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8-29-2005
444 TWELVE Engine Test Progress
It has been about 2 years since we first debuted our engine at Oshkosh, and
since that time, we have been busy testing and perfecting it. Our first
significant power run was performed on 8/8/03. Many runs have taken
place since then, and with each run we learn more and push the designs a
little farther. As Oshkosh ’ drew closer, we were again faced
with a difficult decision: should we stop our testing and engineering development
right at a critical time in order to make an appearance at the show, or should
we forego the show for the sake of continued progress? After careful
consideration, we concluded that progress must come first. We sincerely
missed being at Oshkosh this year, but in our hearts, we know that our time
over the last few months was wisely invested in test time.
The Nagel Engine Company has been testing and improving our engine while running
entirely on the dynamometer.
One of our central testing ideas has been to rely on instrumentation to detect
and isolate problems without destroying parts. This non-destructive
approach has been working so far. We have an optical encoder attached
to the rear of the crankshaft, which gives us an instantaneous interpretation
of the motion of that end of the crankshaft. After much work, we have
applied strain gages to the front of the crankshaft, adjacent to the
output drive gear. These gages are giving us a finely detailed, immediate
picture of the torque output of the engine. Additionally, we have much
other instrumentation applied to the engine, including exhaust gas temperature
indicators, load cells, fuel flow analyzers, and pressure gauges installed
throughout the lubrication and coolant systems. Within the next few
weeks we anticipate installing instantaneous cylinder pressure
measuring sensors.
We have had some troubles with the operation of our unique dynamometer
system throughout the testing process; however, we have taken some simple
steps to alleviate these problems. A common joke around Nagel Engine
is that “"it seems easier to design a good engine than to design
a good dynamometer!"
We have revised the engine's internal oiling passages and outlets to reduce
the volume of oil needed, while still maintaining proper lubrication. Our
instrumentation has identified a problem with the vibration damper on the
rear of the engine. We have recently made revisions to the damper and
expect good results. Some mechanical interferences damaged the ignition
pickup board, but they too, have been corrected.
We have torn down the entire engine - for a 4th time now, for a full inspection
after testing at full throttle. All parts looked excellent. The
main drive gears show excellent contact patterns and virtually no wear.
We are presently
revising the Crankshaft to reduce torsional displacement. Although
we have had no parts fail, our instrumentation indicates a change is
required. Unfortunately, this will take some time and will delay running
for a while.
We continue to resist making any production forecast or setting a schedule. The
engine must run hundreds of hours at maximum power before a realistic schedule
can truly be set.
We appreciate your continued interest in our project, and as we progress,
we will continue to keep you updated.
12-1-03
Video of the 444 TWELVE test start added to site...
8-7-03
We will be testing the 444 TWELVE engine on the dynamometer for the next
several months to determine fuel consumption, instantaneous gear loading,
and crankshaft torsional vibrations. As we go through these tests and
work with the engine, we will be more able to answer questions about
cost and availability. We do not have this information at this time.
Dimensional information has been added to the website. We hope this will
help to determine what applications are practical. We do not know what space
is available in specific airplanes.