RE: JetJoe OWNERS thread
 

That sounds like one credible possibility. If the sticks are too close to the CC wall, then they may lie too deep in the wall's boundary layer. That would cause insufficient heat transfer to the sticks (or at least the side near the wall), and thererfore incomplete fuel vaporization. If the fuel is not adequately vaporized, then it will not be able to burn efficiently in the primary combustion zone. It may not be happening at the lower RPMs because perhaps the boundary layer is much smaller then.

WOW! Sean has gone from "Is it supposed to do that?" to diagnosing a JetJoe in two short years! Who says that rotor blade head strike was'nt worth it???? [X(]

But seriously, Sean is one sharp dude (but the rotor blade was sharper!) [8D]

RE: JetJoe OWNERS thread
 

Well, I ran the JJ 1400 again today and tried following the FADEC manual where it talks about cycling the engine from idle to full power 2-3 times to allow the FADEC to "learn" the engine's responses. I was able to get through two cycles and was up to 140,000 on the third when the engine slowed and the fire moved from the CC to the tail pipe as before. Cooled the engine down and waited a while, started it again, and was very slowly increasing the throttle, got to 120,000 and again the RPM started to drop then flamed out the tail pipe.

So, it appears that it is not an issue with trying to accelerate too fast as I had previously thought since it was accelerating very slowly both times today.

Another question, did anyone else get an engine manual or any kind of instructions with their JJ? All I got was the instructions with the ECU. I was wondering if it was possible that the gas and fuel lines were swapped at the front of the engine. I've never removed mine, they are just as they came from the factory but I have no way of verifying they are right without a diagram or taking it apart. But I doubt it would run well at all if this were the case.

Also, someone mentioned in one of the JJ threads that future engines would come with a turbine wheel certificate, I didn't get anything like that either.

Mike

RE: JetJoe OWNERS thread
 

Hi YLF how old is your JJ1400? I had a small hicup with my JJ1200 which I've changed to 1400
The vaperiser tubes in the CC were to close to the outer wall and at hi rpm it tends to cool the
vaperiser tubes with the added mass flow ,but unless you are comfortable about oppening up
your engine I'd have your service agent look at it

RE: JetJoe OWNERS thread
 

Send the turbine back to China if you still have warranty

RE: JetJoe OWNERS thread
 

Engine is less than a week old, I guess this verifies that they do NOT test run them at the factory.

The strange part to me is that it will run up to 160,000 one time and then belch flames at 90,000 or 120,000 or 140,000 the next time, it's not consistent maybe something is moving a little due to heating and cooling?

Anyway, it sounds like a CC problem is the most likely cause of my trouble.

Mike

RE: JetJoe OWNERS thread
 

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RE: JetJoe OWNERS thread
 

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RE: JetJoe OWNERS thread
 

Russ,
Think I have a spare RPM sensor if you need one let me know...
Todd

RE: JetJoe OWNERS thread
 

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RE: JetJoe OWNERS thread
 

I had a similar problem with a FADEC rpm sensor and was able substitute one from G&B hobbies
it fits better under the cover as it is curved
Make sure all the swirl tubes are the same I/D and orientated in the same fashion
Tankie what type of preload dose yourJJ have?

Phillip

RE: JetJoe OWNERS thread
 

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RE: JetJoe OWNERS thread
 

Hi Tankie,

I just received my baby joe kit. I noticed that the sticks are bend in the opposite direction as the swirl tubes. In other words the sticks make contact with the wall of swirl tubes. Is this correct? Or should the sticks be free and only spray fuel agains swirl tubes?

Need to know before closing up.

Regards

RE: JetJoe OWNERS thread
 

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RE: JetJoe OWNERS thread
 

No Degaussing of these sensors, sounds like it is toast....

RE: JetJoe OWNERS thread
 

Hi all
I have a Wren MW54 MK2, Would anyone know if any of the JJ parts are interchangable with Wren MW54.
Jetjoes prices are very good very low compared to Wren.
Tim.

RE: JetJoe OWNERS thread
 

CC Setup

The setup is described pretty well and is clear. The transition from liquid vapor to fine fuel vapor to a full combustible gas suspension is the key for efficiency and burn. Only comment I have is that if the neddles are to be 10 mm from the inner wall ( not agreeing here) then All JJ chambers would need bigger swirl injector tubes to comply, unless for clarity you mean the needles enter and go down near the outside of the wall of the tubes and point over to the inner wall with an alignment to give an inherent and anti clockwise rotation of the vapour? Mine are usually pointed at the inner hot wall as described, there is no pre heating of the fuel except that provided by any heat gain.

Paul

RE: JetJoe OWNERS thread
 

To clarify what we are taking about and so we're all using the same terminology (and for my own clarification) I marked on Tankie's pictures what I understand to be the sticks and swirl tubes. The "needles" are the very small tubes from the fuel ring that go into the "sticks" and sometimes have a bend at the end so the fuel squirts against the inner wall of the stick.

Is this correct?

Mike

RE: JetJoe OWNERS thread
 

Skymac,

Any update on USA launch?

Dave

RE: JetJoe OWNERS thread
 

Timfly


As we are fairly close I'd lend any parts to compare as there must be fundamental similarities especially the compressor and turbine wheel.

Paul

RE: JetJoe OWNERS thread
 

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RE: JetJoe OWNERS thread
 

J Campbell,

Is it possible the board of the sensor has become grounded to the turbine through it's mounting screw/system.
Don't know if this would be a problem but worth checking.

Gary

RE: JetJoe OWNERS thread
 

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RE: JetJoe OWNERS thread
 

Hi all,

Just assembled my baby joe (5kg) kit. It runs perfect. Ramp, temperature, vibration all very good.

I have had now 75 flights on my JJ1400. I wanted to get this baby joe cause there seems to be a lot of bad press regarding this motor. And i must say i am amazed at the performance. Standard baby joe kit with preload and dual exhaust cone.


Will let you know how is the power compare to jj1400 when i fly over the weekend.

Regards

Exclusive distributor for Skymaster RC jet, Yellow Aircraft, Trim Aircraft and JETJOE in South Africa

RE: JetJoe OWNERS thread
 

Thanks for the clarification, I believe we might be agreeing just using bonnets for hoods, trunks for boots or ECU's and FADECs. Bending the needles and pointing at the hot inner wall allows better distribution of the liquid vapor and a better mix of fuel into the air. In the homebuilts KJ 66 and PT75 the needles/injector (they were hypodermic medical sometimes) were bent a few times round the manifolid before entering the sticks to allow pre heatinging of the liquid fuel. The JJ sticks were bent radially to support the anti clock wise flow and the swirl tube inserted to induce further mixing within the pre burning area of the CC. On my JJ1400 after advice from Andy the UK rep I've switched to his CC with needles bent as described. As this gives me better visible balanced burn with no hot spots and eliminated the early running problems I had on two JJ1400s.

PLEASE NOTE These notes apply only if you are not a home builder, otherwise just see your Rep or go to Joe. These notes are for JJ1400 without any warranty due to the mods, which strictly invalidate all factory waranties. Once you adapt you are strictly solo and need to be fully competent i.e a GTBA member or similar. Also these JJ turbines are not toys and can be dangerous in operation.

Paul

RE: JetJoe OWNERS thread
 

THIS IS FOR jj1400 OWNERS ONLY!!!!!!!!!!!!

i am thinking about getting 2 x 1400's and putting them both on a king kat

but i have had so many mixed opiniouns on jj motors that i dont know what to think.

what would you rate your jj1400 out of 10 ?

thanks.