sunshine
Administrator
Registered: Feb 2002
Location: Amarillo, Texas
Posts: 13 |
The Shafter Twins
The next few questions from Joe refer to the "Big" Shafter Twin:
quote:
3 and 3a. The industrial engine test in the orchard sounds good. Was that a water pump operation? What size engine was it?
4. How many hours of operation did it get?
5. What was the prognosis of the post operation inspection?
The "Orchard Test" was conducted on a farm near Bakersfield, California. Mel's Engine was the "Big" Shafter Twin, a Bourke style engine with a scotch yoke, 200 cu. in., running between 1200 - 1750 rpm, on natural gas.
The other engine was a 200 cu. in. Minneapolis Moline diesel, converted to run on natural gas. The engines were each trailer mounted and were pulled into various irrigation fields on a rotating basis over a six month period.
Each engine produced approximately 35-40 foot pounds of torque at 1500 rpm, although this was not measured directly on a dyno, but extrapolated from the pump requirements.
Both engines ran the same pump, on a rotating cycle that lasted one week each. The "Big" Shafter Twin pumped the same volume of water as the MM, but used 40% less fuel. The BST has been run and disassembled many times, and shows no discernible piston or cylinder wear. As far as we know, this is the longest lived Bourke Style scotch yoke engine ever made.
Part of Mel's local legend arose during this test, because the local gas supplier accused the farmer of fiddling with the gas meter during the weeks the BST was pumping water. I heard this story from one of the regulars at an old restaurant where Mel is known up in that part of California.
During this particular test, both engines were run for over 2,000 hours each. Mel estimates the BST has been run over 20,000 hours in its lifetime, most recently in August, 2001, when it was fired up for a very brief (less than 5 minutes) demonstration run for our new Joint Venture Partner.
You should be able to see a film clip soon of the BST on Wolfey's Bourke Engine website. Visit
www.bourke-engine.com
These test results are developmental. Meaning that they cannot be utilized to measure the present state of art of the DeVaux Engine. The BST has a scotch yoke instead of a Torque Energy Cam, has a different port timing and port placement scheme than the current DeVaux Engines, and is a twin rather than a four cylinder module.
The Baby Shafter Twin displaces less than 5 cu. in., but utilizes a very early modified version of the TEC, and turns at much higher RPM.
The current models of the DeVaux Engine are much different in design than either of the Shafter Twins, and although the Tehachapi Series exhibits superior performance in most every respect compared to the older designs, we have never run any of the current developmental prototypes for longer than 20 hours.
The Tehachapi Green III will be completed soon, and we plan to run a few longer term longevity tests on a generator with that engine.
More of Joe's questions (6, 7, 8 & 9) answered later. (And the rest after that.)
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06-15-2002 08:14 PM
