Hi Mike,

I don't think there's a simple answer. I can't open the link to see the plans in question, so cannot tell what type of file they are or even if they come with a scale bar. However, I ran across Irfanview with regard to CAD drawings, so if that is what you are looking at it sounds like you need to get some CAD skills to print them to a set scale.

Can you look at the files and post a full file name with extension so we can see what type they are?

Regards,

Tom

use paint.net - it is basically a freeware version of photoshop (some of the more advance features not there of course), then follow this proceedure:

1. find out what the proper wing span or some other characteristic length should be (if there is a scale rule, then great). convert this to the scale you desire.

2. open drawing in paint.net (or photoshop if you have it)

3. in paint.net under the view menu, open rulers (if it isn't already).

4. again in the view menu, select either inches or centimeters - whatever units you have converted your characteristic length to.

5. in the Image menu, resize your image file till the characteristic scale length measures out properly on the ruler. this may take a bit of fiddling to get perfect.

at this point you now have a scale drawing. now you just need to make sure that the image prints the same as it actually is scaled out. converting to PDF may help with this if you are having issues with normal printing.

you might also want to double check your scaling with one or two other characteristic lengths, keeping in mind that measurements listed for a vehicle may not exctly match those used in the drawing and that you really can't say which is the more accurate.