canopy glassing on?

[miyu1975]

I am putting together an order for aircraftspruce and would like to know whether people are using S glass or E glass when attaching the canopy.
Please advise.

[Bavafa]

I used carbon fiber, it is much messier sanding it but more rigid and stronger perhaps.

[DanH]

Ordinary E-glass is more than adequate.

[miyu1975]

great thanks...

[miyu1975]

I went ahead and ordered S and E glass...anything wrong with laying S on top of E?

[N8RV]

Ryan, I'm not sure about the -7, but with the -8 there's a propensity for people to grab the canopy rollover bar -- and thus the fairing -- and risk cracking it. Therefore, on the advice of others, I laid up fiberglass then layered a couple strips of carbon fiber, then topped with glass again. That sucker's pretty strong!

I also added a couple of aluminum grab handles to the bar, which pretty much eliminates any urge to push on the canopy fairing. Man, are those handy! They should be part of the kit, IMO ...

[Transporter]

I'm going to give aluminum a try. Keith Schult's RV6A here at Lee's Summit has aluminum canopy trim and it looks great (and is plenty strong).

ML Skunkworks offers patterns and a how-to DVD:

http://www.mlblueskunk.com/Windscreen_Fairings.html

Going the aluminum route requires use of a shrinker/stretcher so I figured I'd add to my skill set and give it a try. If I don't like it I'll drop back and do the fiberglass layup.

Good luck,
Mike

[DanH]

Originally Posted by miyu1975

I went ahead and ordered S and E glass...anything wrong with laying S on top of E?

Nothing "wrong", but if you really wish to optimize the use of higher strength or higher modulus fabrics you need to place them in the right location in the layup.

Imagine 5-ply layup with the plies numbered 1 through 5 starting at the bottom of the stack. Now bend the cured laminate so the ply #1 surface is concave and the ply #5 surface is convex. Ply #1 is in compression. Ply #2 is also in compression, but less so than #1. Ply #3 is at the neutral axis, and so is neither in compression or tension. Ply #4 is in tension. Ply #5 is under greater tension.

The fabric's contribution to bending strength and stiffness is governed by its distance from the neutral axis. If you want to increase bending stiffness or strength, put the high modulus or high tensile fabric in the ply 1 and ply 5 positions, not in the middle of the laminate. You could place an exotic boron fiber super fabric in ply #3 (on the neutral axis itself) and it would not increase stiffness or strength in bending in any useful way. All it would do is waste money.

[miyu1975]

DanH....are you saying to put S glass on lay up 1 E glass on layup 2, 3, 4, and S glass on layup 5.?

[DanH]

Originally Posted by miyu1975

DanH....are you saying to put S glass on lay up 1 E glass on layup 2, 3, 4, and S glass on layup 5.?

Yes, symmetrical layup, stiffer/stronger on the outside.