No problem friend.

This F15 is a single engine and we are going to fly it every week (I hope...)

We have here the same model but with JetCat P120 SX. well, the jj is way stronger
Anyway, I will post more videos in days to come.

JJ is much better today than the early days.
He also have a great service. he replace my 1800 to this 3000 with no extra money, and no shipping fee !!!
Superb
My next engine... another 3000

Wow that sounds good ..

yeah look forward to more vids .

Thanks msni for the feedback on the newer JJ turbines , I think my next plane will have a Jr on it. Problem is I have a few projects ahead of it. I I figured that since they have survived so far that they must be willing to learn from mistakes and improve thier product.

Could someone measure for me the 1400 single piece tailcone, need the outlet dia and length.

I have one but it is not from Jetjoe

Overall length is 45 mm (measured from flange to edge of cone) exhaust side ID is 43mm, Turbine wheel side ID is 58mm, Bolting surface flange OD is 75mm.

Thanks,
The one I have is 42 ID at rear and has a 47mm overall length, since rebuilding my JJ1400 and getting all my injectors working well I have been using the original two piece tailcone, as it had more than enough powere for my Bobcat.

Having to replace my wren 54 with my JJ1400 (bit ironic) after the wren blew up in my Boomerang (funny always thought it was the JetJoes that blew up) I wanted to get the most thrust I could as the boomerang is much heavier than the bobcat.

I have flown it about 10 times now with the two piece tail cone but it needs a bit more thrust so I fitted the single piece tail cone and the EGT's went very high 740-760 I had one flight and did had bags of extra power, but when I downloaded the fadec parameters the EGT's had been up at 785c so I swapped the tail cones back again.

I think now with the fully working needles the single piece cone is two small dia at the outlet and going to machine it down on the lathe (to make outlet dia larger) till I get EGT's about 680-700.
What is interesting is a friend sent his wren 54 back for repair and now it runs in the high 700's and the ECU was re set to 840max? I always thought 800c was a figure set more to protect the bearings and metals as most turbines seem to have a max of 800c

xairflyer.

i have a jj 1400 on a falcon 120.
it had a 2 piece cone on it but i wanted a little bit more,( as you do!)
i had a spare 1 piece cone from my departed mk3 54. after an e mail to brett smith, he suggested that i open it up.
i had a good friend open it to 40mm, tried it and got temps down to 620 at full chat,
hope this helps,

cheers
snatch

Hey Snatch,
Did you lose any thrust by opening the cone up?


Joe

JJ1400 start problem

It's been running great and starting great until now. Maybe someone has some ideas for a fix.

On start, it spools up to a registered 3500 rpm, lights on the propane, using manual propane, no solenoid, then just quits everything on the start sequence. Ignition is still on until timeout, start motor stops and rpm registers 64200 rpm.
fuel doesn't ramp. EGT probe registers. it's like it doesn't want to continue to run on the propane till the temp comes up for the fuel to ramp. maybe a fuel pump related item? which I will look at tonight. Flightworks pump
I had thought initially the EGT probe fell out but that's not the case.

got me baffled

any help would be appreciated

Mark? xairflyer?

Jack

Jack,

I had a similiar issue. Simply turn on the ECU and take a magnet to the speed sensor. This will demagnetize it. After I did this, this glitch went away. Seems the hall effect sesors can become magnetized. A magnet fixes it. Give it a try.....test by hitting starter with a separate battery. The rpm signal should be smooth and reasonable.....

Dave

Hey Jack,
On the ECU you should have a prime option, disconnect the fuel line to the turbine and hit the prime option to make sure you are pumping fuel from your pump. After a pump has been sitting for quite some time the lines will gum and clog a bit. If you are getting fuel and the degausse magnet tric does not work your fuel ring in the cumbustion chamber might warrant a look to make sure it is not clogged.

Joe

If it reading 64,200 rpm during start you are picking up intererence from the glow plug circuit. This will drive the ECU nuts and the turbine will most likely not start. Seperate the rpm sensor lead and the thermocouple lead from everything else as much as possible. Twist the glow wires around each other and the starter wires around each other. Make sure the glow plug lead is well grounded. If you have it under a case screw or on the mount put it back under the glow plug. Since it had been starting ok to this point I would suspect a poor glow plug ground. Also make sure the glow filiment isn't touching the inside of the plug.

Yep... sounds like interference to me too (if it's not the magnets).

Make sure you twitch all the high current leads together, and run your RPM sensor wire back to the FADEC as far away as possible from even twitched leads.

I had no end of trouble trying to start my first JJ-3000 until I took Bretts advice and twitched all the high current leads together and re-routed the RPM sensor wire itself. Twitched-together wires make for a neater job as well.

When I added my second JJ-3000 to the test-bench, I made sure all my wires were twitched together from the outset, and it started first pop

BJ

Well, I tried the degaussing(good idea as I did this with my RAM one time to fix it) but had no change,

ran the fuel test with the test circuit- no change

wires were where they were for many flights, but will move things around

RPM sensor wire separated as it has always been, same with the EGT cable.

It goes thru 1 cycle, RPM comes up to 3500, lights if I have the propane on, then quits and RPM shows 64200, with IGN still on till timeout.(of course I have to shut off the propane to keep from having a fire with no RPM)
wondering where it gets the 64200 RPM from when done with the cycle. Reads this out till I try it again then registers the start up 3500 RPM, then stops.

It should continue to cycle-right?- I forgot, as it always started well 1st time

went back into the ECU parameters(31 of them) to check and all is well.

I think it may be the fuel pump not starting or requiring more voltage to get it going that the ECU is providing for the initial Ramp UP, will investigate it in the morning

thanks for the suggestions

Jack

Just curious, what is your battery voltage at this point?

The RPM sensor saying it's doing 64Krpm+ when it's basically not even running is what intrigues me...

BJ

The ECU will not continue to cycle as far as it knows the turbine is turning at 64k. The ECU doesn't regulate battery voltage at all it cycles full battery voltage and amps at a high frequency to the plug the same way a power panel on your flight box does. Listen and you can hear the ECU squeal when in the ignition phase. The glow circuit is a very powerful magnetic source that is why a good ground at the plug is very important.

Battery voltage is good at 6.9-7.0

fuel pump is good, isolated it and it ran fine.

makes sense in that somehow when it senses 64200 rpm after the initial start attempt that's the reason it won't attempt it again until I reset it.

yes I can hear the glow circuit working in the ECU

So, I will concentrate on the glow plug, and move the wiring around during the start sequence.
holding off on getting into the speed sensor since there's not much to do there, and it looked good when I had the cover off

though, even when I initiate a start with the static RPM at 64200, it immediately drops to 0 to begin the spool up to 3500.

thanks for the suggestions

Mark, I may have to make a trip to see you soon.


Jack

How long after the gas pops does it stay running ? what rpm and what EGT does it go to before stops. What message comes up?

You say you "ran the fuel test with the circuit - no change", still not sure if you are saying that the prime function (pump) worked or not.

If the pump is working in the prime, and you are not sure if it is working during the startup, put a little dab of paint on the end of the shaft, this will let you see it turning.

The 64200 thing looks like an ECU or rpm pickup problem

Xairflyer and others,

When the gas pops, that's all it does as it then begins to wind down, so I have to shut off the propane to put the fire out. RPM never comes up further.
I have seen a 'low gas message' which I initially thought was insufficient propane, but switching cylinders had no effect.

fuel pump is good. prime function works. EGT sensing- good

looks like it could be a speed pickup problem now, having isolated other items.
-although I'm getting an accurate RPM readout initially on the spool up, as it spools up to 3500, then getting a 64200 signal somewhere shutting down the operation which is still baffling.

maybe I'll try to start it with a blower after the initial light off to keep the rpm going and see what changes and get it to the next phase of the start cycle.

Jack

Still sounds like EMF 'noise' upsetting your RPM sensor readings that the FADEC is seeing.

Have you changed anything in your set-up that could have put a source of electronic noise anywhere near your RPM sensor lead? Those things a pretty sensitive when it comes to picking up any sort of interference. e.g. you haven't put a new Servo near the RPM lead? An extra Rx antenna (if you're using 2.4), or moved your 36meg antenna wire near it?

In short, have you changed anything from the configuration you used last time you had a successful spool-up? Swapped-out a component, added something new, moved anything around??

BJ

That's exactly what mine did until I sorted the wiring out. In fact, my RPM 'spike' was so fast I could hardly see it on the Monitor.

I'd go through start-up - starter would engage, revs build, Propane would go 'pop'...then theeeeeeeeeewwwwwww... die in the bum...

Each time it would do that, it would be pumping a little more Kero into the tube if it got as far as the fuel-pump cutting in for a second or so. Occasionally, it would just manage to get past that and the Propane would actually light the flooded Kero and I would get great plumes of Orange flame out the back as it spooled back down from an aborted wet-start (whereas Propane on it's own gives you a clean blueish flame).

Does that sorta sound like what you're seeing?

BJ

I have discovered that the weak gas message also can mean too much gas so don't go by that.

Must be a glitch somewhere in the ECU, try the blower start and see what happens.

Try as soon as the gas lights unhook the glow plug lead andf see if it will start ok then.

joe

yes i did loose a bit of thrust, but didnt want a hot running motor,
never measured it, but in flight i can tell the difference, model weighs 12lbs dry, not overly fast.
just good fun to fly!!!!! had no probs with this engine at all,

cheers
snatch