Xairflyer

My Feedback: (1)

Well actually yes the very carrying of a turbine by the starter motor can twist it out of line, most of them are on three legs fixed to thin alum and when they are out of line they are a real pain to get right again.

And the very fact it is a JetJoe says there could be another problem, what we should'nt do here is kid ourselves, they may be now using the correct materials and making the parts correctly, but they are still not being assembled/balanced to the standard of others.
Yes it is a huge improvement on 5years ago, but the only way you can be sure is either buy the parts and build it yourself or strip it down and rebuild before you run it from new.

There is nothing now actually wrong with a jetjoe 1400 turbine (other than the issue that got posts removed in the past) and the only thing still open for debate is wether of not the turbine wheels have been xrayed, so if you stick a known good turbine wheel on a JJ1400 you should have a good turbine, provided it is assembled and balanced properly, there is no other reason why not.
I am not saying thats what you need to do as my own turbine has been running fine with the JJ turbine wheel as supplied, I just mentioned it as it is the one thing that can't seem to be confirmed.

I cannot personally comment on JJJ or JJ1800/3000 etc as I have no experience of them

BJ64

Do you kinda get my point Xair?

If the Turbine hasn't suffered some kind of physical altercation between simply removing it from it's test bench and placing it into an Airframe, why would it suddenly go out of whack? Assuming, of course, all due care was taken during the transfer, and all parts used in testing are now onboard in the plane.

It's a JetJoe - yes. But bugger me - I carted mine all over the place in the back of a car still mounted on my test bench. And it starts and runs good as gold. There just has to be some logical explanation as to why it's suddenly playing up now.

And I bet the final answer will reveal this...

BJ

Xwingnut

My Feedback: (24)

Do not run it any more if you are experiancing any vibration. If the starter motor is not the issue then it might be possible the compressor spun on the shaft due to the nut not being tight or the same for the turbine wheel. Check the balance marks to see if they are still in line. If you can't see any marks then sending it to Gabe will probably be in order. If you do so be sure to check that you can see the balance (line-up) marks on the outside of the turbine wheel and compressor wheel when you get it back. If not be sure to make the marks more noticable so you can use them for future reference.

Best of luck,
Xwing

BJ64

I'll re-iterate - he's simply taken the Turbiine off the test bench, and installed it into an aircraft.

Why would all these obscene things come into play?

Like...Oh My God... I've removed the electrical plugs...undone the 4 teensy bolts that hold the Turbine down... picked that lot up and carried it all of 10 yards...and put it into an Airframe. Now a) my magnets have gaussed... b) my starter has moved 1cm into the Turbiine... c) my compressor and turbine have moved off-centre on their shaft.... Need I go on??

Maybe....just maybe... the blimin Leprechauns have been into it...?

BJ

BJ64

...but ditto on the "Don't run it"...

Something's not quite right there.

Check everything - twice.

There's a zillion things that could go wrong.

Get back to the basics, and see that what you had working on your test bench is what you have installed in your Falcon. If everything is identical, then we go to step 2...

BJ

Xairflyer

My Feedback: (1)

Yes I know what your saying BJ but the compressor nut could have came loose, one of the screws securing the diffusor to the shaft tunnel could have backed out (seen that happen), things can happen, my car was going perfect yesterday morning, when I parked it up, went out last night and it is now blowing cold air - head gasket gone, things happen !!

Xairflyer

My Feedback: (1)

Some time back I posted about trying to get the fadec software to run on win98.

After today lugging my XP machine out to the workshop and disconnecting the monitor keyboard etc from my workshop machine, connecting to the XP one downloading the data from my two jets then unplugging everything and reconnecting it back up to the win98 machine, lugging the xp back into the house, reconnecting it up again[:@] I said "bugger this not doing that again" I thought I would ask "did anyone have any luck getting the fadec software/win98 to work"[sm=confused.gif]?

I dont want to change my workshop PC as it runs my CNC router and vinyl plotter perfectly, but would like a regular means of downloading fadec info.

I did try it on another win98 machine with same results, anyone wish to refresh what it was all about it is around post 1991.

soupcandogs

The turbine wheels look good, although its hard to see the compressor wheel because of the FOD. Im in the process of checking everything over. Everything I ran it with on the stand is in the jet except the engine support and the fuel tank. Heres a close up on how its mounted, its solid as can be. One thing did cross my mind though, the holes I had to enlarge in the back of the fuse. to clear the starter and fuel lines allow air to be sucked from the inside of the fuse. There could be some air flowing through fusalage causing the symptom. Just an idea.

BJ64

Don't you just HATE that...? LoL

BJ

BJ64

Hmmmm..... quite easy to give the starter a clout there....

BJ

soupcandogs

Well it wasnt air flowing through the fusalage, I taped the over the holes and ran it. The vibration is very slight. I checked to see if the starter was spinning when I was getting the vibration and it wasnt. However the bendix was moving very slightly towards the compressor nut, Im going to remove the starter/cone assembly and check it out. Hopefully its just out of alignment and touching the nut ever so slightly. Who knows maby I did bump it on something when I was test fitting it a hundred times wile cutting the fuse. My fingers are crossed. Also I would like to know what temp your 1400's run at full throttle. Mine seems kinda high at 745 degrees C. - 158,000 rpm.

rcguy!

My Feedback: (69)

Bearing pre-load. OOOPS! I don't own a JJ so I'll assume this post will get deleted as the ones before?

Dave

BJ64

Mate is coming around tomorrow evening with a decent cam so we can do another 'Night Run' - hopefully I'll be able to cobble together a better quality Vid

And, with a bit of luck (and if I can get my act together), I might just have the 'twins' all mounted up and ready to go.

*Double* the fun

Fire in the hole!

BJ

myring

Hi guys,
Is there anybody has experience with jj1800? I did the first run yesterday. It was an unbelievable perfect run due to cool EGT below 400 degrees from idle to maximum rpm. So I suspect the thermocople could be fixed incorrectly. But the protrusion of thermocouple is 1-2MM complied with the manual. Does the engine have such performance or is thermocouple fixed at cool pot? The thermocouple end hole locates 12 clock position. Thanks your comments.

idleup1

I believe you have the plug reversed in the ecu. I ran one yesterday and it rand 600 with a dual tailcone. Ran 480 at 115,000 with stock tailcone.

myring

You could be right. I will test it with reversed plug at ambient temperature. There is another possible cause that thermocouple end retreat a little from the hole by vibration. Is it true jj1800 should be cooler than jj1200 or jj1400?

knobby1

Hey Idle,
The thermocouple will not function at all if it is plugged in reversed, the reading will be 000 and the engine will not get to the fuel ramp. The ECU has to register a rise in temp of 50c above ambient or 100c, (whichever comes first), before the fuel pump is activated for the ramp.

If the engine EGT is above ~100c and you attempt a start, the ECU will initiate a cooling cycle until the temp is below ~100c, then a normal start cycle will be initiated.

Myring,
The 1800 does indeed run a little cooler than the 1200/1400, but not significantly, maybe 30-40c cooler. Have you checked and adjusted the ambient reading against a known good thermometer? If it's within 2-4c when cold and you're still getting very low temps at idle, the thermocouple itself may be faulty.

Cheers,
Smithy.

idleup1

I rreversed the plug yesterday on au-354 and was reading 12 inside went to 22 when I reversed it . thermocouple had a differnt color code than my ecu I was using.

knobby1

Ahh!
An old AU-354, that makes sense, the later one's AU-540 and later will not register a temp with the thermocouple reversed.

Jetbono

Hey BJ

Im Back did you miss me ?

Have you done this video of yours yet ??

Xairflyer

My Feedback: (1)

Yes 745°c is high mine runs at around 620°c

knobby1

Hi Seamus,
Yes, 620-640c is a good temp at max rpm, leaves some room for changes in ambient conditions and has a goodly amount of thrust. A nicely running 1400 will produce ~13-13.5lbs at sea level and ~20c ambient. Getting them to run nicely is the hard part..!

Cheers,
Smithy.

Xairflyer

My Feedback: (1)

Smithy

What are the things that effect EGT ? I know the tailcone can, also bad seal around the case/diffusor anything else ?

knobby1

Hi Seamus,

Forgive my ramblings, but here goes...,

There are many things which can effect the EGT, you've named but two. Throw into the mix poor combustion, poor quality fuel, high humidity and altitude to name but a few. Some things we can also consider are the size, efficiency and map of the compressor/impeller in combination with the diffuser.... combustion chamber size and efficiency, NGV design and it's actual nozzle area compatibility with the turbine wheel and compressor etc...they're too numerous to go through here with any great detail though. Those others who work with these things will no doubt be able to give some more information and correct me if I'm wrong.

Needless to say, plenty of R&D is required to come up with a good, efficient turbine engine design. As most know, all these small turbine engines are very similar in construction and design....it's how they are designed, put together and the attention to detail which separates the men from the boys..!! Top quality engines such as the Wren, Lambert Kolibri, Jet-Central, Merlin, JetCat, Behotec, AMT and the new Evojet range are excellent examples of good R&D. There are many good quality engines out there and I've named only a few off the top of my head. Another couple which spring to mind are the newer Asian engines such as the Kingtech K80E and ATJ-120, both are excellent bang for buck IMHO, I've tested and run them both and have found them to be near faultless and actually deliver the advertised thrust figures, or better.

The little Kingtech K80E stands out here due to it's original combustion chamber and fuel injection design compared to most other engines, very impressive indeed, if you get a chance to have a peek inside one, I'd recommend it.

We should also recognise the efforts of people like Gaspar Espiel, his FADEC units are widely used on a lot of the above engines, without him and his work we'd possibly still be blowing hair dryers into our engines to start them. Some of the quickest, smoothest accelerating engines I've tested come standard with Gaspar's FADEC/ECU units, hats off to him.

Ramble mode off//..!



Cheers,
Smithy.

Jetbono

Nice one Smithy , always nice to have your thoughts and so simple to understand ..

Cheers mate