frema

Hi there.
As a turbine developper and collector i have a lot of engines i want to change and let run better then when they came out of the factory.

This time it was the j850 from sophia who interrested me , so i bought two of them .
one still has to run.

i know old engines ,bla bla ,slow bla ,nonsens , there great , but you have to understand them .

first the engine starts perfect on the mix of panel whipe and kero ,but sudenly the engine refuse to start ,and i took it apart a lot of times .
i couldnt find anything , so i left it for a while.
Yesterday i got an idea to change it.
first of all i tested the swirl in the combustor , there was no swirl ,and no swirl means no mix of feul ,and hot running , bad starting.

so i changed the combustor.
it very simple.
there are two wires in the front of the chamber, take it out , and close the holes by tig welding at the outside.
then drill two rowes of holes in the angled side of the combustor (at the front)
then bend all the holes in the air direction , and then you have mixing in the combustor.
with only this mod , i can let it run 200 deg cooler then normal, no bearing damage ,and the engine is completely black in the back ,even when running in the dark.
then the following mod :
insert a gas line in the combustor.
its very simple to do , just remove the blue cover ,and and then you will see there is a green connector at the front ,thats not been used.
take the connector of , and drill a 3mm hole through the diffusor and through the combustor.
insert a 3mm stainless steel pipe , and there it is ,your gas line .
you only need to bend it a little bitt inside to the glowplug ,then it will ignite easyer.
put the engine together, and adjust the uacell 1 to 1,75 and 2 to 2,50
then you are ready to go.
i only tell all of the sophia owners this ,because i heard a lot of owners all most gave there engins away ,because it would not start anymore on feul.
and it realy is no problem , just do it like me

connect the air to the engine to start ,and open the gasbottle a bitt.
at about 6500 rpm you will see the pump running and the ignition is on .
Then the gas ignites ,and you can open the air fully .
the engine spools up very fast to 89000 rpm ,then it drops to 51000 ,and the sign ready (green light ) is given by the ecu.
with the mods on the combustor the feul consumption is even less then before .
the temps where 590 till 650 max
before the mods they where over 850 fullpower.

The atomizing holes are the next problems.
most of the sophia's leaks behind the ring of the atomizing holes .
you only can see it when you spray a little bitt of kero in the feedline , and then blow it with 3bar pressure with the air bottle .
you will see bubbles , and that causes also high temps and bad running.
heat the ring with a torch ,and seal the leaks with superglue , make shore there is no glue in the atomizing holes ,because you will have a difficult job to get it out.
After sealing the gap between the ring , test it with feul ,and look if all the atomizing holes are open ,and spraying in the right direction .
if everything is allright , you can put the engine together again and run with it.
also notice when you want to balance the engine you have to insert other bearings ,without cases , because they produce vibration.
do not balance the engine with the factory bearings .

I dont know if there are sophia owners that are interrested in my story ,but if you are , i will sent some pictures of the mods of the combustor.

Regards,

Martin.

John Casey

My Feedback: (4)

Thanks for the info on the fuel system fixs and your posting....
they were always good on fuel, maybe a comeback someday.
post it all here....so the knowledge will not all be lost...forever.

frema

Thank you.
Agian its a very nice engine to run with.

here is a picture of the changed combustor before angle the holes at the front.

The second picture is the shaft tunnel .
you see the small atomizing holes , just behind that ,the ring leaks feul.
seal it with superglue .
not all of the sophia engine have this problem ,but still a lot.
this causes bad starting ,slow acceleration , and hot running.

The last picture is the old design chamber with the wires.
you have to delete them ,they burn through easy ,and damage the ngv and turbine wheel.

frema

Something i forgot to tell.
when you want to open the engine ,you have to be very carefull with the sensors for the rpm reading.
they brake easely , but you can fix them with solder.
I saw a questing a few months back about open the front cover of the engine.

its very simple.
the cover and diffusor is one piece ,so you cant do anything with it.
only the inlet of the front can come out.
there is a ring around the inlet with four little holes .
just put a pen or something that fitts the hole ,and carefully ,with using a smal hammer .tap on the pen .
the ring has the same thread as the compressor nut ,and you can unscrew it ,and then the inlet comes loose ,and you can take out the compressor wheel ,and the rest of the engine.
mark everything with a marker ,thats very important.

frema

the NGV is a very nice piece of casting , but also the critical part.
if the turbine wheel rubs to much ,you will loose power quickly ,and the temp go's up.

i didnt open the oilpump yet , i will see if i can do that.
the feulpump is not easy to open.
the electric motor (graupner speed 380 or 400 ) is connected to 2 gears, one from brass and one from alu.
the alu gear is very soft , so be carefull with that.
the seal of the pump is the same as the kavan feulpumps .
the pump has two brass gears and the housing is very soft , i thought it was steel ,but i think it is alu.
if the pump looses his power , simple take the front of the pump of ,and sandgrind carefully the spots where the gears are running, they can damage the front plate of the pump when there is not enough oil in the feul.

frema

the bearings .
there from GMN ,and not for sale anymore, atleast, thats what GMN told me.
JM PRECISION has the right bearings for it ,but witthout the cases.
i think that is even better.
the bearings are a bitt expensive ,but if you want to keep your sophia running ,this is a good solution.

frema

A small video of the sophia running.
I balanced it with the factory bearings , and you can realy hear that there was a lot of vibration.
Especialy on low rpm.

it started on feul in the video.
i use 30 procent panel whipe and 70 procent kerosine with a bitt of oil for the pump.

[youtube]http://www.youtube.com/watch?v=n6upMSH5rGs[/youtube]

GrayUK

You can run them on petrol Kero mix.
Use unleaded, 10% in warm weather and 20% in cold.

I have a friend that still uses them , he has eight [X(].
They run very well, are powerful for their weight and are very low fuel consumption.

Paul

John Casey

My Feedback: (4)

If you bust an IR led Rpm sensor, Jetcat sells them along with radio shack,
there are alot of jetcat parts on that engine...thermocouples...terminal boxes...
there are lots of sophia threads still here on RCU with lots of good info

thanks for the bearing source update.....better buy some more...

http://www.technologie-entwicklung.d...hia_j-850.html

thanks for adding to the knowledge base.
Nice pictures...

lavi rider

My Feedback: (6)

Hey Martin I see you're having fun with our engine..... nice mods.

frema

Well i hope your friend will use them for a long time.
and thank you for the info about the feul.

frema

Yes thats right ,there are a lot of parts the old p80 uses.
I spoke to Markus Zipperer a few time about the sophia , and he helped me with few things

frema

HI Peter.

yes your engine runs like a dream now.
it was a lot of work ,but i did it.

frema

I want as many as possible info about the sophia j850 engines in this thread, because there are still things a lot of people dont know about
for example : i had a very strange thing a few days back , the green led ,and the red led of the terminal where flashing.
but in the manual ,there is so little info about adjusting or setting the ecu .
it was a bad glowplug ,but the terminal didnt show it on the screen.
it took me a lot of time to figger that out.

frema

The glowplug i use is a R8 from Rossi.
i machined it in the lathe to fitt in the hole.
i made a thing brass cilinder and pressed it over the thread of th plug.
i pulled the wire out as far as possible,and set the ecu to 2,70.

frema

i also noticed that there are not many good video's off a running sophia ,or starting.

Theres one on youtube from a japanesse guy ,but he dont want give it full throttle,and the other one is from a guy with a model car , who dont understand turbines at all i think.
you can realy hear this engine die , speacely in the end, and i dont like that.
so i will try to make a few good video's with gas start .

F86_SABRE

Martin,
Thank you for starting up this thread. Unfortunately I could not locate the JM Precision bearings. Can you please indicate to me the link to the Sophia bearings? As for the vibration on low rpm could this be the reason? Please read here for cageless bearings:

http://jmprecision.co.uk/media/Beari...ding_688-1.pdf

Thanks again

Reuben

F86_SABRE

Also Martin, did you manage to eliminate the oil pump in your setup?

frema

Hi Reuben.
Are you a sophia owner too? ,show me some pictures of yours.
Here is the link:

frema

No ,i didnt do that yet.
do you have trouble with your pump ?
or do you have none?
There is an owner in the UK ,i think his name here is mick 15 or something like that , and he told me he is flying with a sophia with out the pump.
i hope he will reply on this thread .

for me i think it is inpossible because i am running with panel whipe ,and thats a cleaner , it cleans the bearing completely.
if you are running on coleman feul , then i think it is possible , because thats more like kerosine.

i will give it a try Reuben ,but the last test on pure kerosine was a dissaster, the combustor realy needs better mixing and vaporizing tubes for that

F86_SABRE

Hi Martin,
I am still using the original system (separate oil and fuel mixture) which has worked very well for me. Like you, I am using panel wipe as well and starting is not an issue. At least for now! However, the oil pump is a bit of a nuisance since the internal pipe gets kinked and one has to work it round again before running the engine. This, especially if it has been idle for a stretch of time.
If you are using the original oil pump have you changed the intenal pipe?
I love this engine...it was my first love with turbines!

Reuben

frema

And its also a favorite engine of mine Reuben , glad you are thinking the same as me.

no i didnt change anything,but if you are afraid of kinking the oil lines , why dont you take of the blue cover ,and drill a hole in the front ,so the lines come out straith .
i always have to pump a few times till the oil is in .
but its easy to do .
a solution for not have to do that every time ,is place valves in the lines , that you can open by hand.
with this engine ,you have to make a check list, before every flyed you have to chech if everything is alright and opened .

if you can , show me some pictures of your engine , maybe a video of running?

F86_SABRE

Martin, the kinking occurs inside the oil pump not in the engine. Since the pipe in the dosing pump is pressed inside the cover then if it is stationery the pipe gets pressed and one has to remove the oil pump cover and work the pipe round again. I have bought a replacement pipe which is softer but larger in diameter so I am using a bit more oil than when I used the original pipe. I would like to find the original sized pipe type so that I will use that than what I am using now. Unfortunately I have not been succesful in finding an original replacement pipe.
Some time ago I had to replace the oil pipe underneath the cover because it started to leak from underneath the cover. I also took time to clean the filter underneath the cover as well.
I will try and take some photos and load them.

Reuben

frema

Kinking inside the pump????
thats new to me.
do you have this pump?

F86_SABRE

No that is not like mine. It seems that my oil pump may be the older type not like the one shown. Was that pump part of the Sophia standard equipment or was it an aftermarket product? That looks like a well made pump.

Reuben