My Wren 44 Turbine T-Rex 700 - Sneak peak

[Calil]

May be just a problem of setup?

[MattJenner]

Speed low normally means the battery is too low to turn over the starter motor. (if that error shows up on startup)

I know I fly a 54, it had to reach 5000rpm for the star sequence to initiate.

If yours is low either your fadec battery is low ( I know Kero do suck a lot of juice on start up) or your start motor is misaligned..

Just a couple of ideas maybe to look at.

Nice conversion

Matt

[Calil]

Hey Matt good to see you arround!! You are still on the heli world then

I use a A123 2s 2300 mah battery for the RX (no regulator) and a lipo 2s 2250 70C battery for the pump.

Yes the fail safe is activated. There is no crack in the frame because I bought a new kit and exchange everything. I'm thinking about getting back to lipo and a fromeco regulator. Also I'm thinking exchange the ECU from place and get the carbon fiber plate out.

If I fly for 1 minute I land and nothing happens. If I fly for 3 minutes or more I land and the turbine shutts off. May be with 3 minutes the blades collects a lot of static?

I'll try landing in some rubber or plastic to test isolation.

[MattJenner]

Hi again
It nay be worth doing a data download and asking Lou to take a look at the data.

[cbergen]

Speed low means the Turbine RPM fell below the predetermined RPM (38,000 I believe but not necessarily correct, Haven't looked at it in awhile), at which point the ECU shuts off the fuel and initiates the cool down procedure IF the trim is then lowered to off.

See other thread for suggestions..

[Calil]

Hey cbergen

I checked that and my last error in the FADEC says speedlow 29000. It's setted at 30000 to stop the turbine.

Should I set it to 25000 for example?

The turbine shuts off with the trim at maximum (stick about 55 to 60%) as soon I touch the ground. I just removed the carbon base and put a plastic one, so now no possible static there. (only if it comes by the fuel line).

Next step (saturday) try to change deceleration parameters and the rpm set.

[DenisFerrari]

Hi all,
couldn't it be some electric noise on the RPM sensor wiring, running of course from engine front to Xicoy FADEC?

In my 2 T-Rex 744 never had that isse, but not the first time I read something like that happening.

I know that the risk is there if put this cable too close to fuel pump (that has magnetic coupling gearings I think) and other noisi devices...

If I'm not wrong, I remember this is also noted on the manual, to pay some particular attention on that RPM wiring positioning, also because on that data (together with temperature sensor and throttle reference recived by the rx) the FADEC runs its engine control algorithm etc. etc.

For sure it won't be the case but - as they told - "my 2 cents"

I hope to read here very soon what's the real cause of such a strange issue.

Happy flying
Denis

[Calil]

Yes Denis, the RPM sensor is isolated from all the others. But I can't say for sure the sensor itself is not damaged.

I found some others that have had the same problem and it' was the fuel pump with some sort of problem. I'll try a new pump and see what happens.

I tested today, I changed the deceleration delay, it reduced the problem but did not solved it.

Either normal mode or IDLE1 the problem happens (when I touch the ground, not everytime but often). So it may be pump, the RPM sensor it self (not the cable). I removed the carbon plate so static is off the table!

Regards, Calil

[Calil]

So new tests today.

Carbon plate out. Problem persist.

A123 out. Lipo and regulator back to the RX. (ECU and Fuel Pump always runned lipo, not A123). Problem persist.

Pump limit and deleceration delay increased. Problem persist.

Either normal mode or IDLE, it keeps shutting down when touchs the ground. Not every time but very often.

I know some people that had the same problem on their jets and they changed the fuel pump for a new one and the problem was solved.

[Calil]

I should pay more atention to the manual.

I hope this solve the problem, I'll change to 4 mm with no valve between the UAT and the pump like rcnz told me to.

In his turbine it solved the exactly same problem. Let's pray brothers to the God Turbines!!!!

[cbdane]

Just saw this post. Sorry I posted the same information on the "Wren44 cutting out" thread. Air in the system; this was my guess from way back when you were seeing bubbles out of the filter. All related, I believe.

[Calil]

Originally Posted by cbdane

Just saw this post. Sorry I posted the same information on the "Wren44 cutting out" thread. Air in the system; this was my guess from way back when you were seeing bubbles out of the filter. All related, I believe.

I really hope its the source

Ill post a video tomorrow

[DenisFerrari]

Great, let's hope that the cause. I told it to you from the very beginning anyway, due to Wren 44 small dimension, you have to follow exactly the manual, otherwise all can get difficult. It would easily be that the cause.

Let us know positive news hopefully

Regards
Denis

[Calil]

Originally Posted by DenisFerrari

Great, let's hope that the cause. I told it to you from the very beginning anyway, due to Wren 44 small dimension, you have to follow exactly the manual, otherwise all can get difficult. It would easily be that the cause.

Let us know positive news hopefully

Regards
Denis

It's true you really did!! like we say here in Brazil : fui cabeca dura!!!

[cbdane]

Originally Posted by Calil

It's true you really did!! like we say here in Brazil : fui cabeca dura!!!

Assim se aprende!

[Calil]

The video. Please you must know that the TX battery only warned few seconds before the end of the video and even with fresh charged battery in the TX the issue occurs anyway. This video was recorded last saturday. I'm changing the fuel lines this night

Wren44HeliIssue (5 min 9 sec)

[garyw76]

I see your throttle curve is a little strange compared to what I run on mine. did you learn the ecu with this curve ? I don't think its a pump issue it starts and runs fine. I would set your normal throttle curve back to linear on the radio and relearn the ecu and fly it before changing the curve back to what you have now.

[Calil]

Originally Posted by garyw76

I see your throttle curve is a little strange compared to what I run on mine. did you learn the ecu with this curve ? I don't think its a pump issue it starts and runs fine. I would set your normal throttle curve back to linear on the radio and relearn the ecu and fly it before changing the curve back to what you have now.

The throotle curve is like that because we are trying to hold the turbine to not shutt down. No success although.

[garyw76]

I don't think running the curve like that will help the issue I would still do a radio relearn and I would go over the fuel system good on the suction side of pump I to think air may be your issue. with the heli running at idle hold it by the head and rock it back and forth and watch for airbubbles coming out of the uat. if non there the system should be air free unless it is sucking air right at the pump

[Calil]

Originally Posted by garyw76

I don't think running the curve like that will help the issue I would still do a radio relearn and I would go over the fuel system good on the suction side of pump I to think air may be your issue. with the heli running at idle hold it by the head and rock it back and forth and watch for airbubbles coming out of the uat. if non there the system should be air free unless it is sucking air right at the pump

I just replaced all pipework before the pump. That's our guess at the moment based on rcnz exactly problem like mine and that is suggested in the manual also.

I'm changing the curve back and doing the relearn also. I'll test today later and I'll inform here if the problem was solved.

Let's pray!!!