Can anyone give me some help with my JJ1400.

I have never been able to start this turbine. The motor was returned to JJ and returned servicable, laterly the FADEC was returned and a new one received back

I now have a new FADEC, new solenoids, wiring well and truly separated and gas flow to the motor. The plug ( I have tried many plugs) is good as is battery voltages. Cables all connected correctly. The motor should surly wind up for longer than 2 seconds!

Today I tried once again ( with the new FADEC) to start the motor and still it cuts out after a 1 to 2 second wind up, there is no ignition, gas is flowing to the turbine and glow plug is hot. The motor makes 3 attempts to start before time out, each attempt only winds the motor for 1 to 2 seconds.

On the Data Terminal the ambient is 24c but when I advance the throttle to max open then closed for the start the rpm reads 64000 and as soon as the motor starts to turn the reading is normal. It winds up to an indicated 14000 then runs down, during the wind down the rpm indications fluctuate between 115000 and 24000 and continue to fluctuate when the turbine has stopped.

Is there a way I can check to see if the glow plug is sited correctly in the combustion chamber?

I am now desperate, months of work trying to get this thing to fire up and no flying.

Please help!

Warwick Laken

Recheck your glow plug cabling and rout it as far from the Tacho pick up and wirring as practical ,twisted together works best .
If that dosn't work try back screan parameter#18 Value 4 and #19 Value-3 and should make it go

Phill

Is JetJoe still around? I signed up on a mailing list quite a while back hoping to hear when the engines were released, but never heard anything. I just figured it died.

Also pull a couple of coils out of the glow plug and set glow power to 40.

Warwick Laken , sounds to me like your RPM sensor is defected since you are getting flase RPM readings..

Warwick,

I suggest you give Gabe an email at JetJoeUSA. He seems extremely knowledgeable, helpful and eager to make JetJoe a success.

DW_Crash

Thanks for the info so far, tried Gabe but as yet no reply so back to the thread.

I have tried all the sugestions so far without any luck.

I think the problem stems from the fact that the turbine spins up to 4200 rpm the winds down. If I could get the start up to last another second or so I might have more luck.

Anyone know how to gei the wind up to between 5 and 10000 rpm, or is 4200rpm normal?

warwick:

The start up rpm limits are adjustable on the FADEC through the hidden menu, parameters 18 and 19, their values should be;

18 --- 4 (4000 rpms) speed at which starter is shut off on the starting phase
19 --- 2 (2000 rpms) speed at which starter is reenergized on the starting phase

Your values seem to be OK based on your comments

Yet believe your false readings are because of worn brushes of the starter motor, I've had the same happen to me, even if you manage to go through ignition, the false readings will come back during the ramp start, rpms will go past the idle limit and trick the ecu into thinking turbine reached idle, then when the rpms come back down to true reading the ECU will abort the starting phase because after reaching the false "running" condition rpms will go below the minimum limit, then you'll get a "speedlow" message as the reason for the shutdown, all this happens within one second.

I do not think your rpm sensor is malfunctioning, like I said I had the same problem, replaced the starter motor and it's working fine.
I use Great Planes T-370 motor as a replacement, remove the bendix clutch from the bad motor with a GWS gear puller and place on the new motor.

To remove the bendix clutch you first need to remove the pin holding the moving part of the cluth.

This is the replacement motor I use, only $8 bucks...
http://www2.towerhobbies.com/cgi-bin...&I=LXGLK3&P=ML

Warwick
Are you sure gas is getting into the engine the orange gas tubing is known to kink inside front cover and shutting off gas flow (should be able to blow through line). Check that the gas line to the turbine from the solenoid is on the fitting at the far end away from the coil. If it is hooked the other way the solenoid can jam and won't allow gas flow. Make sure solenoids are plugged into fadec and not reversed.

Hi.
Here is a quick and dirty guide.
First of all i assume that you have trained the Fadec with you tx throttle movement range,
that the glow plug has at least one turn of its filament brought out of the glow plug's body,
perpenticular to the other filament turns, that the gas and fuel feeds are connected correctly
and that the ECU battery pack is fully charged.

The starting process and some troubleshooting follows below:

1) Advance the throttle to max and then back again in order to give the start command to the fadec.

2) The Fadec should indicate "glow plug test" and during this period it is normal or not unusual if you like
to see the rpm meter fluctuating between ~65000 rpm and 0.

3) After hearing that metallic "click" sound indicating that the gas solenoid is energized then you should open the gas valve on the propane-butane bottle and start feeding gas to the turbine. The starter motor is engaged after the solenoid is activated and the turbine starts to spin.
Check that the solenoid is working and that it let the gas reach the turbine's combustion chamber. You should be able to hear the gas flowing from the exhaust of the turbine (that "SSssssss" sound).
Then comes the magic moment when a somewhat loud pop should be heard that indicates that the gas has iginited in the combustion chamber.
The temperature reading should be rising now. The Fadec need to record a temperature of over 100 C or a rapid temperature increase in order to be sure that gas ignition has commenced.
If you don't hear the "pop" sound and the temperature reading is a constant ambient temperature, recheck that you feed gas to the turbine at the proper rate, most of the time there is too much gas going in the turbine.
In order to give just the correct gas flow follow the below directions:
First make sure that the start gas valve is set to closed position so no gas is allowed to come out from the gas bottle.
Then remove the electric power completely in order to reset the fadec and repeat the starting cycle.
After you give the start command using the throttle stick and the turbine starts spinning and the "click" sound indicates that the gas solenoid is open, turn open the gas valve slowly, you might loose the first starting cycle but there are a couple more so don't be very anxious to start the turbine and choke it with gas. After you hear the pop sound open the valve just a bit more and mark that position of the gas valve so you know how much to open the valve next time.
The glow plug power should be set to 45 maximum!!! for the first few attempts just to be sure that the gas will ignite.
Beyond 45, the glow plug's element will melt. you should get consistent ignition with a good glow plug like the OS 4 stroke with a value of 40 max.


4) The Fadec probably has already started spinning the turbine shaft by applying power to the starter motor.
During the initial turbine shaft acceleration the rpm readings should get clear and consistent when the rpm get above ~2000 rpm.
It is not unusual to see the rpm readings fluctuate below say 2000 rpm.
For example: rpm indication = 1000rpm+noise, noise, 1500rpm+noise, noise, 2000rpm + little noise, 2500rpm clear and consistent after that.
The rpm noise is more evident during spool down than spooling up.
If you can't achieve clear and consistent rpm readings above say 2000rpm then twist hard the glow plug wires together, all the way from the fadec to the glow plug and route them as far as possible from the rpm sensor. Orientation of the glow plug's wiring is also a significant factor. The point where you connect the black wire (ground) of the glow plug on the turbine's body is very significant and it should be as near to the glow plug as possible making a clean and solid connection. Best is to connect the black wire directly to the glow plug's body using a washer.
Some caution here because the black glow plug wire is actually not ground but the + pole of the battery pack.
The turbine's body in reality is at positive potential and not at minus (ground) level.
I believe this is true for Fadec versions prior to version 5, after version 5 the polarities changed to normal i think but i am not sure.
You should not let any other cable than the black glow plug wire touch the turbine's body because this will cause a short cirquit.
As mentioned from other posts make sure that the starter motor has those three capacitors (noise filter) fitted and that it has enough power to start the turbine.
A quick test is to disconnect the electric motor from the fadec and connect it directly to the 6 cell pack.
The turbine should then turn at its maximum non fuel assisted rpm which should be equal or above 12000 rpm.
If your rpm don't exceed this, replace the starter motor.
Also make sure that the starter motor is centered to the turbine shaft axis.
Many JJ engines have their starter motors not correctly aligned with the turbine's shaft and this can lead to many many problems like sticking clutch, high egt temperatures during start up etc.

5) The starter motor might stop turning the motor but when the rpm fall to say 2000 rpm it will start turning the turbine's shaft again. That can happen because the temperature did not exceed 100C fast enough in the first cycle so the fadec will stop the starter
motor and proceed to try #2. This is normal. That can happen up to three times, after that the fadec will issue a fault and stop trying.

6) Now that the temperature is rising fast over 200C and the rpm get above say 8000 rpm or what is programmed in the Fadec's parameters, the pump will start feeding fuel to the turbine and the turbine will start accelerating.

7) The turbine might hesitate a couple times looking at the rpm readings and sit at some rpm ranges for a while but this is normal
and eventually it will reach the idle rpm and the fadec will show "running". Normally from gas ignition to reaching idle it takes ~30 seconds.

8) If everything looks good but the turbine doesn't start get the fadec manual and reset all the fadec parameters to the values
listed for the MW54 turbine (not the KJ66!) and try again.

Thats it, i hope i helped somewhat.
Chris

WWW.WHAM-RC.ORG Warbird Fly-In Pics of my JJ1400 powered Tamjets F-16.

Greg Hames

Thank you Chris,
I will have a another go this afternoon, I will let you know what I find

\warwick

Guys, here is a pic of my JJ1400.

Does that mean i have the older or newer tail cone ? which one is recommended ?

Also, what are the VISUAL differences between the JJ1200 and JJ1400 ?

Hi What is the engine number?

Paul

Serial number 04099.
this engine was bought from China directly on 3\3\07.

Hi.
Change immediately the way you have the temperature probe mounted.
It will short from the pressure!
Make small aluminum mounts for the probe.
Chris

Chris,

I agree there is pressue, but this way worked for many of my friends with no problem.. ?

Hi.
Well it may work but for how long?
Better safe than sorry.
Chris

how do you mount it then ?

and can anyone comment about my tail cone ?

Id3m,

You have the older style tail cone.

My serial number is 04102 and it has the newer one piece style tail cone.

Greg Hames

Looks like the much older twin version, you ordered direct so they might be using up the old stock. Waste not want not. The single exhaust was to improve thrust. The visual checks are the compressor on the 12000 has ten blades and on the 14000 twelve. Also the opening diameter cross section is larger on later 14000 for more thrust.

Your engine number should indicate the very latest version but something isn't right here.

Paul

Greg

His turbine was only made just three engines later than yours and those twin exhausts were dropped some time back?

Paul

i have emailed JJ China to see what they would do about this. the engine does run perfect though.

Aren't the old style more efficient?

Wren dumped the twin exhausts and Joe then copied them, because the new single cone put on all newer turbines were less efficient than the old twins. Don't think so.

I'm off for a left handed screwdriver and tub of elbow grease so I can replace all the single exhausts with twins from the junk box when JJ China answers. Maybe they are just experimenting to reduce the excessive thrust[8D]