Ed Blakeman's Doble Triple

 

This engine was fabricated by Ed Blakeman of Orange Beach, Florida over thirty years ago.  It follows the basic design that is given in the John Walton Doble book, starting on page 139.  Doble never made one of these engines.  It was designed while he was in England working for the Sentinel steam truck people in the late 1930’s.  He designed this triple expansion double acting piston valved engine to produce 100 hp at a 10 pound water rate.  The dimensions are a 4” stroke and the cylinder bores are : 2 ½”, 4”, and 6 ½”   Doble Triple
 
Doble Triple   with receivers running between the cylinders and re-heat between the middle and low pressure cylinders.  Blakeman improved the design by using poppet valves actuated by hydraulic cylinders with the hydraulic controls coming from commercially available hydraulic solenoid valves. It is not immediately clear what the control system was, however, it should be easy to construct some variable electrical timer to accomplish completely variable control of the cutoff timing.
 
Witnesses say that the engine was not perfected.  It is an excellent example of what the size and shape of a Doble Triple is, as well as the great amount of metal fabrication needed to make the heads and valve seats.
  Blakeman's Doble Triple
     
Blakeman's Doble Triple   Blakeman's Doble Triple
     
This version has solenoid operated poppet valves instead of the eccentric driven piston valves in the original design.  The rumor is that it did not make much power and the reason appears to be the very small poppet valves that restricted the breathing.  The receivers are very well fabricated.  It was an immense amount of machining work.