Dave Wilshere

The P-70 should be way less than 4.0v pump voltage at 123,000. I'm guessing (as not run one for a while) 2.9-3.0v) any more and the feed is restricted/blocked.

K.O.

My Feedback: (16)

As I mentioned in my previous post this condition would show an unusually higher pump current draw. Your GSU will quickly show this.

K.O.

RAPPTOR

My Feedback: (41)

Fixed

RAPPTOR

My Feedback: (41)

https://www.youtube.com/watch?featur...AiKLgxYT4#t=90
HUMMM ?? FACTORY INSTALL-- UAT- JUST LIKE I HAD MINE ?????
FACING REARWARD ??

Warwick Laken

Well today was my first attempt at flying my Retrojet, I am back here so all not well.
I stripped everything out and rebuilt and replaced cables and solenoids. No trapped fuel lines and lots of air for the engine.

I put the aircraft all together with great expectation. The turbine started, went to KERO START, engine ran up smoothly then the GSU showed it going to FULL KERO and the turbine wound down. I tries several more times. Each time the KERO START would come on the GSU, it would start ti fire up and shut down.
Could it be the fuel pump? The only spare I don't have.

Any help appreciated.

Thank you

Dave Wilshere

Warwick
Did you notice what the pv (pump voltage) said while it was winding down? If the voltage was increasing but the rpm still drops the ECU is telling the pump to flow more-so a pump motor problem. Usually if the pump starts at the very low voltage given it means the brushes are not clogged.
Sorry, again we need more info to help!
You could disconnect the fuel line from the turbine, place the tube in an overflow tank and in test functions run the pump. Holding the change value button down and + or - key you can vary the voltage the pump sees and note how it pumps at 4v (should be strong)
You are sure that the 4mm tube is fully into the front case festo and also no kink inside the FOD?

Dave

Warwick Laken

Thank you Dave, I will go and try the pump this afternoon. There are no kinks in the tube.
Cheers for now

George

My Feedback: (57)

A video of the start clearly showing the GSU would be helpful. The GSU should be showing a "cause" for the no-start or shutdown.

Just a thought, but if winding down at FULL KERO, it could be a solenoid issue. It would be consistent with what you're seeing because at that state the "start fuel" solenoid is supposed to close; but it sounds like as soon as that solenoid closes, it stops the start process, meaning the "main fuel" is closed or not fully open(?).

Warwick Laken

Hi Dave,
I could only test the pump by using the purge function. The change value button just gave me a screen saying "Cant change values". With the purge function the start voltage was 0.50V and the pump ran smoothly to a max voltage of 3.00V.

George, what you say makes sense, except that I put a new solenoid on the main fuel line. I will check again.

Thanks for the help

gooseF22

Take the fuel line off the motor at the motor and use the purge function or test function to run some fuel through the system into a jar or can.. if it runs fuel, the pump, solenoid, and electrical system is working for the Run side of the house.. for the KERO start function, if the motor lights off on Kero its working if the EGT comes up..

Usually if it stagnates when switching from Kero start to Ramp up Kero/run, then its usually the solenoid or something in the ramp function or something blocking the main fuel line feed.

Post a video of your GSU after you pull the line, purge, pump fuel, and try the start again.

Lastly make sure your battery is healthy and fully charged
good luck

gooseF22

If the pressure side is working, then very likely this is the culprit like David Says.. go after the feed system again.. start with the vents, and clunks. I have seen all kinds of issues with fuel feed.. usually its something that will make you scratch your head until you find it.. been there done that..

If the ecu is cranking up the voltage this high, then the RPM desired isn't matching the RPM actual, so its ramping the voltage to keep up..

My old rookie did this.. it was hard to start.. turned out to be the main fuel tank clunk had slag in the feed hole..

When you start and run, look at your air trap to see if it sucks the sides in.. if it does, then again its a suction problem.. good luck

reo

My Feedback: (130)

Sticky/defective solenoids can create issues and it seems that is the last place we look. I went through the whole process of troubleshooting a JetCat Titan recently that had rough starts and rough running below 65K, tried everything, gas start, kero start, different pumps, etc....and it ended up being a bad solenoid leading to the kero start plug!!

George

My Feedback: (57)

This too ^^^^

Warwick Laken

Today I got my first chance to start mt plane since the weekend. I have done nothing to it at all. See video below.

https://www.youtube.com/watch?v=OjS2I73XBlA I can not explain what is going on. I started it twice and it ran flawlessly.
Tomorrow I will take the wing to work and try again with it fitted.
One thought, the fuel tank was pushing on the Jet Cat plug that is used to block the gas Festo fitting, if this was allowing air into the turbine, could this cause the problem?

I will post video of wing on tomorrow.

Thanks

George

My Feedback: (57)

Now I don't understand...I thought it wasn't getting past FULL KERO

Let me see if I have this straight, first you were having trouble with the engine running to "full power" with the wing on, then you started having trouble with the engine NOT completing the start process, but now it's starting and nothing was done, not even a battery charge? Whatever the case, if it's starting now, it's time to move onto the original problem.

Warwick Laken

You are correct George, The engine would start and when it went to full kero it woulf shut down.. Not to day it seems.

What about air getting into the gas inlet?

gooseF22

possible issue.
take the tygon tubing out and replace it with 6mm clear poly..
make sure the air trap is tight
this way you can see the fuel moving through. I had an air trap lid come loose once..

It was struggling to start a little bit. I would up the glow plug voltage by .1 or .2 in the ECU.. also put an Amp meter on the battery and watch it to see if anything is going on, such as the voltage being pulled down or something excessive like /10 amps..

Now back to the original problem.

redo the tubing, then pull the 4mm line to the motor at the motor and plumb it into a can.. select the pump test function to make an end to end test, but to also watch for any bubbles in the 6mm lines. While you are doing that, stick your finger over the fuel tank vent for about 5 sec to see if the trap or tank sucks in a little.. if it doesn't, then you have an air leak someplace..

Doing a flow test is the way to eliminate the fuel system, and then if its ok, its something in the motor.. does the motor have a fuel filter installed under the cowl like Wrens do?

gooseF22

I see that you are using the 9.9 volt A123 pack, is the ECU set up properly for that? I don't know your system..

Finally mount the jet cat filter vertical guys prefer that to make sure any bubbles are pushed through and are not trapped.

RAPPTOR

My Feedback: (41)

Check radio relearn. No control over shut down is radio or ecu

Warwick Laken

I am back and sadly still looking for a solution.
Firstly, the turbine works perfectly in the garage. I starts and runs time after time. wings on or off.

At the flying field its another matter.

With the aircraft into wind the turbine would get to full kero and stop. (first part of video).
I realised that the aircraft was in a still air garage so I turned the aircraft sideways to the wind and covered the air inlet vents on the side of the plane. The engine ran to a point and during the acceleration phase shuts down. (second half of video). On subsequent starts it always cuts at the same point. The ambient OAT was 13C. the temp on the GSU was from previous attempts to start

All solenoids are serviceable and the pump is good, as are the batteries. I have done a reset of the ECU and re learnt the TX.

I noticed that when the turbine failed at the Full Kero point the the spin up was noticeably faster than when I turned the aircraft across the wind..

Hope some one can help

Thanks

Warwick Laken

https://www.youtube.com/watch?v=UfW7Kv5EtIM Sorry video for my last post

Vettster

I had a P-60 that had a very similar problem. I changed everything! Pulled the motor out 3 times and put it on a test stand and it would work. Put it back into the plane and it would not work. After changing the lines, Wires, Fuelpump, Rx thinking it wasnt playing with the ECU. Batteries where changed.. In the end what got the engine running was to change the ECU. Not saying this is your case.. but it was for me. Maybe you have a buddy with P-70 that can lend you his ECU to check?

Warwick Laken

Thanks Vettster.
I was at that conclusion, I was hanging back as I had sent my ecu to JetCat prior to installing it.
I can get hold of a P60 ECU and will reset it to P70 and send my ECU back to JetCat.

Cheers for now

Jannica

From your video it seems that the battery symbol indicates a very low voltage during acceleration. If you already have changed it. Change it again.


Jannica in Sweden

paulsf86

My Feedback: (52)

I have 2 p-70 that I run regularlly. Pump voltage runs between 1.95 and 2.05. Anything more indicates plugging of fuel filter.

Paul S