Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Here is a special one of a kind Jensen 50.


This engine was Tom Jensen Sr.'s own prototype test bed for the early 3 heater Jensen #50's.
It dates to the time Tom Sr. began lighter blue-green paint and copper clad sheet metal faux brick fireboxes and chimney stands.


When I first got it, I sent pictures to Tom Jensen Jr. and remembered it well sitting on his Dad's desk for about 6 months during the trials period before becoming part of regular production.


It uses the same 2 socket Bakelite plug in block that all #50's from the 1930's through this time used along with a large blanket heater on the underbelly of the boiler. Also there are 2 pigtails coming out of the chimney stand just as all earlier models had. Tom Sr. connected the blanket heater and the inside cartridge heater to the inboard plug. For this test bed, he used a left over #50 riveted boiler. The 2 ceramic cartridge heaters are identical to all those used from the 1930's through the latter 1960's when the #50 got 3 Hot Watt immersion heaters.

It is easily recognizable as the only copper brick fire boxed #50 with a riveted boiler, 2 plugs, and the center screws for the blanket heater in the lip at the top of the firebox.


The standard production #50's after this one had the same 3 heaters with the addition of a 3rd pigtail and a 3 socket Bakelite plug block. They were made this way until the introduction of the immersion heaters late 1960's.


Below are 2 videos of this engine getting a good workout to make those heaters do some meaningful work.


In the 2nd video I swapped the safety relief for one that will hold 30 psi plus.


Enjoy,


Gil