williammillette

the hours go by and im faceing my greatist opponant next to typeing and spelling.

servo slow is on,scuba tank full,turbo spark charged,propane tank full,nice weather pre requested to the weather man

awaiting countdown from houston.

williammillette

will practice starting in my sleep. tonight.


if i burn it up in my sleep i will order new parts midnite express and still be on for tomarrow an noon.

williammillette

STARTED VIDEO CAM,

FILLED PROPANE TANK,
PRIMED OIL ADDED AIR ADDED SPARK ADDED GAS POOF SOME RPM RAISED I ADDED 1/4" OF TRIM AND TURBINE SLOWS DOWN TO ALMOST NOTHING SO I LOWER THROTLE AND IT PICKS BACK UP I TRY LESS I TRIED MORE I TRIED ADJ GRU SCREW IN OUT THEN I CUT OFF FUEL THEN AIR AND SCREAMED THIS PIECE OF .

I REPRIMED OIL AGAIN AND RETRIED SAME AND RETRIED SAME

THE TURBINE WAS NOT EXTREEMLY HOT AND THE BEARINGS ARE STILL GOOD

TURBINE STILL TURNS FREE NO RUBBING

WHAT SHOULD I DO
SELL ,PERFORM DEMONIC RICTUAL,GIVE TO NASA.

PLEASE HELP !

basimpsn

My Feedback: (5)

boca sells turbine bearings starting around $36.00 ea
for ceramics

but the difence is they are not thrust bearing, i spoke to one
of there sells rep he said he have the bearing but on close inspection the inside of the bearing shape diferent.
that could be your problem. at high speed your bearing could be slowing down?????

williammillette

the bearings in it now are correct grw turbine bearings installed in opposed fasion as dennis f has instructed me

i used a shim when i installed the ngv and tailcone

the turbine spins relly free as soon as the turbine starts to get hot from fuel it slows up drastically

is my ngv still out of alignment?

i feel the bearing issue is solved,the compressor is ok,the oil system is fine,the air check valve is ok,the gru is working,the spark system is fine ,fuel to the injectors is ok,no flames outside the turbine,rpm on startup is over 20k,when ignites is probably hits 30k, but cant add fuel or it slows down below air speed!

williammillette

current bearings are rated for 160k for 1 min and are axiel load bearings for the side load installed like this


rear turbine with ridge faceing the turbine and the front faceing the compressor the bearing with the low side are faceing each other.

the turbine will make a great keychain dont ya think



allright guys its your turn!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

listen up . its your duty to keep me out of the mental institution

now all you have to do is tell me what to check,and ill do it and repost .i dont want to have to call unsolved misteries now



please please please help me with a glowplug on top.

Kevin_W

My Feedback: (1)

How are you determining these rpm figures? Although I have never personally run a JPX I have been around many and not one of them had a rpm sensor on it, they were all controlled by compressor pressure.
Is it possible that you are just "listening" for a change in the sound of the rpm's and mistaking the sound of it spooling up under it's own power for the sound of it spooling down without the air applied?? There will be a bit of pitch change when it starts to self sustain.
I'm sure the JPX guys here could help a bit more if you could post the approximate CP readings you are getting during your start attempts.

williammillette

GUESSING AT RPMS,
NO READINGS ON CP STILL
VISUALLY SLOWS ALMOST TO A STOP!!!!!!!!!!!!!!!!!!

Kevin_W

My Feedback: (1)

Any idea why you are not getting CP readings?

What are your exhaust temps during all of this?

Can you visually confirm that fuel is flowing to the engine?

I would suggest getting the CP problem worked out before you try any more starts, that way if you still have problems you can at least have some accurate data for the JPX guys to work with.

Just trying to help, please stop yelling

williammillette

ok fuel visual ok no cp due to compressor slows down slower than supplied start air when fuel is added

turbine is appart now and im sanding the turbine veins to add clearence between ngv and wheel


this time i will leave the inner liner out torrds the turbine and when i install the ngv it will be at o clearence

lots of oil in the turbine thats good due to me blowing in every attempt

Vincent

My Feedback: (61)

Bill,

You are using the "liquid" propane and not just vapors??

Vin...

williammillette

the gas is lpg from uhaul

filled upside down and venting liquid out top.

turbine almost back together again,sanded turbine wheel and adj inner liner ,also sealed can with rtv along with the oring.

wsmalley

My Feedback: (6)

I'm reluctant to pitch in since I have not run my JPX, but have built 2 old Shrecklings and had similar problem with one- slowing down on throttle up. Too much propane will cause this, and too much clearance between wheel and housing-you mentioned a bent vane, was it just one, any sign of rubbing? Are you able to measure clearance at rear, or 'guestimate'? If you increase pressure with your regulator will it continue to gain rpm's? Sounds like the burn is putting pressure on something and causing a rub somewhere, or your bearings are binding. If you tip it nozzle down and spin, can you tell any difference? If your not getting any case pressure sounds like excessive clearance in the turbine end. We're all hoping you can succeed!

wsmalley

My Feedback: (6)

With my Shrecklings, I used a mirror placed 18" or so to the rear where I could observe the turbine. It's great for observing 'hot' spots and color of turbine blades.

williammillette

ok i just reassembled it

the rear clearence is so tight.

i took a pepsi can dumped out the pepsi na just kidding i drank it

and cut it to fit around the turbine and installed it with the tailcone then worked it out after all the cone nuts were tight

nomatter wich way you position the turbine and spin it its free and no noise.

i just attempted to start it again.






low air pressure now on scuba tank will have to fill again this will be my 5th fill .


only 1 vain was bent,and it was ever so slight.

williammillette

possibilities for causing the turbine to slow?

something is heating up and binding like mabye the turbine wheel to the ngv.

too much propane causing a problem?

dribbe

OK... I'll take a shot...

Do you have a temp gauge on the thing? You are not telling us what the temps are doing.

You are holding the air on after it ignites right?
It takes some time (5-10 seconds?) To get it to enough rpm to maintain combustion and cooling.

Do not ever shut it off by slowing down through low idle... just cut the fuel.

Typical turbines run coolest at mid RPM's... They will run Hot at very low, and high RPM's.

Tell us how many degrees C you are getting.
Are you using a scuba regulator that is know to have the right pressure at high flow rates?

Do you have the instructions? Most JPX's I remember were started at a mid idle by opening the fuel valve. If the idle seems to low, you can open it a few clicks while holding the air on. Do NOT have the throttle open very far. follow the instructions.

The JPX is a fine running engine. It is a first generation one that requires some user training and 'skill' to operate.

I must say, that it is a tough thing to user service for a person that does not understand the design and have the proper tools. Turbines require great fits and balances.

DO you ever get a pressure reading? (I can't remember if the gauge will read if you blow in it... I think it might) If it is put together right, and you do not ever get a reading, it is probably not getting to enough RPM. In this case, you should never release the air, as it will surely overheat. Shut it down by shuttin off the fuel valve, and keeping air on.

'bubbles' in the fuel line were common with mine, and no factor... If there is a lot of liquid, that is a good sign.

Good Luck,
Dave

dribbe

Well, in rereading some of this, I know some of this was answered... but you really should obtain/feed us some EGT temp readings if we are to help.
(I know when mine got above 800 C during a proper start (briefly) It was getting sick. In my case, the bearings were going, and the friction was too high). Heat is the enemy of these things... especially the JPX. Please advise your temps.

What throttle position are you using? As I remember it... the 1/16" open technique was ussually enough to get it up and runnint at .2 bar. As I remember it, this is enough to substain operation, cooling, and oiling.

Full throttle was roughly 1.15 bar... right??

Dave

williammillette

ok guys listen to this

I LIVE IN FT MYERS FLORIDA JUST DOWN THE ROAD FROM THOMAS EDDISON AND HENERY FORD I WENT TO THERE HOUSE TONIGHT AT MIDNIGHT WITH THE TURBINE I SET IT IN THEIR MISTS AND LEFT WHEN I RETURNED THE TURBIN HAD BEEN MOVED! I SAW A PIECE OF PAPER INSIDE THE TAILCONE I REMOVED IT AND IT SAID "THIS IS AMAZING I TRIED TO GET IT TO RUN BUT THE NGV CLEARENCE IS OFF ON THE LEFT SIDE IF YOU DRILL OUT THE HOLES IN THE CAN IT WILL CENTER BETTER AND PROBABLY RUN."


SIGHNED THOMAS EDDISON


I FOLLOWED THESE INSTRUCTIONS AND DRILLED OUT THE CAN.

AND INSERTED THE CAN SHIM AND AN ADDITIONAL HALF SHIM ON THE RIGHT SIDE AND NOW THE TURBINE IS DEFFINITLY CENTERED IN THE NGV!.


NOW ALL I NEED IS TO REFILL THE SCUBA TANK TOMARROW



I THINK THIS MAY BE IT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !

Modelman

My Feedback: (7)

Bill, Bill, Bill,

I've been following your thread and can understand your frustrations.

I really think you're going about this the wrong way. You've obviously been good natured about this whole experience and should be lauded. But posts like your last, and the few others where you've specifically mentioned modifying your engine (however slight) make me sweat a bit.

You said yourself it shouldn't take a masters degree to run one of these things. You're correct there... but it does take knowlege, experience and training.

The training involved to adequately service your engine (any turbine for that matter) doesn't come from threads like this. It comes from hands on experience with a professional.

After reading everything you've done to this poor JPX, replaced seals with those from Pep Boys, reground the shaft, installed substandard bearings, "straightened" one of the turbine vanes and now drilled-out the can... I'm inclined to tell you that you really can't beat this poor horse any longer. If it does run, it can very well pose a significant danger to you or those around you.

BV used to sell JPX... Is there any way for you to ask him for pointers in person? Make the weekend a nice roadtrip thing and head up to Bob's place. Maybe he can help you with the starting procedures?

Please tread lightly my friend when attempting to start her. That's all I ask. Be Smart - Be Safe

Craig

williammillette

WILL BE REATEMPTING A NEW START TODAY IM FEELING LUCKY.

six shooter

C-bill

OK, I'll chime in here with a few words since I owned and operated a JPX at one point in time.

But first, let me say that the process your going through is not well thought out, and potentially dangerous. You have undertaken the task of taking apart and modifying a machine that you have little knowledge or experience with, and spent a lot of money doing it too.

With that said.

You are trying to read compressor pressure on starting the engine.

1) Are you sure the pressure gauge is working? Check that.

2) Check the plumbing to the oil tank, hopefully you didn't plumb it like DF fuel tank with an open vent!

3) Is the pressure line to the engine free of all obstructions, check it. Blow some compressed air back in through the pressure line.

The concept of compressor pressure is simple physics, it can't fail as you describe. If all the above check out, it is not possible to not have a pressure reading.

wsmalley

My Feedback: (6)

The threads dealing with JPX engines seem to have not ever addressed the issue as to whether or not a 'standard' 10mm bearing- ceramic, or whatever, with shaft turn down, works. Did you all replace with JPX bearings? In attempting to build a Phoenix (similar design), the shaft has to accurate to about .002 (concentricity) runout. If the machine shop's lathe is not true, you'd have junk, I think. How much does JPX charge for a rebuild? Anyone have it done? If JDE-or someone else does it, what are they using? Bill, if you blow into the air line, you should be able to register .2 1/2 bar on the guage.

ajcoholic

My Feedback: (10)

If a turbine's shaft is out two thousandths, something is seriously wrong. Two ten thousandths's maybe - but definitely not 0".002, that would shake itself to death, if it would even run at all.

Any good machine shop should be able to work to that accuracy, even with my home shop lathe (south bend) I can turn or grind to within half a thou.

AJC

wsmalley

My Feedback: (6)

Zeros and decimals. The point I guess is because a 'machine shop' did it don't neccessarily mean its right! I've had to have more than one thing redone! I'm still working on the jaws on my little lathe to attempt that kind of accuracy.