Xairflyer

My Feedback: (1)

I am curious to this method of balancing can you explain more

HKruisman

You need a quite room and an air compressor. Then you assemble the running parts (in the tunnel only or with cc, ngv and compressor ect). Leave the cone off if you use the assembled engine.

The trick is to spin the rotors by air and feel the vibration. If there is some you will noticed it. If you cannot feel any vibration or hear any, there is not enough to do any damage. You can amplify the vibration when you press the engine or tunnel against a table or a large item.

If you feel some vibration you need to find the right wheel. Most of the times the vibration is in the turbine wheel but you can check the weels sepperate to make sure you have the right wheel. When you have the right wheel you need to find the exact angle. You need to place a counter weight on the opposite of the unbalance. The easiest way is to stick some adhesive tape on the wheel just below the blades. Increase the tape until you notice a difference in vibration. Normally you have not the right spot and the vibration becomes stronger. Now move the tape along the wheel and you can find a point where the vibration is the least. Do this a couple of times and mark the spots. Start clockwise and counter clockwise. The avarage of the spots should be the opposite of the unbalance point. Increase or decrease the tape unitl the vibration is gone or is the hardly noticable. Then try about 20-30 degrees left and right and the vibration should be stronger. Ifso, you now have the erfect opposite point.

On the opposite of the tape ou mark the wheel and use a small grinder (dremel) to take away some material. Just a little at a time and check the unbalans every time. Cover the holes as much as possible during grinding to protect the bearings. After balancing you need to wash the bearings and clean everything because the grinded metal destroys bearings very quickly.

If you cannot find the exact spot then don't grind the wheel. Only when you can reduce the vibration to almost nothing with tape you have the right spot.

I hop this helps. It has worked great for me and does not require any special tools, just some time and a good ear

Btw, i tested a jj1200 today.............. it would not run. Only flames out the back. NGV is way to open and the CC is very bad. The bearings had locked in the tunnel and the compressor has a very low efficiency.....

brunols

At the begnning of this month I recently bought a new 1400 turbine serial on turbine 4420, I installed it on a airplane and tried to turn it on. When I go through the procedure to start it, the turbine starts the glow (verifeid), then the turbine starts to spin for about 2 seconds and up to 3500 rpm and then stops and nothing happens.
I get reading afterwards of 50,000 to 64,000 rpm on the terminal data , the thermocouple seems to work fine, maybe the fadec is faulty. The propane/butane solenoid seems to be working fine at the start of the secuence. I dont know about the kero solenoid cause i have gone that far with the start secuence
Please let me know what to do.

fw190pilot

This is a common problem and most of the time easy to fix. Seperate the glow plug and starter wires as far as possible from the rpm sensor and thermocouple wires. Also is helps to twist the glow plug wires around each other.

HKruisman

Check the gas supply and make sure you hear gas in the engine. Check ghe glowplug, the wire should be pulledout of the plug. Sepperate wires as much as possible.

One other problem: The compressor nut. The sensor magnet is not always positioned correctly. In the 1400 series it should be OK but if it is wrong then accurate readings are always a problem.

Xairflyer

My Feedback: (1)

Errating readings are nearlly always due to rpm wires too close to plug wires, do as Fw190pilot said and seperate them and twist glow wires together.

Once you have done this try to get the turbine fired up first with just the gas, before you introduce fuel, other secret is very little gas needed for start.

HKruisman

Use a restrictor in the gas tubing or use a valve. Less is more

In the 1200 series the magnet was positioned wrong in the spinner nut. You cannot get the engine working correctly with a starter motor as it would influence the rpm reading way to much. Change the magnet and all problems are over. This sould not be needed with the 1400 but if all other tips don't help, check the magnet in the spinner.

gio

My Feedback: (26)

Did you get the 1200 to run?

HKruisman

No, not yet. The NGV clearance is way to much and the compressor has not enough power to get enough pressure in the cc. It won't runt on it's own even at 35.000 rpm. There were still flames outside the engine so i think the vaporizing capacity of the sticks is also very low.

Xairflyer

My Feedback: (1)

If you have a problem with the compressor pressure then it must be due to the front cover clearance as there wont be anything wrong with the compressor itself.

Is the combustion chamber not the exact same as the JJ1400 ? I though the only differences were the compessor and front cover.

gab_arm75

My Feedback: (1)

who can tell me why jj1400 have white smoke and kerosine from glow plug on idle rpms? and very long start time? pump start point is +1, ramp+2. if i increase it, i have flame out..

HKruisman

Smoke from the glowplug means it leaks there. Try a washer to seal it.

The 1200 has a different cc than the 1400. It has curved stainless steel sticks where the 1400 has straight inconel sticks. Also the hole pattern is different.

It really feels it wants to run if the flame kan be kept inside the cc.

NUNU

gab arm..sounds like a possible fuel leak at the fuel ring....with the engine running stand a safe distance behind it..you should see a nice ring of fire in a healthy rngine..I am guessing yours may look like the letter C ..if so its confirmation of a leak also note if you see raw fuel seeping around the exhaust cone wile its running...respond back and let us know[8D]

Xairflyer

My Feedback: (1)

Try increasing the pump start ramp rather than the point, there are also values in the back screens that effect this as well.
What ecu are you using ? I posted my 1400 settings for the Gasper AU-540 ecu here
http://www.rcuniverse.com/forum/fb.asp?m=9044468
I used my settings on another 1400 and it got the turbine working fine, only needed a few tweaks then to fine tune, so it is a good starting point.

Write all your settings down first and only adjust small amounts at a time

fw190pilot

There is only 5 main differences in the 1200 and 1400. Compressor, inlet cover, cowl, tail cone and the 1200 use 3mm lines under the cowl. JetJoe supplies the 1200 with the 45mm tail cone and the 1400 with a 42mm tail cone. The 42mm tail cone can be used on the 1200 . It will produce more thrust but temps will run higher in the 710c range at max rpm. Also fuel consumption will increase a little as well around 1 ounce per minute at max rpm.

HKruisman

This one has a different cc also. Maybe they where the same in the earlier 1400 series but the newer 1400 have a straight stick cc. This 1200 has a bent stick cc.

fw190pilot

That would be a very old chamber. All of the 1200 1400 now have the exact same straight stick chamber.

HKruisman

OK, that is possible. This 1200 will be nothing more then a paper weight i think Maybe i can keep it and use it for spare parts

BJ64

I had similar problems with start-ups on my JJ3000.

First and foremost, like others have suggested, is to make absolutely sure that your RPM sensor wire does not pick up any electrical interference from anything else. Carefully twitch the wires together all the way back to the FADEC. In fact, I twitched ALL my high-current (thick) wires together. Next thing I did is I mounted all my gear along a line on the opposite side of the Turbine to where the RPM sensor goes into the Turbine (looking at it with the compressor end facing me, Turbine end facing away). The RPM sensor wires and EGT (exhaust thermocouple) are on the right hand side - so I mounted everything else on the left hand side.

Most Turbine FADECS use two basic things to tell it what the engine is doing - RPM, and EGT (exhaust gas temperature). If either of these signals it not reliable, the FADEC will go nuts. A common problem with JJ Turbines is the RPM sensor picking up stray electrical signals, or 'spikes' - you'll usually see these on your 'Monitor' during start-up, as the RPM will seem to be jumping all around the place, even if the engine 'sounds' like it's more or less holding the same RPM. Twisting the RPM sensor wires together so they look a bit like a rope helps them to stop working like an 'antenna' and picking up stray pulses.

The JJ solenoids can also leave a bit to be desired - my Propane solenoid wouldn't shut off. In the end, I bypassed both solenoids so that I run Propane straight from the can, and Kero straight from the bottle. The Propane is easy enough to control with the supplied valve that fits on the can. I don't open mine until my Monitor says 'Glow Test'. You don’t really want the Turbine filling up with gas before the glow-plug starts up – blue flames everywhere if you do that. And you don't need to open the manual gas valve up all the way either - it's a bit like a gas cigarette lighter - turn it up too high, and the lighter won't light - but you can still hear the gas.

I also have a beefy 20-amp ‘kill switch’ between the battery and the FADEC. That way, if anything does go wrong, I can turn off the Propane using the gas valve, and kill the electric power to the unit – no pump = no fuel. And it all just stops.

Oh, and do have a good fire extinguisher handy – just in case. CO2 is best, if you can get one.

I don't know what fuel-pump you got with your JJ, but mine has 'JetJoe' written on it (a newer variety?). A tip I got was to make a closed loop, and let the fuel pump run a couple of times for 5 to 10 mins at a time. By 'closed loop', I mean grab a source of Kero - feed it into the inlet of the pump (there should be arrows telling you which pipe is 'in' and which one is 'out'), and feed the hose from the outlet back into the fuel source (can, bottle - whatever you're using). That should 'bed' the fuel pump in nicely. By using a ‘closed loop’, the fuel pump will pump fuel just as it would if you were firing the Turbine. But don’t ever run the fuel-pump ‘dry’ (without fuel going through it) – quick way to burn it out.

My Turbine 'weeped' a bit around the glow-plug recess. Particularly on start-up, but seemed to go away once the Turbine was running. I carefully pulled the plug out, checked that it had a base washer, then put it back in again and re-tightened it. I ain't perfect yet, but a hell of a lot better.

If you've got white smoke or fuel pissing out everywhere during start-up, I'd suggest that there's something really wrong. Either a leak somewhere, or it's ramping onto Kero way too soon. The reason you use Propane during start-up is to get the internals of the Turbine nice and hot - Kero needs to vaporize before it will ignite properly. Shunting Kero into the engine too early can cause the Kero to try to ignite before the combustion chamber is hot enough to do the job properly (vaporize, then burn). Could be blocked injector 'sticks' too, but I'd reckon it wouldn't smoke at all if Kero wasn't getting through. I would think it would more likely want to sit there burning Propane forever while it waited for the RPM and temp to increase, eventually telling the FADEC that it was running properly on Kero. Sounds like it’s not getting that far (??).

Hope you get it started.

Post your results, huh?

BJ64

PS - silly question I suppose, but you did remember to 'prime' the Kero system - yeh?

You have to make sure that the fuel line has solid fuel in it from the the pick-up from your fuel source through to the solenoid (if you're using one), fuel pump, and then all the way to where you see the fuel-line go into the Turbine - no air bubbles.

If you've got great gobs or air anywhere in the line the Turbine will spit and fart and carry on like a pork-chop...

HKruisman

Thanks for the reply! The 1200 has an old cc and it won't vaporize enough. It had an egt of 200 on gas so is should be hot enough. A 1400 starts at 100egt with the right cc. During startup it reached 600egt on kero. The cc is just plain wrong and useless. Maybe i will modify it but not right now, i have another engine that needs work and that one does run

BJ64

Hmm... you sure your EGT is reading correctly?

I can't help thinking that white Kero smoke indicates that the fuel is being vaporized to some extent, but not quite hot enough to ignite.

Are the Propane 'sticks' still ok?

It sounds to me like the fuel is either being introduced too early, or the Propane flame isn't where it should be...

BJ

HKruisman

You are mixing up posts Mine does not produce smoke.....

BJ64

LoL.. I should read closer then, huh?

leopaul

I would like to know from were you get good service? I purchased a new Jetjoe 1400 new freshly out of Mark shop. After my first start, this engine vibrate a lot around 92krpm and shake my nano very badly.....I want to re-send to engine to re-do the balancing, i'm trying to reach the Jetjoe service for more than a week now and i receive no answer back to my email...

Who is the best person to contact top have good support?

thanks,
Alex