Windshield pattern

[FredN]

I want to make a windshield. How do I figure
out the shape of the pattern? The side view is
a triangle with the top long measurement is "A", the
up and down measurement is "B" and the third
measurement is "C". The top view is a a half of
an ellipse with the side to side measurement is "D"
and the front to back measurement is "C".
I think it should look like a football, but how to I
figure out the exact shape and size?

thanks,
Fred

[steve lewin]

It may not be very scientific but I always just make paper/thin card templates and chop them about until I get a decent fit.

Steve

[BMatthews]

Originally posted by steve lewin
It may not be very scientific but I always just make paper/thin card templates and chop them about until I get a decent fit.

Steve

Yep.....

[DICKEYBIRD]

Double yep....One thing I stumbled across after I'd been into the CAD thing a while was that if you make your front upper fuselage a true half ellipse or I suppose a portion of an elliptical arc, your windscreen will have a perfectly straight line where it meets the fuse, regardless of the angle of the screen as seen from the side view. Doesn't seem logical but there must be some geometric truism that applies here. I've done it several times now and it worked every time.

Also when making a one piece w/screen that wraps around the fuse sides, cut and fit your 2 side screen patterns 1st, then do the front screen and tape it to the 2 "wings." I guess a 3D CAD wizard does this in about 2 seconds!;)

Here's a pic:-

[FredN]

I played around with my CAD program and came up with
this technique. Looking at the diagram below, the side
top and front view are shown in blue. I drew the side view
with dimensions of "A", "B" and "C". The windshield has
a width of "D" as shown in the top and front view. I then
took measurements "C1" and "B1". I then drew a line
of length "A". I then drew 2 circles of radius "B1" and "C1"
and centers at the ends of line "A" as shown. I then drew
the curves shown in red from the intersection of the circles
and the end of the line.

Fred

[FredN]

Lets try this again:

[FredN]

I drew the pattern and cut it out clear plastic and then
glued it on a flat piece of plastic:

[FredN]

I then attach the windshield to the plane with just the
rubber bands that hold on the wing. For more information
about the plane, please see my post:

http://www.rcgroups.com/forums/showthread.php?s=&postid=1177045#post1177045