Simjet 1700 overheating at startup
05-27-2008, 02:21 PM
#1
Thread Starter
Simjet 1700 overheating at startup
My Simjet 1700 with a Gaspar Fadec shows overheating at startup (up to 800°), while idle temperature is about 540°C and top speed is about 640°C (120,000rpm ~8.3 Kg of thrust).
The only solution I found is to reduce the amount of propane flowing in as soon as I see "Fuel ramp up" message on the ECU terminal.
Can this be corrected by changing some parameters on the ECU ?
The Gaspar Fadec documentation mentioned a factory parameter called "Start Gas switch off temperature, Real temperature is the value multiplied by 4",
any recommendation on what this temperature should be set to ?
The startup sequence is a bit tricky then as I have to monitor the ECU terminal carefully and afraid to damage my turbine
(ps: I'm a newbie as you can probably guess).
Hints welcome :-)
The only solution I found is to reduce the amount of propane flowing in as soon as I see "Fuel ramp up" message on the ECU terminal.
Can this be corrected by changing some parameters on the ECU ?
The Gaspar Fadec documentation mentioned a factory parameter called "Start Gas switch off temperature, Real temperature is the value multiplied by 4",
any recommendation on what this temperature should be set to ?
The startup sequence is a bit tricky then as I have to monitor the ECU terminal carefully and afraid to damage my turbine
(ps: I'm a newbie as you can probably guess).
Hints welcome :-)
05-28-2008, 08:13 AM
#2
My Feedback: (2)
RE: Simjet 1700 overheating at startup
jcsotto,
Reaching 800C during start in not that uncommon as "hot spots" do exist at various locations around the exhaust nozzle and perhaps your EGT probe is located with-in one of these zones. I'm assuming that you do not have excessive YELLOW flames present during the start which would indicate excessive fuel input during the start which is not desired. The running / idle temps are good /normal.
Putting that aside, having not stated what your "start pump ramp value" is set at, I suggest that you use a value 2 points lower than its current setting OR if your at Auto+2, try Auto+1 with out making any other changes and try that.
Your looking for very short, intermittent to no yellow flame present during the ramp to idle.
Best Regards,
Reaching 800C during start in not that uncommon as "hot spots" do exist at various locations around the exhaust nozzle and perhaps your EGT probe is located with-in one of these zones. I'm assuming that you do not have excessive YELLOW flames present during the start which would indicate excessive fuel input during the start which is not desired. The running / idle temps are good /normal.
Putting that aside, having not stated what your "start pump ramp value" is set at, I suggest that you use a value 2 points lower than its current setting OR if your at Auto+2, try Auto+1 with out making any other changes and try that.
Your looking for very short, intermittent to no yellow flame present during the ramp to idle.
Best Regards,
06-22-2008, 05:45 PM
#3
Thread Starter
RE: Simjet 1700 overheating at startup
Thanks for your answer Vampire,
I've followed your advices on start-up ramp plus changing the gas solenoid valve (I found that it did not close very well) and it seems to have cured the problem.
I've followed your advices on start-up ramp plus changing the gas solenoid valve (I found that it did not close very well) and it seems to have cured the problem.
