Wren Turbines Ltd. MW54 Mk2 & Mk3 Turbo-Jet, kit assembly instructions, Jun 2004
Page 26
Starting the engine.
OK, so you’ve assembled and balanced the engine perfectly, mounted it on a stand, got all your running gear set up and got a helper - you’re now
at the point where you turn from spectator to fully fledged turbine operator!! You should be out in the open and definitely not tucked into your
garage hoping no-one will hear – they will, and you will suffocate with the fumes! Make sure you are wearing your ear defenders and have your
fire extinguisher close to hand. Re-read the safety Instructions at the front just to be sure you haven’t forgotten anything. Have a colleague on
hand to operate fire extinguisher if needed. Do not make these first runs in public – you’ve a lot to concentrate on as it is.
Ready?
First, check any set-up information supplied with your ECU. Connect your ecu readout. Place your transmitter where it can be easily
reached (not on the ground). Set your trim to “stop”, turn on transmitter then the receiver and watch for the display coming on. Verify ECU is at
“stop”. Check the temperature at which the fuel ramp starts (usually 100’C)– you will need to get to at least this on the gas, to start. You can now
raise your trim to the “start” or “ready” position – verify this on the display and there is also a green led which lights on the end of the ecu. Turn on
your glow-plug supply and spin the engine up gently to a few thousand rpm with the starter motor and let the rotor spin down whilst opening up
the gas.
The rest happens quickly so be ready!
Starting.
You will hear a “plop” as the gas lights back into the engine and this is the signal to open the gas a little more. Blip your starter motor or
starter wand to spin the engine up gently – not too fast or you will blow out the gas – say about 8-10,000rpm. You should see the ECU showing a
temperature rise and once over 100’C it will then start to ramp up the fuel pump and fuel should then start flowing to the engine. Keep blipping
until you hear the engine note change to indicate the fuel has arrived at the engine and it will start to accelerate quickly. Switch the starter full on
at this time
and keep it on
while it to accelerates up
past
30,000rpm
- it is not able to run on it’s own below this speed. The engine should now
be accelerating nicely and once over 32,000rpm or so you can remove or switch off the starter and the gas and glow-plug may now be turned off.
The ECU should continue to ramp the engine up towards the idle where it will settle at the point set – normally around 45,000rpm and that is it!
The engine runs at its coolest at about 80,000rpm and this is a good “soak” speed to let the engine settle down, where the temp is often around
480-520’C depending on the air temperature.
Your first time?
A common mistake for first time turbine operators is to spin the engine too quickly whilst on the gas, which will cool the engine below 100’C and
the pump will then stop. Simply increase the gas if required and remember to only blip the starter during this phase. Watch also to confirm fuel
travelling along the lubrication line.
The 2
nd
common mistake is to remove the starter too early, as the engine makes a noise like a jet engine a long time before it is capable of running
by itself. If you have a hand starter you can feel when the engine is beginning to overrun the starter as the fit on the cone becomes “looser” and
tends to wander slightly. With on-board starters the clutch pressure will lower as the engine picks up. The engine will be able to overrun the starter
motor where the clutch will let go and make a horrible buzzing noise. Listen out for this and turn it off just before this point if you want your starter
Summary of Contents for MW54 Mk2
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