Fuel tank in Fuselage problem

[leshoman]

Something to e aware of before mounting fuel tank near windshield, it appears that lexan, pycarbonat, can be lived with, using automotive fuel eats the windshields up.  Something has changed i the fuel in last few months and getting it near windshield results in lots of cracks and windshield replacement.  Much worse now than a year ago.

[Chuck in Indiana]

Fuel and oil has always been a problem with polycarbonates. We built a Pitts with a Lexan belly so my building partner Ed the Rocket Scientist (RIP)could better see the aerobatic box. Just one overflow filling the fuel tank was enough to trash them. I made several over the years.

[pappyadkins]

interesting... I'm amazed when I see the various damage these 'new' fuels cause... I guess the positive way of looking at it, you don't have to clean those bugs off the old one now...

[Chuck in Indiana]

https://plasticexpert.com/learn/how-does-polycarbonate-fail/

Polycarbonate (PC) is an amorphous (non-crystalline) plastic. PC is nicknamed “bullet-proof glass” because of its highly ductile response to high-speed impact. PC is highly impact resistant because of its “free volume” between the long chain molecules. However, the amorphous nature and high free volume between the molecules, causes PC to have exceptionally poor chemical resistance. PC readily absorbs many hydrocarbon chemicals causing it to become brittle and fail by a process known as Environmental Stress Cracking or ESC.

It has never played well with hydrocarbons, and is one of the reasons I put the fuel tank in the wing.. as much as I *hate* fuel tanks in the wing.