One last thing.
I noticed that the outer exaust cone changed color.
It is something like blue with violet.
The turbine wheel is very clean though.
Is this normal?
I also changed to a 8 cell GP3300 mah NiMh (good to 30 Amps tested)
and i lowered the glow plug power to compensate for the increased voltage.
That should spool it up like crazy...
Sorry for asking too many questions but believe me you know more than the local guys.
Chris

Chris

The tail cone is normal rather like full size F15 they get hot and discolor.
Ask away, many will usually read and not bother to post here. Some may have given up and your success will make them solve their running problems. On the first run up I would imagine that your JJ never went to 160000 as the pump needed more voltage to turn faster. After reaching 45k any JJ will run up to and even way past a safe 160k if given enough fuel[&:][&:], only to stop when temp or the bearings give up life[:@][:@] There is a good safety margin above 160k but you need to hit 160k any time the stick is at max. Reset up your TX and FADEC, to be sure you have no sub trim or reduced ATV on throttle before you start up.

Paul
RCdriver

Ok my tx is setup right so i will go later and try to start it up.
I also verified my installation and everything looks good!
I will post the results later this evening.
Chris

Well it started spooling up and reached 32000 rpm with the Kerosene trying to ignite
(pump start Auto+0, ramp 004) but it didn't made it as usual.
During cooling the starter motor gave up.
I just tested it and the fadec is fine only the starter motor is burned.
Looks like 8 cells are much so i will try 7 cells later.
Maybe that was the problem all along, the starter motor failing gradualy.
That would explain the easy first start, the more difficult second one and the failed third yesterday.
Anyway i ordered a Permax 280BB for the starter motor as i heard that it is the best for the job.
The Fadec manual also states that if the engine does not reach idle and the temperature is excessive
then replace the starter motor or the battery or incease number of cells.
Btw i checked the fuel lines and everything is running freely and bubble free.
When i prime the pump the excess fuel that goes to the engine starts dripping
after a while from a screw in the front of the compressor, is this normal?
(it runs between the outer steel cover and the engine casing)
Anyway if the motor is not the problem then i guess that something is wrong with the CC or fuel injectors
as i cannot find any other problem and friction is very low.
So finaly here is my new set of questions:

1) How much does your motor last? I read somewhere that the Wren starter usualy lasts 3 starts before it dies.

2) Any ideas on how to remove the bendix clutch without any special tools and what type of motor is
used for the starter motor?
UPDATE: Heating with a blow torch, two screwdrivers and a drop of blood from my finger
instantly removed it.

3) Could i have damaged something in my first run using 7% oil or blocked any fuel injectors or something?
When the engine reach ~30000 rpm and it doesn't increase rpm, i hit the throttle cut switch and the
engine spools down very nicely with no friction.

Of course please remember that i am not asking like you should have the answers right here and right now
but i am just trying to find my way...
Chris

Hi Chris,

It must be frustrating so say the least! Well lets see what we can do:

Firstly 8 cells are too much for the speed 300. The brushes will be arc welded!

If the starter motor can not take it beyond the first ramp point , then you have a problem. Excesive temperatures and a "hung ecu" will wait for correct RPM/EGT parameters before proceeding to next level and idle.

Please also check fuel supply for no small hole clunks or filters for at will restrict fuel flow.

The fuel coming out of the casing is not normal. This will only happen if the motor was flooded. Are you using a fuel solenoid?

I hope that the fuel line to combustion did not brake off. We will try this as last resort.

The turbine must self sustain at 28K. No starter motor needed beyond this point.

Let me know your findings..

Regards

Hi.
Yes it is frustrating i must admit.

I agree. The motor is history anyway but a new Permax 280BB is on the way.
I already have a 6 and 7 cell 3300mah ready.
As i described earlier the motor had a harder and harder time to idle up every time i was starting it
so it maybe the starters fault. It only made it up to 130000 rpm twice and then forgot how to idle...
After that it would reach ~30000 rpm but terribly hot at about 770 C and stay there for ever.
The only thing i dont know yet is how much gas it needs and if a wrong gas flow would be the cause of my problems. I know it is very hard to describe it from the internet but what is the behavior (in terms of rpm )
of the turbine if the gas flow is excessive or not enough?

No the fuel flow is fine everything looks good.

Yes i am using a fuel solenoid. The engine was flooded as i used the priming function of the Fadec and the fuel went in to the motor(i didn't had any gas or anything else connected just i wanted to test the pump.

You mean that the fuel line might be disconnected internaly? I hope not[:-]

Thank you very much for your help as i need some encouraging right now.
Btw is there someone in EU that i can send the engine for checking or repair or i must return it back to JetJoe if i dont find the problem?
Chris

HI Chris,

Firstly you will not get the bendix off the shaft. Or you might , but it will be damaged... sorry.

Yes you can set the voltage for the starter motor. I will go through this parameters once you have sorted out your starter motor. If you have compressed air we can try a manuel start to see if the starter motor was the problem.. Also check your ECU for many ECU's had been damaged due to bad starter motors..

The problem now is that all ecu data is corrupt due to fail starts and shutdown. You will need a good start up and a 30 sec idle before new values are stored. Hope we can fix this - if not it will be best to send motor back for inspection.. Excesive heat may damage your bearings..

Regards

I've notice on the JJ's with the electric starter; the bendix O-ring sticks to the compressor nut and doesnt retract. This caused the engine to try to spool-up under the drag of the electric motor. This was solved by a little dab of silicone grease on the o-ring and the bendix then shuttled forward and back off the nut without holding back the turbine rotor.

Watch the bendix at cool down, it should move back and forth. A few black marks on the brass bendix ring will show it spining and stopped when the ECU comands it.

The JJ does not have a spring retracted bendix. The O ring is rubber and was binding on the nut. I use silicone grease on my JJ.

I checked the ECU and only the starter motor is bad and the bendix looks good after removal.
I was afraid that the ECU might have stored bad paramters since it encorporates fuzzy logic.
The bearings so far look good and i cannot detect any friction.
When i spin it up with my hand it takes 5 seconds to stop so i guess thats fairly good.
I will wait for the new starter motor and try to reset the parameters as the manual has them.
Is there any master reset on the Fadec?
Thank you very much for the help i really need it[&:]
Chris

I will watch it when i get the new motor.
I have watched it a couple of times it it retracted back well enough when i hit the throttle cut switch on my Tx.
Btw can you tell me the parameters programmed in the Fadec?
I mean the numbered parameters (1 to 31).
I see strange thing in there, for example the recommended second ramp rpm point (parameter 27)
says 30 for the Wren54 but mine was set to 35.
Chris

Hi Chris,

I have had my JJ1400 since early last year and apart from a blocked fuel needle and a rebalance
it has behaved flawlessly.

By the way the rebalance and needle unblocking were carried out after the videos below were taken

apart from a blocked fuel needle and a rebalance I have not had a problem.

It does sound from your engines symptoms that it could have been caused by a faulty starter motor.
If the starter motor was dragging on the compressor nut then the FADEC will keep pumping fuel at
an ever increasing rate to get the RPM's up to idle thus causing the high EGT's.

The setting I used on my FADEC ECO with Hausel pump are below.

Full Power Speed: 160k
Idle Speed: 45k
Stop Speed: 28k
Start Temp: 100ºC
Max Temp: 800ºC
Acceleration Delay: 30
Deceleration Delay: 30
Stability Delay: 40
Pump Start Point: Auto+1
Pump Start Ramp: 6

These are the settings that you should only need to adjust, you will probably find that with the FlightWorks
pump you might have to tweak a few setting but the one above should be a good starting point.

Here is link to a discussion of the JJ1400 and a few videos I posted a while back (forum name is GROGGY).

Rear view, http://www.rcgroups.com/gallery/show...7205&nocache=1

Front view, http://www.rcgroups.com/gallery/show...cat=500&page=1

Link to discussion, http://www.rcgroups.com/forums/showt...6&page=5&pp=15

Greg

Well if the starter motor switch off rpm (parameter 23)was set to 34000 rpm as mine was then the starter motor would not disengage at all because i only saw 30000 rpm.
Now that i remember i didn't hear the motor disengage at 30000 rpm.
but i can remember the motor disengage when i lowered the trim with the motor spooling down freely.
There is a distinct sound of the clutch engage and disengage i remember.
Also the parameter 22 which is the gas switch off temperature was set to 25 on mine which means 100 C
where in the manual it says 100 (400 C) for a Wren54 which i think is similar to the JJ1400.
My Fadec settings are almost identical to yours with the exception of the pump start ramp which is set to 4.
I think that withthe new motor and armed with the information you all gave me that i will fix the problems because honestly i can't find (or i dont have the knowledge) anything else wrong.
Chris

I will try this method also.
I have some silicon grease so i will give it a try.
Chris

I have a manual start jj1400 and with the motor that came with the starter wand, the turbine would not start, it kept on overheating (800 deg+) i changed the motor on the wand to a gruapner speed race 400 and it started but still took a long time to start, i then changed the motor to a graupner speed 300 but on 7.2 v it kept burning out, but it started the turbine great, i have now bought a Wren starter wand, i do not know what the motor is as all it has on it is "made in china" ( which i think is quite suitable) but certainly with my engine when you are starting it you have to keep the gas turned on and the starter engaged untill the turbine reaches 30,000 rpm as if you remove the gas or starter motor before that figure the engine just will not ramp up and indeed the rpm just starts to slow down.
And with the Wren starter and 7.2 volts car buggy battery pack it does 2 starts fine and then the 3rd start really struggles to spool the turbine up to 30,000 rpm
My fadec setting are thus

full throttle pulse 1931
idle throttle pulse 1255
cut throttle pulse 976
idle speed 44,000 rpm
stop speed 24,000 rpm
full power speed 160,000 rpm
start min temp 100deg C
max temp 800 deg C
acceleration delay 016
deacceration delay 015
stability delay 030
pump start point auto +0
pump start ramp 009

Chris

When you said "I will change with a 7 cell 3300 mah GP and see what happens"
I wasn't that clear in stating that upping by one cell to seven resolved the 'basic JJ starter motor' spool up problem for me and was confirmed by Gasper the FADEC designer regarding low voltage drop on run up. I missed the move to 8 cells though I also replaced the electric motor but have used the Chinese motors for Twister or Honey Bee Electric Helis are rated for 8.4 volts, and are a direct replacement. They can take 9.6v and cost as little £4 or $7 online.

If you want one FOC just PM your address over you might get it in Saturdays post. The higher revs on the starter motor are a real direct benefit. Combined with a 'ramp setting of 6' and other parameters suggested today get the JJ1400 up to idle quicker before ever hitting temps any where over 700C+ The dropping voltage on the pack will effect the start up success rate. The leaking fuel is going to effect running, as it will effect the CC pressure as there is also likely an air leak. Its strange for the factory to set up the FADEC parameters with the 'fuel ramp as low as 2' from whuich is where you first started from. Anyway the leaking fuel could well be the manifold problem but that then would be a warranty matter.

"Full throttle again and the max rpm still 130000. On all three runs the EGT was 720 Celcius which seems too high i think" Indicates the typical CC problems well known here that scuppered the JJ German importer for Europe.

Paul
RCdriver

I guess i went too far but in any case i wanted to fit a better starter.
Dont worry i knew that i would overload the starter motor but i had to try.
The Permax 280BB is the one used by Wren so i guess it will be fine if it fits length wise as the diameter is the same.
About the leaking problem Paul i need to get it straight in my mind.
Let say that you have the JJ1400 on the test bench, not running and the fuel lines are full of fuel from the previous start.
Now accidentaly you enable the Fadec priming function by fist lowering the trim, then raising it and finaly open the throttle
stick to full and leave it there for 5 seconds for the pump to start pushing fuel for 1 second.
Now because the fuel lines were full in the first place, this 1 second worth of fuel is entering the JJ1400 and stays there.
Is it normal for the fuel to start leaking (not much but say one drop every minute) after say 1 minute or it should stay inside the engine without leaking? If the answer is no leak at all then i have a problem.
I was ready for adventures with the JJ1400 so dont worry i will fight my way through
I believe that the information i gathered from this discussion is enough to get me going and find the problem.
Update: I remembered that in the two first succesfull runs i had the gas directly connected to the engine and not through
the solenoid.
My problems began after i connected the gas solenoid but it might be a coincidense or may be not?
I will try without the solenoid after i get the starter motor.
Chris

The fuel on that 'short 1 second priming burst' has to flow into and through the fuel ring manifold, along the sticks drip through the CC holes and exit at your leak. As hinted by MNModels thats not right, in the sense it might leak with a loose fitting but its leaking far too quickly. If it was only at idle or running you might see a pressure leak there at a looose fitting but at prime up, certainly not right.

My reasoning for the next run was if you started with 'fuel ramp 2' and got some kind of ran up then go to 'fuel ramp 4'. The guys here rightly would expect the default setting by Gasper for Joe on the CMOS sram memory 'data hold on power off' to be a setting of 'fuel ramp of 6' and some successfully use a 'fuel ramp 10' but if you are having the suspected problems internally the higher settiings may only exascerbate the overheating problem with maybe an Over temp Cut Off or then go on to really fry the rear bearing.

Every fuel ring received has needed some basic adjustment except those from Andy the retired JJ rep. From some of the PMs to me in the last few days others have received replacement CCs from Joe with needles barely into the sticks, others the orientation of needle ends have not been facing onto the hot face and this will all add to poor atomisation and air mixing of the fuel, which effects the running and power if just left as is.

I know many wish you have favorable experience with your first JJ turbine and others may follow your lead. There is not much that cannot be resolved one way or another, so I know you will get there and its really worth it.

Paul
RCdriver

I guess that if i dont make it work i will ship it back for service.
I will give it a good try though before i do.
Chris

Hi Chris,

You have mentioned about the gas. I think this may be your problem. Connect direct and only close once at idle.

Some people use a camping gas canistor and i have found that the pressure is sometimes too little to go through valve.

Also check the gas off parameter...

Regards

Yes i also think that this is my problem.
100C looks very low to my eyes for gas shut off temperature.
The Fadec manual says 400C (100*4) which looks about right.
I use a propane blow torch bottle (US imported) which says
propadiene something. (they use the chemical term rather than plain language)
Thats exactly what i did in the initial succesfull attempts.
Chris

That sounds like MAPP gas which is *not* propane.

It burns much hotter (almost as hot as acetylene) and also releases a lot of carbon (soot) if not burnt at a proper stoiometric ratio.

I'd strongly recommend going to a proper propane/butane (LPG) mix.

You are right i am working on it.
I am trying to find a suitable gas valve for the bottles i can find here.
Here is the best i can find here.
It is a propane,isobutane and butane mix.
Chris

Ok now.
I made a gas valve for testing and i located the right gas valve.
I am pretty confident that there is nothing wrong with the JJ1400
but my ignorance when it comes to rc turbines is to blame.
I am almost convinced that the gas feed is my problem after some testing i did so when i get
the Permax 280BB i will resume testing.
Chris

Well i replaced the starter motor with the Permax 280BB and the clutch is working perfectly.
I also used some silicone grease and did some black marks for visual aid as suggested and the
whole starter system is working very smooth, smoother than before.
I also made a homemade propane-butane gas valve that is working fine so
Sunday i will try to start it up again. That was fast dont you think?
Thank you all for your help and tips.
Chris

Does the gas valve have a regulator? It's not necessary but makes it a little easier with constant flow rate every time.