In the course of getting back into this hobby, and in attempting a tiny Gnome engine for my FG Sopwith Tabloid, I found I needed something to tell me how many layers and what lengths were required for rolled tubes.wall1 Tapping on the calculator all the time got boring. So I used VB6 to throw together the attached little utility to calculate it all for me. To use it, unzip and double-click RPLCalc.exe (if you're totally paranoid, virus check it first). If you get messages about not being able to find some files, see the note about VB6 runtime below. Follow the instructions on the app's window and click the Calc button. It will then display the total length required and the length of each layer - useful for stepped or tapered rolls. The entries are all in mm to three decimal places. Which sounds like massive overkill - but remember you will need to allow for the glue layer and any resulting moisture expansion. You will need a bit of experimentation and comparison of results with the calculator will give you a reasonable figure - about 0.05 mm worked for me with a white 'craft glue'. You need to be very accurate in getting the thickness and inner diameter right. Paper manfacturers' specs are not always that accurate, and wire diameters can be a bit off spec too. Digital calipers are the go, although you can use the 'stack and measure' method to get a reasonable figure (stack 10, 20, 30, etc thicknesses together and measure with a ruler; then divide by 10, 20, 30, etc to get the single thickness). The source is included with the EXE for anyone who wants to tinker with the code (I hereby relinquish all rights to this code, etc, etc, blah, blah, blah). Any mods welcome. There's a little error checking and some crude bounding for entered values. Anyone familiar with VB won't find it hard to mod. It uses no ActiveX controls, so should run on most machines. At worst, you might need the VB6 runtime package, which is freely available from http://support.microsoft.com/kb/290887. Not tested in Vista, but is anyone in their right mind still using Vista? Hope it might be of use to some of you dedicated scratch builders.