There is an Excel format "arc calculation" now in alt.binaries.pictures.woodworking. It's a small spreadsheet, so it's easy to download.
It's primarily for those who don't use a CAD program but like to layout on a grid. It calculates the heights to the arc from various points along the half-chord length. This is done for 20 divisions of the chord for 20 points on the arc, but you might not need all of those. Just enter your half-chord length and height into cells D7 and D8, and press F9 to calculate. Print, and use the heights to find the required points. The sheet is not protected, so don't overwrite formulas, but otherwise use as you want.
Enjoy! Suggestions welcome on this one or for any others [except compound angles which have been beaten to death ...but OK if you insist, or for more complex ones involving costs etc.] I do this for free, so don't want to get too involved in them. I'd consider a more complex one if it payed, so any suggestions there also appreciated.
Bill.