The parts list for the 1956 Fox 29R "bathtub" engine is attached. Unfortunately, the part number for the crankshaft is '29RC' and a Google search for that will get you every Fox 29 R/C engine ever made, but not a 29R crankshaft with that part number. You will probably have to cannibalize a donor engine -- if you can find one. Are you trying to make a running engine? I also included the 29R engine test from the May'58 Aeromodeller FYI.