swissflyer

hello
does somebody have the baiscs parameters of the ECU for a "old" wrem MW44 green?

today icould not run mine and having those üarameters iu can check with mine..

just to describe my problem:
starting as good as always, then going from idle to full, even with slow stick movement i got flames out..
so tomorrow i will try to find out where the problem is, if is the pump, the kero or some others parameters..

i'm reading trough the forum, but i could not ind those ECU parameters..


thanks for the help

alessio

Boomerang1

Hi Alessio,

I had the same problem so check this first, the easiest check.

Make sure you have not lost any screws from the rear of the engine, both those that hold the nozzle on
& the ones that seat through the larger holes in the nozzle.

I run a 4.8 volt nicad pack to the ecu for this engine.

Full power speed 190k

Idle speed 57 k

stop speed 35 K

start min temp 100 degC

Max temp 800 degC

Acc delay 021

Decel delay 020

Stability delay 040

Pump start point auto + 1

Pump ramp start 014

My other engine has a 3.6 volt nicad pack, the difference in voltage may affect the settings.

- John.

swissflyer

Hey John

thanks for the help...
but i did solve my problem 50/50..
[]

after reading your settings, i did run my wren 44 without problems.

yesterday on the flying field, the problem did reappear!
starting was smooth
idle was ok, but as soon i moved the stick to accelerate, the engine quit..
now is troubleshooting..
or is a problem in the pump
or in the ECU

no idea...

Wren Turbines USA

My Feedback: (39)

Alessio,

The listed parameters, with the exception of the accel and decell...are for startup.

When the motor quits...does it smoke??

Easiest diagnosis would be air bubbles in the system.

Worst case would be pump or ECU...probably pump.

rb

swissflyer

thanks Ron
i'm betting the same

no air bubbles can be seen by me and my helper..

the pump is not somehow working properly..

no smoke when shutting down

or the ECU output is Screwed...

i have a spare pup that i will test

alessio

jfrost

Hi John, just looking at your figures they vary so much to mine. Can you tell me which pump are you using? Really puzzled that you are running only 4.8v, did you have to change your values because your lower voltage? I'm going to run mine on stand tomorrow first time after today's drama calibrating my TX with dig. throttle trim. I had some issue to work out the trim/fail safe function, hoping it worked out after some dry trys, Joe.

Boomerang1

Hi Joe, the figures may be different because the early 'Green' engines were manual start. Your 'Gold' engine is full auto start.

The manual engine ECU is different as the manual start engines have no solenoids to power up, no glow plug to energise & no starter to engage.

All the ECU does on the manual start engines is monitor the RPM & exhaust gas temp & start & run the pump.

With just a small motor on the pump to run they use a smaller, lighter battery, either a 3.6 volt 500 mAh 3 cell nicad or a 4.8 volt 4 cell. I don't know what brand pumps these engines use, as far as I know they are Wren items, all machined from aluminium with two small allen head screws with pink thread locking compound holding them together. John.

jfrost

Thanks John, I didn't realise you had the Mark1 engine, Regards Joe.