Help needed from experienced jet pilots
08-15-2018, 07:25 AM
#1
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Help needed from experienced jet pilots
Dear all,
I need your input in a matter my first jet has a maiden and flew beautifully. Now I am planning to put more flights on it and get a waiver signed off. However, one thing bothering me is fuel leakage in the engine bay. I wasn’t able to trace where the leakage is coming from so I went ahead and replaced all reducers and Y-splitter for solenoids with brand new Festo ones (kingtech 140F) it still leaked. Is the leakage coming from the Festo fittings ? Another friend suggested it might just be extra oil coming out of the turbine. At this point it is puzzling. Should I switch to brass reducer and Y splitter ? Or does anyone have an idea of what the reason might be ?
any help is greatly appreciated.
I need your input in a matter my first jet has a maiden and flew beautifully. Now I am planning to put more flights on it and get a waiver signed off. However, one thing bothering me is fuel leakage in the engine bay. I wasn’t able to trace where the leakage is coming from so I went ahead and replaced all reducers and Y-splitter for solenoids with brand new Festo ones (kingtech 140F) it still leaked. Is the leakage coming from the Festo fittings ? Another friend suggested it might just be extra oil coming out of the turbine. At this point it is puzzling. Should I switch to brass reducer and Y splitter ? Or does anyone have an idea of what the reason might be ?
any help is greatly appreciated.
08-15-2018, 08:58 AM
#5
Minimise connections, as above solid connections where possible, ensure all the fuel lines are cut square at 90 degrees prior to seating in the festo fitting
08-15-2018, 09:09 AM
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You are right I might not have them at perfect 90
then I will remove the Festo I have and use solid hopefully this helps.
I have two right now 4mm to 3mm reducer for the burner and 4 mm Y for solenoids to SOV
then I will remove the Festo I have and use solid hopefully this helps.
I have two right now 4mm to 3mm reducer for the burner and 4 mm Y for solenoids to SOV
08-18-2018, 08:25 AM
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So I switched to all solid connections and got rid of the Festo still got leaking. I observed the engine while starting and seemed like the engine dumbed a bunch of fuel out of the exhaust and since I don’t have a bipass the tailpipe bell drains that fuel back into the engine Bay Area. What is the reason for that? This is my first jet. It is also important to note that the engine starts with a bunch of flame out of the back
Last edited by alfawaz; 08-18-2018 at 11:31 AM.
09-21-2018, 02:03 PM
#8
So I switched to all solid connections and got rid of the Festo still got leaking. I observed the engine while starting and seemed like the engine dumbed a bunch of fuel out of the exhaust and since I don’t have a bipass the tailpipe bell drains that fuel back into the engine Bay Area. What is the reason for that? This is my first jet. It is also important to note that the engine starts with a bunch of flame out of the back
sounds like to me your start parameters are too high.
09-21-2018, 02:23 PM
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Not entirely but I was able to determine where it is coming from and what is causing it. I have been working on it.
It seems like my fuel ramp was turned up way too high causing the fuel to come out of the engine unburnt so I turned down the fuel ramp on my GSU from 140 to 120 and now 100 but planning to turn down to 80 tomorrow because there is still little bit of fuel coming out and a lot of flames
It seems like my fuel ramp was turned up way too high causing the fuel to come out of the engine unburnt so I turned down the fuel ramp on my GSU from 140 to 120 and now 100 but planning to turn down to 80 tomorrow because there is still little bit of fuel coming out and a lot of flames
09-21-2018, 02:26 PM
#10
Not entirely but I was able to determine where it is coming from and what is causing it. I have been working on it.
It seems like my fuel ramp was turned up way too high causing the fuel to come out of the engine unburnt so I turned down the fuel ramp on my GSU from 140 to 120 and now 100 but planning to turn down to 80 tomorrow because there is still little bit of fuel coming out and a lot of flames
It seems like my fuel ramp was turned up way too high causing the fuel to come out of the engine unburnt so I turned down the fuel ramp on my GSU from 140 to 120 and now 100 but planning to turn down to 80 tomorrow because there is still little bit of fuel coming out and a lot of flames
I suspect your flames are coming before the fuel ramp stage...
fuel ignition or possible pre heat stage
09-21-2018, 02:28 PM
#11
Not entirely but I was able to determine where it is coming from and what is causing it. I have been working on it.
It seems like my fuel ramp was turned up way too high causing the fuel to come out of the engine unburnt so I turned down the fuel ramp on my GSU from 140 to 120 and now 100 but planning to turn down to 80 tomorrow because there is still little bit of fuel coming out and a lot of flames
It seems like my fuel ramp was turned up way too high causing the fuel to come out of the engine unburnt so I turned down the fuel ramp on my GSU from 140 to 120 and now 100 but planning to turn down to 80 tomorrow because there is still little bit of fuel coming out and a lot of flames
09-21-2018, 02:35 PM
#12
Not entirely but I was able to determine where it is coming from and what is causing it. I have been working on it.
It seems like my fuel ramp was turned up way too high causing the fuel to come out of the engine unburnt so I turned down the fuel ramp on my GSU from 140 to 120 and now 100 but planning to turn down to 80 tomorrow because there is still little bit of fuel coming out and a lot of flames
It seems like my fuel ramp was turned up way too high causing the fuel to come out of the engine unburnt so I turned down the fuel ramp on my GSU from 140 to 120 and now 100 but planning to turn down to 80 tomorrow because there is still little bit of fuel coming out and a lot of flames
you need to turn down your pump PW and possible your pre heat
turn down your PW until you dont get a positive start. Then increase the value a couple. Try that first before you lower your pre heat .
you may have to turn down your pre heat if you get flames when it switches to ramp.
your ramp value only adjusts the speed of acceleration AFTER it hits 100 degrees. Too slow of ramp and it will tend to hang up. Too fast of ramp and it will over shoot idle and ramp way too fast and be a blow torch
Last edited by aaronforth; 09-21-2018 at 02:52 PM.
09-21-2018, 05:47 PM
#13
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That’s very helpful I will give it a try tomorrow morning.
Honestly whenever I see flames and looked the GSU it is in the ramp stage. It seems like the flames come out as soon as it starts fuel ramp. But I will try to turn down the pump pw and the preheat and see what happens
Honestly whenever I see flames and looked the GSU it is in the ramp stage. It seems like the flames come out as soon as it starts fuel ramp. But I will try to turn down the pump pw and the preheat and see what happens
09-21-2018, 05:52 PM
#14
That’s very helpful I will give it a try tomorrow morning.
Honestly whenever I see flames and looked the GSU it is in the ramp stage. It seems like the flames come out as soon as it starts fuel ramp. But I will try to turn down the pump pw and the preheat and see what happens
Honestly whenever I see flames and looked the GSU it is in the ramp stage. It seems like the flames come out as soon as it starts fuel ramp. But I will try to turn down the pump pw and the preheat and see what happens
09-22-2018, 12:38 PM
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I turned down preheat by 5% and PW by 2 points. But that was almost catastrophical got an extremely hot start luckily had the extinguisher handy paint got little screwed up on the bottom
09-22-2018, 12:42 PM
#16
if not then remove the fuel line from the engine then start a start sequence. You should only have a slow drip. If too much fuel decrease PW more
09-22-2018, 12:46 PM
#18
09-22-2018, 12:56 PM
#19
My Simjet 1200 was leaking a lot of fuel , i had to screw off the front cover ,(left hand threads) and changed the short fuel line under it , it was bent too much into the festo fitting , after i did that it is not leaking any more.
09-22-2018, 01:39 PM
#21
hard too say that's why I said remove the line at the engine. Do a start sequence and watch the fuel flow
it should only drop like every second or so..not a stream
after you have that set close you can fine tune with line back on. The goal is to have just enough fuel for ignition. But enough fuel to have a reliable start. After that pre heat takes place.
it should only drop like every second or so..not a stream
after you have that set close you can fine tune with line back on. The goal is to have just enough fuel for ignition. But enough fuel to have a reliable start. After that pre heat takes place.
Last edited by aaronforth; 09-22-2018 at 01:42 PM.