Hello Paul,

I rate the JJ1400 10/10 and JJ1200 10/10. Not because i am a rep but because of actual testing. I have now 75 flights on JJ1400. Every motor i receive is test run and checked for problems before shipping to customer. I have not received a motor that is not working. (touch wood) Serial numbers starting from 614 and my latest batch is 700 +. Do not know about there accessories. They do not recommend their own pump. And i also heard that there is a problem with starter motor.

I use the Gaspar electronics only with hausl pump. I do not like auto start on any turbine and therefor all my motors are manual air start. More reliable and cooler on bearings. Just my opinion.

Any turbine is not a toy and if you do not know what you are doing things will go wrong very quickly. I must have been lucky so far or JJ is doing something right.

Regards

Hi All,
The problem with the rpm sensor's is a small surface mount capacitor mounted directly under the cable tie, if to much pressure has been applied it can damage the capacitor.This can easily be replaced new heat shrink cover fitted.The cable tie can be left off.
Andy.

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My 1400 ran OK but would not accelerate well and would push the combustion out the tail pipe at higher RPM's.

I tore it down last night and have found that three of the nozzles are not flowing right. One is 99% blocked, one is 85% blocked and one is probably 40% blocked. Based on the size of flame when hooked to propane.

I ran a fine wire into the two worst ones and was easily able to insert it down to where it would hit the fuel ring but this did not help the situation at all. So, I assume the blockage is more than just crud in the nozzle, but I would think Joe would test each fuel ring before putting it on an engine??

I'm glad that I found an obvious problem/cause for the my engine's poor running. Now I just have to figure out how to fix it.


Mike

Hi,

Yes i would also like to know any issues customers might have. Blocked needles is a pain. I have 2 filters in my filling line and 1 filter in the fuel supply. Clean fuel is very important.

I compared the JJ1200 with JJ1400. The JJ1200 runs 120 deg hotter than my JJ1400. 640 deg compares to 520 deg.

No problem with ramp or power output.

Regards

Paul

This thread is certainly for all JJ owners including those JJ1200 owners, but any mods or changes to a JJ1400 that are not factory or rep approved, puts the risk and responsibility clearly on the modifier who needs to be competent. You cannot modify a factory set JJ1400 then complain on the warranty.

I rate them 8/10 in comparing to say a commercial turbine like a Behotec, especially in regard for the for value and performance 10/10. I had two rigged on a delta but wanted a single supply from a UAT header which gave a few head aches as one was full FADEC auto and the other semi manual.

Remember with JJ turbines there is no glossy packaging, no long written instructions, just a lump of turbine and the bits you've ordered. No real problem if you've had a turbine already, but maybe a heart stopper for a complete turbine tyro just starting out. Also not every JJ owner can do these suggested tasks or should even attemp them.

Paul

Mike

As a suggestion try upping the number of filtering points, as most fuel is dirty, the carry cans are dirty, sometimes even rusty. Filter into the plane, then filter into the header (I use a UAT) and last an extra fine filter after the pump. On a brand new rig this last one was blocked after only two runs with micoscopic debris which would easily blocked an injector needle. This is easiest provention to many problems the Rep have on returns. As there are no written JJ instructions so it highly recommended by the Reps and so simple as even the pump gears have wear and tear over time.

Paul

Sounds like a candidate for triple bypass surgery
Earlier in this thread or maybe another, someone suggested that the needles were imbedded too deep into the ring and actually bottoming out. I think they had to heat the joint up and pull the needle out a bit.

In my experience with blocked fuel needles, 90% is trash in fuel. I have 2 fuel filters on my filler and the UAT is also a filter of some sort. As for the other 10% i think the FLUX used in the silver solder blocks the openings at the base. I have found that if you take a torch and CAREFULLY heat the base and the needle, not to get it too hot and blow through the fuel ring at the same time via a 4mm line it will unstop needles. BE CAREFULL as the needles get red-hot real fast.

You must be VERY diligent on keeping your system CLEAN especially when you first install it. Any small amount of plastic, silicone, tygon etc that is in those tanks WILL end up in the engine: ask me how i know [&o] Russ

All the fuel that this engine has seen has gone through two filters. I can insert a small wire all the way to the bottom of the needles (comparing the length after I pull it out). So I am looking at a blockage at the base of the needle guess I will try the heating and blowing trick then if that doesn't help, try heating and pulling the needle up slightly in case they are bottomed out in the fuel ring.

What is the material used in these fuel manifolds? Brass tubing, steel needles and silver solder? or brazed?

Thanks for the suggestions.

Mike

YLF, this is a brand new engine, right? Why don't you simply send it back under warranty and ask for one that runs right? Am I Missing something here? Not trying to be a smart a__, but really, why not send it back?


Thanks.

The needles are put in with Silver Solder and flux. I DONT think they are in there too deep. They are Hypodermec needles, slanted on the end so even if it was in there to deep it would still get fuel. I think the flux or trash has it stopped up. If this does not work i would certainly send it back. DId you have fuel in the can when you pulled it off?? If you had unburned fuel in the can you probably have a combustion stick issue along with stopped up fuel ring.

cheersc Russ

Be VERY carefull about this. Send it to China if you are at all uncomfortable with the processes involved especially if you have a warranty.

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Mainly because I'm one of those people who likes to work on my own stuff and I have built a Wren from a kit, and I was pretty sure from the people I had talked to that it was an issue with the combustion chamber, something that I could fix (or get a replacement part for) quicker and as cheaply as sending it to China and back. Joe charged $80 to ship it to me the first time and the warranty only covers parts, not labor.

Russ,
Don't worry, I don't intend to do any balancing or precision machining, if an unclogged fuel ring and straight combustion chamber doesn't fix it I'll send it to someone more qualified.

Mike

Thankyou to everyone who replied!!!!!!!! i am SOOOOOOOOOOOO glad that you guys are having success with your jj 1200 and 1400's.

For me i have been concerned about the quality of the jj's but now i am convinced and have seen far more positive evidence and success than i have bad.

I have decided to buy a jj 1400 and put it into my Spectra that currently has a Ducted fan set up in it. I will be getting every thing reinforced for the added load and replacing all the servos with NEW 13 kg digital servos. I like to fly fast and aim to have it flying at 400 km/ph +

I haven’t ever had a turbine so it will be a learning curve, but everyone has a first time.

I would like to thank Jet Joe for providing the world with affordable turbines. For me a 19 year old it’s the only option at this stage in life (currently at school doing y12) for me to get a turbine.
I worked it out that I could get 3 x jj 1400's and still have $ left over or get 1 P80
! HA i know what i would rather have.


Tankie : you are fine mate, yes it will be my first turbine and any help would be great.


THANKS TO YOU ALL.

Paul

Please let me know when you intend to fly your Spectra at 400 kmh with your Jetjoe and I will arrange not to be in the Southern Hemisphere!

John

LOL thats funny that youthink im joking!

im seriouse! i have had it at 320 km on the gun with the DF fan but with 50 % more power 400 km is going to happen.

Can you guys take that conversation to another thread, as it would be nice to keep this one just for JJ owners and troubleshooting and such...IF you could...no offense intended...

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Thanks to help from Russ and Andy I had two successful bench runs on my JJ 1400 this afternoon, burned a total of 90 oz of fuel with no flame outs or abnormal behavior. I set the accel and decel delay down to 15 and did several runs to full power from different RPM's with none of the issues I had before. I'm planning one more run on the test stand and then it will be going into my Boomerang Intro.

In the end, the changes that I made to my JJ1400 to get it to run correctly were:

1. Fixed three poor flowing needles in the fuel ring (heated and pulled out slightly)
2. Adjusted the geometry of the fuel sticks and swirl jets in the combustion chamber.

Thanks for all the help guys.

Mike

John,

Thats not funny I live HERE ! (But I am in the northern hemisphere for 4 months of the year !)
Regards,

David Gladwin.

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