Can't get my Turbine to fire?????

[Denny22]

We are trying to shoot video today, and we were able to make 1 run and now I can't get it to re-fire. I have tested the fuel pump and it works fine, I have hooked up the Data Terminal at start up and it does not give me any errors as far as bad glow plug or anything like that. I have no idea what else it could be. I can hear and smell that the gas is shooting in to be ignited, but it will not lite. Anybody have any suggestions?????

Thanks
Denny

[cbergen]

Replace the glow plug.

Even though it may test and even light up with a regular glowdriver, it may not be getting bright enough.

[v22chap]

Make sure that the teased glow wire of the plug is not touching itself or the side of the plug case,,,or one of the fire sticks inside the turbine just below the plug hole.

Make sure that you are getting electric to the plug (wire not cut or shorted out or the like ) ,,by running a start cycle with the glow plug hooked to the turbine electric supply and grounding it against the turbine ground wire while holding the plug with a plier

O.S. 8 and A 5 plugs will work o.k. incase you don't have another one from Wren ...

[Denny22]

Alright guys thanks, but that didn't work. I replaced the glow plug with an O.S. 8 and samething, hooked the Data Terminal up and same read outs. Should I increase the power of the glow plug? Its set at 39 right now! I checked the wires real good and they all look good. Chris should I try a different glow plug besides the O.S. 8?

Denny

[cbergen]

You did tease the wire out, correct?

The power should not be any higher than 40, that will burn up the plug.

Do the test as Larry stated to ensure the electronics are working correctly.

Empty and refill the white gas canister. You could be full of Butane with no propane to ignite.

OS8 works just fine.

[Denny22]

Chris I should probably add that the last time it started, once it ignited it continued to try and go through start up stage 3 or 4 more times, then she started reving up and it quit. First time it has ever done that.

Denny

[cbergen]

Plug the HDT in and attempt a start. Look at the Temp and RPM,s.

The RPM's should come up immediately,the Temp when it lights off.

[Denny22]

Yes I did tease the wire on the glow plug!

Here is what I have done or tried.

1. Emptied the gas canister, flipped heli upside down per your instructions last time.

2. Completely emptied the fuel tanks, mixed up new fuel and refilled.

3. Unhooked fuel pump and tested with 9V battery. Fuel pump worked properly!

4. I hooked up a glow plug warmer that I bought with my Rapter, and it showed in the green, but the Wren would not go through start up proceedure without the wire hooked up to the glow plug.

I can try Larry's suggestion, but I don't completely understand how to do this, I will try though, hope I don't mess anything up.

Denny

[v22chap]

That sounds more like what Chris talked about ,,, butane left --no propane..

Turn the heli upside down and pull the hose from the quick fill disconnect that goes to the white canister with the propane in it and shake the heli up and down until the white can stops despensing its contents ... then hook up the hose and refill it .... this gets all the butane out and lets you start anew with the proper butane/propane mix
edit :
whoops see you did that and the proper way ,while I was thinking and typing

[Denny22]

The RPM's do come up immediately, temp shows 38 deg C, but it never lights, so the temp doesn't go any higher than that.

Denny

[Denny22]

Alright I will go try these things and let you know!

Denny

[v22chap]

Open your propane valve a little more and see if it runs longer and gets hotter .

[cbergen]

Just hook up both wires to the glow plug AS IF it were installed. Do a start procedure and watch for the glow.

It needs to glow OUTSIDE of the plug or it won't light the gas.

[rkeith2]

Did you get the turbine up and running again.

Sounds like all proper steps were taken so far.

Here are some things I do when the big girl fails to behave.

I hook up the HDT and look for glow test and listen for gas release and ignition. If no ignition I pull the plug and repeat the test watching for a yellow glow on the plug (I run 32 on glow) with OS 8 teased out 2 turns. I then flush and make sure I have good supply of fresh propane/butane and check that the 1st stage is spinning freely after the starter motor disengages as the gas is released and the glow is lit this is where the proper fuel air mixture is reached and the fire ball begins. I have had some cases where the bendix did not retract properly and slowed the turbine down stopping the ignition as well as too little gas released.

Using the HDT its easy to see when the fire starts and then the starter re-engages to keep the temp down and get to the point where the kero is released and rpms increase and then temp starts to stabilize. If you removed the fuel line testing the pump then it may take a try or two to start on kero unless primed back to the entry line at the spray bar.

If you still have problems perhaps you could do a video of the HDT as you attempt a start and put it online her via you tube or another means.

Ron

[Denny22]

No we didn't Keith, but Chris Pm'd me and told me to call him on his cell phone. On a Sunday, that is incredible! I have never had service like that from anybody. Thanks Keith for those things to try!

Anyway we determined that the ECU took a dump, it will not heat up the glow plug, so Chris is going to send me a new out tomorrow, and I will get that put in and keep you guys up to date.

Thanks Chris and Larry, for all your help and quick responses!

Denny

[cbergen]

What we determined was that the ECU can "see" the glow plug during the initial glow plug test, but it is NOT putting power to it on startup.....

We attempted a start with the glowplug disconnected and got the "Bad Glow" message. With the plug hooked up to the wires, it began the start sequence.

This tells me the wiring is good at least. But without power going to the plug to heat up the coil, has to be ECU.....Unless......

Denny, grab the end of the wire with the loop on it and give it a tug. If there is barely any wire holding it together, the signal will go through for the test, but it can't take any higher power....Check the boot connections as well...

[Denny22]

Hey Chris, no the wire looks good and solid, both of them do.


Denny

[cbergen]

New ECU on the way. When you get it tomorrow, call me so we can set it up.

[Sara]

Trouble-shooting when you are new to turbine engines is never easy, but there are several basic things to be aware of. The engine starts on propane/butane and the kero doesn't start flowing until the engine is hot, so if you have a problem where the engine won't start because the gas didn't light, then checking fuel pumps and fuel mix isn't any help.

As you discovered, you need to test the ECU and glowplug with the glowplug attached to the wires from the ECU, and this showed you that the glowplug wasn't glowing during the start sequence. As you are not getting a "Glow Bad" message, current is getting round the system somehow, probably because the glow drive transistors in the ECU are short-circuit. This can happen if the glowplug wires have been shorted together at some time. We have also known a glowplug failure to cause a short-circuit, although this is very rare.

Substituting a new ECU should prove the point. If the drive transistors are short-circuit the ECU can be repaired.

Sara Parish
Wren Turbines

[bcook01]

"probably because the glow drive transistors in the ECU are short-circuit"

Sara

If the drive transistors are shorted wouldn't the glow run down the battery?

most transistors fail with open emitter/collectors. A simple voltage check across the glow plug should tell it all.

Bob

[rkeith2]

I think Sara may have been trying to say that a short on the lead takes out the MOSFET that drives the glow.

Both devices for the starter motor and glow are capable of delivering available current but are still not crowbar enabled to protect against a short or just end of life.

[Sara]

Thanks, Ron, that sounds about right! I'm no electronics expert, so that post was really from Roger (although I typed it). He's the one who usually repairs the ECUs when they have minor problems like this. Major repairs go back to Gaspar Espiell, the manufacturer.

Sara Parish
Wren Turbines

[bcook01]

"crowbar enabled to protect against a short or just end of life"

Ron

Technically a crowbar circuit provides a short circuit to provide an overvolt protection.

In this case you are looking for a current limiting circuit to prevent a short circuit from taking out the driver transistor.

A simple series resistor with an LED across the glow plug is a great confidence indicator when starting. Likewise a voltmeter can do the same thing.

Sara

"so that post was really from Roger" .............. Plagerism ? Oh Heavens no..... not Sara!

Bob

[rkeith2]

Bob,

You been on Wikipedia again?

Just stop it little mister

[bcook01]

Ron

No I haven't......... BTW You might be surprised who frequents this board.

Perhaps it would be wise to check Wikipedia or other sources if you are not sure of the facts.

Bob