mauryr

Glad you got it running again!
Feel free to post detailed pictures of your updated fuel system setup: I personally would be happy to let you know if I see anything else that looks bad to me, as I am certain others would.

Good luck!

George62

I enclose the picture of the cockpit and turbine installation after the repair and based on the given advice.

Today we have flown again - we did two flights, the turbine runs normally. We will continue flying in the next days and will make some video for reference. When we complete 20 flights without a problem we will prepare the second model of the Black Horse L-39 we have with another K-45 engine.
Once again many thanks for your expert advice which really helped

extra 300

My Feedback: (3)

George,

You are welcome. this all what forums are about. sharing information, knowledge and experience. if it wasn't from the forums, I would have never been able to fly jets where I live.... No turbine experience around. I must admit that it has been quite costly and hectic when I started 11 years ago!

Wishing you guys safe flights and happy landings

Regards,

George62

Just want to let you all know we have completed 11th flight since the sudden shutdown and the K-45 turbine works fine due to the changes of the fuel system set-up



Video of the 8th flight since the shutdown/13th in total::

https://www.youtube.com/watch?v=r1sAkRX1kuY

mauryr

Glad it's working out for you!
Nice flight, by the way!

George62

We have been experiencing the FlameOuts again even our fuel system was fixed as per the advices given here and we became more familiar with the turbine specifics. The turbine always shuts down at the begining of a flying session/day as soon as we execute one or two rolls or loops, however it runs perfectly right after the same day. Therefore we started to proceed with a "controlled" FlameOut on the ground by holding and moving the model nose up and down with the running engine. Once the FlameOut happens we know can fly safely on a given day. We checked that there are no bubbles going down the visible parts of the fuel system, i.e. thru the fuel tubes leading to the engine so we assume some bubbles might nest somewhere inside the engine and that they can only be released by moving the engine as described.
We would appreciate if somebody has an idea on how to fix the problem. I enlose two recent videos to illustrate the problem - one with the FlameOut occurred during the flight and the other with the "controlled" FlameOut on the ground after which we enjoyed our flying on the day with no more repeated FlameOuts.

https://www.youtube.com/watch?v=XKTw8JEmnkk https://www.youtube.com/watch?v=cQiKoN7rV90

Dr Honda

My Feedback: (4)

A couple years back... I had a Wren 44 that would flame out at randome times. I couldn't figure out what was wrong... so just for giggles, I put a felt clunk on the main tank and removed the bubble tank. (to reduce the suction needed) After that... it never flamed out again. I eventualy made a small 2oz bubble tank, and it didn't give me any issues.

My thoughts on it were...

1) Too restrictive with a bigger bubble tank.\
2) There was a slight leak in one of the hoses, or the bubble tank lid.


Anyway... I would personally remove every fuel connection, and re-fit. If you have festo fittings on the suction side... they can leak. (They were meant for pressure)

mauryr

Could you post a picture of your fuel filter and its tubing?
A friend's plane had a similar problem and it was caused by the fuel filter position

George62

We have decided to remove the filter from the fuel system as there are two filters on the way already - first is the felt clunk in the main tank and second is the diffuser in the Intairco air trap. We removed the filter after our initial problems with the FlameOut (as described earlier in this thread) when we were replacing the improper Tygon tubing and made loops where necessary to avoid sharp turns - the engine ran smoothly for the next 24 cycles then.
I will tell Karel (the pilot) to take some photos to post them for the reference soon.

George62

Here are two pix of the installation for reference :

mauryr

This?


Not sure, can't really see all of your system, but this seems easily kinked

George62

Thanks for your comment, I will try to make better pix than Karel as soon as the local weather gets better and we meet at the airport ...

Dr Honda

My Feedback: (4)

I see push in festo's on the suction side. That's a no-no. I know people do it... and it works most of the time... but they are designed for pressure. (not suction)

ravill

My Feedback: (11)

I had a similar issue with a brand new jet with ALL brand new systems. Unfortunately for me, my flameouts happened right after take off. As you can imagine, this is the worst place to get a flame out.

I repaired the aircraft TWICE before I caught this.

My issue turned out to be my UAT. (I was using BVM's at that time). It would throw a bubble ONLY after refill and ONLY after rotation of the jet and ONLY at full throttle. Very, very strange. It was uncanny how I could duplicate this phenomenon.

I replaced my UAT and I never had the problem again.

On the pics you have sent, is your UAT empty after flying or defueling? Your UAT should never go empty, a little air here and there, is exactly what it's meant to have, but it should NEVER go empty.

Anyways, that's what worked for me. Thank you for sharing your trouble shooting with us, as we learn right along with you.

Mav1967

Hi guys, I am running a Kingtech K45s in a Mini Avanti S. Had a many sudden flame outs after the first half dozen flights, and then a failure to start for a while. Turned out to be fuel pump.

Got another pump the same as the original one supplied with the engine, lasted half dozen flights, then faulted in the exact same way.

Acquired a jet cat p60 pump from motors and rotors, installed it and dialled down the pump voltages in the ecu because of higher delivery volume of this pump.

Had about 20 flights since, better throttling, and not missed a beat since. Worth checking. Have also read in jet magazines reports of similar failures with the Hausl type pumps supplied with some Kingtech engines. (The ones with flat sides on the motor housing)

Mav1967

Sorry, that should read "Kingtech K45G"

Desertlakesflying

My Feedback: (28)

Has anyone Contacted Dirk or Barry at www.pacificrcjet.com

I'm sure Barry would be very interested in this.

[h=3]626-808-6122[/h]

George62

I had a similar issue with a brand new jet with ALL brand new systems. Unfortunately for me, my flameouts happened right after take off. As you can imagine, this is the worst place to get a flame out.

I repaired the aircraft TWICE before I caught this.

My issue turned out to be my UAT. (I was using BVM's at that time). It would throw a bubble ONLY after refill and ONLY after rotation of the jet and ONLY at full throttle. Very, very strange. It was uncanny how I could duplicate this phenomenon.

I replaced my UAT and I never had the problem again.

On the pics you have sent, is your UAT empty after flying or defueling? Your UAT should never go empty, a little air here and there, is exactly what it's meant to have, but it should NEVER go empty.

Anyways, that's what worked for me. Thank you for sharing your trouble shooting with us, as we learn right along with you.

Many thanks for sharing your experience and we would definitely follow your advice on our next flying session which is to happen as soon as the local cold and snowy weather allows for that. I will post here if it works or not.
George

marquisvns

It seems to me you have a stuck clunk or some other plumbing related issues. The shutdown message with speed low and high PW at around 500s confirms this.

Please pull out your fuel tank(s) and remove your pick up line, lay them one on top of the other and take a picture. I would think we just may be able to solve the mystery.

Regards,
Barry

skunkwurk

My Feedback: (18)

Hi,

Do you fully empty the plane of fuel when you're done for the day? I've heard of issues like this which were solved by never completely emptying the system. For example, you top it off when you get to the field, you top it off after each flight and you do not empty it at the end of the day. You repeat the cycle each time you go to the fuel. I don't love the idea of transporting a plane with fuel but I know several prominent jet pilots which do not empty their planes for this specific reason.

Just my two cents, good luck.

sc

ravill

My Feedback: (11)

Many of us don't want to stress out our fuel tanks with repeated high voltage drainage from our fuelers. That, and I'm lazy.

skunkwurk

My Feedback: (18)

That's a good point too. I wonder if the OP does this or not. It may help...

George62

So we finally resumed our flying after a lenghty break due to the winter weather. We proceed with following your advice not to empty the fuel system completely after the flying session and we now abandon defuelling once the main tank is empty leaving the UAT almost full of fuel. And guess what - the problem seems to be over ! The jet engine did not shut down during our preventive ground "exercise" with the model nor during the first flight of the day as it did before. Yet flying very cautiously we are quite positive about finding the real cause and the issue being likely over Many thanks for your advice !
https://www.youtube.com/watch?v=ewjiH-EisBc

skunkwurk

My Feedback: (18)

Super!

It was advice I received from a good friend and it helped me as well. I figured I'd pass the tip along, I'm glad it helped.

Take care.

DenisFerrari

Hi guys, just curious to know how your flights are going and if you experienced more flameouts

Reason of my curiosity is that after +40 flights with my Wren 80 DCi I had a very strange flame out , around 3.5 mins after first flight, during a fast roll and I could safely land my Xcalibur.

As soon as inspected nothing wrong appeared, no bubbles, nothing at all.after the checks I took off again no problems at all.

And then I took 3 more flights, all good as before the flame out.

I found so many things in common with your experience, but in my case Xicoy fadec is one for brushless pump.

I've also downloaded last 51 mins and my glamour seems like yours, that is with no evidence of low Rom or temperature.

On the DT, just after landing I had "Speed Low" or something similar. But Rpm we're much higher than idle.

I have BVM UAT and I wouldn't want is because a remove half of the fuel up after every flight session. Is this really correct ?

​​​​​​WWhen refuelling I normally incline little bit the model to leave all the air go back to main tank and finish refuelling with UAT full. Like I find it after every flight and even after the flame out.

Also, no problems or evidence of any leak in my fuel system and I rely this is good. The same for main tank clunk and the rest.

I know its not easy with these few details, but any idea ?

Thank you.