Scotch Yoke Formulas Scotch Yoke Formulas patma12345 (Mechanical) (OP) 24 May 15 18:01 I need to see if anyone can help me. I am needing how to calculate torque on the slot at different angles on a scotch yoke. if you have an Excel spread sheet I can plug in values that will help. Does the Bourke formula book have any of this so I can do it?. Has anyone used the book to generate an Excel Spread sheet that works. RE: Scotch Yoke Formulas GregLocock (Automotive) 24 May 15 22:07 ok, taking theta=0 at top dead centre and F as the force in the connecting rod between the piston and the yoke, and r as the throw of the crank, then CrankshaftTorque=F*r*sin(theta) Please do let us know how you get on with the Bourke engine. Cheers Greg Locock New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm? RE: Scotch Yoke Formulas patma12345 (Mechanical) (OP) 26 May 15 15:45 thanks for the help. RE: Scotch Yoke Formulas EHudson (Mechanical) 5 Jun 15 04:00 The place to start with Bourke engines is an article by J. David Kirk in the EAA magazine 'Sport Aviation' of many years past. Essentially debunks the Bourke myth with real engine tests.