High start temperature
02-22-2009, 10:18 AM
#1
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High start temperature
Hi,
For the past 3 starts on my P80, I had been experiencing high starting temperatures between 920-933 deg Celcius. I read in the manual that this might be caused by low gas supply during start up, thereby causing the turbine to overheat. I use 35% propane 65%butane gas. I do not use a gas solenoid valve and during start, I connect my gas bottle directly to the gas inlet of the turbine via a manual gas regulator. When starting, I usually turn the knob of the gas regulator slowly until I hear the gas igniting inside the turbine. Then I would usually increase the gas flow by another 1/2-3/4 turn of the regulator knob while the start process progresses. It had always worked fine.
I was wondering if there are other possible reasons for high starting temperatures besides low gas supply. I do not suspect that the bottle of gas that I was using had depleted since I can still hear liquid sloshing around inside the bottle when I shake it.
Any advise would be appreciated.
Thanks.
For the past 3 starts on my P80, I had been experiencing high starting temperatures between 920-933 deg Celcius. I read in the manual that this might be caused by low gas supply during start up, thereby causing the turbine to overheat. I use 35% propane 65%butane gas. I do not use a gas solenoid valve and during start, I connect my gas bottle directly to the gas inlet of the turbine via a manual gas regulator. When starting, I usually turn the knob of the gas regulator slowly until I hear the gas igniting inside the turbine. Then I would usually increase the gas flow by another 1/2-3/4 turn of the regulator knob while the start process progresses. It had always worked fine.
I was wondering if there are other possible reasons for high starting temperatures besides low gas supply. I do not suspect that the bottle of gas that I was using had depleted since I can still hear liquid sloshing around inside the bottle when I shake it.
Any advise would be appreciated.
Thanks.
02-22-2009, 11:46 AM
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RE: High start temperature
Hi,
Gas I suppose. I usually leave the gas can standing upright (gas regulator on top) on the ground while I turn the regulator knob with one hand and steady the can with the other.
Gas I suppose. I usually leave the gas can standing upright (gas regulator on top) on the ground while I turn the regulator knob with one hand and steady the can with the other.
02-22-2009, 12:08 PM
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RE: High start temperature
I am using Rothenberger multigas 300... I am not sure if it has a clunk... I don't hear any knocking sound when I shake the can except for liquid sloshing...
Will liquified gas entering the turbine cause overheating problems?
Thanks for your replies.
Will liquified gas entering the turbine cause overheating problems?
Thanks for your replies.
02-22-2009, 12:15 PM
#6
RE: High start temperature
I've never used that brand of start gas but on all the butane/propane mixes I've used you can hear the clunk when shaking the can. feeding liquid to the turbine can give higher start temps, not sure it would be 200 C though but with wind blowing slightly at the tail during starts I've got considerably higher start temps from that.
02-22-2009, 08:23 PM
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RE: High start temperature
Hi,
Thanks for the tip...
I am uncertain if the cause may be due to liquid propane/butane entering the turbine though. The reason I said this is because I had been using the same brand of propane/butane and the same starting up procedure for the last couple of months. I only started to notice increasing start temperatures in the past 2 weeks (last 3 flights)...
My initial suspision was drawn to the amount of propane/butane left in the can which may be causing a drop in gas flow/pressure... however, as I had mentioned when I shake the can, I can still hear a lot of sloshing sounds.
Any other opinions please?
Thanks for the tip...
I am uncertain if the cause may be due to liquid propane/butane entering the turbine though. The reason I said this is because I had been using the same brand of propane/butane and the same starting up procedure for the last couple of months. I only started to notice increasing start temperatures in the past 2 weeks (last 3 flights)...
My initial suspision was drawn to the amount of propane/butane left in the can which may be causing a drop in gas flow/pressure... however, as I had mentioned when I shake the can, I can still hear a lot of sloshing sounds.
Any other opinions please?
02-22-2009, 09:04 PM
#8
RE: High start temperature
i don't know what the temps are in Singapore but in cold weather you have to constantly shake the can to get proper gas flow from the butane/propane mix, it's one reason i went to 100% propane off board starting on all my turbines.
02-22-2009, 09:41 PM
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RE: High start temperature
Hi,
That's a good tip... thanks... weather in Singapore is always on the hot side.... 32-35 deg Celcius all year round. However, the past couple of weeks had been rainy and cold... maybe I should shake the can on the next outing and report the results.
That's a good tip... thanks... weather in Singapore is always on the hot side.... 32-35 deg Celcius all year round. However, the past couple of weeks had been rainy and cold... maybe I should shake the can on the next outing and report the results.
02-23-2009, 04:00 PM
#10
RE: High start temperature
ORIGINAL: mun_iz
Hi,
For the past 3 starts on my P80, I had been experiencing high starting temperatures between 920-933 deg Celcius. I read in the manual that this might be caused by low gas supply during start up, thereby causing the turbine to overheat. I use 35% propane 65%butane gas. I do not use a gas solenoid valve and during start, I connect my gas bottle directly to the gas inlet of the turbine via a manual gas regulator. When starting, I usually turn the knob of the gas regulator slowly until I hear the gas igniting inside the turbine. Then I would usually increase the gas flow by another 1/2-3/4 turn of the regulator knob while the start process progresses. It had always worked fine.
I was wondering if there are other possible reasons for high starting temperatures besides low gas supply. I do not suspect that the bottle of gas that I was using had depleted since I can still hear liquid sloshing around inside the bottle when I shake it.
Any advise would be appreciated.
Thanks.
Hi,
For the past 3 starts on my P80, I had been experiencing high starting temperatures between 920-933 deg Celcius. I read in the manual that this might be caused by low gas supply during start up, thereby causing the turbine to overheat. I use 35% propane 65%butane gas. I do not use a gas solenoid valve and during start, I connect my gas bottle directly to the gas inlet of the turbine via a manual gas regulator. When starting, I usually turn the knob of the gas regulator slowly until I hear the gas igniting inside the turbine. Then I would usually increase the gas flow by another 1/2-3/4 turn of the regulator knob while the start process progresses. It had always worked fine.
I was wondering if there are other possible reasons for high starting temperatures besides low gas supply. I do not suspect that the bottle of gas that I was using had depleted since I can still hear liquid sloshing around inside the bottle when I shake it.
Any advise would be appreciated.
Thanks.
Yes, there are other reasons. how much total time does the turbine have on it?
Also, is there a reason you are not running in accordance with the manual (i.e. with a starting gas valve connected to the ECU)?
Regards,
02-25-2009, 07:05 AM
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RE: High start temperature
Hi,
The total run time on my P80 is 4 hrs 39 mins.
I ever tried using the gas valve for my first few runs. However, I noticed that with the gas valve attached, there is always a "pop" sound when the gas ignites. I found that the ignitions tend to be smoother without the gas valve and using the procedure I had described earlier.
Can you kindly share the other reasons for high starting temperatures?
I will be flying this coming Saturday and will try with another can of gas for starting.
The total run time on my P80 is 4 hrs 39 mins.
I ever tried using the gas valve for my first few runs. However, I noticed that with the gas valve attached, there is always a "pop" sound when the gas ignites. I found that the ignitions tend to be smoother without the gas valve and using the procedure I had described earlier.
Can you kindly share the other reasons for high starting temperatures?
I will be flying this coming Saturday and will try with another can of gas for starting.
02-25-2009, 11:53 AM
#12
RE: High start temperature
Hello,
First, let me say that 900 degrees on a P-80 is FINE, if I were you I would not worry about it.
My guess is that the pump might have broken in some since new and is pumping more fuel for a given voltage.
If you want to experiment, you can lower the Uaccel1 and Uaccel2 voltages a bit (maybe 1-2 units at a time) and I am sure your temps will drop.
To change these values, hold the "Limits" key down and then press "+". This will bring up a sub menu to change the 2 voltages. After you change the voltages with the "+/-" keys, press any blue button to save the values and exit.
Let me know how it goes.
Regards,
First, let me say that 900 degrees on a P-80 is FINE, if I were you I would not worry about it.
My guess is that the pump might have broken in some since new and is pumping more fuel for a given voltage.
If you want to experiment, you can lower the Uaccel1 and Uaccel2 voltages a bit (maybe 1-2 units at a time) and I am sure your temps will drop.
To change these values, hold the "Limits" key down and then press "+". This will bring up a sub menu to change the 2 voltages. After you change the voltages with the "+/-" keys, press any blue button to save the values and exit.
Let me know how it goes.
Regards,
02-26-2009, 06:08 AM
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RE: High start temperature
Hi Mr Matt,
Thanks for your reply and suggestions. I will try out the suggestions this coming weekend and keep you posted on the outcomes.
Thanks for your reply and suggestions. I will try out the suggestions this coming weekend and keep you posted on the outcomes.
03-01-2009, 06:33 AM
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RE: High start temperature
Hi,
Managed to test the P80 today. I reduced both the Uaccel1 and Uaccel2 voltages by 1 decrement step each (from the default factory settings) and used the same bottle of gas and start up procedures. The starting temperature was 860 deg C (as compared to 930deg C earlier). But have a couple of questions to ask:
1) What does the parameter Uaccel2 do to pump operation? I noticed that it is originally at a much higher setting than Uaccel1.
2) Does the decrement in Uaccel 1 and Uaccel2 voltages have any effect on turbine spooling time? Or are these 2 parameters affecting only the starting pump voltages?
Thanks.
Managed to test the P80 today. I reduced both the Uaccel1 and Uaccel2 voltages by 1 decrement step each (from the default factory settings) and used the same bottle of gas and start up procedures. The starting temperature was 860 deg C (as compared to 930deg C earlier). But have a couple of questions to ask:
1) What does the parameter Uaccel2 do to pump operation? I noticed that it is originally at a much higher setting than Uaccel1.
2) Does the decrement in Uaccel 1 and Uaccel2 voltages have any effect on turbine spooling time? Or are these 2 parameters affecting only the starting pump voltages?
Thanks.
03-01-2009, 06:54 AM
#15
RE: High start temperature
Hello,
These parameters are for open loop control of the turbine during start up. U1 just gets the kerosene lit, and U2 ramps it up to a steady running state.
Once the turbine is started they are not used hence no effect of performance.
Hope that helps,
These parameters are for open loop control of the turbine during start up. U1 just gets the kerosene lit, and U2 ramps it up to a steady running state.
Once the turbine is started they are not used hence no effect of performance.
Hope that helps,
03-03-2009, 07:34 PM
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RE: High start temperature
i use the green coleman bottles with dreamworks fitting outside the plane. starts right away and is safer then being in the plane.. i am new at turbines and the easier the better..
