and a top layer of 5oz S-glass (smoother finish). I ran this by a friend of mine from my Pulsar flying days...he's an ex-composite engineer, so I figured he'd provide some good feedback.

That left me with a new question. He said that fiberglass is 1/3 as stiff as aluminum (note I didn't say "strong"), so I would need roughly .09" thick fiberglass skirt to be as rigid as the .037" aluminum skirt.

Question #1: Is the aluminum skirt structural? It doesn't seem to be, but I'm not an aeronautical engineer.

Question #2: If it's not structural, does the aluminum really need to be .037" thick? Hence, could I get away with a much thinner layer of fiberglass than .09"?

I've already done a search on VAF, but this hasn't been discussed. I'd rather not go with Carbon Fiber for 2 reasons - cost & it's ability to corode metal. Any advice is greatly appreciated.

[mburch]

This doesn't directly answer your question, but: I'm about done with my fiberglass rear canopy skirt (RV-7 slider) and in order to get a level of stiffness equivalent to the metal skirts, my composite skirts ended up substantially thicker than the original aluminum. They sure do fit nice though.

I have zero experience with carbon fiber so I don't know how much that would help here.

For what it's worth, I didn't have any trouble making the aluminum side skirts fit well.

mcb

[lostpilot28]

Originally Posted by mburch

This doesn't directly answer your question, but: I'm about done with my fiberglass rear canopy skirt (RV-7 slider) and in order to get a level of stiffness equivalent to the metal skirts, my composite skirts ended up substantially thicker than the original aluminum. They sure do fit nice though.

I have zero experience with carbon fiber so I don't know how much that would help here.

For what it's worth, I didn't have any trouble making the aluminum side skirts fit well.

mcb

Hi Matt, how many layers did you put down? What type & weight of glass did you use? Thanks.

[mburch]

I think I have a total of 7 plies of 8oz-bid cloth on it. You might be able to leave off a couple of those layers, but I sort of went for overkill. It is after all my first canopy skirt!

mcb