reborn in america - 1996
Following the decline of the Dakeyne engine and Its derivatives in the middle of the 18th century and the conviction of most engineers then and now that it was a preposterous idea anyway, the thought that the concept should be the basis for a prime mover 150 years later seems an impossibility. But It was, or perhaps one should say it is.
U.S. patent number 85619 was granted to Leonard Meyer in 1996. This was for a nutating internal combustion disc engine. Although the pattern made reference to various other 20th century nutating engines in the United States,there was no reference at all to the Dakeyne engine or to the many steam versions that were built subsequently. Yet the similarity to its predecessors is quite clear from the section shown below. Indeed it is very similar and layout to the Bishop engine. Other than it clearly being a much more modern design and adapted to run as an internal combustion engine, the biggest change is that the disc is not flat but consists of two shallow cones back to back.
With partner Mike Boruta, Meyer formed a company called Kinetic R&D retaining Theodosios Alexander, then a Professor at Washington University St Louis, to advise on the thermodynamics and seal design. The U.S. Army granted a SBIR (Small Business Innovative Research) contract in 2001 to fund development. The military interest stems from the requirement for compact and lightweight yet powerful engines to power UAVs (Unmanned Aerial Vehicles).Designed to give two power impulses per cycle compared with the one power stroke of a two stroke single cylinder engine per crankshaft revolution, the concept has the potential to be quite revolutionary in terms of power to weight ratio.
Baker Engineering Inc of Nunita, Michigan were contracted to build the prototype. The demonstrator was designed to run on gasoline rather than the more challenging task of making it work on heavy oil which would demand higher pressures to achieve compression ignition.
NASA issued a comprehensive report in October 2006 on which the following summary is based.
The complexity of the seal design is illustrated below.
The disc moves over and depresses the radial seals although there is some sliding contact between the respective surfaces. There is no contact between the rim of the disc and the casing but the seal can be seen.
The prototype engine had two discs/chambers on the same shaft and was designed to deliver 130bhp at 3000rpm. The discs were only 8in in diameter. Although the engine weighed 148lb it was built from steel and an aeromotive version would be very much lighter. A projected design suggested a 50bhp output from an engine weighing 32,5lb and just 16in long. This illustrates just how much power could be developed from a very compact engine - a characteristic of the steam versions 150 years before.
Initially the separate engine modules ran on compressed air. Compression efficiencies were good and actually improved as the seals bedded in. The complete engine was tested briefly running on gasolene and it became self-sustaining.
Although the US Army funding ran out in 2006 by June 2008 testing of the first prototype was continuing funded by the USAF Research Laboratory. Mike Borruta, President of Kinetic R&D since the death of Len Meyer in 2005, says those tests are directed to understanding the thermal dynamics. A second prototype made of aluminium rather than steel, is being constructed with the ultimate objective of developing a 77hp power plant weighing a mere 36lb.
In March 2008 the engine won the Silver Award at the World's Best Technology Showcase (WBTshowcase) in Arlington, Texas. It was selected from 70 finalist technologies.
Whether the prototype engine above was ever tested is not known.
In January 2009 the USAF Small Business Innovation Research group reported that Kinetic BEI ( as it now is called) was finalising development of a second generation engine. Several key steps have been taken including the testing of 150 hp demonstrator Compressor and Expander which together work as an engine.