TREADSTONE

Tom in Cincy, MattyC-130 et al

Wiser and more learned people than yourselves are genuinly trying to help you move forward.

They have taken time out to offer advise.

When you fail to comprehend what it is they are refairing to the thread starts to drift ...as in this dazzling offering.

Their are reasons for so many hits on this thread.. its been going for so long and people have a morbid facination with it.

It will no doubt continiue ad nauseam .

Gaspar

This thread will never end because it seems that each month there are new JJ supporters and reps (most anonymous), while those of the last month fade away.

Anyway, just for the info of those that don't have a clue of what is going on and keep feeding the "conspiration theory".

1) Currently I OWN 3 JJs. Used to have 5, one exploded and the other was sold recently to a homebuilder. Thus, this make me 100% qualified for to participate in this thread, and surely, I know much better what's inside in a JJ than all his reps together.

2) I spent lot of time (just for fun) tweaking one 1400. I managed to have it running pretty well, and had over 16lbs out of it. BUT I have modified all of the parts, and made several new ones. Countless hours spent. Had to machine myself the turbine wheel and EGV from blank, the original ones where way out of specs.

3) I'm tired of to receiving mails each week from people like monkeyking ask¡ng for help, who have purchased one of these things in good faith to someone who claimed here "excelent performance" and the result has been problems and more problems (you can find several of these guys over the 62 pages of this thread). There was one case recently that really I felt very sad for the guy, a guy very limited in economy who had saved money during over 2 years to acomplish his dream of a jet turbine only to find later that he have purchased isn't working at all. I helped him in some parts and advice to have the thing running a bit decently, but this story was what make me to jump here and expose these facts, after all the crap read here. At least now I sleep well at night, if someone reads this thread now he can see both sides of the story.

4) Chinese could be a threat to the current turbine manufacturers, like are for all other products. But all manufacturers that I know aren't worried at all with JJ now. Stop the conspiration theory, at least in my case, my contribution here is only to not receive more mails like the one that I commented above.

Regards,

Gaspar

rcdriver22

My Feedback: (1)

I purchased three JJ 1400s from Joe and the engine numbers are a matter of record in this thread. So I feel I can contribute my 2cents. I have also had home made turbines PT75s, JG100 and commercial behotecs and wrens so can fairly comment on the respective qualities I have found in operating them.

In regard to Monkeyking I know a little of the background of his turbines, so I am assuming from the two unoperatable JJs at least one working could be pulled together in a working format. That would at least gets his Stingray back flying in the air.

Paul

rorrock

There are a lot of people posting on this thread i would hardly consider to be bipartisan..
namely the many people with vested interest in maintaining the status quo, especially those who sell competitors to jetjoe .
Namely high cost items that they wish to retain their value.
I find it the lowest form of professionalism for that these people hijack a thread for owners of a turbine that they see as a threat
to bash it whenever possible..
If you wish to come on here and offer support to "owners" of Jet Joes, welcome and go for it.
If you wish to continue to bash people for owning them and in the process destroying your own reputation.. create you own thread and do so there.

Myself, I dont own a turbine yet.. and given the action of some of their reps, there are some I will never own.
Here in australia, the "name" brand turbine start close to au$3000 and go up from there..

Rob

TREADSTONE

Are you plannig to invest in one?...if so, given all the information available which one do you envisage it will be ?

Boomerang1

Rob, I have never seen the Oz Jetcat rep, Intairco, bagging Jet Joe or any other turbines. Judging by the number of Jetcats at jet fly ins he is too busy doing other things like selling engines. I may have seen one Jet Joe.

Model Engines in Oz seem to be having another attempt to sell Jet Joe engines. From their ad in RCMN.
JLT900 - 20 pounds quoted thrust - $2198

Intairco:
Jetcat P-80 - 18 pounds quoted thrust - $3400

That's the state of play in Oz at the moment if you buy from the distributors. Interpret that any way you want. Like I said, this thread is to help Jet Joe owners. What experience do you have to offer to help Jet Joe owners? - John.

rorrock

John,
I came on this thread to see what people who had actually owned one of these engines had to say about them.
What i found instead is nothing but people intent on bagging these engines. Now i can understand people being evangelical about their own choice..
However i find it greatly distrurbing for any rep to be on here bagging a competitor in the ways its been done.
Even more disturbing is that they are not sanctioned or asked to stop by the manufacturer they in turn represent.
Now I cant offer a lot to jet joe owners, i came on here to hear from them.
ANd it seems they are being drowned out..
Rob

rorrock

Treadstone,
At the moment im tossing up between the behemotec 66 kit that id have to importe from the states....
or a jetjoe which i can get from a local rep and has local service, hence my reason for being in this thread in the first place.
After some 60+ pages of having any actual owners being drowned out by the nay-sayers and bagger..
particularly people who sell competitor turbines it just plain annoyed the hell out of me and I had to speak up.

Rob

molo_30

Hi guys, interesting reading on this thread. I have recently taken on the job as one of JetJoe's reps here in Australia and am quite disturbed by what I'm reading. I understand that Joe has had some problems with his turbines in the past and I can assure you that he is working his butt off to get his engines to the level that we in the rc jet community expect.

What I don't understand is why these customers are not going back to their dealers with these problems. And if they are why aren't the dealers helping them to sort these problems out? I think if its the latter then maybe its a dealer with not so good morals.

I personally will help any of my customers out with any of their problems to get there engines running sweetly. I feel all other dealers should do the same.

As for Joe, he knows he's had problems in the past and this is proven by the fact that he will replace any parts that are known to be defective.

If any of the JetJoe owners out there need some advice, drop me a pm and I'll do everything in my power to help you out.

Happy Flying.

erazz

Hi Rob,

You should note that even the nay sayers have some important info in what they're saying. The ethical issues aside, the JJ engines are low quality to the point of actually being dangerous.

This is not being said to bash JJ. I couldn't care less about these engines. I DO care to give you a heads up into what you may be getting yourself into and what may happen to your money. You might get an engine that works and let you enjoy turbine powered flight (albeit with reduced performance). You might be buying an engine that would not run and/or give you a lot of grief.

I've been tinkering on and off with model jet engines for almost 4 years now. Building and modifying. I think I've got a pretty good idea of what works and what doesn't. Some of the "features" on the JJ turbines scare the hell out of me. I do believe that they are substantially more dangerous than the other engines I was able to inspect (Wren, Jetcat, ModelMechanics, AMT and Simjet).

Ultimately it's your decision. Just be aware of all the facts before you plunk down $2k.


Erez

rcdriver22

My Feedback: (1)

Rob

This just about takes the buscuit, as this thread is for JJ turbine owners. I might have guessed that someone with ZERO turbojet experience would question the editor of RC Jet International or one of the founding fathers like Gasper with thousands of hours of operational FADEC knowledge.

Rob has happily posted suggestions ranging from pipe work arrangemnets for afterburners to the basis of turbine manufacture and relative turbine sale costs. Implying by posting here on this thread that he was an owner.

He has posted on RCU " Next step for me is to earn my Bronze Wings here in Aus.. then start learning for my gold.."
and he may "move into jets one day".

WOW just the kind of non Jet Turbine flyer we need to "hijack a thread" and give his authorative and worldy opinions to. [:-][&o]

Paul

i3dm

My Feedback: (51)

erazz, me and my buddies (which you probably know) have 5 JJs running perfect - can you advise what are these so called "dangerous features" so we could be alerted as well ?

erazz

Certainly (though I think I already told you what I think of these engines).

Just a couple of things that pop up in my mind.
1) Sub standard balancing. The stresses on the turbine wheel are incredible (250,000G's!). The great imbalance cause high loads inside the wheel.
2) Improper balancing methods. Some wheels where "hacked" by a dremel or a mill in order to balance. This severely weakens the wheel in the areas where the stresses are greatest (ei. root).
3) Non x-ray certified wheels. Though you might think this is unimportant, a single crack or bubble (which can happen even if you cast Inconel properly) can cause the turbine wheel to explode. And there have been reports of these exploding.
4) Non concentric tunnels - lead to premature wear on the bearings and ant the tunnels themselves.
5) Poor fit of the c.c. - leads to premature wear of the c.c. and as is illustrated above can lead to hotspots and deformation of the NGV and turbine wheel.
6) Poor construction of the fuel lines - lead to uneven combustion, poor performance.
7) Poor material choice. These lead to premature wear and compromise structural integrity...


I can go on but you get the idea.


Now you may think that just because the engine you have seen all SEEM to work fine then JJ's are alright. They may very well be alright. I suggest you try to compare a well made c.c. (from a Jetcat maybe) to the JJ c.c. after a couple of hours. I'll bet you'll see the difference.

Trust me, it's easy to make a crappy turbine. Making a good one that is safe and reliable is hard.

WrenTurbines

I have watched this thread from the beginning, but have only posted on it once - posts 1005 and 1010 on P41. If you check this, you will notice that I was actually trying to help, giving impartial information about single vs double tailcone performance. I haven't seen any other jet manufacturer post on here at all. I haven't seen any Wren reps, and I don't think I've seen reps for any of our competitors, either. Gaspar has posted, but as an owner of JetJoes and supplier of the ECUs used by Joe for the last three years, I think his comments must be regarded as relevant.

What I have seen is Wren's, JetCat's, JetCentral's, Simjet's, AMT's Behotec's and PST's CUSTOMERS querying the wisdom of buying JetJoes. Some of these people were actually keen on the JetJoes originally but have changed their minds. I'm sure rcdriver (who isn't associated with any manufacturer) won't mind me pointing out that if you read the earlier part of the thread you will see him as an advocate of JetJoe, saying that he was flying with the engines and giving help to other people because, as a member of the GTBA, he has a good knowledge of turbine engines. He became disillusioned when after 2 years there were still big QC issues with the JetJoes, and is now trying to warn people of potential problems

Along with other turbine manufacturers, we have a reputation for honesty and integrity. I felt I couldn't see us, collectively, accused of being "nay-sayers and baggers" who were drowning out the comments of actual owners. The nay-sayers are jet fliers who are trying to help and they aren't looking to profit from selling other turbines, they are concerned that people don't get a bad deal. The jet guys are genuinely helpful - read the thread on Steve Scott if you don't believe me.

Sara Parish
Wren Turbines

rorrock

erzz,
I have read some of these, but never heard from a jetjoe owner about them finding their engines dangerous. I also value the input of these people.
I just question why this thread.. why not create one to list the faults in all turbines.. im sure there is some in every one of them.
I have been reading the various support forums to see what i could find.. This what this thread appeard to be when i orginally entered it only for jetjoe.
However it has not really proven to be that.

Paul, nice.. a personal attack now.. If you read my post in full, you would see i got on here purely for informational purposes.
To investigate my options as to what turbine would offer me best value for money. Something I have always done.
If you are the sort of person that flies jets, I think I would rather not be one at all.
I have never stated I have owned a jet joe... My earliest post was purely something i had come accross researching in university..
It is not something new or particularly fantastic, it was purely information for another modler..
Other than that, my primary posts have been about my inability to fathom the attitude of some people on here and question some motives.
And to put forward my views regarding their profesionalism, something I do know something about after 20+ years in IT making my way to COO of a software company.
As well as to question the odd post later on in this thread after I got sick of seeing nothing but senless bashing with no proof other than anecdotal evidence.

For your information, I have now completed bronze and am working on gold, as well as completing a 1/8th scale p-47 from a kit to maiden this year. I have been modelling on and off for 20 years. I love this hobby and i have meet some amazing people during my time. Most that I have met have been informative and helpful.
I have no problem with people if they wish to raise concerns about a turbine, however I believe it would be most profesional if it was done in its own thread and by those who had experience with the turbine and could back it with science or facts. (eg a metalurgic analysis) before stating something as otherwise it comes accross as fear mongering.. something I am very familiar with when dealing in the sales world.

So why not start 2 new threads, one for those true owners to provide help and information to each other.. and a second for anyone to list faults they have personal experienced with any turbine..

Rob


p.s. It will most likely be the Behotec 66 kit i get, just like you have recomended in another thread Paul

erazz

Sigh... (slightly exasperated)

If you spend the time and read this thread you will find what owners think of their engines. Gaspar wrote that he had one explode (post #1529). I remember seeing a post from an Oz flier who had one explode as well. If the NGV thing doesn't scare you than you really have no idea what's going on.

My guess is that most turbine users do not have a good idea of how their engine looks from the inside and therefore find it hard to understand the problem with JJ. Even when you spell out the problem in clear print you are still met with disbelief.

Please try to reread these posts with a different mindset. You'll find that although there's little love for JJ among experienced turbine builders and users most of the information is factual and informative.

Erez

i3dm

My Feedback: (51)

erazz,

im with rorrock, there's a difference between a turbine not running right or not producing power, and dangerous.

Was there ever any documented proof of a JJ engine being dangerous ? if so i'd like to see it.
Also, our engines all have ZERO vibration through out the RPM range - is that enough proof that theyre balanced right, or not ?

erazz

Hmmm... A Pitbul might look innocent until it decides to bite you..

Nothing I can say would probably convince you of the problem at hand. Your hand is not an accurate tool for measuring vibration. If you could feel the vibration then the engine would probably not start or reach max rpm.

Vibration and concentricity issues manifest themselves as bearing wear and shaft tunnel wear (and you KNOW what that looks like).

Just my $0.02

rcguy!

My Feedback: (69)

id3m,
Can you tell us all how many hours are on each one of there JJ1400 your buddies have? No guesses please, real numbers. AND the service history on each, in detail?

Has any gone 25 hours without needing service other than a glowplug or starter Oring?

How about if YOU start stating some hard facts for the rest of the JJ1400 owners to follow?

I've asked this same question several times and I 've only seen 1 reply with real numbers.

Dave

Tom in Cincy

My Feedback: (16)

Nice page of bashing guys. Couple of notes.
Gaspar supplied ECU's to JJ for 3 years and not a peep out of him.
JJ dumped him as a supplier and guess what.. Bash Bash Bash
All turbines have blown up. It was an AMA stipulation to over-rev them to destruction to get on their now defunct approval list.
Sara, your very sweet but RCU frowns upon competitors posting in each other threads.




The JetJoe OWNERS Thread.
1547 Posts, 102425 Hits and the 6th most popular thread on RCU's Jet Forum
We owe it all to you..

Tp
Happy JJ1400 owner sn# 04142.
C ya @ the field....

TREADSTONE

Tom,

With the greatest repect...When you find yourself in a hole its wise to stop digging.

molo_30

Tell you what, lets stop now, everyones had their say and put their point across. Can we now get back to the Name at the beginning of the thread?

Yes its dangerous and no its not. Of course they are going to blow up and they never will. They are dangerously balanced and safety comes first.

There, now I think I've covered it for everyone on both sides of the fence. Can we get back to whats important?

rorrock

Erez,
Thanks for pointing that post out, I had read it before and i re-read it again just to be clear about it.
I believe Gaspar when he says he had one explode, but there are no details on what caused it..
He mentions tinkering with one JJ-1400.. could this have made it explode.

I am sure that if someone trys hard enough they could make any turbine explode.

However, i would love it if Gaspar could provide more info on this.

Rob

Woketman

My Feedback: (6)

I seriously doubt that Gaspar's "tinkering" caused the JJ to explode. He has been in the turbine game, from the inside, for a VERY long time and is quite reputable. I am VERY inclined to believe that the JJ he had that blew did so due to inferior manufacturing techniques, inferior materials, inferior workmanship, inferior quality control, or a combination of all of the above. The JetJoe line is not exactly known for high standards of quality.

Don't get me wrong, I wish there were viable low cost turbines. I certainly do not want to pay more than I have to for a turbine.

rorrock

Wocketman,
I too doubt that Gaspar would do something, let alone by intent to make a turbine explode. But I'd love to hear from him the
details surrounding it, ie. how long ago, what was determined to have caused it, where was the turbine and what was it doing..

Rob