The more I look the more it hurts, [link=http://www.roymech.co.uk/Useful_Tables/Drive/Epi_cyclic_gears.html]Site 1[/link], [link=http://www.technologie-entwicklung.de/Gasturbines/TS-21/Gear_Box_Details/Gear_Calculation/body_gear_calculation.html]Site 2[/link]. Fourier transforms using laplace was about my limit.

Yours Simon M.