RE: JetJoe OWNERS thread
 

I guess these are so cheap that instructions are not included!!????

Dave

RE: JetJoe OWNERS thread
 

Hi Hendrix,

OK thats great thanks, why do they supply capacitors for the motor by the way?

RE: JetJoe OWNERS thread
 

For interference suppression.
The motors brushes produce sparks=interference while the starter motor is running and interfere with the rc receiver.
Solder one to each motor's power supply terminal and the motor's case and the third between the motors supply terminals.
Chris

RE: JetJoe OWNERS thread
 

I know...
Those landing gear prices are killing me....
Chris

RE: JetJoe OWNERS thread
 

You are right, the instructions manual is a word document (not included in the package!!! )with a few pictures of the intake fuel and gas connections and what oil to use.
Nothing more about operating it or troubleshooting.
As i was (i still am but i learn as i proceed) a complete rookie i didn't knew what to do but thank God i found this thread and
finaly found my way.
Without this thread i would be lost in space.
Chris

RE: JetJoe OWNERS thread
 

Dave,

Don't forget it is not a Wren. We have been spoiled.


Regards

RE: JetJoe OWNERS thread
 

Tommy,
Not spoiled at all on this point. Clear and concise instructions should be included no matter where or who manufactures it. Buy a $50 2 cycle model engine to see what's included for setup and operating instructions.

Hey JJ if you're listening...put some instructions in the box please!

Dave

RE: JetJoe OWNERS thread
 

Yesterday i decided to bite the bullet and remove the cover in order to inspect the engine prior to installation.
Well it is a very big move from my part as i am afraid to touch anything on this engine.
Everything looked nice and clean, the CC was in excellent shape and the preload seemed to work as i pushed the turbine wheel and i could feel the spring's tension pushing back the rotor.
No leaks were evident but i got scared by the very thin fuel injection needles so i better fit yet another fuel filter.
The fuel injection needles seemed to be well centered inside the sticks but i am not that sure that they dont touch the inside of the sticks.
I did found that the fuel manifold brass supply line has a rather sharp bend where it avoids the diffuser (an S bend) and that limits its inside diameter considerably but it works ok so far.
Overall i was pleased by the construction of the JJ1400. I am not an expert, far from that but the materials seemed to be
of excellent quality and the workmanship very good.
Btw i am using a 2 cell 2100 mah 20C lipo for starting and rx power (using a Ubec) and i did 10 starts with it, all succesfull
and the battery only needed 600 mah for a full charge so a 1500 Mah 20C pack can do the job and save a ton of weight.
Chris

RE: JetJoe OWNERS thread
 

Hi.
I runed the engine after removing the outer cover for inspection and i couldn't make it work right afterwards.
EGTs where sky high and the turbine was not holding a stable rpm constantly or idle well.
After removing the steel cover again and found nothing i decided to do a trick that i read somewhere.
I layed some red ceramic silicone after the case O ring in order to seal the engine from air leaks.
Today i burned 4 litres of fuel and the engine worked great with EGTs ~150 degrees down.
The thermocouple was set at 1 - 1,5 - 2 and 3 mm deep.
The hotest i got was 590~620 at idle and 550C at 120Krpm and the thermocouple 3mm deep. At 160K rpm the EGT was 700C but definetely the engine gets smoother all the time. Maybe the preload system is working better (that is my conclusion as everything else is perfect).
Using 2mm depth for the thermocouple the EGT at idle was 575C and at 120Krpm 530C.
Start up using pump start rump 006 and pump start point AUTO+2 was within 10~12 seconds with EGT never exceeding
600C.
Acceleration is still somewhat slow as it takes 6~7 seconds to accelerate from idle to full power.
This silicone case sealing method realy works miracles.
Chris

RE: JetJoe OWNERS thread
 

hendrix_gr ,
The next time you take it apart, if you do, how about posting some pictures.
Sounds like you're getting it sorted out very well.[8D]

RE: JetJoe OWNERS thread
 

It was a mistake from my part not to do so. My only excuse was that i was sooo frustrated that the last thing i had on my mind was to take pictures. I remember being very dissapointed and down. [&o]
Now the engine works great so i am reluctant to open it again but who knows.
Another thing that needs attention is air leaks form the fuel lines. Some fuel tubing has lost its flexibility and air is coming in under heavy suction before the pump (fuel filter connections etc.).

Thank God people are discussing technical matters openly in the forums so i can learn something otherwise
things would be very tough for me.
I am getting better but not anywhere near as other people in this forum or elsewhere.
I tried to seek some local help but i found out that all others (that i know) buy their stuff ready to fly and already setup
and they can't help me with technical tips. When they encounter a problem they just ship the whole plane back for repair
which is something i can't afford nor i want to.
Chris

RE: JetJoe OWNERS thread
 

hendrix_gr
Did you use any sealing on the rear of the case? What kind of silicone did you use for the front of the case. I'm rebuilding my jj 1400 complete over haul. If I cant get it to run good its going bye bye.

RE: JetJoe OWNERS thread
 

Hi.
No i didn't used any sealant on the NGV but i dont know if i should have used something.
For the front case cover i used Loctite High temp RTV silicone.
I am still having some problems with flameouts but i am working on it.
Chris

RE: JetJoe OWNERS thread
 

Hi Paul.
I tried to rectify whatever i could but after i removed the front cover i have some problems.
Today i runed the engine with all air leaks sealed and the temperature with the probe 3 mm in
was 540 at idle and going as low as 500 at 100k rpm. At 160 K rpm EGT was 640C.
The problem is that i get a very consistent flameout at 80 to 90 K rpm no matter what acceleration delay i use.
If i advance the throttle slowly after 70K rpm then the engine works great.
it almost looks like the fuel dont want to burn and the EGTs are way to low.
The EGT probe is fine, i tested it.
The acceleration delay of the fadec (Gaspar 05) seems to work on the lower side of the rpm range only and after 80Krpm the acceleration is very fast no matter what the setting is (i used up to 130)
All people have problems with high EGTs but i have problems with very low EGTs.
Yesterday the engine worked great and the only thing i did was to open a new canister of fuel and tighten the glow plug as it was very loose yesterday and i didn't noticed that. It almost looks like with all that case sealing the engine supplies more air
than needed or the fuel is bad.
Ijust cant explain the very low EGT readings, idling at 500 ~520 C for example.
Any help welcomed before i strip the engine completely.
Chris

RE: JetJoe OWNERS thread
 

Hi Chris,

Did you put the tailcone back in same position reference to all other parts? Does the temp drop when you increase RPM from idle? If yes to both the ECU will shut down because of incorrect RPM VS TEMP.

Check the flames at the back of NGV to see cold vs hot spots. Rotate cone and EGT probe for best position.

Regards

Morne

RE: JetJoe OWNERS thread
 

Well i did rotate it a bit.
I also think that the NGV was rotated a bit but i think the NGV does not have an orientation, the exaust cone does have because of the thermocouple hole.
At idle the temperature is say 540C and at 100 K rpm is 500C then it rises to 670C at 160Krpm.
Is where i record the lowest EGT when the motor flames out.
Usualy around 90K rpm.
I will rotate it back to where it was and see what happens.
Chris

RE: JetJoe OWNERS thread
 

Hi Chris

As Morne has suggested return to EGT probe hole to its first position and later you might try moving it through 180 degrees to the opposite side. However, if you do see hot spots or cold areas (try this at dusk with a mirror for better sight) thats not good at all. Take notice that uneven combustion is not a feature on well set up commercial turbines. A normal test of mine before reassembly is to apply gas to the fuel ring and observe the flame heads on all sticks, there are photographs here on line of this test. It can happen that even though no sticks are blocked, with additional pressure as occurs when the pump gives higher pressures, there is unevenness on some sticks giving more or less fuel (or gas). So while idle and higher pressure/revs is OK this gives an uneven mixture and burn at higher revs/ pump pressure. Glad you invested in more filters as blocked injectors is a result of not filtering and then blocking up.

The temps you currently have don't give much concern at all and are not indicative since temps below 600c are normal on most commercial turbines, higher temps are not common and usually the highest temp is at idle dropping across the rpm range to 160k. In fact it is at the higher revs that most of us then use the kill switch since it usually running cooler.

Seek out any further leaks, I have used clear silicon at the cool front end and exhaust red at the rear on occasion. On the old home builts the pressure was monitored and a major guide to a good running turbine in the early days.

Paul
Rcdriver

RE: JetJoe OWNERS thread
 

Hi Paul.
I already made arrangements to send the engine to a secret place :D for repair as it seems that the combustion chamber seems to be the culprit.
It is not far away from you. :D:D:D
Chris

RE: JetJoe OWNERS thread
 

Hi All,
Looking at the pics of the chamber is the mk1 type, the sticks are not inconel, the later combusters have straight sticks and are inconel.
regards Andy.

RE: JetJoe OWNERS thread
 

Hello All!! I'm totaly new to turbines.....and I don't know CRAP. I bought a Yellow A-4 skyhawk from someone on RC-Universe. It's jet ready and hase everything ready to go except the turbine! SO, the question is; what is the best name brand turbine I should by that is MOST reliable. MAX performance is not my TOP priority....reliability IS. I don't want a flame out, I've seen it happen to a guy at the airfield and it's quite discouraging. I know the previous owner had a 14 lbs JF-50 BEE turbine. I know all the bis names out there, but I just don't know which one to by!! HELP!

-John "The Scale Master"

RE: JetJoe OWNERS thread
 

Hi Andy

The pics posted have been the old 'S' 12 stick chambers. Is Joe shipping 12 stick straights as an upgrade on all JJ1400 shipped? Chris was going to take a picture but in the end didn't open his up. Nice to hear from you, are you flying much?

Paul

RE: JetJoe OWNERS thread
 

Buy a Wren cant go wrong.:D

RE: JetJoe OWNERS thread
 

Jim

Wren is the best for support and quality of goods but some guys have to go the cheaper route. Hope yours runs OK but if not, there are some who would buy it to repair a JJ1400. Two JJs flew at the LMA Longhorsley major UK show last weekend.

Paul
RCdriver

RE: JetJoe OWNERS thread
 

Buy ANYTHING but a JetJoe if you are not well versed on turbines- Any of the current marks of 12-14 pounders are a good bet. Best as you live local would be a P-60 , good engine, great support. Next would be a WREN, Simjet, Artes,PST, T-500. Good luck, Scott
PS if you buy a used WREN, make sure it is a WREN and not a dressed up JJ.

RE: JetJoe OWNERS thread
 

I think it is complete useless to buy a jetjoe at this time. You get a proved autostart working turbine for as little as 1595€, for example here: http://www.hobbydirekt.de/product_in...roducts_id=501
Who wants a jetjoe then anymore ? If you can get 16lbs proved turbine for nearly the same price ! And you also have well proved Projet ECU !