Light Aircraft Association

I'm considering renewing the transparencies on my Jodel D112.. The windscreen is fine, but the side and rear windows have star cracks, are faded and could do with some sprucing up.

I've looked at Perspex, Makrolon and Lexan and I've seen one of these stained by MOGAS before, but can't remember which one. I would fabricate the windows and bend them myself.

Has anyone got any recommendations before i part with cash?

Dave
I used 3mm perspex for the windscreen on my project, (D11 new build),and 2mm polycarbonate on the sides.
I have found in the past on a couple of single seaters, that if you get any fuel at all on to polycarbonate which is bent it cracks almost immediately.

The polycarbonate is very easy to work , easy to cut and drill , with no risk of cracking, but you need to be very careful with perspex, and always use the correct drill bits

Good luck,

John Macleod

I have used polycarbonate for my windscreen but I already know that I must keep ALL fuel and solvents away from it and that it is softer and able to be easily;y scratched. I saw a screen on a plane shatter and turn pink from the affect of the fuel breather on the tank in front. It happened whilst parked in the hangar and others thought that it was vandalism at first.
Be prepared to allow for the downside and reap the benefit of the strength that it gives, Just don't clean it except with soft soapy water.

For those that don't know, Lexan is clear polycarbonate.

John,
how did you make your D11 screen in 3mm perspex? I presume you made a wood former and you have an oven? Can I get away with bending a sheet with a little heat persuasion during a gradual clamping session around the windscreen hoop? I need to make a new screen for my Sipa 903 (which is similar in size) there isn't one to use as a pattern though and as my fuel tank cap is 6 inches from the screen, Lexan is out!

regards,

Andrew

Hi Andrew
I made a flat screen as on the original drawings. Most jodels have curved screens which would be very difficult to form without specialist equipment and knowledge. I bent a flat sheet over the frame to make a template, trimmed it slowly to size and then transfered it on to the perspex.
I think I used a small ammount of heat from a gun to to help bend the screen, but it is better to have a warm workshop, and store the perspex in a heated room prior to bending. I have found previously that it is very easy to apply a bit too much heat with a hot air gun, and damage the perspex. I bent the sheet over the frame and used plastic clamps to hold it down. then drilled the holes with a perspex drill, using a slightly oversize drill

John

Dave
One basic difference between Perspex and Lexan not so far mentioned.
You can take hammer (or your fist ) to Lexan and it won't shatter whereas Perspex will.
I have a friend who had to extricate himself from his Jodel when it was in an "unusual attitude", if the side screens hadn't been Perspex he would have been badly placed, but he scrambled out with no external assistance.
2mm Perspex for the sides makes more sense, especially as they're all "flat" panels.

Hi Andrew

The best heat source I found was a 4 ring gas cooker, but you have to
keep moving otherwise you get the bottle in the door affect

Mike

Would be nice if we still had the old forum.
There was a good thread on forming perspex canopies on that.

Unless, of course, anybody knows different....

HI,

here are some links to some useful articles on forming canopies which make interesting reading:

http://www.sdplanes.co.uk/misc_files/Br ... nopies.pdf

http://www.sdplanes.co.uk/misc_files/mo ... nopies.pdf

http://www.sdplanes.co.uk/misc_files/pa ... iglass.pdf

I've never tried to do anything like this myself........

regards

Colin

Dave, it appears I have 'hijacked' your thread , sorry about that but thanks to all for your advice. I will attempt the 'heat gun and clamping' route first, as my screen doesn't have too much of a curve longitudinally.


Andrew