Hey Paul
  I ran across this today and found it interesting... What do you think?
I would think it would be pretty tough to dynamically balance the
thing....they are making some pretty impressive claims 1.6 hp/lb.

Mike C.


 http://gltrs.grc.nasa.gov/reports/2006/TM-2006-214342.pdf

Aluminum nutating engine in combustion tests
By Rob Coppinger
DATE:11/09/09
SOURCE:Flight International
Tests using heavy fuel are under way for an aluminium nutating engine
that could deliver the power density that the US military requires from
its internal combustion powerplants.
A nutating engine uses a disk that "wobbles" inside a housing so that
its edge pitches up and down, creating voids that increase and decrease
in volume. The wobble is known as nutation and effectively each disk
takes the place of four pistons as each disk has four voids.
The aluminium version is considered the second generation, following a
first-generation steel prototype. Development of the nutating engine has
been supported by the US Army and continues to be by the US Air Force
Research Laboratory (AFRL).
For AFRL an 150hp, 40.9kg (90lb) aluminium nutating engine is being
developed by Illinois-based Kinetic Research and Development as part of
a joint venture with another US company, Baker Engineering.
Nutating engines are expected to achieve a power density that would
enable a 14.7kg (32.5lb) powerplant to produce 50hp (37.3kW), which the
US military says cannot be matched by other internal combustion systems.
A 50hp engine with a mass of 14.7kg has a power to weight ratio of 1.54.
However Kinetic and Baker's aluminium nutating engine will achieve a
power to weight ratio of 1.6 if its combustion tests are successsful.

According to Kinetic Research and Development president Michael Boruta,
"this [aluminium] engine would be good for a [General Atomics
Aeronautical Systems] Predator size class of [unmanned air vehicle],"
and he added that testing is now "concentrating on combustion" with a
focus on "different spray patterns, fuel injection methods and timings".

As well as UAV propulsion for near-term applications the US military is
also interested in nutation for electrical power generation.
The companies are also developing a smaller 7hp version for miniature
munitions propulsion for the AFRL. This has a single disk, the larger
aluminium powerplant has two, and after six months of testing the 7hp
engine hardware is now being manufactured. The company has another
contract, with the US Defense Advanced Research Projects Agency, for a
single disk 8hp engine purely for power generation.
http://www.flightglobal.com/articles/2009/09/11/331644/aluminium-nutatin
g-engine-in-combustion-tests.html

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If one things a piston engine is a mechanical nightmare one must take
a look at this. This thing has a snowballs chance in the hot end
of a 777 engine. :)

The qualifications for a job at NASA just took a nose dive :)

Paul Lamar