I have never had any problems whilst starting my engine and after about 40 starts was getting quite confident in my start procedure and my setup. I had got to the point where I would leave the extinguisher 20 yds away or so whilst starting my engine.

Today I left the fuel tap open after a flight. I did notice but decided that it would be ok to start anyway. Well I was wrong. The fuel had pooled in the engine and caught fire. Fortunately I had a fellow jet flyer with me (for the first time ever) and he was holding the extinguisher in the intake when it happened. A quick squirt and it was all over.

I have learnt a lot from this, namely;

Always have the extinguisher to hand, 20 yds away is no good.
Never start the engine if the fuel tap has been left on until the engine has been drained/blown through.

Fortunately I suffered no damage but consider myself very lucky.

Hi Darren,

I had this situation on one of my first starts with the 44. Got a cracking video of it luckily it was on the bench, and all we did was initiate shutdown/cooling, and then went for another start.

We've now got accustomed to turning the valve off after shutdown, however I don't want to risk forgetting at the field, so ordered a solenoid valve, which arrived today. Better safe than sorry.

Another new situation we found last night, was that we slowly shut the gas off, and after letting it sit at idle for a few seconds, went up towards full power. We got a lot of flaming and the temp rocketed. I quickly brought throttle back, and initiated shutdown.

Went for another start, and all was fine. We presume it was air in the line?


One other question from newbie me: If the fuel tap is left on, to get the fuel out, is it just a case of initiating the start proceedure, just without the gas on?


Cheers matey
Dave

You can never be too careful with these things. BTDT !!!!

I had a problem in that I turned the gas and fuel off and tried to vent the engine with the starter motor. However, I had the ignition left on. As the temp was still high, every time I tried to vent the engine the ECU thought I was trying to start and ramped the fuel that was left in the line aft of the fuel tap. This caused repeated fires until the ignition was disconnected.

I'm not sure how the autostart one works, but if you can turn off the ignition all the better. Even better than that would be if you could disconnect the fuel line at the engine too but it's a bit tricky with the L39.

The FADEC will only do that if the temperature is over the min start temp. If you unplug the thermocouple (if it's easy to get to), that'll do the trick!

Darren and Dave,

The way to get fuel out of the engine is to put a rag over the front inlet and tip it vertically, nose down, letting the fuel run out of the front. Tip it vertical - if you only tip it a little the fuel may run under the green cover. It's impossible to get all the fuel out of the back via the exhaust.

Starting any MW44, you should always take the engine slowly to full throttle and then down to idle to clear any buildup of fuel that may have accumulated in the case during the start. Failure to do this can cause the engine to flame out as you accelerate down the runway, because it suddenly picks up the extra fuel during the acceleration run and this disturbs combustion.

"Another new situation we found last night, was that we slowly shut the gas off, and after letting it sit at idle for a few seconds, went up towards full power. We got a lot of flaming and the temp rocketed. I quickly brought throttle back, and initiated shutdown.
Went for another start, and all was fine. We presume it was air in the line? "

It's not air, it's a buildup of fuel in the engine. Throttle up SLOWLY, as instructed above.

"If the fuel tap is left on, to get the fuel out, is it just a case of initiating the start proceedure, just without the gas on? "

No, that's a bad idea because you will blow the wet fuel into the exhaust area and when the engine starts it could ignite. Empty it as instructed above.

Mike Murphy
Wren Turbines Ltd

Thanks Mike,

Great info.

Many Thanks.

Guys,

What Mike said happened to me two weeks ago. I did not slowly pushed the throttle stick
to test the full power, I just slamed it forward at the end of the runaway, ready for takeoff.
Just MW44 just stalled on me. I'm glad it did not happen 10 seconds later...
Lesson learnt. I'll do AS STATED IN THE MANUAL, slowly push the throttle stick to the maximum
once, to flush the injectors from residual kero.

Yann

I have accidently forgotten to close the shut off on my MW54 several time and caused a fire so I keep the extinguisher close.

I have a couple of questions for Mike.

I purchased a full auto-start 44 from an individual but I have no manual. When I turn on the power what do I do to initiate the start procedure?

Does Wren have any pod starters available yet for the MW44? Sara said
the parts were back ordered.

Thanks.

Hal

Now this is really a well done hotstart! btw this guy is a RCU member...

this is the best fireball I saw since I quit using the turbomin!

[X(] Man, now that's a hotstart!!! Good info here also.

Actually, startup fire can occur even with a piston engine. My mustang caught fire during the starting process. The engine was a saito 100. Dont know why it happend. I consider myself very lucky, i had snow to throw on the plane. I saw the shadow from the fire. Its a bit hard to see metanol buring.

youve probably all seen this,but....
http://www.rc-expertise.com/wrap.php...os/jet/hot.htm

[]................looks like the whole tail section was flooded with fuel???

Gerald

DAVE

There is another excellent way of getting a good tail fire.

1. Start your engine with the manual fuel valve switched off.

2. When it is nice and hot - Notice your mistake . Swear loudly and turn on the fuel.

3. Swear even more loudly as model resembles an army flame thrower.


MOTTO - RECOGNISE FALSE START AND LET THE ENGINE COOL.

Switch off, open valve and then restart in normal manner.

I think that must be on of the most common cause of flaming, as the Wren manual devotes quite a good section to do's and don'ts regarding fuel on/off.

Not to digress from this thread, but how is your hawk? Perhaps you could updtae your thread? I'd be interested to hear how its going.

Cheers for now,
D

True but it's not just Wren....any turbine on the market will hot start if there is excess fuel inside. The FIRST thing I do after every flight is turn off the fuel valve. Even having a fuel solenoid is no guarantee that fuel will not get past and to the engine during fuel-up, I've seen it happen. Experience has also taught me that you can't just "blow" the fuel out, you've got to get the engine vertical and hold it there for a while. Additional dry motoring after this will help remove residual fuel.

Craig

Is the engine destroyed after a fire?

Not if you're fast enough to jump on the fire extinguisher. Worst case, you're good to change the bearings...
But your plane can get a little hot. If your engine is mounted inside, your plane can completetly burn down in no time.

Always get "a big enough" fire extinguer...not a micky mouse one...



And in the same "subject", is interesting to know what i found out:

I friend of mine, just buyed a model turbine, with if i corrected understood manual start.. When i showed him how i started mine RAM500 converted to manual start, he was surprised by my use of a manual valve..lately he told me he already had a lot of fire when starting his turbine...

no surprise to me...

wow... can that happen in the air? If it can, i want to see a video

hi darren

what model are you coming with on sat

andy

Andy,

Sent PM.