Ian Davidson

Thank you Martin, Henke - it was indeed the starter-motor slipping. I'veexperiencedthis with my Wren 54 before, but never the P20-SX.I'venow resolved it - thank you :-)<o></o>

This brings me on to however the problem I wasexperiencingbefore the starter-motor began slipping...<o></o>

The P20-SX goes through it’s normal start-up sequence, but the turbine never quite reaches the 85,000 RPM idle speed. If I’ve understood it right, only once the turbine reaches 85,000RPM is throttle control passed over to the throttle stick on the transmitter?<o></o>

During the start-up sequence the RPM reaches about 83,000 -> 84,000, but not quite 85,000 RPM. I eventually get the message AccTimOut and then -Cooling- even though the turbine is still running around 83,000 -> 84,000RPM. Also, once it reports AccTimOut/Cooling the throttle-kill switch on the transmitter doesn't do anything!? The only way I can kill the turbine is to pull the power!<o></o>

I certainly never experienced anything like this with my ECU before I damaged it and sent it back to JetCat for repair. Are there any settings with this repaired/replaced ECUI should be checking?

[youtube]http://www.youtube.com/watch?v=W9kT5mLtK6s[/youtube]

Henke Torphammar

Ok I think that is easy one too. You can se the pump value increases without the engine reving up. That indicates the fuel does not reach the engine. Check the clunk, fuel filter and all connectors. If thats right check the solenoids. These small *******s(haha censured b a s t a r d s) seem to jam from time to time, this is the exact same valves as on the Kolibri uses but buildt in to one block. On the Kolibri you can run the engine without the solenoids, I do not know if this is possible on the P20. Maybe if you bypass the main fuel solenoid useing only the starter solenoid for the kerostart.

Ian Davidson

Thanks Henke and thank you Martin too (who PM'd me) - you both diagnosed the same fault, so I'll investigate the fuel line. :-)

frema

let me know Ian
i think you will find it
succes
Regards,
Martin.

BaldEagel

I have been told by JetCat and others that the P20 fuel pump sees the full voltage to the ECU at switch on, hence for the P20 it can not be used with a 3 cell A123.

Mike

Ian Davidson

Ahhh, in that case my P20 fuel pump could be toast !! :-(

Ian Davidson

Something really strange is happening. I'm sure it must be either a ECU or fuel pump problem ?? :-(

Simply selecting the ‘Purge FuelSystem’ function via the DataTerminal sometimes works – sometimes doesn't. In this first video it does nothing!

[youtube]http://www.youtube.com/watch?v=wS7fDRZ2tx0[/youtube]

When it does work, if you hold down the ‘Change Value’ to active the ‘Purge FuelSystem’ function for more than around 3 seconds, the pump sticks on and cannot be turned off other than by removing the power. Once the fuel pump has stuck on, changing the fuel pump voltage/speed (either up or down) has no effect.

With hindsight, I actually witnessed the fuel pump sticking on in this way yesterday, but was unsure what was happening at the time.Yesterday I witnessed the turbine go into cooling mode (with the starter motor engaged), but the fuel pump was still running! The result was bellows of relentless white smoke as fuel was being pumped into a hot turbine.

[youtube]http://www.youtube.com/watch?v=tBbISsElTpk[/youtube]

frema

sent it back to jetcat agian
i cant do nothing about this
either pump or ecu fails
Regards,
Martin.

Ian Davidson

Thanks Martin, My money is on the fuel pump this time... and they're not cheap :-(

Henke Torphammar

Whats inside the purple CAN bus thingy? I cant imagine the pump motor being damaged that fast. Pump and motor seem to be the same as on the Kolibri except for the Jetcat CAN bus addon.

Ian Davidson

I've just got back home from a couple of days away. I've yet to take the pump apart, but I'm not sure there would be much I could do if I did. There are 4 wires going to it, 2 for power and 2 for data/signals, so there must be some control or feedback circuitary inside I guess.

Henke Torphammar

Did you get the problem solved yet or still waiting for parts?

Ian Davidson

Many thanks Henke forenquiring! :-)

I've emailed JetCat in Germany but their tech-support (maybe the whole of JetCat) is away until the 7th January, so sadly I'm unlikely to get a response until then.

BaldEagel

As I said previously the pump/bus sees the voltage plugged into the ECU when powering up, therefore I would think the Bus is toast, motor may still work, but without control, all seems to fit together with the posts above, hope you get this sorted.

Mike

Henke Torphammar

We did some checks with the FLIR to see which trempratures we are looking at. Important when installing the engine in an aircraft, specially if made of foam. This is how it works, the FLIR gun presents the temprature that I aim at in the upper left corner of the picture. That's of course not the only value to read out. At the bottom of each picture there's a bar showing which color that indicates which temprature. Diffrent on all pictures so look closely and draw your own colclusions :-)

Each engine were let at the current state for some time for the temps to settle before takeing the snapshot.

The tailcone is way out of range for the FLIR (max 350°C) so it shows funny values.


.....................P20.........................................Kolibri T25

Idle


Idle


Full power


Full power

Ian Davidson

Hi Mike, yes I'm sure you are right. I sent both my ECU and pump back to JetCat on Monday (as per their request), so I hope to have a working solution back soon. Many thanks indeed for your help.

Ian Davidson

Wow! Amazing photos Henke!! :-)

So what is the technical reason that one runs hotter than the other, and is running hotter necessarily a bad thing?

<o></o>

Henke Torphammar

My guess is efficancy but I really don't know. The test is performed as a step in developing the turbine convertion kit, not a performance test. As the P20 has a bulky mount we had to replace it with a custom clamp. Light yet very strong. Engine accessable from behind by 4 screws(!) The kit is in in final evaluation now and will soon be available. If I'm correctly imformed it will sell for under €99 includeing fueltank.

Ian Davidson

The 'turbine conversion kit' for what?

SpiderJets

EDF foamies (I guess)

Henke Torphammar

It's for the Ready2fly Venom but will fit any 90mm EDF.

Ian Davidson

I recently noticed the Skyrunner 300+ fibreglass plane which has been specificallydesigned for the P20/Kolibri- it looks amazing!

Ian Davidson

New ECU and new fuel pump - my P20-SX is now back and running on all cylinders again! Yippee!

Henke Torphammar

Cool! I'm reciveing my new ECU in a couple of weeks and if lucky the new Super Kolibri which does 3800grams of thrust in room temprature with a efficiency index of 0.0501 g/s/N, still in the same size and weight. Looks like a fun spring this year

Ian Davidson

Super Kolibri !?! What !? Who !? Where !? - Tell me more !!