Flame out
03-21-2011 | 10:59 AM
#1
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From: Curacao, Willemstad, NETHERLANDS ANTILLES
Flame out
This weekend I had a flame out when I back off the throttle at half.
The last-off PmP Volt is 1.15
The last-off rpm 20800
the last temp 320 c
The last off Cond low RPM.
I checked, Voltage was ok, no air in the system.
What could have caused this flame out.
The is a P120 #1086 - 6.0 ECU.
Thanks
Gio
The last-off PmP Volt is 1.15
The last-off rpm 20800
the last temp 320 c
The last off Cond low RPM.
I checked, Voltage was ok, no air in the system.
What could have caused this flame out.
The is a P120 #1086 - 6.0 ECU.
Thanks
Gio
03-21-2011 | 11:11 AM
#2
My Feedback: (11)
RE: Flame out
Hmm, your pump volt seems to be just above idle but your RPM is low (obviously the ECU is telling you) and the temp seems low (which seems to indicate that the Kero isn't burning).
I really dislike the dreaded low RPM off.
It could be so many things...
Like kinked fuel line, leaking fuel pick up IN A TANK, clogged filter or UAT, debris in the fuel line, the clunk getting stuck to the back of the tank.... Bob Wilcox and the rest of Jetcat crew are really good at trying to explain these things but sometimes, its impossible!
Look for things like that which don't necessarily leave bubbles in your lines.
I hope your airplane did well.
Raf
I really dislike the dreaded low RPM off.
It could be so many things...
Like kinked fuel line, leaking fuel pick up IN A TANK, clogged filter or UAT, debris in the fuel line, the clunk getting stuck to the back of the tank.... Bob Wilcox and the rest of Jetcat crew are really good at trying to explain these things but sometimes, its impossible!
Look for things like that which don't necessarily leave bubbles in your lines.
I hope your airplane did well.
Raf
03-21-2011 | 11:12 AM
#3
My Feedback: (24)
RE: Flame out
This is really a question for the JetCat forum, but 9.9 times out of 10, low-RPM off condition is an air bubble. You may not see any air in the system, but I'll bet there was some there. It likely accumulated somewhere from small bubbles and then "burped" out as an engine-stopping bubble when it got large enough. Also, the last temp. is cold which further suggests that the fire went out. If memory serves, the idle pump voltage for a P120 is somewhere less than a volt, so it would also seem that the ECU was trying to maintain an RPM above idle as well.
Bob
Bob
03-21-2011 | 11:42 AM
#4
My Feedback: (1)
RE: Flame out
No easy way to tell. You didn't say whether there was white smoke out the back when the engine quit. If so, a positive indication of air in the line. There wouldn't necessarially be air in the line afterwards. With a 1.15 pump voltage at Low RPM cutoff, there should have been white smoke. If not, then there was some other interupton of fuel to the engine. The Low RPM off conditon says the ECU didn't do it. Numbers like those usually represent the condition at the time the ECU gave up trying to keep the engine running and shut down. The flameout itself would have been at a much higher rpm.
Possibilites:
1. Empty UAT - air leak in the fill line which caused no fuel to reach the engine - unlikely if the lines are air free
2. Low ECU battery - I've gotten airborne with batteries that started the engine but couldn't finish a flight - should get a Pwr Fail for that but I have seen some odd issues with marginal batteries.
3. Latent air bubble in filter which finally passed thru - I've seen flameouts for this as much as 6 flights after the lines were purged.
4. Air leak at the engine festo - I've seen 2 flamouts for this - solution is to trim off the fuel line and reinsert or change the festo.
5. Festos which leak air in the fuel feed lines - you'd think these wouldn't leak under pressure but problems seem to go away when you remove them.
6. Pump interuption or failing fuel solenoid
7. Internal engine issue such as bad fuel needles in the engine
What I've done when I can find nothing else wrong is to re-purge the fuel lines and go fly the airplane. Maybe even run it on the ground at high power.
Assuming you've not tried to start the engine since, you get get out the manual and use the GSU to look at what the pump & rpm did in the last few seconds before flameout.
Possibilites:
1. Empty UAT - air leak in the fill line which caused no fuel to reach the engine - unlikely if the lines are air free
2. Low ECU battery - I've gotten airborne with batteries that started the engine but couldn't finish a flight - should get a Pwr Fail for that but I have seen some odd issues with marginal batteries.
3. Latent air bubble in filter which finally passed thru - I've seen flameouts for this as much as 6 flights after the lines were purged.
4. Air leak at the engine festo - I've seen 2 flamouts for this - solution is to trim off the fuel line and reinsert or change the festo.
5. Festos which leak air in the fuel feed lines - you'd think these wouldn't leak under pressure but problems seem to go away when you remove them.
6. Pump interuption or failing fuel solenoid
7. Internal engine issue such as bad fuel needles in the engine
What I've done when I can find nothing else wrong is to re-purge the fuel lines and go fly the airplane. Maybe even run it on the ground at high power.
Assuming you've not tried to start the engine since, you get get out the manual and use the GSU to look at what the pump & rpm did in the last few seconds before flameout.
03-21-2011 | 01:09 PM
#5
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From: Curacao, Willemstad, NETHERLANDS ANTILLES
RE: Flame out
ORIGINAL: Thud_Driver
No easy way to tell. You didn't say whether there was white smoke out the back when the engine quit. If so, a positive indication of air in the line. There wouldn't necessarially be air in the line afterwards. With a 1.15 pump voltage at Low RPM cutoff, there should have been white smoke. If not, then there was some other interupton of fuel to the engine. The Low RPM off conditon says the ECU didn't do it. Numbers like those usually represent the condition at the time the ECU gave up trying to keep the engine running and shut down. The flameout itself would have been at a much higher rpm.
Possibilites:
1. Empty UAT - air leak in the fill line which caused no fuel to reach the engine - unlikely if the lines are air free
2. Low ECU battery - I've gotten airborne with batteries that started the engine but couldn't finish a flight - should get a Pwr Fail for that but I have seen some odd issues with marginal batteries.
3. Latent air bubble in filter which finally passed thru - I've seen flameouts for this as much as 6 flights after the lines were purged.
4. Air leak at the engine festo - I've seen 2 flamouts for this - solution is to trim off the fuel line and reinsert or change the festo.
5. Festos which leak air in the fuel feed lines - you'd think these wouldn't leak under pressure but problems seem to go away when you remove them.
6. Pump interuption or failing fuel solenoid
7. Internal engine issue such as bad fuel needles in the engine
What I've done when I can find nothing else wrong is to re-purge the fuel lines and go fly the airplane. Maybe even run it on the ground at high power.
Assuming you've not tried to start the engine since, you get get out the manual and use the GSU to look at what the pump & rpm did in the last few seconds before flameout.
No easy way to tell. You didn't say whether there was white smoke out the back when the engine quit. If so, a positive indication of air in the line. There wouldn't necessarially be air in the line afterwards. With a 1.15 pump voltage at Low RPM cutoff, there should have been white smoke. If not, then there was some other interupton of fuel to the engine. The Low RPM off conditon says the ECU didn't do it. Numbers like those usually represent the condition at the time the ECU gave up trying to keep the engine running and shut down. The flameout itself would have been at a much higher rpm.
Possibilites:
1. Empty UAT - air leak in the fill line which caused no fuel to reach the engine - unlikely if the lines are air free
2. Low ECU battery - I've gotten airborne with batteries that started the engine but couldn't finish a flight - should get a Pwr Fail for that but I have seen some odd issues with marginal batteries.
3. Latent air bubble in filter which finally passed thru - I've seen flameouts for this as much as 6 flights after the lines were purged.
4. Air leak at the engine festo - I've seen 2 flamouts for this - solution is to trim off the fuel line and reinsert or change the festo.
5. Festos which leak air in the fuel feed lines - you'd think these wouldn't leak under pressure but problems seem to go away when you remove them.
6. Pump interuption or failing fuel solenoid
7. Internal engine issue such as bad fuel needles in the engine
What I've done when I can find nothing else wrong is to re-purge the fuel lines and go fly the airplane. Maybe even run it on the ground at high power.
Assuming you've not tried to start the engine since, you get get out the manual and use the GSU to look at what the pump & rpm did in the last few seconds before flameout.
03-21-2011 | 01:14 PM
#6
RE: Flame out
Low rpm seems to be the most common flame out condition, due to heaven knows what, to try and ovid this issue I have programmed in an idle up with gear retract, so low rpm is about 15,000 higher than normal idle, this only works in flight mode with the gear up, obvious what happens when you lower the gear to land.
Mike
Mike
03-21-2011 | 01:35 PM
#7
RE: Flame out
Hi
If you had a white smoke trail after flame out, it is a fuel feed problem. there is an air intake somewhere in the fuel line system. Some possible causes:
1 - tygon as harden over time and clunk does not move with plane
2 - UAT or other connections in the fuel line are allowing air to enter in the system
3 - Suction side of the pump is sucking air. Check the lines and eliminate all festos and connections in the suction side
Was your UAT empty after flame out?
Regards
nuno
If you had a white smoke trail after flame out, it is a fuel feed problem. there is an air intake somewhere in the fuel line system. Some possible causes:
1 - tygon as harden over time and clunk does not move with plane
2 - UAT or other connections in the fuel line are allowing air to enter in the system
3 - Suction side of the pump is sucking air. Check the lines and eliminate all festos and connections in the suction side
Was your UAT empty after flame out?
Regards
nuno
03-21-2011 | 01:47 PM
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From: Curacao, Willemstad, NETHERLANDS ANTILLES
RE: Flame out
ORIGINAL: jetnuno
Hi
If you had a white smoke trail after flame out, it is a fuel feed problem. there is an air intake somewhere in the fuel line system. Some possible causes:
1 - tygon as harden over time and clunk does not move with plane
2 - UAT or other connections in the fuel line are allowing air to enter in the system
3 - Suction side of the pump is sucking air. Check the lines and eliminate all festos and connections in the suction side
Was your UAT empty after flame out?
Regards
nuno
Hi
If you had a white smoke trail after flame out, it is a fuel feed problem. there is an air intake somewhere in the fuel line system. Some possible causes:
1 - tygon as harden over time and clunk does not move with plane
2 - UAT or other connections in the fuel line are allowing air to enter in the system
3 - Suction side of the pump is sucking air. Check the lines and eliminate all festos and connections in the suction side
Was your UAT empty after flame out?
Regards
nuno
03-21-2011 | 03:50 PM
#10
RE: Flame out
Sometimes they just get a low speed compressor stall, once they start to slow down they over compensate and slow down too much especially if the airflow through the compressor is turbulant or slow due to flight angle, direction, slip or skid, but check your fuel lines for any air leaks, as I said above put an idle up on the UC retract switch it may well help with what may be a odd airflow instaltion.
Mike
Mike
03-21-2011 | 04:50 PM
#11
Senior Member
My Feedback: (21)
RE: Flame out
Check to make sure that you have vented the tank properly.
I have a Boomerang Torus that I had flown over thirty times with a 30# Super Eagle with out a hiccup. Just before Florida jets I put a new kero start Rhino in it. At Florida on Friday I had three flame outs in a row. I asked Juan at the Jet Central Tent to help me out with it. he came over and downloaded the parameters from the last few minutes of run time and showed me how the pump power was increasing yet the Rpm would start decreasing to the low rpm cut off point. There was a fuel delivery problem. I.E. fuel was not getting to the pump after just a couple of minutes of run time. Examination by my self and and some of the other fellows there (thanks for the help Joe Raf. and everyone else that took a look at it) we determined the vent tube going into the Sullivan tank supplied with the boomer was too small. While the clunk line tube was a larger dia. brass the vent tube was the same size as what we use on .40 size glow motors! I changed out the vent tube for a larger dia., changed out the UAT for new BV unit (nothing wrong with the old one, but while I was in the mood....) and changed out the tygon for large, harder, poly line. Six flights on Saturday at FJ and five more with it here at home and it has been flawless. When I put in the more powerful Rhino the fuel draw was greater but the vent could not move enough air so I was starving the pump. Lesson learned.
It is the little stuff that will drive you crazy. the big stuff is usually obvious.
Good Luck!
mike
I have a Boomerang Torus that I had flown over thirty times with a 30# Super Eagle with out a hiccup. Just before Florida jets I put a new kero start Rhino in it. At Florida on Friday I had three flame outs in a row. I asked Juan at the Jet Central Tent to help me out with it. he came over and downloaded the parameters from the last few minutes of run time and showed me how the pump power was increasing yet the Rpm would start decreasing to the low rpm cut off point. There was a fuel delivery problem. I.E. fuel was not getting to the pump after just a couple of minutes of run time. Examination by my self and and some of the other fellows there (thanks for the help Joe Raf. and everyone else that took a look at it) we determined the vent tube going into the Sullivan tank supplied with the boomer was too small. While the clunk line tube was a larger dia. brass the vent tube was the same size as what we use on .40 size glow motors! I changed out the vent tube for a larger dia., changed out the UAT for new BV unit (nothing wrong with the old one, but while I was in the mood....) and changed out the tygon for large, harder, poly line. Six flights on Saturday at FJ and five more with it here at home and it has been flawless. When I put in the more powerful Rhino the fuel draw was greater but the vent could not move enough air so I was starving the pump. Lesson learned.
It is the little stuff that will drive you crazy. the big stuff is usually obvious.
Good Luck!
mike
03-21-2011 | 07:06 PM
#12
My Feedback: (1)
RE: Flame out
White smoke and a full UAT pretty much gets us down to the pump to engine installation.
Fuel lines on pump safety wired?
Jetcat fuel filter cap lubricated and on tight?
No festo's or instant style fittings in the feed line?
Using Jetcat ball valve for manual shutoff?
Good air purge from filter by hard shaking with the filter while vertical, i.e., fuel in at bottom and out at top? I usually do the purge at around 2v - 2.5v on the GSU. How many flights since the last fuel system purge to the flameout?
Fuel line attaches straight into engine festo without side force on the line from inlets, structures, or loops?
Low probability thought: I've seen pumps put air bubbles / fuel vapor bubbles in the line. Probably due to a leaking seal on the motor shaft. Tends to collect in the filter and pass to the engine at a bad time.</p>
03-22-2011 | 09:40 PM
#13
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From: Curacao, Willemstad, NETHERLANDS ANTILLES
RE: Flame out
I went in,How to diagnose a shut-down from the saved data.
time -4.4
-4.2
RPM-100
-100
set rpm-100
-100
EGT-616
616
PMP-2.0
-2.0
Sta-11
-11
Th-70
-70
Au-50
Au-50
Bat-8.1
Bat-8.1
time -4.4
-4.2
RPM-100
-100
set rpm-100
-100
EGT-616
616
PMP-2.0
-2.0
Sta-11
-11
Th-70
-70
Au-50
Au-50
Bat-8.1
Bat-8.1
03-23-2011 | 01:27 PM
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From: Hvidovre, DENMARK
RE: Flame out
Vacuum due to too small fuel lines seems to extract air bubbles to a complete airtight fuelsystem. These could be the problem.
Try to purge fuelsystem vith high pumpvoltage into a can and watch fuellines..
Other problem could be vaccum in fuelsystem after highspeed flight, whitch could cause flameout in idle..
Hope you find your problem..
Try to purge fuelsystem vith high pumpvoltage into a can and watch fuellines..
Other problem could be vaccum in fuelsystem after highspeed flight, whitch could cause flameout in idle..
Hope you find your problem..
