Wren 44 TurboProp Users Manual. Copyright Wren Turbines Ltd February 2008 Page 30
Preparing the engine for running
Select a clear area for running – keep clear of areas with loose leaves, sand or other debris that could be
picked up or drawn towards the propeller and intake.
Ensure the fuel tank is position well clear of the exhaust area and secured. The same applies to the starting
gas canister.
Fire Extinguisher
Equip yourself with a fire extinguisher whenever you are planning to run your engine. The best extinguisher
for our purposes is the Carbon Dioxide (CO
2
). Use of dry powder, foam or water based extinguishers will
cause serious damage to the engine and should only be used as a last resort. If you have a helper who
holds the extinguisher always brief them what to do and where to point the extinguisher. You should be the
one to decide if the extinguisher is to be used, and where.
In Case of Emergency
If you are unfortunate to have an engine problem which results in an engine fire or excessive flaming in the
exhaust pipe or fuselage, shut the engine down immediately by lowering stick and trim to zero. This will
initiate the cool-down sequence on the ECU. If the engine had not reached idle then reset the ECU by
turning it off then on again, leave trim down and raise the throttle stick. This will force the starter on to cool
the engine. Do not waste time doing this if you have a fire in progress though – put stick and trim to off and
get the extinguisher in quickly.
The extinguisher should then be positioned to discharge into the engine intake or the passage leading to the
intake, or alongside the engine towards the exhaust. Do not point the extinguisher into the exhaust as this
will surely carry hot gases back through the engine and into the aircraft and potentially cause more damage.
Never attempt to restart an engine, which has been involved in a fire without a thorough and detailed
examination and investigation to confirm the integrity of all pipe-work and fittings and associated electrical
wiring. If there are any doubts about the serviceability of the engine and its accessories following such an
incident or accidental crash damage the engine must be examined and serviced by Wren Turbines Ltd or
their appointed service agent.
Fuel
The engine is designed to run on a mixture of fuel and oil to a ratio of 95% fuel to 5% oil, ie 20:1.
The fuel recommended is standard Jet A1 kerosene, available from most airports, or paraffin used for
greenhouses and available from most hardware stores.
Central heating oil, gasoline or methanol based fuels may not be used in this engine. Such fuel can cause
severe damage to the combustion chamber components fitted to this engine.
The fuel needs to be carefully filtered before use to eliminate carrying over of solid particles or water into
your fuel system.
Oil
The oil required is standard turbine oil available from Airports and jet suppliers.
Suitable turbine oils are:
Aeroshell 500
Exxon 2380
Mobil Jet Oil
Castrol TTS
Mix 50ml of oil for each 1Ltr of fuel, seal the container and shake well to mix
thoroughly.
Handle these fuels and oils with care – avoid all direct contact with skin. In case of contact wash the affected
area with soap and warm water immediately.
