The most common type of engine dynamometer today used by engine builders the world over, must be the eddy current machine. But few will ever forget, of those who ever used them, the DPX water brake. Made by Froude in Worcester, England since shortly after the turn of the (20th) century, and once to be found gracing some out-of-the-way engine test facility at University, to many this would be their introduction to the subtle art of engine testing. Classed as a fluid friction device,...