Wren 44 TurboProp Users Manual. Copyright Wren Turbines Ltd February 2008 Page 35
After running
Always allow the engine to idle for about 30seconds after running before shutting off. This will
allow temperatures to stabilise and oil flows to normalise after the flight. Pulling the trim to off will
shut off the engine and start the cooling cycle. This will continue until the ECU registers a cool
enough temperature and will then read “Stop”.
As the temperature is measured in the heavy interstage casting there will be some heat creep
after the engine has come to rest and the temp may creep back up to even 150-160’C, this is
normal.
Waiting to fly again
If you have refuelled and want to make another flight and after you have turned the ecu back on
there is still a temperature showing over the minimum start temp of 100’C. If you keep the trim set
to off, you can blip the starter by raising the throttle stick briefly to apply a quick cool-down pulse
which should bring the temperature down quickly. Don’t hold the throttle stick at full for more than
a second or so as this is also the signal for priming the pump which is not recommended at all as
it can be the cause of flaming starts.
Once showing below about 98’C you can raise the trim and go for a start in the usual way.
Storage
The unit does not need any special attention after running although some thoughts on storage
can be considered:
Always
remove or disconnect the LiPo at end of the flying session. Charging must always be
done with the LiPo disconnected but the ecu will draw a few milliamps even in the off state and
after a couple of weeks this can drain a LiPo to nothing and ruin it permanently.
On shutdown oil will remain in the gearbox for the following run so it is not recommended you
hang the plane on the wall with its nose at the top as the oil can run out into the exhaust area and
can cause a large cloud of smoke on the next start. If you absolutely have to hang the plane on a
wall, keep it nose down. Horizontal storage is better if you have room.
Always empty the propane tank in the plane (if you have on-board propane) after you are finished
for the day. Don’t even wait to get home first as if the system springs a leak it might be in the car
on the way home.
Place a small polythene bag over the vent on the fuel tank to prevent your workshop dust getting
into the fuel tank and clogging your expensive filters. Use a plastic bag rather than a solid plug as
it will still allow for expansion in the tank if required.
