Wren now offering new digital bus Xicoy FADEC and brushless starters & fuel pumps

[Kiba]

While for now it's only offered on the Wren 80 and Wren 100, maybe this is a hint at what is to come for us heli flyers using the 44...

http://www.wrenturbines.co.uk/turboj...en-80-dci-kero

The new Xicoy BL130 FADEC uses a single cable digital bus between the turbine and FADEC and the new FADEC drives a brushless starter motor and fuel pump.

Besides cleaning up the wiring between the turbine and FADEC with the single cable bus the biggest benefit that I see to the new setup is the brushless fuel pump.

I'm currently in the middle of sorting out uneven and lazy starting issues with my 44 as it appears the fuel pump has become "sticky" at the low voltages supplied to it during ignition and preheat causing either failed starts or prolonged lazy starts. With a brushless fuel pump the fuel pump flow characteristics should remain nearly constant over the life of the pump as there are no brushes or commutator to wear and get sticky-- so once the fuel pump is initially tuned to the turbine it shouldn't require any additional adjustment as the pump accumulates more run time.

Ron at Wren USA has said a "digital" version of the 44 is in the works, but it might be a while until it is available... and expect about a $500 price premium over the current FADEC and brushed starter & fuel pump.

Nice to see some progress and upgrades coming down the road...

[Calil]

Hey Kiba!! (helifreak anf airgunfreak!)

Wren is really trying to make some deep changes on their turbines, with everything internal and clean!

It would be nice to see everything brushless, specially the pump, so with the natural wear it would be necessary change the pump values in the fadec along the time?

for Wren!

Question: why all the turbine manufactures only now are using brushless? 10 years later than the electric motors and PC coolers?

[cbdane]

Yep, saw the FB announcement about 2 weeks after I placed my 100 i-Kero order with Ron.

[Kiba]

Originally Posted by cbdane

Yep, saw the FB announcement about 2 weeks after I placed my 100 i-Kero order with Ron.

So... did you upgrade? And what did you put it in?

The new FADEC and brushless starter & motor certainly isn't a necessary upgrade as the turbines run great as-is... but it would certainly be nice to have. I'd really like to have one of the brushless fuel pumps right now as then my 44 probably wouldn't be having any starting issues!

I'm hoping the replacement fuel pump arrives Wednesday, I want to be able to fly over the new few days. It flies great right now but startups aren't guaranteed...

[Calil]

It it's time to replace the pump so go brushless, why not? But i have a question: will the traditional "old" fadec works with the new brushless pump?

[Kiba]

Originally Posted by Calil

It it's time to replace the pump so go brushless, why not? But i have a question: will the traditional "old" fadec works with the new brushless pump?

The current V10 FADEC isn't capable of driving brushless motors. You would need to upgrade to the new BL130 FADEC that can drive a brushless starter and fuel pump. Unfortunately the Wren 44 uses a smaller starter motor and fuel pump than the rest of the Wren lineup and they haven't manufactured the necessary smaller brushless starter & fuel pump for the 44 yet. As Ron said, they're working on it but it won't be released for a while.

As of now I'll be sticking with the current Hausl brushed fuel pump; down the road I may upgrade my 44 to the new BL130 FADEC and brushless starter & fuel pump but right now it's not even an option.

[Calil]

Yes I won't either spent more $$ on this for a few years.

It's working perfectly, no need to to this right now. But it will be nice to do later.

[Kiba]

New fuel pump cured my hard starting issues. Arrived yesterday, ran it on the bench for a few hours, installed it last night. After reducing the pump start, min flow, and preheat fuel values I tried a start. Had to do a little minor tweaking to get clean starts but now it starts very quickly again and I got 6 flights in today.

Almost ran out of fuel and had to auto it in though... I land when the telemetry says to (Jeti MUI30 monitoring cumulative fuel pump consumption and also the Xicoy Jeti telemetry interface calculates fuel remaining.) With the old fuel pump when the low fuel alarm went off I could bring it in to land and still have a tiny bit left in the tanks and the air trap would be full of fuel. Forgetting the new fuel pump would likely have different current draw vs fuel flow characteristics compared to the old pump I took off and flew with the low fuel alarms set for the original fuel pump... and after landing the main tanks were dry and there was less than an inch of fuel left in the air trap. Yikes! Turns out the new fuel pump is more efficient than the old one in regards to mah consumed vs fuel volume delivered and the alarms needed a 13% correction!

Also... Ron at Wren USA is one seriously nice guy to work with, I sent an email late last week asking about the starting issues and next thing you know he replies with "sounds like the fuel pump is sticking at low voltage, a new pump is in the mail. Let me know if it works and send your old one back in."

[Calil]

As always, Ron and Wren are the best customer support ever.

Kiba

I don't know where I read it but the pump get it's parameters changed along the time because of use. So that's why that happened.

That's very nice to see you back to air with no problems! I know that feel bro! I was since july trying to fly and only two weeks ago I got my issues solved!

That's a wonderful feeling!

[Kiba]

The original pump seems to have become *very* sticky at the low voltages used to drive it during startup-- and it happened without any warning signs. One start and flight was perfect, after landing I refueled the heli and it refused to start.

While tweaking some of the startup parameters a couple of points up or down is expected over the life of the pump the turbine went from about 150 perfect starts using the same parameters to totally failed starts over the course of a single flight... and to get it to start after that required increasing some values by 12-15 points... that's a huge change!

[Calil]

We could email wren or ron and ask about the original magnet pump lifetime.

But in your case I believe that it was somehow almost failing. You did well getting a new one. And to Ron:

[cbdane]

Originally Posted by Kiba

So... did you upgrade? And what did you put it in?

Stuck with standard order. Ron had already placed it and didn't want to be a pain. Also, couldn't quite justify the extra cash. It will be hard to get the number of flights on the jet that I do with the 44K heli so it should be fine for a long time. BTW: my 44K is still running on the original fuel pump from almost 5 years ago. I'm not quite the prolific flier that you are, though. Got 6 flights since last Friday; good week! I have a new video to post of one of my boring flights. I'll start a thread once I download it from the camera.

You haven't thought of a way around the 32k limit on the JETI RPM alarm, have you? Still bugs me a bit.

[Kiba]

No, still haven't found a way around the 32k limit but I haven't really been searching for a way around it either. I'm still basing the primary "flameout" alarms off fuel pump amperage through the MUI30; if it drops below 0.2A during any of the flight modes the alarm is triggered. There are also redundant flameout alarm triggers using the EGT sensor and pump voltage from the Xicoy telemetry module.

An RPM-based flameout alarm probably would be the fastest responding alarm especially if you set one for say RPM < 130K rpm in any active flight mode, but basing the flameout alarm off fuel pump current, voltage, or low EGT reponds very rapidly as well.

I've only had one flameout in flight when I was still tuning the fuel capacity alarm using the MUI30 (ran out of fuel, oops!) and it worked perfectly. The alarm went off just before I heard the change in sound from the turbine-- but I was flying pretty far away at the time.