When your jet is talking to you
09-23-2018, 05:10 PM
#1
When your jet is talking to you
Have you had it before? your jet was talking to you and you didn't listen, went up anyways and something went wrong with it during the flight.
My Boomerang was talking to me on the Friday before our jet event, few times ago during the starting sequence I noticed the starting sequence was not smooth buy it run good then I went to fly, all good, till Friday, I was going to do two shake off flights in preparations for the jet event the next day, the start up sequence was not smooth but it run good, I taxi out, got ready and released the brakes, she began accelerating, trust 100%, one second before rotation, she passed in front of me, all looking good, rotttt....piiiiiiuuuiiusssss, flame out, stoped at the end of the runway.
I try to make her run again but all I was getting was flames, then the starter was not engaging and so on, I stoped and dropped down everything, decided that was it for the weekend, no flying for me during the event.
Now at home I'm finding a worn out starter O ring, fuel leak under the front cover ( the festo fitting was loose enough to be able to rotate it with my fingers ) a loose center exhaust cone because it was missing one of the three screws that holds it in place ( found it in the very back of the fuse )
I'm still digging in, not sure what else I'm going to find, a possible bad fuel pump, don't know at the moment
How about you guys? Do you have any stories when you listened to you jet or when you didn't
Last edited by CARS II; 09-24-2018 at 04:06 PM.
09-23-2018, 06:48 PM
#2
I'm finding out my starter O ring was not engaging properly because the fuel leak from the festo fitting got the compressor nut wet with fuel, just enough to make the starter O ring slippery.
This my be the root of all my problems, the starter O ring getting some of the leaked gas, just enough to make the O ring slippery, that makes sense, I was experiencing not enough rpms during the ramp up sequence.
I cleaned it all with glass cleaner and tested it, it is engaging and accelerating normal.
This my be the root of all my problems, the starter O ring getting some of the leaked gas, just enough to make the O ring slippery, that makes sense, I was experiencing not enough rpms during the ramp up sequence.
I cleaned it all with glass cleaner and tested it, it is engaging and accelerating normal.
09-23-2018, 06:50 PM
#3
n7
Im finding out my starter O ring was not engaging properly because the fuel leak from the festo fitting got the compressor nut wet with fuel, just enough to make the starter O ring slippery.
This my be the root of all my problems, the starter O ring getting some of the leaked gas, just enough to make the O ring slippery, that makes sense, I was experiencing not enough rpms during the starting sequence.
I cleaned it all with glass cleaner and tested it, it is engaging and accelerating normal.
Moving forward.
Last edited by CARS II; 09-23-2018 at 09:49 PM.
09-23-2018, 07:50 PM
#4
I reinstalled the engine back in the Boomer, did two start ups to idle, all looks good, I will have to take it to the flying field to do more test runs there, I will keep an eye on the pump power.
During the run the numbers I got are almost identical to a run I did in 2013, the switch to Diesel has not change the running number by much, pump PW up by 2 points and idle temp by around 50° or so, it looks like all is back to normal.
During the run the numbers I got are almost identical to a run I did in 2013, the switch to Diesel has not change the running number by much, pump PW up by 2 points and idle temp by around 50° or so, it looks like all is back to normal.
09-24-2018, 01:04 PM
#8
My Feedback: (11)
Good investigative work.
My jet was talking to me yesterday. One of my flaps was not operating smoothly as it normally would. I removed the wing and plugged in a servo tester. All is good, servo worked excellent. Decided not to fly and took it home. I pulled the servo extension wire out of the fuselage and found the signal wire was barely attached. I installed a new extension and it is back to working like a champ.
I try to always listen to my instincts and have missed out on some great flying days. Better to be sure than chance something.
Jeff
My jet was talking to me yesterday. One of my flaps was not operating smoothly as it normally would. I removed the wing and plugged in a servo tester. All is good, servo worked excellent. Decided not to fly and took it home. I pulled the servo extension wire out of the fuselage and found the signal wire was barely attached. I installed a new extension and it is back to working like a champ.
I try to always listen to my instincts and have missed out on some great flying days. Better to be sure than chance something.
Jeff
09-24-2018, 05:31 PM
#10
Great observation and investigation!
I just had something happen to me that almost made me walk away from Jets completely! (Emotional reaction of course). So here is my story!
At the end of 2017 I changed careers and have been travelling more than I ever have before. Weekends have turned into valuable family time and flying got moved to the back of the list. My son convinced me to get my BVM Cougar flying and I finally made the effort to sneak in the shop and get some work done. I have always had build procedures and practices that have always made my projects successful. On this day I had completed my K140G2 install and was going over things when my neighbor stopped by and got me all fired up to beat the rain and get a test run in. This is when I got excited and forgot to follow my own procedures. Normally I would disconnect the 4mm fuel line to the turbine and use a container to capture the fuel as I tested the fuel pump and purged all the air out of the line before connecting it back. (I have done this on every turbine I have owned and never had one hiccup at startup)
Except for this day. I was too excited and in a hurry to beat the rain that I had sold myself that it was Ok to skip this step. I continued on with pre-start up and placed my Extinguisher in the same spot I always do, knee pad in the same place, transmitter ect.
Start #1. no fire "low gas"
Start #2. no fire "low gas"
Start #3. no fire "low gas"
Not familiar with ever seeing this on my engine test, I moved on to trouble shooting things. I had changed all the tank lines and put the start up failures to air in the line and getting suction going from the tank. As I inspected the lines I noticed that the 4mm discharge from the fuel pump was kinked. I replaced that section and started all over again. (Sill didn't purge/test fuel pump).
Start #4. Engine is spooling up and then **FIRE** **FIRE** **FIRE**
My first hot start ever in 5 years!!! AS fast as I can remember I closed the ball valve to the fuel supply, killed the motor and jammed the throttle to cooling mode, grabbed the extinguisher and hit it!!!!!!! FIRE under control....Turbine in cooling mode kept the incipient fire that was still burning going down the thrust tube....I grabbed my shop blower and forced air down the intakes to help cool the engine down. Once this was accomplished the small incipient fire went out completely. It took me about 1 hour to calm my nerves to inspect the damages. I put the jet back on the bench and was just blown away at what I had found. The fire was put out so fast that it did no damage to plane at all. The lower former had slight discoloration but that was about the extent of the "Damages". Now for the wake up call...Upon inspection of the aircraft, I noticed that when I lowered the tail to inspect the plane in detail, jet fuel poured out of the rear. I had fuel in the fuselage below the thrust tube. A LOT OF IT!!! As I pulled the motor to clean things up, fuel pours out of the turbine as well. Honestly, I have no idea how the whole tail section didn't go up in flames!!!!!! This really set me back emotionally....The whole week I was out of town I really considered getting out of jets. The only thing that changed my mind was the challenge not to give up so easily. Guys deal with hot starts all the time. I made a mistake and I owned up to it. It was completely my fault and had it burned down to the ground I would have to live with the fact that I took a shortcut and almost paid the ultimate price. So what did I do? I placed the turbine in the vertical position to drain out and let the fuse dry (tail section) out as well. When I came back a week later (after calming my nerves) I put everything back together and did what I always do. Followed my rules and she fired up on the first start!!! Nerves gone and I am now ready to move on.
So what did I learn?????
Turbine waiver process works. This should be the minimum training you get before operating a turbine.
Safety Equipment is a HUGE Investment. I haven't used my fire extinguisher in 5 years and when I needed it she was there!!!! (inspected yearly)
Knowing your equipment!!! shut off valves, engine kills, cooling mode!!!
Turbines are a huge investment. have your personal checklist, follow it!
Don't rush, listen to your jet when she / he (gender bias jet) is talking to you.
Learn how to handle emergencies!!!
Most important, this is a hobby. Take your time and do it right.
I just had something happen to me that almost made me walk away from Jets completely! (Emotional reaction of course). So here is my story!
At the end of 2017 I changed careers and have been travelling more than I ever have before. Weekends have turned into valuable family time and flying got moved to the back of the list. My son convinced me to get my BVM Cougar flying and I finally made the effort to sneak in the shop and get some work done. I have always had build procedures and practices that have always made my projects successful. On this day I had completed my K140G2 install and was going over things when my neighbor stopped by and got me all fired up to beat the rain and get a test run in. This is when I got excited and forgot to follow my own procedures. Normally I would disconnect the 4mm fuel line to the turbine and use a container to capture the fuel as I tested the fuel pump and purged all the air out of the line before connecting it back. (I have done this on every turbine I have owned and never had one hiccup at startup)
Except for this day. I was too excited and in a hurry to beat the rain that I had sold myself that it was Ok to skip this step. I continued on with pre-start up and placed my Extinguisher in the same spot I always do, knee pad in the same place, transmitter ect.
Start #1. no fire "low gas"
Start #2. no fire "low gas"
Start #3. no fire "low gas"
Not familiar with ever seeing this on my engine test, I moved on to trouble shooting things. I had changed all the tank lines and put the start up failures to air in the line and getting suction going from the tank. As I inspected the lines I noticed that the 4mm discharge from the fuel pump was kinked. I replaced that section and started all over again. (Sill didn't purge/test fuel pump).
Start #4. Engine is spooling up and then **FIRE** **FIRE** **FIRE**
My first hot start ever in 5 years!!! AS fast as I can remember I closed the ball valve to the fuel supply, killed the motor and jammed the throttle to cooling mode, grabbed the extinguisher and hit it!!!!!!! FIRE under control....Turbine in cooling mode kept the incipient fire that was still burning going down the thrust tube....I grabbed my shop blower and forced air down the intakes to help cool the engine down. Once this was accomplished the small incipient fire went out completely. It took me about 1 hour to calm my nerves to inspect the damages. I put the jet back on the bench and was just blown away at what I had found. The fire was put out so fast that it did no damage to plane at all. The lower former had slight discoloration but that was about the extent of the "Damages". Now for the wake up call...Upon inspection of the aircraft, I noticed that when I lowered the tail to inspect the plane in detail, jet fuel poured out of the rear. I had fuel in the fuselage below the thrust tube. A LOT OF IT!!! As I pulled the motor to clean things up, fuel pours out of the turbine as well. Honestly, I have no idea how the whole tail section didn't go up in flames!!!!!! This really set me back emotionally....The whole week I was out of town I really considered getting out of jets. The only thing that changed my mind was the challenge not to give up so easily. Guys deal with hot starts all the time. I made a mistake and I owned up to it. It was completely my fault and had it burned down to the ground I would have to live with the fact that I took a shortcut and almost paid the ultimate price. So what did I do? I placed the turbine in the vertical position to drain out and let the fuse dry (tail section) out as well. When I came back a week later (after calming my nerves) I put everything back together and did what I always do. Followed my rules and she fired up on the first start!!! Nerves gone and I am now ready to move on.
So what did I learn?????
Turbine waiver process works. This should be the minimum training you get before operating a turbine.
Safety Equipment is a HUGE Investment. I haven't used my fire extinguisher in 5 years and when I needed it she was there!!!! (inspected yearly)
Knowing your equipment!!! shut off valves, engine kills, cooling mode!!!
Turbines are a huge investment. have your personal checklist, follow it!
Don't rush, listen to your jet when she / he (gender bias jet) is talking to you.
Learn how to handle emergencies!!!
Most important, this is a hobby. Take your time and do it right.
09-25-2018, 12:06 AM
#11
WOW! I don't think my flames were that impressive like yours, I got fire spitting out the back of the turbine and like you haven't had a hot start in over 10 years, when I did, like you I had my CO2 bottle right next to me and I got to use it twice the same day.
Last edited by CARS II; 09-25-2018 at 11:17 AM.
09-25-2018, 03:34 AM
#12
Join Date: Nov 2003
Location: Curitiba, Parana, BRAZIL
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Absolutely. Any machine "talks" claiming or warning about something. Usually using sounds or behavior.
However, there is a area in wich we are usually blind or deaf. One of the best things I did in my rc career was installing a onboard led voltimeter in all my planes. It helps me to see how the voltage fluctuates in the electirc system and this can provide the following information:
1) Low battery voltage
2) Deteriorated battery discharging capacity. (leds go red while while moving the tx sticks)
3) Some dragging/stuck control surface discharging the batteries
4) Moisture/humidity warning (leds act crazy while moving the sticks. this happened flying in a rainy day, after splashing some water puddles on takeoff)
5) Faulty contacts/ switches.
6) Empirical data about rhe batteries discharge curve in your particular plane = how many flights you can safely get without recharging.
7) Warning about bad servos. This saved me a plane recently. While starting the engine, I saw the led bar going crazy.. didnt knew what is was, and shut off the turbine.. moved the sticks/ inspected wires and then everything went back to normal, with one solid green led turned on. However, when I moved the sticks, I felt a difference on the led pattern ...checked everything again and then found that a elevon servo was dead (!)
This humble device helped me a lot, Otherwise, I would had more than one misterious crash,. This also helps to avoid blaming radio brands, model planes, manufacturers, etc.. :-)
http://www.myrcmart.com/tower-pro-led-rc-receiver-battery-low-voltage-monitor-indicator-p-8729.html
However, there is a area in wich we are usually blind or deaf. One of the best things I did in my rc career was installing a onboard led voltimeter in all my planes. It helps me to see how the voltage fluctuates in the electirc system and this can provide the following information:
1) Low battery voltage
2) Deteriorated battery discharging capacity. (leds go red while while moving the tx sticks)
3) Some dragging/stuck control surface discharging the batteries
4) Moisture/humidity warning (leds act crazy while moving the sticks. this happened flying in a rainy day, after splashing some water puddles on takeoff)
5) Faulty contacts/ switches.
6) Empirical data about rhe batteries discharge curve in your particular plane = how many flights you can safely get without recharging.
7) Warning about bad servos. This saved me a plane recently. While starting the engine, I saw the led bar going crazy.. didnt knew what is was, and shut off the turbine.. moved the sticks/ inspected wires and then everything went back to normal, with one solid green led turned on. However, when I moved the sticks, I felt a difference on the led pattern ...checked everything again and then found that a elevon servo was dead (!)
This humble device helped me a lot, Otherwise, I would had more than one misterious crash,. This also helps to avoid blaming radio brands, model planes, manufacturers, etc.. :-)
http://www.myrcmart.com/tower-pro-led-rc-receiver-battery-low-voltage-monitor-indicator-p-8729.html
09-28-2018, 06:18 AM
#14
I just had a situation this last weekend. on the last flight of the day the jet did not seem to have the normal ground tracking. I had a hard time turning to taxi down wind to get to the end of the runway. I just attributed it to the wet grass being slippery and the very large vertical fin area and the wind picking up. I do have the plane set up so that when the gar are up the steering servo is centered and turned off. After landing I was completely unable to turn around to taxi back. The steering servo had failed. That sluggish steering on the taxi out was the plane trying to talk to me, and me not really listening. Fortunately the landing was straight and needed no ground corrections. I did have to walk out and carry the poor thing back to the pits.
Sometimes the plane will talk to you but it may speak very softly, you just have to pay very close attention
Sometimes the plane will talk to you but it may speak very softly, you just have to pay very close attention
09-28-2018, 01:26 PM
#15
I like to thank everyone that has posted here, some of the comments and suggestions you posted here have reinforce my knowledge and I have learned a few new things or checks that I can do before and after flying my jet.
Thank you, thank you for participating
Thank you, thank you for participating
10-01-2018, 05:53 PM
#16
The starter problem was more than just a grommet swap. I noticed the bendix was not moving forward enough, dipped the pump in water the run it for a about 30 sec to clean it, after that the bendix moved all the way forward when the starter was run, replaced the grommet with a slightly different one ( smaller ) and the starter slipping problem is gone.
Moving on to the next problem, I had a flame out on the runway on TO the day before our jet meet, today I was able to start the engine normally and after a few runs at high rpms I went for a flight,TO was normal, I got to fly for about 5 min then, a flame out at high altitude, landed just fine.
What do you guys think, I didn't see any air in the lines, pump? thermocouple?
Last edited by CARS II; 10-01-2018 at 05:58 PM.
10-01-2018, 08:44 PM
#18
Tank setup, UAT setup, would help as well. Your pulling air from a fitting for sure. Five minutes in and flameout? Do you remember if the fuel level was below the suction fittings? I have seen loose fuel tubing in the tank that eventually gets "soft" start pulling so much air that the UAT just cant keep up?
10-01-2018, 11:20 PM
#19
Dr:cito I think you are looking at the smoke tube.
I didn't notice any air on the lines at the moment, I've changed a small piece of fuel line near the engine but I will look for any loose fittings.
I started the engine again after a few minutes and all was normal, it feels like air is getting in there some how as mention above, I will have to do a more detail inspection.
I didn't notice any air on the lines at the moment, I've changed a small piece of fuel line near the engine but I will look for any loose fittings.
I started the engine again after a few minutes and all was normal, it feels like air is getting in there some how as mention above, I will have to do a more detail inspection.
Last edited by CARS II; 10-02-2018 at 11:22 AM.
10-03-2018, 12:49 PM
#21
It has been some time since I change the fuel lines and checked the fuel system, something may have come loose after nearly two years of flying and is allowing air in the lines, pump PW is normal at idle and max rpms, the thermocouple has not acted weird ( had that one go bad years ago ) and it is displaying ambient temp when the FEDEC is on.
Dblex, Thanks for the suggestions.
Dblex, Thanks for the suggestions.
Last edited by CARS II; 10-03-2018 at 01:36 PM.
10-05-2018, 12:42 PM
#22
Has anyone experienced fail safe shutdown? Is the picture showing a fail safe shutdown? What will the GSU show if there is a fail safe shutdown?
That is what I got out of the FEDEC after the flame out.
Questions, questions???????????
Last edited by CARS II; 10-05-2018 at 12:46 PM.
10-05-2018, 04:43 PM
#23
Carlos,
As long as you have correctly programmed the ECU with your TX then it should say Failsafe following a failsafe shutdown. What you are showing is a flameout indication.
You can test the Failsafe function by turning off the Tx once the engine is running to confirm that it shuts down correctly and with the correct message.
All my unexplained flameouts were due to filter restrictions, with a secondary indication of elevated Pw at full throttle. I'm running 2 Merlin 140XBLs (brushless pumps) so the Pw value is different from the older brushed pump motors, but the issue and indication is the same.
I have back-flushed my fuel system with a gallon of fuel as a temporary work-around prior to replacing the MAP Air Trap with integral filter.
Paul
As long as you have correctly programmed the ECU with your TX then it should say Failsafe following a failsafe shutdown. What you are showing is a flameout indication.
You can test the Failsafe function by turning off the Tx once the engine is running to confirm that it shuts down correctly and with the correct message.
All my unexplained flameouts were due to filter restrictions, with a secondary indication of elevated Pw at full throttle. I'm running 2 Merlin 140XBLs (brushless pumps) so the Pw value is different from the older brushed pump motors, but the issue and indication is the same.
I have back-flushed my fuel system with a gallon of fuel as a temporary work-around prior to replacing the MAP Air Trap with integral filter.
Paul
10-05-2018, 06:57 PM
#24
Hi Paul and thank you for the detail info.
I was told by one of my rc jet pilot friend about the restrictions of the filter, it was removed, it is back on now, the UAT sack was replaced about two years ago
My next move will be to disconnect the fuel tube from the engine to check the fuel flow pressure, I will also concentrate on the pump wire lead connection to the FEDEC, that connection may be loose and moving causing the pump to just turn off as the GSU display shows no pump PW at all during the flame out.
I was told by one of my rc jet pilot friend about the restrictions of the filter, it was removed, it is back on now, the UAT sack was replaced about two years ago
My next move will be to disconnect the fuel tube from the engine to check the fuel flow pressure, I will also concentrate on the pump wire lead connection to the FEDEC, that connection may be loose and moving causing the pump to just turn off as the GSU display shows no pump PW at all during the flame out.
Last edited by CARS II; 10-05-2018 at 07:03 PM.
10-06-2018, 05:11 AM
#25
Carlos,
I think 0 Pw at the point of flameout is correct, as the ECU has shut the pump down once it detects falling rpm below a certain threshold.
Download the ECU data (assuming you have the correct ECU to PC cable) and look at the data immediately before the flameout. The ECU stores over 50mins of run data every 0.5sec (if I recall correctly).
You could always e-mail the ECU data to Gaspar for advice, as he is excellent at customer support.
Paul
I think 0 Pw at the point of flameout is correct, as the ECU has shut the pump down once it detects falling rpm below a certain threshold.
Download the ECU data (assuming you have the correct ECU to PC cable) and look at the data immediately before the flameout. The ECU stores over 50mins of run data every 0.5sec (if I recall correctly).
You could always e-mail the ECU data to Gaspar for advice, as he is excellent at customer support.
Paul