RE: JetJoe OWNERS thread
 

You mean the one i made or the ready one i ordered?
The one i made has a restrictor (0,5mm) but i dont know about the one i ordered.
Well i think it wont be difficult to fit one afterwards.
Chris

RE: JetJoe OWNERS thread
 

Today i start it up and everyhting went very smoothly.
The Permax 280BB is excellent for starting the JJ.
It idles fine but at 47000 rpm not 45000 as stated in the specs (it stays nicely at 45K rpm but sometimes the rpm fall down to 40000 and flameout occurs. Maybe some parameters need tweeking
No flames or strange sounds were present and everything looked and sounded very smooth.
No vibrations at all either, the JJ1400 must be well balanced indeed.
The engine reached idle (in repeated starts) in no time and the the EGT was around 620C at idle.
The only things still wrong is that the RPM only reach 147000 and the EGT raise to 800C when in fact it should be lower than idle.
I watched the turbine accelerate and indeed the EGT fall untill the turbine reaches ~100000 rpm and then rise again.
Well in the first starts i only reached 130K rpm so this is an improvement.
Acceleration is slow though but i suspect that this is caused by the high EGT.
Also the turbine seems to hasitate at ~80K - 90K rpm and then increases rpm very fast to 147K rpm.
I also noticed that each run went better and better so maybe some values are still wrong.
I also suspect that the Festo 50 Micron filter may present a flow restriction to the turbine so i will try without them and use the Hangar 9 filters.
Ohh i forgot to say that i used pure butane gas and that i had the gas connected directly to the engine untill idle.

Basic Fadec parameters:

Acceleration delay= 15
Deceleration delay= 15
Stability delay=50
Pump start = AUTO+1
Pump ramp = 4 (i will try 6 later is that ok?)
Pump pwm at idle is 100

Chris

RE: JetJoe OWNERS thread
 

Chris

Just for interest was the gas fully off when running at idle? I have given my temp ranges expected on a well set up JJ1400. Greg, MNModels and others might post their
may give their normal temp ranges. I'd be concerned and stripping down if at 160000 rpm I was reading 580C max

Andy Owen the retired UK rep for JetJoe spent much effort in rebuilding these turbojets
new from the factory, to then run flawlessly for continuous operation.

Looks like QA/QC is still an issue for Joe, at the defunct British Leyland these were termed a Monday Motor and no employee bought a Monday Motor (or a Fridays)

Wrap it up and send it back to Joe under warranty its not right. I received a new fuel manifold from Joe as a spare, one needle blocked and three partially. It would take seconds in china to either run these with air under water or on propane to check them
out before any dispatch. Of the the four JJ1400s three needed fixing from new only one from Andy needed no work to operate it.

Paul
RCdriver

RE: JetJoe OWNERS thread
 

Hi Paul.
Yes the gas was off when at idle.
I will probably send it back.
I dont think that there is anything else i can try in my level.
Thanks for Advice Paul.
Chris

RE: JetJoe OWNERS thread
 

Just a final question before i pack it up.
Could the thermocouple be the problem?
I dont know but i have this last minute idea that maybe the thermocoulple as i routed it might picking
up residual gas temperature due to the wide angle i created.
I saw in a picture you posted that the tip of the thermocouple enters the hole at an angle.
Should the tip be vertical to the exaust outer cone or at an angle?
It seems that if it enters verticaly in the hole like mine, the escaping gases through the hole which is a little bigger than the thermocouple's diameter might increase the effective thermocouple depth (just a thought).
The thermocouple looks discolored at least 3mm outside the cone which looks very suspicious.
I changed the position of the thermocouple for the next test just to see what happens.
The color of the exaust cone has changed and it looks not very hot thats why this thought came up in my mind. Somehow despite my inexperience the exaust cone doesn't look like it has seen high temperatures but i maybe totaly wrong.
For those that might be interested here is how i secured the Permax 280BB.
Its length is 40mm so the bullet starter cone wont reach the threads for securing the motor.
The brushes are external to the motor case so it will need even more than 40mm in length.
I drilled two 1,6mm holes, 120 degrees apart and made threads for 2mm set screws.
This way i can fine adjust the bendix depth which now works flawlesly.
Dont look at the tape it is only used temporarily until i make an aluminum retaining collar.
Chris

RE: JetJoe OWNERS thread
 

T

RE: JetJoe OWNERS thread
 

Tim What serial number is your JJ1400?
Mine is 00790.
How much running time you have with the JJ1400?
This is very interesting and i certainly would like to know more about this CC issue.
About my problem now.
I moved the probe and now it is 2,5mm inside but at an angle of 30 degrees(see the attached third image in my previous post) and when i started up this morning the turbine with everything connected (all solenoids and filters) it started immediately without any flames or strange sounds and at idle temp was 620C and at 100K (i was advised by JetJoe to run it up to 100k rpm for the few first times, "and then things will smooth out" he said ) the temp went somewhat below 600C which i think is good news. I didn't tried to go beyond 100K but the engine looked happier than ever.
No vibrations, no flames, no nothing, it was behaving like the best turbine in the world :D.
Acceleration and Deceleration was nice and smooth and i found no problem what so ever.
I did increase the Acceleration and deceleration delay to 30 (from 15).
The only thing i noticed is that after the run the rotor appeared to run smoother than ever with a noticeable
reduction of friction, not that it had much before, but now it was even less friction which seems a little strange.
Maybe the Bendix was dragging the spinner nut just a bit, i dont know.
When i installed the new starter motor i moved it a little backwards so the bendix must move further to engage to the spinner nut so there is more clearance now.
Previously when i spinned the rotor (normal rotation direction) with my finger giving it a strong push
it needed ~4 seconds to come to a halt. Now it takes ~6 seconds!!!
I think i am learning my lessons. Probably there was more than one problem with my installation
(gas selection, thermocouple's position, etc.)due to my ignorance and inexperience.
Chris

Chris

RE: JetJoe OWNERS thread
 

T

RE: JetJoe OWNERS thread
 

Thanks for the info.
I certainly agree that they need some tweaking.
I am sure that an experienced individual can make them run as good as any turbine with a significantly lower cost.
Besides the actual operation, the materials used in the construction look very good.
Next time i will get a kit instead (maybe a JJ1800...) so i can have the final word on the construction and assembly.
I hope i have the new CC and not the old one [:-]
Chris

RE: JetJoe OWNERS thread
 

hey Todd, you all moved yet ?

RE: JetJoe OWNERS thread
 

Help needed
After a good change of underware i have a quick question.
My father asked me to run the turbine because he can not understand how come it can possibly make the tremendous noise i described him.
It was totaly dark outside and when the turbine reached idle the exaust cone was glowing red.
Not bright red hot but clear red.
The EGT was 640C and when i throttled up to 110K the exaust started to fade in color significantly and became dull red.
Is this normal or i was lucky???
Any comment on the glowing (by anyone) is more than welcomed as i am very afraid to start it up again
The good thing is that i didn't saw any sparks or any flames and the exaust cone was TOTALY uniform
in color so i guess no hot spots in my turbine.
As i final word despite my shock the turbine run EXCELLENT!!!!!
The starter cone was dragging a bit it seems slowing down the engine in previous runs, not to mention the wrong placement of the thermocouple and the totaly wrong selection of gas (MAAP gas).
In Greece the sound of "MAAP" is similar to "MAPA" which means "useless".
I now use butane only with 100% success.
Chris

RE: JetJoe OWNERS thread
 

Chris

Having fun scaring the neighbors at night? :D:DThis is normal as in daylight you dont see the glowing that well in the sunlight. Whats more good news is that it became dull at higher revs means the EGT is dropping maybe even into sub 600C. Time to run it to max and get a temperature. The FADEC needs this top end info/parameters to settle top voltage for the pump to give max rpm.

Paul
RCdriver

RE: JetJoe OWNERS thread
 

Well thats good news because i got scared enough to say the least.
Well except for the dogs (i live inside Athens in a dense populated area) that started barking and howling
:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D
some people came out and started yelling "what the hell is that" as they could't see me because i live in a hill in a tall buiding, in the last floor :D.
Not to mention the smell of Kerosene that filled the whole area:D
My father started to move away further and further and while the turbine was at idle he was shouting
" lower it, lower the rpm". I replied "well that is idle, i can't go any lower than that" :D:D:D:D:D
I doubt that he will ask me to fire it up again....
Chris

RE: JetJoe OWNERS thread
 

Chris

What a great story[8D][8D] I know a few mothers of young children and shift workers here at home who might lynch me if started doing late night or midnight runs.[:-][:-]

Paul
RCdriver

RE: JetJoe OWNERS thread
 

Btw if anyone is interested i have a spare NIB Permax 280BB motor (somehow i managed to get three of those:D )
that i could trade with something like say ~5 suitable glow plugs, a broken starter motor with bendix on, a quart of turbine oil, or something similar worth ~20 Euros(with postal charges) The Motor is new and i bought it 25 Euros + s&h.
I am not after the money but maybe someone has something that he dont wants anymore (turbine related).
Chris

RE: JetJoe OWNERS thread
 

As i final note i would like to post my impression about the JJ1400.
I came to a conclusion that it was only my inexperience that caused my little problems on the very first runs.
I also came to the conclusion that JetJoe has come a long way since the first engines because from the
previous posts is evident that my S/N 790 engine is improved from the previous engines and this implies that JetJoe
listens and adjust the engines accordingly.
I have read all post regarding JetJoe turbines over 10 times in all forums and i even remember who said what.
Probably even if i or you could inspect say S/N 750 with S/N 790 engines someone could identify small modifications.
After weighting things i dont regret for a moment buing the JJ1400, it was a good move as far i can say for me.
If i was to get the JJ1400 or even worst the JJ1200 some time before i did i would be in big trouble as only experienced
turbine users could make them work well back then but now i think things have changed and the newer production
JJ1400 engines made my dream come true (at least for me) by introducing me to the rc turbines.
I have now aquired a lot of information that can keep me going even if the JJ1400 decides to leave this world
and go to the turbine heaven :D .
I also dont forget the people who helped make this turbine work well without gaining any money and i know that there are many of them.
If JetJoe survives for one more year the competition which i think was unfair sometimes to him we might see
Jetcats P60 for under ~1600 dollars complete with ECU.
I may be wrong but that's my opinion right now so if someone thinks otherwise i would be more than glad to hear his opinion and rethink mine.
Chris

RE: JetJoe OWNERS thread
 

Looking back through this thread the change and outlook is totally different for most JJ operators. No more suggestions that JJs don't run or might explode[X(]. To a realistic focus on running and operating successfully flying these Jetjoe turbojets. I know in North Wales many JJ1400s put in some considerable flying and operating time each week.

Timfly1 had a problem as his JJ had had dozens of hours running and flying until the 'S' sticks had deteriorated completely. This Combustion Chamber was replaced with the newer Inconel by Joe. So it is worth a check if performance drops or temps rise above normal parameters and you are below #690.

I looked again EGT data comparing to temps given by MNModels and others here. At 160000rpm at temp of about <550C with a maximum 600C on idle, seems to be in the norm when fully a adjusted FADEC has settled in. As a further guide a max of 650C seems to be the top EGT for most manufacturers expect.

Paul
RCdriver

RE: JetJoe OWNERS thread
 

Well i measured the thrust of my JJ1400 today and it outputs 17,5 lb !!!!
WOW!
Chris

RE: JetJoe OWNERS thread
 

At what RPM?

Dave

RE: JetJoe OWNERS thread
 

Got you!
:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D:D

Only in my dreams 17,5 lb are real:D:D:D
Seriously now i am building a thrust measurement test bed so i can decide if i will get the stingray or
something like the hot spot.
Hot Spot does seem a little heavy for this engine right now.
I am searching for a trainer that is no heavier than 7 Kg AUW and has big wing area.
I dont care much about top speed but i would like something easy to fly.
When i measure it i will post my measurement.
I dont think that it will go over 11-12 lb based on other's experience but who knows?

Chris

RE: JetJoe OWNERS thread
 

What is the diameter and length of the jj1400

RE: JetJoe OWNERS thread
 

Hi.
It is 90 mm (3,54'') diameter and about 23 cm (9'')length including the starter cone and exaust cone.
My JJ1400 has a longer starter motor by 10mm so it is 24cm long (9,45'')
Basicaly it should be the same as the Wren 54.
You have something in mind or you planing on fitting one somewhere?
Chris

RE: JetJoe OWNERS thread
 

Hi tim

I have been building turbines for a few years now and your pictures and description is a problem i experenced early on. Im guessing that your turbine is out of balance, what i have had happen is when the rotor is not balanced 100% the shaft tunnel is actually getting moved around inside the rear NGV, This causes the shaft tunnel to either develop a trench like ring or turns it to a oval shape causing it to stick to the NGV.

My fix was to first balance the rotor and then i made the shaft tunnel out of aircraft grade aluminium.

Hope this may help

Jared

RE: JetJoe OWNERS thread
 

;

RE: JetJoe OWNERS thread
 

I got the right oil at last so i will go for full power measurements.
You can't believe how difficult is to get the right stuff here.
Thank God for the Internet.....
Chris