Windscreen fairing question

[kpaulsen]

I've installed my windscreen using Sikaflex, the attachment is at the roll-bar and fuselage skin. I was wondering if instead of doing a fiberglass layup for the fairing between the windscreen and the fuselage if I could just use SUPER FIL. I've already used SUPER FIL to create the fillet between the windscreen and fuselage and it seems like it would be straight forward and easy to extend this to cover the complete windscreen to fuselage transition.

I will do a fiberglass layup for the fairing between the windscreen and the canopy.

Any one see any problems with this approach?

 

[stevemcgirr]

My opinion

I am on this step at present. I used Sika to set the front plexi on, and to the roll bar. Next I used West 403 (sorta similar to superfil) to the transition, with three layers of fiberglass over this. I dyed both the 403 and the glass black. Next I built smooth contour with a thin topping of West 410 balloons. Next will be more glass, then pore filler/ primer.

I think this area needs fiberglass, not just superfil, IMHO

 

[kpaulsen]

Windscreen fairing

Thanks for the response Steve, I guess I'll do the layup per the plans.

 

[jimbo]

Black dyed Fiberglass for windscreen fairing?

Quote "I am on this step at present. I used Sika to set the front plexi on, and to the roll bar. Next I used West 403 (sorta similar to superfil) to the transition, with three layers of fiberglass over this. I dyed both the 403 and the glass black. Next I built smooth contour with a thin topping of West 410 balloons. Next will be more glass, then pore filler/ primer."

I heard others do this and wondered why it is necessary when the fairing will be painted on the outside anyway? Also, how does one dye the glass cloth, or, do you only dye the epoxy with the epoxy mfg dye?

Jim

 

[instructor_bill]

just did this

pigment added to one half of the epoxy mixture and well stirred turn the pot totally black.

Once it is all mixed in, add the hardener and mix well. You can then add it to your glass in either a wet layup, or wet out your cloth and apply. Your choice.

Dying the glass separately is not necessary. The result is a black layup when viewed from the inside.

After the layups are cured, sand your rough shape and you can fill the lows with polyester filler that is also dyed for any thin spots from your previous sanding.

 

[Paul K]

Just did it that way as well. I have a series of photos in my Picasa album below if you are interested. Just scroll about 3/4 of the way down.

Here is one of the photos of the layup, one change being I used carbon fiber instead of glass.

 

[Flying Scotsman]

I thought carbon fiber against aluminum was a no-no?

 

[BSwayze]

I just did all this work a few months ago, too. It wasn't as bad as I had thought and the results are really great. I used fiberglass cloth and some black pigment in the epoxy mix. If you don't use black pigment, you won't like what you see from inside the canopy! I feel very secure knowing that the glass is in place holding the windscreen down. It ain't goin' nowhere.

I have a lot more pictures and details, starting here:

Canopy Fairing Fiberglass Work

 

[Paul K]

Carbon fiber against aluminum is another one of those old beliefs without any proof! Also, if you do buy into that, remember that there is a layer of epoxy between the two anyway.

 

[Flying Scotsman]

Carbon fiber against aluminum is another one of those old beliefs without any proof! Also, if you do buy into that, remember that there is a layer of epoxy between the two anyway.

I don't think there isn't any proof...a quick search turns up numerous technical reports from military and NASA analyzing galvanic corrosion between carbon/graphite epoxy layups and various metals, including aluminum, steel and titanium.

Whether it's significant in our application, I can't tell, as I'm not a materials scientist. But there is definitely something worth exploring and understanding there before just charging ahead with it because it looks cool.

 

[Bob Kuykendall]

Carbon fiber against aluminum is another one of those old beliefs without any proof!...

The plural of anecdote is not data, but I have seen carbon/aluminum galvanic corrosion in person and I know others who have. It is a known problem for airliners where carbon sandwich floor panels come into contact with aluminum frames.

...Also, if you do buy into that, remember that there is a layer of epoxy between the two anyway.

That questionable. I once tried to use a piece of pultruded carbon fiber rod as a hotwiring bow, but it didn't work because the bow conducted enough of the current that the wire wouldn't get hot. I had to insulate the wire from the carbon bow at one end to make it work.

My general experience is that epoxy will serve as an insulator on cured parts. However, when you are laminating carbon cloth against metal, I think that there is a good chance that some of the carbon fibers will establish electrical contact with the aluminum. I'll try this the next time I go to my shop, and see if I can make a battery.

Whenever I need to embed steel parts in a carbon fiber layup, I am always careful to insulate the steel from the carbon with a ply of fiberglass.

Thanks, Bob K.