RE: JetJoe OWNERS thread
 

What plane do you guys think will go fastest with the JJ-1400 in it?

RE: JetJoe OWNERS thread
 

Hi.
What i am about to say is not a fact but an opinion based on more than one months worth of search and thinking.
I think that the most suitable plane is the the yellow aircrafts STINGRAY.
It is the right AUP weight and it must be very slick and fast.
Thats why i am having second thoughts on getting it as i would prefer a slower jet as my first one.
You can see it at http://www.jetpower.at ->online store EU -> jet models->jets->sport->kits
I am sure i have seen it in a USA based store also
Another plane i am considering as it looks more versatile is the black shark http://www.jetwelt.de/2-jetwelt_1.html
Dont take my word on the plane selection as i am speaking theoriticaly only from my experience with large electrics
so you beter get more opinions.
I posted my opinion just to help anyway i can.
Btw i was talking with my girlfriend on the phone and instead of charging the FADEC battery pack i charged the fadec itself so i burned it thats why i was soooo silent lately.
I send it back for repair and also ordered the newer version 05 but it is out of stock [:o]
Chris

RE: JetJoe OWNERS thread
 

Thanks for the links Hendrix,

What do u think of the Starfire II at the http://www.jetpower.at website? It too is in the 12-14 pound thrust range (50-60 Newtons) and looks pretty sleek (BVM Bandit-like)....I wonder how fast it and the Stingray would go with the JJ-1400 in them?

RE: JetJoe OWNERS thread
 

Chris

I have a Black Shark and its a great flyer, looks Vulcanish from below and has great prescence and landing is to within 6-7 paces after practice. On grass the JJ1400 gives about < 13lbs in normal setup and you'd struggle with a very long RoG, though on a paved area it leaps off with a Behotec 18lbs thrust. The YA stingray is on my buy list too for size and looks

Paul
RCdriver

RE: JetJoe OWNERS thread
 

I think that a delta winged aircraft is more stable and it doen't stall easily in tight turns.
I had a EDF plane like the Starfire that would stall in very tight turns and loose altitude like a rock.
I may be wrong but i prefer delta winged aircrafts by far.
From what i have heard the Stingray is also easy to construct.
If you buy a heavier plane the good thing is that you can later fit a bigger turbine but with the Stingray i think you are limited to small turbine units.
I also like th looks of the Hot Spot.
Chris

RE: JetJoe OWNERS thread
 

Hi Paul.
I need your advice once more.
Today i finally reached 162 Krpm easily but the temperature was 790-800C.
Despite this the engine works very well and accelerates fine with no problems.
It gives me the impression that something is breaking in and run after run things go better and better.
It really looks like the break in procedure of a piston engine!
Temperature at idle is 620 C, at 100 K 580 C and tend to go lower and lower, run after run.
This was the first time i reached 160K so something is breaking in.
The pump Pw is 770 at 160Krpm and no hot spots are evident on the inner exaust cone
so it looks like there is no problem with the fuel needles.
Any ideas?
Chris

RE: JetJoe OWNERS thread
 

Just a thought ... it could be the depth or position of the thermocouple giving a false high reading.??

RE: JetJoe OWNERS thread
 

Yes it could be as the engine works flawlesly (i suspect it but i need to get a spare and try it).
It is 2 mm in but there could be something wrong with it or gases escape from the hole and heat a larger portion of it.
The strange thing is that acceleration and deceleration times are improving run after run and overall there is no visible problem.
The rotor also seems to rotate freely, without play and vibrations and with no strange noises.
The engine starts so easily that it reminds me an electric motor and it holds idle at 42000 rpm and 620C
(i did it as an experiment).
I started it up 4 times in a row without any problem what so ever.
Chris

RE: JetJoe OWNERS thread
 

Today it reached 160Krpm with 720C!
Overall the temperature is going down run after run.
It definately looks like something is breaking in.
The only problem now is that when i stabilize the engine at 100K rpm and then raise the throttle quickly i usualy get a flame out.
If i go from idle to full power raising the stick as fast as i can it works fine.
Maybe the acceleration delay is too small.
I also found one nut missing from one screw that holds the inner exaust cone in place.
In order to replace it i had to remove the exaust cone assembly and i also found that the holes are not machined but opened by hand so
the holes do not align with the Ngv,outer steel case and the exaust cone.
Some screws were forced in so i had to replace them as the threads were worn out.
I machined the holes a bit and now the holes align better.
I also found that the turbine wheel fins are not level.
The turbine wheel is rotating straight without any error in diameter but if you say remove the turbine wheel and place it in a level table sitting on one of its sides some fins are higher than all the others.
Not much but i dont know if this is normal.
Chris

RE: JetJoe OWNERS thread
 

Chris

I have been off line for a while with a computer fault, so unable to post. As the ECU fuzzy logic gets more runs upto 160k things will improve in running and throttle response. Can you post a photo of the fins? Obviously there was no binding up etc. The lost or even any loose fittings can reduce the CC pressure with direct effects so make sure all is secure.

Paul

RE: JetJoe OWNERS thread
 

Hi Paul.
Well i cant post a photo as i didn't removed the turbine wheel, i just spinned it up by hand and saw that the fins were moving
in and out of the NGV (towards and backwards from the tail cone) but the spinning disk of the turbine wheel was holding
a perfect and stable diameter ie it maintained a stable distance from the NGV wall.
Dont think that there is a big movement, just a slight one only visible under strong light and close examination.
It looks almost like the turbine wheel was balanced in two planes than just the rotating plane.
There is no visible damage to the wheel and there are no scratching signs of the fins on the NGV either.
I realy would like the NGV bolted down to the shaft tunnel or something as whenever you remove the tailcone
you have to align the NGV walls for equal distance from the turbine wheel fins and i am a perfection maniac.
About the flaming out i think there might be a problem with my fuel lines as i saw a big bubble traped inside the filter after the engine flamed out both times.
The bubble does not propagate down the line but it looks locked in the filter! It also looks that there might be a restriction from the tank to the pump inlet so i will invastigate this issue some more.
Overall i think that is the last problem i will have to solve as everything else is working fine.
I am using the new Nades Fadec 05 now so the fadec must learn the engine for a while before it runs really well.
One thing that i am sure i am not mistaken is that something is getting freed up and the rotor looks like it turns with less friction each time.
I am fighting my way through as you see and i realy appreciate yours and everybody else's opinion or advice.
Btw the jj1400 realy comes to life beyond 150K rpm as the sound is getting more bass and you can feel the thrust increase dramaticaly.
Chris

RE: JetJoe OWNERS thread
 

As usual Paul it was my fault about the flame outs.
I suddenly noticed that the Festo big plastic 50 micron fuel filter was completely empty of fuel and despite all my efforts
it wouldn't get filled with fuel.
As i was using the priming function and a metering cup is saw that the fuel filter wouldn't get rid of the air inside and the fuel coming out was mixed with air.
It pured out only 14 ml of fuel when typicaly it outputs 17 ml of fuel during priming (after filters and solenoids)
I connected it the opposite way id magicaly it got filled with fuel instantly. It now ouputs 17 ml+ of fuel.
I dont know why but the air was traped inside the filter, 90% of the filter was full of air instead of fuel.
Probably during high fuel demand the air could affect the pumps output.
I also checked the turbine wheel again and with naked eye and sun light i coudn't spot the differences i was talking about so
the difference is very small. The turbine wheel is dead center to the NGV and everything looks good.
I will fire it up again this evening.
Chris

RE: JetJoe OWNERS thread
 

If you are using the Festo filter (the one with the screw on end caps that hold on the tubing), there is no issue with the bubble. I have used these for years with P-120 class turbines. The bubble will not leave the filter. I have tried and tried and never got the filter to cause an undesirable fuel bubble in the line - ever. Works fine.

RE: JetJoe OWNERS thread
 

Hi.
Yes that is the filter i use.
You are right but it made a big difference when i reversed the connections and made the inner filter area as an input and the outer as an output.
I fired it up just 10 minutes ago without a problem except that my neighbors look at me funny after that as i fired it up in my balcony (i live in a last floor penthouse , is that the right word?)
I did noticed that a huge bubble propagated down the line coming from the fuel tank.
There is probably something wrong with the clunk.
The jj1400 works flawlesly.
Chris

RE: JetJoe OWNERS thread
 

Anyone has measure the real thrust of this engine???.

I have two JJ-1400 one of my engines has around 3 hours in a test bench just playing waiting for my stingray be ready to fly. My plane is almost ready and I think I am going to fly next week. I will let you know what happens with the madden flight!!!!!!!!!!!!!

RE: JetJoe OWNERS thread
 

Chris..

It might be a good idea to get some photo's of this ..even if it means taking the turbine apart..... and post them up for a few people to see.. before you run the engine again.


You have had some quite hot gasses washing over that Turbine disc.. better safe than sorry;)

Dave.

RE: JetJoe OWNERS thread
 

I will try and post some photos.
Maybe a small video of the disk turning.
I run the engine again with no problems.
I also checked for vibrations but the engine runs very smooth, there is no vibration feeling at all.
Today i tried to see the fins play with direct sunlight but i couldn't spot the difference which is visible only when using a flashlight.
It could also be an optical illusion as any misalignement should produce vibrations shouldn't it?
Anyway the max temperature that this engine has seen is 800C so there might be a quality check issue.
I suspect that when you say "quite hot gasses" you mean above this temperature.

UPDATE:
False alarm, it was an optical illusion.
I rechecked with a strong flashlight and as parallel to the turbine disk and i couldn't spot a difference.
If i dont look exactly parallel to the turbine wheel some discoloration creates this illusion.
The Turbine disk is perfect so i can rest now :D .
The JJ1400 runs fine also so i am quite happy now.
During the last test it realy pushed the test stand at 120K rpm and beyond.

Chris

RE: JetJoe OWNERS thread
 

Hi. I was a bit (well enough) alarmed yesterday by this turbine wheel issue so i decided to investigate the matter some more.
As a complement method i used a stick mounted on a vice which i placed in a position just touching a turbine fin end
and then i retracted it just enough not to touch the fin.
Then i rotated the turbine wheel and there was no rubbing.
I then selected some different turbine fins and repeated the whole procedure just to be sure that i didn't selected an outwards bent fin.
One more thing about the oil.
I used both fully synthetic TC3W (Amsoil) and Mobil Jet 2 and my opinion now is that the Mobil Jet 2 has far less friction than the TC3W and also i noticed that the exaust cone which had been colored blue something, with the use of Mobil Jet 2 is now clean as it looked when the engine was new. The turbine wheel is also cleaner now!
One problem still remains with the screws that hold the inner cone of the two piece exaust cone.
I always find that those three screws insist on unscrewing themselfs during operation and i already lost one nut located inside the inner cone.
Maybe it is better to try the one piece tail cone.
Any opinions on the one piece tailcone?
Today i will mount a Dubro 1,5 litre tank and redo the plumbing.
UPDATE:
I installed the Dubro tank and things look better now. The tank i used was just a plastic bottle with terrible nipples as i have to order them from abroad.
I also found that clips are needed on the fuel line connections where the nipples go in the fuel tubes otherwise air is sucked in during high pump suction. Everything now looks good and runs good!
I think that after a couple more tanks the jj1400 is ready for the Stingray.
Chris

RE: JetJoe OWNERS thread
 

I know that this might be out of topic but for me it is some kind of a victory over the overpriced turbine market.
Mine and all others decision to try something else seems to start steering turbine makers mind.
Have a look there:
http://www.funsonic.com/prices.htm and pay attention to the FS70 price!!!
I could be wrong but....
Chris

RE: JetJoe OWNERS thread
 

I stand corrected about the filter.
Air is again traped inside the filter and i am trying to find a way to get it out.
So far it resists any attempt i have made but i will try some more.
It doesn't seem to affect anything significantly as you said except that i find a small reduction in fuel flow
which is not that bad.
The only thing that is bothering me is that this air looks bad to my eyes.
Chris

RE: JetJoe OWNERS thread
 

I know. But trust me, if you can't get it out of there while trying hard and shaking and tilting and so forth, it ain't gonna come out while flying!

RE: JetJoe OWNERS thread
 

HI guys,

I am complete rookie jet owner and have just bought 2 JJ1400s. I am still unclear about a few things before I spool them up so I'm hoping that you can help me. Due to the lack of literature that you get with the jetjoe some basic things are still left unclear E.G which line is for kero and which is for propane. I'm assuming that the clear line is for propane but not 100% sure. Also my kit came with a bag of resistors (no. 473). I can only assume that they are for the flight works pump right/wrong? If so do they get soldered between the pump terminals. any help is appreciated. Oh yeah and also could anyone tell me what pressure the propane should be feed at during spooling. I have a coleman max propane bottle and not sure is the pressure needs to be regulated or even if the pressure from the coleman is sufficient for starting. thanks guys.

RE: JetJoe OWNERS thread
 

Hi.
The orange line is for propane and the clar is for kero. You better verify that the diagram in the "manual" agrees with the fuel
and gas connections, just unscrew the three socket screws and remove the intake blue cover.
There is a "Y" festo connector underneath which feeds two fuel inputs.
One is the fuel input to the Combustion chamber and the other is the lubrication line to the bearings.
The remaining input should be connected to the orange(or yellow) line for the starting gas.
The reason that the fuel line is clear is to be able to see when fuel is coming in and any bubbles in it.
The capacitors are for the starter motor. The flightworks pump already has them on a small PCB on the back of the motor.
The coleman power max is fine and as i found out you have to find the sweet spot where the gas flow is perfect by experimenting. Start half way open and adjust during spool up after the starter motor disengage.
Chris

RE: JetJoe OWNERS thread
 

Hi.
Yesterday i tested the engine for the last time and everything worked just fine.
The temperature is 560Cat 120Krpm and gets upt to 670 at 160K rpm but it has a clear falling tendency.
No flame out either no matter what i tried and the acceleration was perfect and fast.
It does sound lean at 80K rpm though but no ill effects are present.
The gas solenoid does not open if i have the gas already turned on
(using 2 lipos and a Ubec for both starting and rx supply, with 7 cells it works fine)
so i had to first initiate the starting sequence and then turn on the gas.
It is now ready for installation he he he.
I want to thank all those kind people that helped me giving me information and encouraging me to continue as this was a
totaly uknown area for me.
Chris

RE: JetJoe OWNERS thread
 

Chris..:)..

.. Your journey has just begun.....your overdraft will now increaseth..:D