If I remember right, someone posted that the polycarbonate rear window has a special coating to protect it from gasoline and sunlight.
Maybe this is old ground, but why not just replicate the window in plexi? Maybe the window itself is structural? Hope not
Dick, I am pretty sure it is considered structural. Someone was making a premolded plexi unit, but I haven't heard anything of it in several years.
I have similar crazing in my lexan but its on both sides and I know I haven't spilled any fuel on the pilot side so I suspect there is more going on here.
Over stressed?
I think a plexiglass replacement would be nice.
This is what I am working on.
http://www.joesrv12.com/Builder Log/al_07_01.htm
If anyone has experience bending Plexiglas please let me know.
Can I heat the small side windows and bend them around the aluminum or do I need to make a mold for bending
any help will be appreciated
Thanks
Joe
Joe,
If you heat those small pieces to a pliable state, your heat source needs to be pretty close to the aircraft. The acrylic will start to cool very fast, and you won't have too long to work with it. IF you went this route, you'd need a helper to quickly hand you the 'D' windows while you are inside the fuselage, then you kind of hand form them into position while waiting for them to cool. But even then, you may not have enough time to work the material. I'd build a simple form and drape form them outside the aircraft, let them cool, then proceed.
It should be very easy to measure/map the radius of that area, and build the form. You can obviously map the radius' from the outside and build the form. Cover the form in felt, heat your material, and drape it onto the form while it is still very pliable. Hold flush on all edges until the material cools.
Dick, I am pretty sure it is considered structural.
Joe,
Won't that make it tough to remove the fuel tank if you ever need to?
Rich
How about this idea? To make a female form, put some wax paper on the fuselage to protect it, then layup some some wet fiberglass on the wax paper. Some wooden battens can be laid on the wet fiberglass to reinforce it. Cover the battens with another layer of fiberglass. Keep in mind that I have never done this.
Or how about covering the outside surface of the aircraft with felt. Then heat the acrylic and lay it onto the felt and hold it until it cools.
How about this idea? To make a female form, put some wax paper on the fuselage to protect it, then layup some some wet fiberglass on the wax paper. Some wooden battens can be laid on the wet fiberglass to reinforce it. Cover the battens with another layer of fiberglass. Keep in mind that I have never done this.
Joe
This was my first thought but I am not sure that the Plexiglas will stay hot long enough to get from the kitchen oven to the shop, however I think I will try this first.
Thanks
Scott,
I'm curious as to what the forces are on the window that makes it structural. I assume it's part of a stressed skin analysis, but is it in tension, compression or both?
Rich
I am curious? What do you use to evenly heat the plexiglass? It is getting interesting.
Please take several pix from different angles so we can really see how the plane looks. Also, what thickness?
Just what is "drape-formed" plexiglass?Talking with the Mother Ship today, I learned there is a drape-formed plexiglass window option now available. Kinda expensive though; I think I heard $389 plus crating plus shipping. I think it's also available as a substitution in the finish kit....but it's way too late for me - think I'll wait til mine crazes!
Just what is "drape-formed" plexiglass?
Thank you.It is when heat softened acrylic sheet material is draped over the outside of a male mold of the desired finished shape and allowed to cool while on the mold. this can generally only be done when the curve wraps in just one direction (not a compound curve)
In contrast to the fwd canopy of the RV-12 (and other side by side RV canopies) which is forced into a female mold using vacuum / atmospheric pressure.
Hope that this is the 'fix' for the 'splash and craze' problems. If so, then will this be the the standard part for the finish kit? Hope so. Best to everyone at Van's.
Talking with the Mother Ship today, I learned there is a drape-formed plexiglass window option now available. Kinda expensive though; I think I heard $389 plus crating plus shipping. I think it's also available as a substitution in the finish kit....but it's way too late for me - think I'll wait til mine crazes!