Fiberglass windscreen fairing

[rodsmith]

I'm about to layup my lower windshield fairing. I'm questioning how thick this needs to be. In my mind this piece is primarily cosmetic and not structural. Just seems to me that 10 layers of glass is more than necessary. Is the thickness for additional stiffness or to allow the use of flush head screws. This is one of the very few areas on the plane where I planned to use truss head screws. If it is for stiffness, fewer layers of carbon could be used. Soller composites has a 4" wide carbon tape that is quite thick, .027. I'm thinking 4 layers of that would be adequate, maybe even 3. I like the idea of using a tape rather than cutting strips as the edges tend to unravel, especially with carbon.

[svyolo]

I think I used 6 layers of 5-6 ounce cloth, about half of which were carbon. I can't say if that is correct or not. It is enough I think, maybe a bit more than necessary.

[Mark Goldberg]

I remember Bob saying 8 layers of medium weight cloth is what he liked to see. Mark

[robcaldwell]

Here's how I did mine. I am very happy with the results.

https://bearhawk4place.blogspot.com/2020/07/installing-windscreen-windscreen.html

I also used Flex Tape between the windscreen and boot cowl for an air and water tight seal.

https://www.amazon.com/Flex-Tape-Rubberized-Waterproof-Black/dp/B06XBZ82C8/ref=sr_1_3?dchild=1&keywords=flex+seal+tape&qid=1620833422&sr=8-3

[Bcone1381]

Flex Tape...Thanks for sharing Rob! Seems like a great way to seal things up. Gliders use a tape kind of like electrical tape to seal gaps but I had not thought about it in a application like ours.

I'm wondering if you have done any experiments removing it. Does it leave any residue behind?

[robcaldwell]

Oh yeah. Make sure you put it where you want it because it's a real mother to get off. Terrible residue. I hope I never need to remove mine.

In the case of the wing roots where I will need to open up for condition inspections, I used foil tape similar to Cessnas.

[svyolo]

That is a good idea. I was wondering what I was going to use.

[rodsmith]

I made the fairing, now wondering what the easiest method of attachment is. I am hoping to never have to remove the windshield once installed so wondering if soft aluminum pop rivets would be adequate. If using screws I will not go to the trouble of installing nut plates, and will have to work around installed equipment. That doesn't sound fun. Like John I used the 4" wide .012 fiberglass tape. 6 layers resulted in a finished thickness of .090. If you mask with clear plastic tape there is no waxing necessary, the fairing pops right off. Using peel ply reduces the amount of finishing work necessary. I will trim the fairing to a uniform 2 1/2" evenly split on the windshield and boot cowl. DSCF1153.JPGDSCF1152.JPG

[svyolo]

I am a week or two from finishing the fuselage firewall - aft. I haven't attached the fairing yet. I was thinking of just bonding it to the windshield. I doubt any two windshields are exactly alike, so I don't know if you could reuse the strip on a replacement windshield.

[geraldmorrissey]

I would go with MS426A rivets. I would make a test coupon first to see how the c/s looks.
Gerry
Patrol #30