Take your drawings to Fedex/ Kinkos. They can size and print it for you. If there is no scale on the drawing you just need one 'known' dimension to work from, ie, a 2" spinner or wheel size. Maybe the actual wingspan is known. With one known number they can scale it for you. If only half a wing is shown then mark off length and rib locations on each end of a full length leading and trailing edge. It's really pretty easy once you think it through and start.
Dave