Building the JU-02 gas producer

[Johansson]

Hi folks!

I thought I should separate the new gas producer build and the ongoing turbine bike development, that build thread can get messy enough without another engine build in the middle of it.



John is the guy behind the calculations for the JU-02 and has donated a set of rotary parts, it is sort of a combined effort where he is the brains and I am the muscles. *LOL*



I will build the JU-02 as an updated big sister for the JU-01, most of the design is sound and the gremlins are sorted out so I´ll only change a few things that I think I can make improvements to. To start with I made a drawing in Inventor Fusion of the sand casting pattern for the compressor diffusor, and yesterday I started 3D printing it.



Here is a series of pictures from the printing process, it took 18 hours to complete with 0.2mm layers and 20% infill.









The wedges has a 1° taper to make it easier to remove from the casting sand, after some sanding down I think it will be smooth enough to work.



I got the rotor assembly 3D scanned this summer and a couple of weeks ago I printed a copy of the compressor wheel just for fun. It lacks the protruding rear centre so I could fit it to the diffusor to see how things line up.



As you could see in the pics during printing there are two alignment holes on the back of the pattern, the thrust bearing housing on the rear of the diffusor plate has to be printed as a separate piece since it needs to be removable during the sand casting process.



Cheers!
/Anders

[madpatty]

Woooow.
Another sexy build thread from Anders.

I am excited about the forum activity coming back.

Was bored of seeing the same no update screen for so long now.

Cheers,
Patty

[rythmnbls]

The rotor looks like its doing 100mph just sitting still


Steve.

[Johansson]

Sept 21, 2015 12:25:32 GMT -5 madpatty said:

Woooow.
Another sexy build thread from Anders.

I am excited about the forum activity coming back.

Was bored of seeing the same no update screen for so long now.

Cheers,
Patty

It has been a bit quiet here of late, too bad since there are lots of cool half finished build threads in here. Oh well, I´ll try my best to keep the dust from settling.

Sept 21, 2015 13:58:49 GMT -5 rythmnbls said:

The rotor looks like its doing 100mph just sitting still


Steve.

It sure does, even though you get used to the size faster than expected. It wasn´t that many years ago when I thought a 70mm compressor inducer was huge!

[racket]

Hi Anders

Very nice pattern

LOL, I don't know about me being the brains, you'll be doing more thinking on this project than me , I'm just happy to see another great engine coming from your workshop .

Yeh Patty its been a bit quiet on the build front , it tends to be seasonal , once the cold weather starts in the northern hemisphere guys move indoors and start building whilst here in the southern hemisphere its the reverse , once the hot weather arrives I stop my other activities and get back in my workshop , so things should get more active in the next few weeks

Cheers
John

[rythmnbls]

It has been a bit quiet here of late, too bad since there are lots of cool half finished build threads in here.

I'm hoping to help fix this in the near future, I've finished a CNC conversion on my mill and almost finished a power hacksaw build. I'm getting sick of making tools to make tools. In the near future I hope to get back to the GR180 and replace the turbine wheel and NGV and post some more pics and video

Steve.

[Johansson]

Sept 21, 2015 16:19:32 GMT -5 racket said:

Hi Anders

Very nice pattern

LOL, I don't know about me being the brains, you'll be doing more thinking on this project than me , I'm just happy to see another great engine coming from your workshop .

Yeh Patty its been a bit quiet on the build front , it tends to be seasonal , once the cold weather starts in the northern hemisphere guys move indoors and start building whilst here in the southern hemisphere its the reverse , once the hot weather arrives I stop my other activities and get back in my workshop , so things should get more active in the next few weeks

Cheers
John

Thanks! I will print a couple of test patterns to try some different approaches to smoothing the surface, I might even try to make a sand pattern out of an untreated piece just to see if the slipepry PLA plastic will release from the sand without problems.

And I am just as happy to have you on my team John, this will be one hell of an engine!

Sept 21, 2015 16:29:49 GMT -5 rythmnbls said:

It has been a bit quiet here of late, too bad since there are lots of cool half finished build threads in here.

I'm hoping to help fix this in the near future, I've finished a CNC conversion on my mill and almost finished a power hacksaw build. I'm getting sick of making tools to make tools. In the near future I hope to get back to the GR180 and replace the turbine wheel and NGV and post some more pics and video

Steve.

I would really like to see more of the GR180, it is a sweet little engine!

[Chuks]

my master is doing it again, i hope to learn more from all of these experts here this time around.... thanks for bringing this ideal of turbine stuffs for jet junkies like me...lol

[Johansson]

You are welcome Skynet!

I am continuing collecting parts for the JU-02, I managed to find a suitable length of stainless pipe that has 3mm thick walls. That is probably necessary since the engine will be pumping out P2´s close to 4 bar!



John pointed me to an Ebay auction for a 4th stage C20 NGV that would fit my c20 freepower turbine wheel like a glove, I bought it and it arrived last week. A small piece from the edge has broken off but it doesen´t matter since it is not in the gas path.



There is probably more than a few horsepowers to be gained with this NGV compared to my home build one from stainless pipe sections, plus that I won´t have to worry about cracks any more.



Cheers!
/Anders

[racket]

Hi Anders

That was fast delivery :-)

There should be ~1mm diametric clearance between wheel and shroud .

Is there an "area" marked on the outer side wall of the NGV , something like "14.41" , there could be even a couple of earlier areas as well which are a slightly smaller number , this will give us the flow area to fit into the calculations .

Cheers
John

[enginewhisperer]

Sept 22, 2015 5:10:59 GMT -5 Johansson said:

I will print a couple of test patterns to try some different approaches to smoothing the surface

I've heard that putting it in a container and vapourising acetone around it will smooth the surface nicely. I haven't tried it or seen it done though

[Johansson]

Sept 27, 2015 16:22:26 GMT -5 racket said:

Hi Anders

That was fast delivery :-)

There should be ~1mm diametric clearance between wheel and shroud .

Is there an "area" marked on the outer side wall of the NGV , something like "14.41" , there could be even a couple of earlier areas as well which are a slightly smaller number , this will give us the flow area to fit into the calculations .

Cheers
John

Very fast indeed, I was surprised when I found the delivery note in my mailbox.

The clearance is probably close to 1mm, I haven´t measured but it must be close to it. I´ll check for area writings on the NGV wall next time I am in the workshop.

Sept 27, 2015 17:17:32 GMT -5 enginewhisperer said:

Sept 22, 2015 5:10:59 GMT -5 Johansson said:

I will print a couple of test patterns to try some different approaches to smoothing the surface

I've heard that putting it in a container and vapourising acetone around it will smooth the surface nicely. I haven't tried it or seen it done though

It works for ABS plastic but not PLA that I use, for ABS printing I need a heated bed to keep it from warping.

[racket]

Hi Anders

Thats a fine coupling of NGV and wheel , they should hopefully make lotsa horsepower .

Jon Burrell from the GTBA Site has kindly helped me out with parts of the freepower calculations/velocity triangles that were giving me concerns, things I just couldn't seem to reconcile, and he's confirmed that ~300 HP isn't an unreasonable figure to aim for ..............thanks again Jon :-)

Cheers
John

[Johansson]

Hi John,

I read the conversation you emailed me, it was great of him to help out.

300hp it is then!

Cheers!
/Anders

[Johansson]

Hmm, what might this be???



Another 4th stage NGV! John very kindly sent me one he had in storage, it has a small crack in the middle but I think I might be able to repair it. Great to have a spare NGV, thanks a lot John!



Cheers!
/Anders