Below
can bee seen some pictures of a Nimbus turbo shaft converted
into a turbo
jet by the separation of the gas generator from the rest
of the engine, however
the engine itself looked a little rough. So while it was
apart to do a few things
I gave it a once over, an internal clean up and external
restoration.
The cell below was built for investigating the suitability
of different fuels to
be run in small gas turbines. The Nimbus has centrifugal
fuel injection and
thus no high pressure fuel system at all and this is an
excellent system for
burning rubbish fuel. In the cell I installed three different
fuel systems that were
all able to be interconnected in different ways with selections
at the control
consol. One of the fuel systems was normal kerosene or diesel,
one had a
macerator in it and an agitator to try fuel containing light
fats and solid plant
material, the other had a very powerful heater and pumps
along with trace
heated pipes for running heavy fuels like tallow and palm
oil (which is solid
below 25-30 degrees)
The
most severe fuel that I succeeded in running was Tallow
(rendered
animal carcasses). It ran fine when it was heated to 90'c
with no smoke or
smell. It did however dissolve my magnesium filter bowl
after a while which
was a pain as the entrained airflow through the cell covered
everything in
quickly solidifying smelly glue...
Don't let the covers
on the test cell intake and exhaust fool you..
the tops and reducers were only on as weather covers when
not running
Half
way through my build I decided to turn the engine around
and add servo hp cock and throttle controls.
As
test cell aerodynamics do not have to be far out to be completely
wrong
and trial and error will simply not succeed, I decided to
go for a sealed
exhaust. I controlled the airflow in the cell with variable
louvred apertures.
After a few hours messing around with it I managed to keep
the air in
the cell below 25'c with the cell remaining at just below
atmospheric pressure.