A BRIEF HISTORY OF THE SOLAR #1, AND THE COMPANIES THAT MADE ITJust been doing some comparative studying of a couple of my different versions of the rather common Solar #1 Stirling Engine, as produced since the late 1970's by Thermal Energy Engines of Phoenix Arizona, (TEEPA), Solar Engines of Phoenix Arizona (SEPA) until the mid-1990's and since then it is now produced by PM Research of Wellsville New York (PMR). There are strong possibilities, verging on certainty, that this basic Stirling Engine, in a slightly different form, was originally designed, produced and marketed, starting in the mid-1950's by Davies Charlton Ltd on the Isle of Man in the United Kingdom, a noted maker of petrol powered model aeroplane engines.
Due to another Thread on this Board, rather casually started by member Jasper, that has seemingly taken on a life of its own, suggesting disconnected details and speculations, while attempting to delve into the details and history of this rather interesting, typically inexpensive and otherwise generally excellent running little engine, a number of possible origins, people and companies associated with it through time have been identified and discussed, if not fully understood as to their place in the history of the design.
That thread can be seen here:
https://www.officeofsteamforum.com/general-discussion/stumbled-upon-a-vintage-solar-1/Much like the ubiquitous VW Beetle, this little Stirling Engine has actually changed but little through its production by at least three and likely four separate entities, through a span of at least something over thirty years, and likely more than twice that time. But changes there have been, and so to define those changes, and thus help in identifying the variants currently known to exist, it seems opportune to set down for reference the details that can be known.
This thread should also be good to provide details of the individuals and companies that have been associated with the production of this Stirling Engine through the years, as information is gleaned from various sources, to help define the overall history of what has been an ongoing mystery rife with speculation and uncertainty.
I'll start with a thumbnail of the Solar #1's possible production history:
1.)
Davies Charlton Ltd (D-C Ltd) .... Isle of Man UK, from 1956? to mid-1960's?, or perhaps a bit later?
Possibly (probably) designed and produced the first iteration of this Stirling Engine, which was simply called by Davies Charlton, the Hot Air Engine, and while the basic layout was nearly identical to all later version, right down to the Red/Green/Bare Metal color scheme always used, there was a major difference in the burner style used, back then it being a separate, large flat rectangular tank with a single wick appropriately located on top, and the Quonset hut/mailbox shaped housing for it, which required a large rectangular mount hole in the back part of the base. Hefin Davies, Alan Allbon and Arthur Firth appear to have been the principles in the company during the early part of this time frame, and so could be responsible for the original design and development of their Stirling Cycle Hot Air Engine.
2.)
Thermal Energy Engines of Phoenix Arizona (TEEPA) .... from 1977? to 1977?
Engines with this marking on the underside of the base seem to be the first iteration of this engine to exhibit a modified base to accommodate the integral round burner and cylindrical vertical chimney housing, but otherwise appears little changed in overall appearance to the prior DC Ltd production. If this is in fact (almost certainly) the off-spring American made version, of the former UK product. Interestingly, the names in the literature seemingly first associated with this product are Clyde & John Griffin (Brothers? or Father/Son?) so perhaps they are the ones who worked out the licensing/purchase from DC Ltd to be able to produce such a close copy, if that is what happened. Quite possibly (again almost certainly) tooling was also acquired to produce the parts. It should be noted that the earliest advertisements thus far found in Popular Science (March 1978) magazine, show the rectangular hole in the back of the base for the DC Ltd style burner, but are actually referenced to the next company name (SEPA) associated with these engines ... so there may be some question as to whether TEEPA ever actually marketed any engines, even though it appears there is good evidence that at least some 6,000+ bases were produced with that name molded in underneath, before being machined out of the mold and replaced with the Solar Engines name. It was also somewhere in this time-frame that the engine went from being referred to as the "Hot Air Engine" (aka: DC Ltd), to being marketed as the "Original", and eventually "Solar 1", likely as the other heat engine offerings started to make their marketing appearance.
Though nothing substantive concerning the Griffins has as yet turned up, it may be that they were engineers and or machinists with the technical know how and ability to upgrade and modify existing tooling, or build new tooling from scratch, as well as design the entire line of subsequent offerings produced under the Solar Engines banner. However it is also possible that much of the initial redesign work on the Solar 1, as well as the designs for the subsequent line of engines, could be attributed, at least in part to Andy Ross, who clearly came into association with the engine at an early stage, and besides authoring the book that generally accompanied the Solar 1 engine, was an accomplished Stirling Cycle Engine designer and experimenter in his own right, making numerous significant contributions to the field!
3.)
Solar Engines of Phoenix Arizona (SEPA) .... 1977 to 1995?
This is perhaps the most famous name associated with the Solar #1 Stirling Engine, and it is under this company's banner that the full range of more than a dozen heat engines were produced carrying the Solar Engines brand name. The Griffin's hinted at more models to come in some of the earliest ads, that still had them listed as principles in the company, though by about 1980 or even earlier, they seem to have disappeared from the scene, and the whole show seems to have been under the direction, if not actual production of Ed and Jeanette Morgan. The Morgans and their JEMCO (Jeanette & Ed Morgan Company?) Imports enterprise, may well have bought out the Griffins, or possibly the Griffins were just in as operations personnel under the Morgans all along? Once the Solar Engines logo started appearing under the engine's base, other minor changes to the engines are noted as well, such as no longer having the inboard tab for holding the chimney in place drilled and tapped for a thumbscrew, and having a small vent / pry slot, for the alcohol reservoir fuel cell cover, notched into the back edge of the base. Sometime in the early 80's the practice of hand stamping consecutive serial numbers was abandoned, but not until the count was well up into five digits, with the suggestion that it might have continued into the 20,000 range at least. Solar Engines of Phoenix Arizona actually developed and produced an impressively wide array of heat engines, many being recognized as classics and widely produced, while others were made in very limited numbers and were hardly ever advertised, so remain as extreme rarities to this day.
4.)
PM Research (PMR) .... Wellsville, New York, 1995 to Present
With little change noted, other than the company name molded in underneath the base, the Solar #1 is still being produced today, essentially unchanged from SEPA production. PMR has continued production of many if not most of the SEoPA line, and certainly has continued producing all of the more common engines. The prime operatives for PMR at the time of the SEoPA purchase, appear to have been Gary Bastian and Paul Vossler. There is some suggestion that SEPA and PMR were in some level of association prior to the outright purchase of SEPA by PMR.
Note: this is just a start, and hopefully this thread can be somehow preserved, added to and be refined as information and artifacts come to the surface to flesh out this rather interesting and obviously dynamic story of a wonderful line of heat engines that all started with the humble, ubiquitous and rather excellent little Solar #1, or rather the Davies Charlton Hot Air Engine, as that actually seems the true start.
Needless to say all additions, corrections and observations are welcome here, and I do plan to come back thru with more details that I already have to hand (but am too tired of typing just now to add), along with adding pictures, as I get around to finding, taking or "stealing" them as will best suit the reference.
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