The
first attempt at a TurboTurbine is a very crude 'Heath-Robinson' affair. There are more
pipes, bits of wire and dodgy connections than I really like but it works and that is all
that's important right now! The whole thing was rushed together so that I could have it
working at the end of my weeks holiday - and it was a rush job too.
The main components are as follows: -
The turbocharger is from a Ford
Escort RS turbo. It is a Garrett - model TBO 355, s/n QLO 408A. The turbocharger was
kindly donated by my good friend Kevin Wallis (from Wallis Motors). It had already done
good service on his car and was replaced due to the oil seals leaking (loads of smoke from
his car). It was still perfectly serviceable for my purposes and has proved to be quite
easy to connect to the other parts of the TurboTurbine.
The combustion chamber is manufactured from steel with
the following parts: -
-
The outer tube is a piece of 4 inch steel steam pipe 13 inches long.
Each end of the pipe has a large round steel flange welded to it to take the end caps. The
flanges were cut from a large propshaft.
-
The end caps for the tube are made from 8mm steel plate (6 inches
square). This may seem rather heavy but allows tapped holes for spark plugs, gas inlets
etc.
-
The internal burner pipe is made from a 10inch piece of 2 inch steel
exhaust pipe, drilled with a (guessed) hole pattern for gas mixing.
-
The end of the burner pipe carries a flange plate which directs all the
airflow through the burner pipe. This produces a cooler gas stream from the burner as well
as aiding combustion.
-
The inlet and outlet ports are welded into the outer steel pipe at the
top and bottom ends. (Thanks to Steve, Dave and Craig at TIS Services for gas cutting the holes in the pipe which has 1/4 inch
walls and was too much for drill and hacksaw!)
Cut Away view of the combustion chamber.
The gas injector is made from a 10mm bolt drilled
lengthways to take a piece of copper brake pipe. The end of the brake pipe is squashed
flat to make two small jets for the gas to flow through.
The spark ignition is provided by a home made spark
circuit. This was made from a small windscreen wiper motor assembly. With the case off the
wiper motor, one of the drive gears was filed to make a small cam. A microswitch was glued
to the case with epoxy glue so that the switch actuator is in contact with the cam. The
switch was then wired up to a 12 volt car ignition coil. This system seems to work OK but
is a bit fragile. I intend to replace it with an electric fence supply (the kind used on
farms to keep sheep and cows in their field!)
The air starter is made from a 750 watt vacuum cleaner
motor blower mounted inside a wooden box. This produces a very good blast of air which is
piped to the inlet of the turbo charger via a length of vacuum cleaner hose (I might as
well use as many parts of the cleaner as possible.) The air starter is very noisy in
operation and ear plugs are needed when standing near it for any length of time.
The oil supply is from a car windscreen washer pump. This
does not provide much flow or pressure but is adequate for now.
Running the TurboTurbine
The first tests were made on the combustion chamber without the turbine
attached. This was to allow me to modify the burner pipe to get the most efficient burning
without melting the turbine blades. The air starter was used to provide airflow for the
tests.
After a few testing cycles, the burner pipe produced quite good combustion
at gas flows (propane) with 1 bar pressure. The limit to pressure was the airflow from the
air starter. The air injection end of the combustion chamber stays cool to the touch when
in use (even after 20 minutes) whilst then hot end gets rather hot (but not glowing).
Planned Modifications
The oil supply needs sorting out. I have got hold of
a power steering pump from a Landrover which I will power with an electric cooling fan
motor from a car. This has been tested by powering it with an electric drill and gives
good flow and pressure. An oil system with a controllable bypass tap should give reliable
oil supply to the turbine.
The spark ignition also need sorting out to give a
neater system and as mentioned previously, I now use a simple car
coil circuit.
The turbine also has a water cooling circuit which I
will connect soon.
The whole thing also needs to be mounted in a
suitable frame to make all the connections permanent. It is currently all loose which
takes some connecting together when testing.
