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JetJoe OWNERS thread

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Old 11-12-2011, 09:01 AM
  #3326
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Default RE: JetJoe OWNERS thread

Martin,

Mine still have the orings but the issue has to do withOzjetboy'smotor that has this mysterious overload condition on cooling.I also have blown up a couple of bearings and have a bag of the loose balls.I've been told that the ball bearings themselves don't wear that the races do so if ever needed, I use some of the spare balls to repack a bearing when needed. I also find thatheatingthe tunnel helps to get the bearing out without blowing it up.Either that or do it over a bin or somethign to catch the bearings so you can put them back.

Andy

Quote:
ORIGINAL: frema

Oh you still have the o ring in the back?
oh i took it out inmediatly, but if you dont have any problems with it , dont do anything.
i had problems with getting out the shaft , the outer ring was stuck ,and there go's all you balls form the bearing.

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Old 11-12-2011, 01:59 PM
  #3327
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Default RE: JetJoe OWNERS thread

Yes - youre right - they are only 16.60euro
Ive ordered another 2 of these from him plus a few other bits and pieces.
They should be here in a week or so

Quote:
ORIGINAL: Xairflyer

Gasper has the EGT probes on his site they are only 16.60euro
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Old 11-13-2011, 02:49 AM
  #3328
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Default RE: JetJoe OWNERS thread

How can Itell if Ihave a bad bearing or if I have excessive preload??

Irecall when I assemble the engine that I left a little movement of the shaft (with preload) but I wasnt sure how much was too much or too little

Also - Ithink the rear O-ring was installed - what effect does this have if it is removed?

Quote:
ORIGINAL: croatiablu

A bad bearing is not going to get better once it starts to bind and/or whine but excessive preload or a gummed up oringwill definely cause bearings to become draggyfor sure.

Andy


Quote:
ORIGINAL: frema

maybe i have a solution for draggy bearings.
i had it with my homebuild 54 turboprop, and what i did was spreading only kerosine in to the feedline from oil .
Then spin it a few times with air , and then start it up.
the bearings ran much nicer after that.
what i noticed was , after a while the front bearing will be stuck a bitt in the o ring, and if you spread a bitt of feul into the feddline , the bearing came loose again , and the running was much better.
i dont do it every time , 2 or 3 times in a year.

Regards,

Martin.
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Old 11-13-2011, 03:01 AM
  #3329
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Default RE: JetJoe OWNERS thread

the back o ring is installed to prevent runnning the outer ring of the bearing in the shaft tunnel.
atleast thats what they say ,but i always take it out, i had never problems with it running without it

I think your preload is fine , i always test it , to push it on a scale ,and when the pressure is around the 4 kg when you feel the shaft move , then its oke .

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Old 11-13-2011, 03:25 AM
  #3330
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Default RE: JetJoe OWNERS thread

Ill check that next time I strip down the engine.

Ill also try your trick of injecting kero through the lubrication line to see if there is an improvement

Quote:
ORIGINAL: frema

the back o ring is installed to prevent runnning the outer ring of the bearing in the shaft tunnel.
atleast thats what they say ,but i always take it out, i had never problems with it running without it

I think your preload is fine , i always test it , to push it on a scale ,and when the pressure is around the 4 kg when you feel the shaft move , then its oke .

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Old 11-13-2011, 03:36 AM
  #3331
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Default RE: JetJoe OWNERS thread

ok, let me know how it went.

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Old 11-13-2011, 05:55 AM
  #3332
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Default RE: JetJoe OWNERS thread

Hi,

I saw a trick somewhere in this thread where someone removed the O-ring and took a steel punch and made 3 dimples at even points (120 degrees) around the outside of the rear outer bearing race which creates enough of a rise in the race material to make the outer race grab the tunnel. I'll look for the post and put it up. I have never tried this but it makes sense. The dimples are in placeof theO-ring.I wouldn't think your preloadchanged either but sometimes the O-ring does hangon thebearing which can cause the dragging issue. I just took apart a motor recently that had a real bad issue with the bearing hanging at the O-ring. I cleaned and polished the tunnel sleeve insert and made sure the insert was moving freely. I even went as far as torun some very fine grit wet sandpaper (~1000 grit) with oil alongthe O-ring and tunnel interior to make sure itwas smooth.I would have changed the O-ring but Ihave no clue whatsize it is. You really want free movement of the sleeve and for the insert to protrude about1 mm orso when you press it in. If you press it in and it stays there, you have an issue.The O-ring keeps the outer race from spinning with the inner race in the tunnel. Ihave heard a lot of people say they take out the O-ring and that they have not had issues but if you look at what happens when the bearing does start to spin from not having an O-ring,there can be some resultant damage to the tunnel.

General rule I have heard is that you are better to have preload too low than too high.

I would try lubing the thing before ripping things apart.

Martin... Question for you ... if you spin the turbine by hand, how long does it continue to spin for?

Quote:
ORIGINAL: OzJetBoy

How can Itell if Ihave a bad bearing or if I have excessive preload??

Irecall when I assemble the engine that I left a little movement of the shaft (with preload) but I wasnt sure how much was too much or too little

Also - Ithink the rear O-ring was installed - what effect does this have if it is removed?

Quote:
ORIGINAL: croatiablu

A bad bearing is not going to get better once it starts to bind and/or whine but excessive preload or a gummed up oringwill definely cause bearings to become draggyfor sure.

Andy


Quote:
ORIGINAL: frema

maybe i have a solution for draggy bearings.
i had it with my homebuild 54 turboprop, and what i did was spreading only kerosine in to the feedline from oil .
Then spin it a few times with air , and then start it up.
the bearings ran much nicer after that.
what i noticed was , after a while the front bearing will be stuck a bitt in the o ring, and if you spread a bitt of feul into the feddline , the bearing came loose again , and the running was much better.
i dont do it every time , 2 or 3 times in a year.

Regards,

Martin.
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Old 11-13-2011, 07:01 AM
  #3333
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Default RE: JetJoe OWNERS thread

Yes that was my idea for the punching.
i do it many years now, and it works great.
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Old 11-13-2011, 07:03 AM
  #3334
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Default RE: JetJoe OWNERS thread

Martin... Question for you ... if you spin the turbine by hand, how long does it continue to spin for?

I think 5 or 6 turns , not inmediatly stop , then there is something wrong.

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Old 11-13-2011, 07:07 AM
  #3335
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Default RE: JetJoe OWNERS thread

I knew I read it somewhere.... How do you grab the bearing to punch the outside of the race? I take it that the punh has to be below or above the area where the Oring groove is.

Andy


Quote:
ORIGINAL: frema

Martin... Question for you ... if you spin the turbine by hand, how long does it continue to spin for?

I think 5 or 6 turns , not inmediatly stop , then there is something wrong.

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Old 11-13-2011, 07:12 AM
  #3336
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Default RE: JetJoe OWNERS thread

are you shore it was at the bearing outer ring?
i always punch the seat where the bearing slides in .
In the shaft tunnel just below the oring groove.

maybe there are more people with tricks then
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Old 11-13-2011, 07:58 AM
  #3337
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Default RE: JetJoe OWNERS thread

So you punch the tunnel or the bearing race?


Quote:
ORIGINAL: frema

are you shore it was at the bearing outer ring?
i always punch the seat where the bearing slides in .
In the shaft tunnel just below the oring groove.

maybe there are more people with tricks then
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Old 11-13-2011, 09:24 AM
  #3338
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Default RE: JetJoe OWNERS thread

Punch the tunnel or you could end up knocking the race out of shape. (If the tunnel is machined properly you should'nt need to punch anything.)

Wren also now don't use the rear O ring, when I rebuilt my wren 54 the new tunnel came from wren with no rear O ring groove, The preload on my JetJoe used to stick a lot after stripping it numerous times and cleaning fitting new O rings I eventually removed it altogether and had no problems since, EGT's are also lower as the preload is working properly now.
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Old 11-13-2011, 09:32 AM
  #3339
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Quote:
ORIGINAL: croatiablu



General rule I have heard is that you are better to have preload too low than too high.

Funny to me it is reverse of that but could be wrong, the bearings are designed to operate with a certain amount of preload it is too little preload that makes the bearings fail.
Jetjoes all tend to have too little preload coming from the factory.
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Old 11-13-2011, 09:40 AM
  #3340
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Default RE: JetJoe OWNERS thread

I have some motors that run fine with the sleeve sticking out about 1 - 2mm and Ihave others that run fine with the sleeve flush with the end of the tunnel. I think this is the one thing about these motors (preload) that is not difinitive as opposed to the diameter of say an 1800 compressor which is obvisouly very specific. The quesiton is what might cause the bearings to drag. I had pointed out that preload could be an issue or the turbine bearing hanging onthe oring (if present). I have definitely seen the bearings drag when preload is to high and when the oring is stuck.



Quote:
ORIGINAL: Xairflyer


Quote:
ORIGINAL: croatiablu



General rule I have heard is that you are better to have preload too low than too high.

Funny to me it is reverse of that but could be wrong, the bearings are designed to operate with a certain amount of preload it is too little preload that makes the bearings fail.
Jetjoes all tend to have too little preload coming from the factory.
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Old 11-13-2011, 11:27 AM
  #3341
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Default RE: JetJoe OWNERS thread


Quote:
ORIGINAL: croatiablu

So you punch the tunnel or the bearing race?


Quote:
ORIGINAL: frema

are you shore it was at the bearing outer ring?
i always punch the seat where the bearing slides in .
In the shaft tunnel just below the oring groove.

maybe there are more people with tricks then
Yes i punch the tunnel.
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Old 11-13-2011, 11:28 AM
  #3342
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Default RE: JetJoe OWNERS thread


Quote:
ORIGINAL: Xairflyer

Punch the tunnel or you could end up knocking the race out of shape. (If the tunnel is machined properly you should'nt need to punch anything.)

Wren also now don't use the rear O ring, when I rebuilt my wren 54 the new tunnel came from wren with no rear O ring groove, The preload on my JetJoe used to stick a lot after stripping it numerous times and cleaning fitting new O rings I eventually removed it altogether and had no problems since, EGT's are also lower as the preload is working properly now.
Wren use stainless steel tunnels
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Old 11-13-2011, 02:10 PM
  #3343
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Default RE: JetJoe OWNERS thread

Hi guys,

I have just become a Jet Joe owner, and so I thought it appropriate to join this thread. I recently purchased a Junior here on RCU. Have not set it up or run it yet, but am very keen to do so. I will be engaging the assistance of Mr. Brett Smith (turbine Wizard of Oz?), our local Jet Joe service guy, to help me get it set up and running. I hope to go through this entire thread, eventually, but in the mean time can someone please let me know if the Juniors actually produce the claimed 4lb of thrust?

Regards,

James.
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Old 11-13-2011, 03:55 PM
  #3344
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Default RE: JetJoe OWNERS thread


Quote:
ORIGINAL: frema


Quote:
ORIGINAL: Xairflyer

Punch the tunnel or you could end up knocking the race out of shape. (If the tunnel is machined properly you should'nt need to punch anything.)

Wren also now don't use the rear O ring, when I rebuilt my wren 54 the new tunnel came from wren with no rear O ring groove, The preload on my JetJoe used to stick a lot after stripping it numerous times and cleaning fitting new O rings I eventually removed it altogether and had no problems since, EGT's are also lower as the preload is working properly now.
Wren use stainless steel tunnels
Yes they do now but I have bought both from them without O ring grooves
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Old 11-13-2011, 04:07 PM
  #3345
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Default RE: JetJoe OWNERS thread

Welcome to the club James

Nothing quite like the sound and exhillaration the first time you start your engine up.

Being in Glebe - I hope your neighbours dont mind a bit of noise (my wife hates is as she cant out yell the engine when its running to tell me to turn the "thing" off)

I built the engine from kit - which was really enjoyable, Used the information from this forum to help with tips and avoid pitfalls - and when Im stuck on something - the helpful members here have the answers!


Quote:
ORIGINAL: jymster

Hi guys,

I have just become a Jet Joe owner, and so I thought it appropriate to join this thread. I recently purchased a Junior here on RCU. Have not set it up or run it yet, but am very keen to do so. I will be engaging the assistance of Mr. Brett Smith (turbine Wizard of Oz?), our local Jet Joe service guy, to help me get it set up and running. I hope to go through this entire thread, eventually, but in the mean time can someone please let me know if the Juniors actually produce the claimed 4lb of thrust?

Regards,

James.
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Old 11-13-2011, 04:12 PM
  #3346
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Default RE: JetJoe OWNERS thread

Hi OzJetBoy, thanks for the friendly welcome. I actually live in Grays Point, in the Sutherland Shire. Not really any noise restrictions there. I work in Glebe. Which turbine did you build from a kit? The Junior, or a larger one?
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Old 11-13-2011, 04:18 PM
  #3347
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Default RE: JetJoe OWNERS thread

While Im waiting on a new Thermocouple from Gaspar Ithought it would be a good idea to revisit the Xicoy manual and the ECU settings to try and figure out more on what the cause and effect of adjusting the settings actually do.
The instructions in the manual are Ok - but there is still some mystery to the novice knowing what to change and under what condition to make the changes. Seems to be a lot of try this and try that - which is great - but I like to understand more about what each adjustment is meant to or actually does.

Has anyone know of or put together a more user/ technical manual (call it diagnostic and remedy)with a bit more depth into the setup of an ECU to the perfect running of an engine?

I think if something like this did exist - what a great benefit it would be to those starting off with turbines to quickly build the confidence in operating these type of engines.


Leighton
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Old 11-13-2011, 04:27 PM
  #3348
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Default RE: JetJoe OWNERS thread

I built the JJ-1400 from kit which is a larger one

A great excercise that Ithoroughly enjoyed! I decided early in the piece that investing in good electronics was the way to go, so I bought the Fadec, Solenoids etc from Xicoy and the Turbine from JetJoe.

To have the engine start first time what absolutley a blast - a day Ill never forget - grins from ear to ear.

Ive done a couple of runs - always having a problem with the cooldown cycle and they guys on here have been helping me to sort out. Ended up burning up a Thermocouple sensor so that ends the fun until a replacement arrives.

Glad to hear the youll be ok at Grays Point

Do you know if the JJR is comparible to the JetCat P20SE??

Quote:
ORIGINAL: jymster

Hi OzJetBoy, thanks for the friendly welcome. I actually live in Grays Point, in the Sutherland Shire. Not really any noise restrictions there. I work in Glebe. Which turbine did you build from a kit? The Junior, or a larger one?
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Old 11-13-2011, 04:55 PM
  #3349
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Default RE: JetJoe OWNERS thread

Leighton,

I did not realize thatyourmotor is so young. I thought you had some miles on this. I highly doubt there is anything wrong with either of your bearings with minimal time on them.I don't even know about gummed up O-rings as this tends to happen with more hours but who knows. Hearing that you have minimal time on this motor leads me to thinkthis cooldown issue might besomething more simple than preload or anything else we have been discussing. I did not have the issue with the JJ ECU then it started somewhere after I changed to the Xicoy ECU. You might want to ask Gaspar about this since it sounds like you just bought the ECU or I can run it by him as I purchased one from him recently and had the same issue.I would be curious to hear if there is a simple electronic fix to this.
Andy


Quote:
ORIGINAL: OzJetBoy

I built the JJ-1400 from kit which is a larger one

A great excercise that Ithoroughly enjoyed! I decided early in the piece that investing in good electronics was the way to go, so I bought the Fadec, Solenoids etc from Xicoy and the Turbine from JetJoe.

To have the engine start first time what absolutley a blast - a day Ill never forget - grins from ear to ear.

Ive done a couple of runs - always having a problem with the cooldown cycle and they guys on here have been helping me to sort out. Ended up burning up a Thermocouple sensor so that ends the fun until a replacement arrives.

Glad to hear the youll be ok at Grays Point

Do you know if the JJR is comparible to the JetCat P20SE??

Quote:
ORIGINAL: jymster

Hi OzJetBoy, thanks for the friendly welcome. I actually live in Grays Point, in the Sutherland Shire. Not really any noise restrictions there. I work in Glebe. Which turbine did you build from a kit? The Junior, or a larger one?
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Old 11-13-2011, 05:09 PM
  #3350
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Default RE: JetJoe OWNERS thread

Thanks Andy - Ibought the motor in August and built it up, first start was 23rd October.

Being first turbine motor and my first start I was expecting some problems - but to my amazement it just worked!

Sofar its only racked up 11minutes of run-time over 4 starts - so not much use yet

I did think of posting a question to Gaspar - but I wasnt too sure how well he would receive it knowing his electronics are coupled to a JetJoe motor - maybe its worth a try but Ill listen to your advise too.

Quote:
ORIGINAL: croatiablu

Leighton,

I did not realize thatyourmotor is so young. I thought you had some miles on this. I highly doubt there is anything wrong with either of your bearings with minimal time on them.I don't even know about gummed up O-rings as this tends to happen with more hours but who knows. Hearing that you have minimal time on this motor leads me to thinkthis cooldown issue might besomething more simple than preload or anything else we have been discussing. I did not have the issue with the JJ ECU then it started somewhere after I changed to the Xicoy ECU. You might want to ask Gaspar about this since it sounds like you just bought the ECU or I can run it by him as I purchased one from him recently and had the same issue.I would be curious to hear if there is a simple electronic fix to this.
Andy
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