DIY Backpack patterns?

[Reverse]

Hey folks,
I have a large piece of used DCF (3yrds by 65in). I already have a tarp etc. what I am looking at making with it is a backpack.so my question is who knows of a decent backpack pattern of about 40L. I keep finding kits that include the fabric I only need the pattern. :)
Cheers

[scuddr]

take a look at the "lightweight backpack" in the projects section on thru-hiker.com
its a little smaller than 40 liters, but may be what you're looking for.

[atraildreamer]

Try a google search. Lots of stuff out there.