RE: JetJoe OWNERS thread
 

GRW 688 bearing can operate up to 300 degrees as well as other GRW bearing without retainer. Higher thrust means higher EGT which deteriorate bearing. The inner race of rear bearing in my engine has gotten a blue color on the rear side due to heat impact. I don't know how long it can work for.

RE: JetJoe OWNERS thread
 

I will try a print of a run with single cone. Gaspar au-354 usb cable.

RE: JetJoe OWNERS thread
 

What thrust do you have with this cone and what temp at 160,000 RPM?...

RE: JetJoe OWNERS thread
 

What thrust do you expect with large diameter cone at 160,000 RPM?..

RE: JetJoe OWNERS thread
 

I did 2 run today on a stock engine .first on with a flightworks 200 pump and again with a jetjoe pump.It got to 720 with a 44mm dia tail cone. stock clearance motor . can not say for sure on thrust as it was on test stand and I check thrust in air frame tied to strain gage. I was surprized that jj pump ran just as good. It is 0c out and it pulls hard at this temp.

RE: JetJoe OWNERS thread
 

myring

Forget tail cone design and size (or twin or single) for the moment, you are even able to run it without a tailcone at all. Yes tailcone
will effect temps but they are much more related to getting more thrust from the turbine exhaust gases.

Blue as found is a good indication of very hot running. The likely fault is an uneven burn from an uneven or blocked manifold. If the manifold when tested on gas set up (see pic http://www.rcuniverse.com/forum/m_29..._3/key_/tm.htm )
Note the needles are clear but the flames are not even height and need to be corrected.
The fuel needs to be directed towards the hot face of the sticks to vapourize quickly and evenly.

As Shadow9926 stated
" Idle is often when the EGT is highest, but your temps are too high. If you can notice any hot spots on the tail cone at idle , then I would suggest that you may have an uneven burn problem, either to do with the combustion chamber or a blocked fule manifold (more likely).

I have seen blocked fuel manifolds cause engines push the flame out of the exhaust and the needles on the JJ-1200 are only 24g so any small amount of dirt or flux from the soldering process could be blocking one or more needles"

THere are other reasons for the tailcone to glow bright red but not on the latest JJs.

How old is yours??

Then if all is fixed and corrected you can use my earlier post on the FADEC set up and training which directly helps temps to achieve cooler running (only with a very good turbine pump, buy the best and filter fuel regularly.)

Paul

RE: JetJoe OWNERS thread
 

myring

The FADEC advice is still good for the Regal semi auto FADEC,

Pump start point, The values of “pump start point” from 0-8 in a auto mode, will adjust itself pump power to start it slowly. Settings
are either Auto or manual a value of 0-255. On manual the higher the number the poorer the pump or its running condition. So if fuel is slow getting to the engine go to a higher Auto say +4 to test it. I use manual to tell me changes in pump condition each year as a check.

Start Ramp the increase of fuel flow during the start phase. To greater value, more quickly the motor will accelerate until the idle (also note the hotter things get at the exhaust)

Test if your TX is correctly aligned, min throttle is may be 36k and max 160k.

Stability delay, the parameter allows to stabilize the power once this has arrived at the value set with the throttle control. The value must be increased if the power is not stable. normal set say 50 but you can use 100 if things are unstable with rpms up and down.

Change too many parameters and it defeats itself and so then return back to factory settings.

Paul

RE: JetJoe OWNERS thread
 

I tried turning gas off early 10,000 and it stayed running but was not burning completely in engine . flames out back and high power pump .did not want to reach idle. Stuck at about 20,000. I opened gas for 1 sec and flames stopped and it went right to idle . Perhaps he is turn gas off so early not all tubes are lighting in motor so it burns in tail cone?

RE: JetJoe OWNERS thread
 

Its a good point, this a maual start ECU, so obviously after many many starts myself, I also look to hear for a small POP on the gas as it lights up to 10 to 15k and even then sometimes the spinner can simply blow the gas flame out.
The temptation is to go for a big WHOOSH start on the gas, so it is running on propane, when the jet A1 fuel arrives the temp goes up high really FAST. So the advice is a small small amount of gas (a click open at a time till you know the setting by sight) that can stay lit to 20k+ and then also a really small small trickle of fuel, it is extremely small flow. At 25k the gas should be going off as temps rise and engine spools fast to idle. Good job done, if all else is OK.

Paul

RE: JetJoe OWNERS thread
 

Hi to all!
I am having the same problem... temp too high...
I had to replace the NGV because of the high temps.... it destroyed two of them.
I think that the problem is in the CC... I believe that the fuel is not being vaporized ok.
My manifold doesn´t have any tube blocked, but the flames are not even height as the ones in this link http://www.rcuniverse.com/forum/m_29..._3/key_/tm.htm

So... my question, how can I clean the manifold? There is a little difference between each flame...
On the ther hand, how I have to assembly the manifold? What position?
I attached a photo as I am doing...

Thanks!
Mauro.-

RE: JetJoe OWNERS thread
 

hi all who is the uk dealer for the jetjoe turbines regards jonathan

RE: JetJoe OWNERS thread
 

Used to be NW Turbines but Dave is now doing the funsonic range.

A while back I got a starter housing from
http://www.jetturbineworld.com/
the website dos'nt seem to be working, the email and phone was: [email protected]
Tel/Fax: +44 (0)207 806 8253

RE: JetJoe OWNERS thread
 

The Guy is Alan Blackmun of ABCmicroturbines.com who made 6 stick CCs in the UK that we used to replace originals when the early CC's were disintergrating after a relatively few runs. but his web site has been down for some months. I remember he wasn't so well but he is a member of the GTBA so I will drop him a line. If interested drop me a PM as I have a used spare and fuel manifold on the shelf.

Paul

RE: JetJoe OWNERS thread
 

Mauro
It distroyed two NGVs? WOW! that is really HOT. Can I ask did you replace the rear bearing and O ring each time as at these high temps they are most likely effected and this will affect smooth running at high 75k+ rpms which will add to your running problems. What I am discribing is at these high temps, probably at 800 degree c, even if still lubricated you can easily get flats, which will degrade bearing performance.

The needles point to the inner face of the tube i.e the hot side and don't touch but spray onto the wall, its a matter of adjustment then fixing in place.

Paul

RE: JetJoe OWNERS thread
 

Jonathan

As far as I know it has gone full circle back to being the original rep Andy Owen e-mail: [email protected].
From the early posts here Andy was key to getting these turbines operational and tuned up. I would bet $20 that he has had a hand in R+D on the larger turbines now on sale.

Paul

RE: JetJoe OWNERS thread
 

Thanks Paul！
I did a test run again yesterday. This is a little cooler start not exceeding 750 degrees by reducing start point setting to AUTO+0. But the engine need raise the fuel level higher than engine to reach idle. This makes me believe that JJ pump is so poor. Do you think that intermittent flame and pop noise occur is due to blocked fuel manifold at idle speed?

Another problem I have is engine only can reach max 110k rmp. Is it due to poor JJ pump again?

RE: JetJoe OWNERS thread
 

Hi idleup1,
Does the JJ1800 really have a turbine wheel of 68mm diameter? Why did others say that its diameter is same as KJ66's turbine with 66mm diameter?
Thanks.

RE: JetJoe OWNERS thread
 

myring

I am pleased that some things are improving for you. Three things I think confirm your thoughts and point to the pump, fuel needs to be above the pump (not usually necessary at all), flame and popping noise point to irregular flow +/or cavitation (i.e air in the line). then lack of max rpm. The last needs checking in three ways, is pulse on second screen showing max pulse width when stick is at max, is battery voltage reading above 6.5v at max rpm (might be a failing cell) and this lastly also checks the ECU is calling for more rpm, therefore higher voltage, therefore more pump rpms to deliver more fuel leading to max rpms on turbine.

Time to try a really good pump I think.

Paul

RE: JetJoe OWNERS thread
 

Max pulse width is checked more than 2000 when stick at full up position. Also pump battery voltage is confirmed 7.5v at max rpm.
If I did not raise fuel level higher than pump, engine will not reach at idle and has a hot start because of poor pump.

Is it necessary to check fuel manifold for blockage so far? I don't want to disassembly the engine due to some trouble such as rear bearing reassembly everytime.

RE: JetJoe OWNERS thread
 

Myring

You basically have to decide to purchase a new dedicated miniture turbine pump either like a Flightworks or Hausel (who manufacture for about six major turbine companies). While waiting before any internal checks, you may inspect the internal burn and running. Near dusk or in overcaste conditions run up the turbine as far the pump may permit.
Taking a mirror (never directly) and from all angles inspect the rear exhaust. You want a nice blue burn (like a cooker or camping stove flame) inside the turbine. Look for any uneveness or yellow-red areas. I'll try for some pics to show what is required and when there are problems. Others here might post their pics.

Paul

RE: JetJoe OWNERS thread
 

I also recommend testing your turbine with a Flightworks pump before touching your turbine... If you still get this problem it may also be a good idea to check your tubing from the tank to pump inlet. These pumps are usually poor in suction however very powerfull in pumping... I had to change all my plumbing to 6mm Tygon before getting good results ....

RE: JetJoe OWNERS thread
 

Can you suggest me where I can bu this compressor with 14 blades.I would like to try this on my JJ1400... Thanks

RE: JetJoe OWNERS thread
 

I gave the reference on an earlier post for the 14 blade comp, then you need to do a google search to locate one. There is still then a little work to reprofile so it may be better just to order one from JJ for you to try if you don't have the tools.

Paul

RE: JetJoe OWNERS thread
 

Hi to all

anybody can tell me can i have kerostart on JJ turbine? i have JJ1400, its running normal, running time 3h.
i have jetcat with kerostart its work fine!! so can i use jetcat keroburner on jj turbine ? if yes please say how?

Arman

RE: JetJoe OWNERS thread
 

Arman,
The engine itself will probably be able to use the Jetcat kero start unit assuming it will screw into the normal glow plug hole, but the normal ECU/Fadec which comes with the JJ engines, (AU-540 and the Regal clone) does not accommodate a kero start function.

Cheers,
Smithy.