i3dm

My Feedback: (51)

Guys,

I have some bad news. on flight #1 today with my JJ1400 (about 3-4 hours run time so far) i had an engine cut, and landed safely...

After landing i noticed th engine wasnt cooling so i used compressed air at the inlet (front) and outlet (back) of the engine to slowly cool it down.

After cooling down to about 40C degrees i tried to see if the engine would spin, and noticed that it does spin, but not freely. there is definitely friction in the system, and not very little of it too ! BUT, this seems to be like a bearing problem, since you could feel the impellers are not scraping against the side walls of the engines, and all the blades look intact, the feeling is like a notchy bearing !

Anyway, what i would like to know is:

1. where can i get new bearings ?
2. where can i get instructions on how to take the engine apart and replace the bearings without damaging anything ?

I know i could send the engine to service in China, but it seems to me like an expensive and mainly time consuming procure.

Please advise what shall i do ?

dw_crash

My Feedback: (6)

I3DM,

Try Gabe at JetJoeUS.com. He is really helpful and has parts. His shop is in New Mexico.

DW_Crash

hendrix

My Feedback: (2)

Hi.
You should contact your USA distributor first and ask for help especially since your engine is in warranty.
Other options are to send it here for service:
http://www.ukpraezitec.de/index-e.html
Have a look at the impressions page where a couple JJ1400 show up after being serviced.
You could also try your US based service center RTI (Carlos something i dont remember)
Try to push the turbine wheel from the exaust side forward, several times.
Maybe the preload system jammed like it used to in my JJ1400.
What was the reason of engine cut off (it is displayed on the lcd screen if you press the left most button)
My guess is over temperature due to friction.
You can get new bearings from JetJoe or from Boca bearings.
http://www.bocabearings.com/main1.as...&pg=10&mfr=311
Look for the MW54 bearings.
JetJoe has them cheaper but i dont know if they are genuine CRW.
kEEP IN MIND THAT PROBABLY THE ROTOR WILL REQUIRE REBALANCING.
Did you felt any vibrations prior to the flight?
Also have a look at the lubrication line inside the engine.
The main reason of bearing failure is vibrations (it will be evident from the damage done to the shaft tunnel)
or bad lubrication.

Good luck.
Chris

i3dm

My Feedback: (51)

lubrication line seems fine, and i didnt notice any special vibration.

Temps at the shut down was less than 600C.

Pushing the turbine wheel forward didnt change anything, but i could feel it spins more free while im pushing forward.

Im in Israel so im not sure if i should go with US or China. i know Gabe is a great guy !!

i3dm

My Feedback: (51)

Guys,

Can anyone post instructions on how to take the engine apart and back together again ?

Also, which size bearing is needed ?

http://www.grw.de/english/frame.htm

hendrix

My Feedback: (2)

I just noticed that you are in Israel.
If i was you i would either try Gabe (JetJoeUS) or turbine sevice (that link i posted earlier.
In any case i wouldn't send it back to JetJoe.
Anyway it looks like the preload is jammed but i can't be sure.
You should be able to move the rotor a few millimeters forward and it should spring back on it's own.
Chris

i3dm

My Feedback: (51)

Can you advise how i should do this ?

i3dm

My Feedback: (51)

Guys,

Since sending it across the world back and forth is an option i would like to avoid (if i can), with the help of a few of my turbine knowledeable buddies, we decided to give this a shot. we decided that if this engine is sold as a kit, we can do it too.

This is where im so far with the tear apart, havent taken out any of the really interesting parts though. Anyone care to give some instructions from this point on ?

F106A

My Feedback: (2)

"I finally flew the JJ1400 today in the Jetmach, and it performed perfect ! one thing that did happen was that the small inner cone of the 2 piece tail cone flew off on the test flight."

HUH? How does an engine perform perfectly with parts coming off it?
Unbelivable!
I'm surprised that AMA covers JJ's under their insurance. Years ago, they would ask for engineering and performace info, then decide if it was airworthy, and I'm sure they would not have it included in their list of covered engines.
Oh well, keep tinkering, you guys seem to be having fun trying to get, and keep, these things running.
Me, I want to fly!

i3dm

My Feedback: (51)

F106A, that cone is held by 3 bolts with nuts thats all.. dont be so mad.. Hehehe

In all honesty - i love this hobby, both the flying, and the technical stuff too ! i enjoy this.

Flying freak

I have a question for you guys (im entrested in jets but dont ahve the $$$) is it an ECU problem with the jet joe, ie if you were to replace it with a jetcat ecu would it run better and get rid of most/all of the problems?

just wondering

Steven

i3dm

My Feedback: (51)

GUys,

The threads on the font nut (compressor) and on the back nut (turbine) - are these regular threads or reversed ?

ALso, how can i check the preload ? when i push the turbine whee forward NOTHING moves, maybe thats my problem ??

hendrix

My Feedback: (2)

Hi.
You should be able to move the whole rotor assembly a little (turbine, shaft and compressor wheel)
by simpling pressing hard the turbine wheel nut forward (towards the compressor wheel).
The preload is ~3 to 5 kg (just a guess) so you need to press that hard in order to move the rotor.
It could be jammed though for some reason.
I could be wrong but i could push mine a few millimeters, Someone else please step in in order to confirm or
correct me as i am not the best turbine technician in the world....
Chris

i3dm

My Feedback: (51)

Well, i pressed as hard as i could (and i got pretty good arms) and NOTHING moved - maybe thats why my engine seized up and is not turning freely ?

Please advise how do i take the front nut off to chekc the bearings ? what kind of threads does it have, and what do i hold in order for the shaft not to spin (to unthread the nut) ?

hendrix

My Feedback: (2)

HI.
I have never took one apart so i am not the right person to help you.
I guess that you should try and get the compressor wheel nut off first.
I think it has the preload force on it so when you unscrew the compressor nut be carefull because it will fly off.
I am sure that if you have patience (yes i know that this is hard right now) other more knowledgeable men will step in and help.
Chris

i3dm

My Feedback: (51)

Well guys, patience is a virtue, but so is basic engine technical skills.. Hehehe Honesty.. disassembly was easy enough.

Anyway, i got the turbine apart very safely (marked all the parts positions before i did) and i found the culprit !! the front bearing is messed up so bad that all the balls were loose in its cage and with the slightest touch of my hand completely crumbled and fell out. it also made a nice notch on the shaft, and threw shavings all inside the engine.

Watch the pictures and behold in amazement. im sending JJ these pics as well for them to asses the damage and advise of a fix.

i3dm

My Feedback: (51)

Here is JJ China's reply:
---
Pls send back to us to check and fix.
The Bearings is not under warranty, but if any other parts damaged we will replace a new one.
We will replace you a new CC for free.
---

The CC replacement is because the glow plug sleeve disconnected before (you can read in an earlier thread).

Overall sounds like a very fair offer - what do you guys think ?

PS - is there a way to tell if these bearings are genuine GRW bearings?

rcguy!

My Feedback: (69)

What do I think?
4 hours on my JetCat TitanSE and nothing has fallen off or destroyed itself.

Dave "going flying this weekend" Rigotti

fw190pilot

Sounds fair to me. Getting it repaired will cost about $100.00 bucks plus some shipping not too bad. Did your engine vibrate? If it did that could be why the bearing failed.

hendrix

My Feedback: (2)

Send it back (that's the sensible thing to do) but make sure he finds what caused the front bearing to fail in only 4 hours of operation.
If it is not lubrication then some serious rebalancing is in order.
The problem with my JJ was that many components were not correct not just one.
Good luck.
Chris

Shadow9926

The rear bearing of the JJ-1400 is GRW, but the front bearing is a different brand (information from Joe). I have a JJ-1400 that has just done the same thing, although I have not taken it apart yet to see what the problem is.

i3dm

My Feedback: (51)

Shadow9926 , are you planning on taking it apart and snapping some pics ?

dw_crash

My Feedback: (6)

I3DM,

I agree with Hendrix. It is best to send it back and have JetJoe 'service' the engine. I had teething problems with my JJ1400. So, I contacted JetJoe and they advised to send it in. I did, and it runs like a top now. They had some teethig problems that they worked out. When they sevice the engine, they corrected as many as possible. Hence, I ended up with an engine with all the latest improvements. It was well work the cost of postage.

DW_Crash

MNModels

I do not like the looks of your shaft. Something very wrong. I suggest send all back to JJ for service.

Regards

Morne

i3dm

My Feedback: (51)

Yes i am sending it all back to Gabe for service, Gabe has already seen the pictures and advised that a new motor is in order in this case, since all internal parts are damaged to some degree from the bearing letting go at 160K RPM.

Now how is this for service ? i give Gabe a huge two thumbs up yet again - this guy is unbelieveable !! [8D]