Hi All,

I have a question about Combustion Camber. My old no Inconel CC last for about 3 hours till melted. Now I have installed a new Inconel CC, So how much time this CC should last?. Till now 5 cycle and 60 minutes and working great but not sure for how long[&o]

Hi airbuspilot

With TLC and very few hots starts it should last for the best part of your life time, seriously I've seen old inconel KJ66 and PT75 turbiners over 10 yrs old in very good order, so lets hope the new JJ last that long.

cheers Paul

RCdriver22

Paul, good point

I edited that to be a little clearer. Plus I ask them to press on the turbine end of the shaft so hopefully the flame will stop them before they touch the spinning turbine

Mike

3 more flight with my JetJoe powered Stingray

That stingray looks like a fast machine to me, i know that u have some videos to share with the jet comunity so why don´t you upload them here ? one of those high speed fly by will be nice [sm=shades_smile.gif]

YES Fernando, put up some of those videos with YOU flying the jet...... Too much rumors in the field, you need to show us proof...

WATCH AND BELIVE IT

http://www.youtube.com/watch?v=Fdo8XV5AcxE

NiCE ViDEO [8D]

Paul

Rcdriver

Excelent Fernando, know we all believe... That jet is a bulet....

Congrats...

Fernando

Thanks again for the video, what fadec settings for flying did you go for.

Paul
RCdriver

Hi,

I was wondering if you could give me some advice and help with my JJ1400 engine. I just got the rotor assembly back from being dynamically balanced at RTI, and I made all modifications described in post number 608 of this thread. I also sealed up the front case seam and rear tail cone seam with a high temp copper silicon. When it was run without being sealed up, there were excessive blue flames coming out the back, and a jet of air coming from the front seam of the outer case. It was too much to ignore.
So, I just got done running it with it being all sealed up, and at the lower rpm's the engine experiences a rpm drop of about 1,000 rpm just about every 4 - 5 seconds. I am sure that it is not the fuel pump because pump power is constant and doesn't fluctuate with the rpm drop. Temps are very good at about 520 C at idle. I am just trying to figure out what is causing the rpm drop. It doesn't experience the drop at high throttle positions. When I say higher, I mean from about 20% all the way up to 100% power. Do you know what might be the problem??? Maybe I should just ignore it and go flying?! It would make me feel a lot better if I knew what was causing the rpm drop.

Thanks for you time,
Brandon

Brandon

The tips in 608 were given to Airbuspilot2 in earlier PMs with Fernando as he will confirm. His earlier problems was rear bearing failure in part. So either removing the O ring or cutting it flush was a part answer as the machining tolerances vary. If getting rear bearing failure the lubrication delivery amounts/flow was another problem that required to up the flow by 200-300%. Since the early restrictor barely gave enough.

The drop in of 1K is the fuzzy logic adjusting say at idle when set 46k it hunts beween 45-47k trying to settle and is a feature of the stablity delay. Nothing to wory about if it goes up to 160K as over a few runs it will settle down. Unless you want to tweek FADEC setings for aerobatics (then PM over). The other major problem was the Non iconel CC breaking up at happened for Fernado loosing performance but Joe replaced it.

I'm just curious what FADEC settings Airbuspilot2 decided to use from those PM'd over to try out. The vid and performance was spot on.

Paul
RCdriver

Hi Paul,

Here are my Fadec setting, let me know if you need hiden parameters too

Max speed: 160000 RPM
Idle speed: 42000 RPM
Stop speed: 28000 RPM
Max temp: 800 C
Min temp: 100 C
pump start point: auto+2
Start ramp: 6
Acceleration delay: 40
Deceleration delay: 30
Stability delay: 50

Equipment:

JJ-1400
Pump Flight Works A-200
Fadec Nades V05
Battery Lipo 7.4Volt 2200 Mah

Gents,

After a number of emails with EasyTiger and JetJoe, It was determined that my engine has a flawed combustion chamber. It will only run is the accelerations are set so slow as not to be useable. So, it is off to JetJoe for a combustion chamber upgrade and servicing. Thanks for the help.

I am a bit annoyed though at having to spend a couple of hundred bucks to fix the problem. But, Joe guarntees a perfectly running engine after it's done. Makes me think......


DW_Crash

Good result as its a 2nd hand engine. Joe has previously posted out new CCs to many customers who were lucky enough to get their JJ turbine running then found running actually destroyed the non inconel sticks in the CC. So if yours is >No 750 it is worth while getting the right CC put in. If you are direct Jetjoe customer that will be FOC since it has to be fit for purpose. Makes me think why a Turbine manufacturer would put inferior metals into his engines[:-][:-].

Paul

Its flying fine so no need to adjust the settings I've adjusted my thumb to move slowly and progressively, this only critical on a missed landing or a go around.

Paul

Hi paul,

As you see in the video we make a go around and acceleration is not fast but I think is pretty normal for any turbine

Cheers,

Fernando

Well, I test ran the JJ1400 again to make sure that I could accelerate to full power quickly without the engine acting up...and I am very disappointed to report that the engine is still up to its old tricks of blowing flames again...... I am absolutely positive 100% I put the engine back together correctly. My acceleration delay was at 70. I took it up to 100, and it still blows flames on spool up.
It idles very nicely, and if I slowly accelerate to full power everything is fine, but when I slam the stick forward, it shoots flames and eventually flames out.

I just don't know what to do! I have tried everything short of kicking it in the tail pipe! I just spent 223.00 for a dynamic balance and new bearings. I bought the new inconel CC. I used the outer race of one of my bad bearings as a spacer to make the preload push harder. I made sure that the rear oring wasn't sticking to the preload. I made a new lubrication line from the old CC gas line, so the bearings are getting plenty of lubrication. I have sealed everything up....... What more could it ask for? My bad luck I guess. I just want to go flying!

Some thing that would help me a lot would be if you could give me a detailed explanation as to how the preload system works. I have been told that this is my problem, but if I can't get an explanation as to what it is doing while the engine is running, then I have a hard time being sure that it is in working order. From the looks of it, it is a spring with a sleeve that applies pressure to the outside race of the rear bearing. I understand that by applying pressure to the outer race it is in fact applying pressure to the whole rotor assembly. Because of this, when the engine is fully assembled I am able to reach through the tail cone and push on the turbine wheel and feel the rotor assembly slide forward and spring back. I placed a spacer inside the tunnel so that the preload had more "pushing power." Is it possible to have too much "pushing power"?


Let me know if you have any suggestions for fixing it or what I should do,......... could it be a software problem in the ECU??
Brandon Vazquez

Hi Brandon,
If you spin the shaft with your fingers, how long does it take to stop turning? Three to five seconds is about normal, less than this, your preload is to high.
Do you still have the rear o-ring fitted to the shaft tunnel?
If so I would suggest removing it along with your extra spacer, also check that your sleeve & rear bearing slide easily in the shaft tunnel.

Cheers
Darrel

On set up after say a rebuild or replacing a pump or battery etc, the FADEC instructions suggest for your first run, to teach the ECU.

Max speed: 160000 RPM
Idle speed: 45000 RPM
Stop speed: 28000 RPM
Max temp: 800 C
Min temp: 100 C
pump start point: auto+0
Start ramp: 4
Acceleration delay: 120
Deceleration delay: 30
Stability delay: 4 to 6

At these setting with slow throttle control there should be no flames but a few splutters until things settle in. If you have flames at these settings you'll never fly and may need to investigate the internals again.

I am assuming this is fairly standard for anyone running a 54mm turbine first time. What version date are your FADEC instructions?

Paul

Buy cheap by twice!

Brandon,

I think and I am pretty sure you are having problems with combustion camber, maybe the vaporizing stick are melted or are bend and not in position, also I would check the fuel ring, maybe a needle is blocked, work with fadec setting. But don't worry about preload, I don't think your flames came from a failure in that part. When I have all problems with the preload my turbine start to loose rpm at max rpm (160K) then increase the temp and I have to shut down the engine, also I have problem with lubrication if you have too little lub bearing get stuck or destroyed like happens to me.

Paul I have an Idea

if you have too much lubrication and I said maybe more fuel going by lubrication pipe than fuel rings maybe you could get flame going by the back of the engine like an afterburner, what do you think[:-]

Just my two cents

OK. Hey thanks for the posts guys. I will go ahead and take the engine apart again. I will remove the rear oring completely, and make sure that there is free movement of the preload system once again. I am sure that the needles were not blocked because I checked them. It is a brand new inconel CC, and EGT's have been well within bounds. When I reassemble the engine, I will run it with the posted settings according to the FADEC manual. y manual must be old, because it doesn’t say anything about this..

Later,
Brandon

Connect the fuel ring and lubrication pipe to gas and check the flame size. Flames from lub pipe should be 2 or 3 times the flame from one needle at the fuel ring but no more. Also check distance from diffuser to combustion camber, should be 6mm. Remember to use silicon to seal the engine, because the oring in the diffuser is not enough.

airbuspilot2

Hmmm[8D][8D] cool wet bearings, no rear bearing failures and an after burner to boot, nice thought The afterburner has been tried on our small turbines but as always there was a down side as you would need to quadruple your fuel load [&:][&:] for a minimal duration on burn.

Paul