The humble beginnings of something BIG; JU-03!

[Johansson]

Ok, will take some next time I work on the parts.

I was stretched out on the sofa with the cat on my stomach when I figured out a solution to a problem with the bearing housings.

The idea is to make the rear bearing take the thrust load, since the shaft is straight without recesses I plan to mount the bearings solidly in the shaft tunnel and fit a bushing between the turbine wheel and rear bearing inner race.

The front bearing will manage the thermal expansion with the shaft free to move inside the inner race.

I made the bearing housings with a tight fit for the bearings, but that left me with a problem since I wouldn´t be able to pull the bearings without risking damage to them by hammering on the inner race.

The solution that came to me was to add two small threaded holes 180 degrees apart on the backside of the bearing housing, then a pair of screws can be inserted that pushes on the outer race and pops out the bearings. Simple and elegant.

You are right John, a couple of pics is nice to break up a wall of text.

[Johansson]

Couldn´t go to sleep knowing I´ve disappointed you guys, so I went out and took a photo of this evenings work.



These chunks will have a flange welded to them for bolting to the diffuser and NGV, and a length of shaft tunnel pipe will be welded in between them.

I´ll have the bearings and shaft fitted during welding so I can check alignment of the parts, a magnet foot and indicator clock will show when the bolt flanges are perfectly in angle to the shaft.

Cheers!
/Anders

[racket]

LOL......thank you :-)

[Johansson]

I made the final lathe cuts on the bearing housings tonight.



The housings have recesses on their backsides that centers the shaft tunnel, I cut a 500mm long section of shaft tunnel and fit the bearing housings and shaft together.



I made four short welds on each housing just to hold everything together, before I weld them completely I will make a pair of flanges that will fit outside the bearing housings for bolting the shaft tunnel to the diffuser/NGV.



My idea with the screws to extract the bearings didn´t work, the threaded holes would have to be exactly where the pipe is welded. I blame the cat for that idea.

I will just use a bearing puller like normal people, when the engine is complete there is no real reason to pull the bearings out when disassembling the engine so this will not be an issue.

Cheers!
/Anders

[racket]

Hi Anders

Those bits look rather large when scaled against your tools , ................heh heh , you need a bigger hammer :-)

Cheers
John

[andym]

Hi Anders

can only think what its going to sound like spooling up 

[Johansson]

It really messes with ones perspective when you are used to rotors 1/4th the size, makes me feel like Nils Karlsson Pyssling. (look him up )




Spool up will be interesting, I still hold the Ice yacht twin turbo-afterburning turbofan engine to be the one I look forward to most, but still.

[andym]

Jan 11, 2024 0:38:55 GMT -5 Johansson said:

It really messes with ones perspective when you are used to rotors 1/4th the size, makes me feel like Nils Karlsson Pyssling. (look him up )




Spool up will be interesting, I still hold the Ice yacht twin turbo-afterburning turbofan engine to be the one I look forward to most, but still.

LOL.....   did me for a minute.... picture...   the Mini was a fun start, but the yacht would be something else..... is it any closer to spool up

[Johansson]

My friend Olof is trying to find time for it, he found a crack in the dividing wall in the turbine scroll that he is trying to grind down. Been looking everywhere for a replacement S500 turbo but they are hard to find at humane prices.

After that it is wiring and programming the control box and that is all his business, I am electronically retarded.

[racket]

www.turbochargerx.com/Search/s500/1.htm

[Johansson]

Great link, I´ve emailed it to Olov!

[Johansson]

I made one of the shaft tunnel flanges tonight.



Instead of a 5 minute laserjob I did a 1.5 hour handjob.

Hmm, that didn´t sound right...



/Anders

[Johansson]

Friday = Tacoday, an ancient Swedish folk tradition.



While the African Birds Eye chili peppers slowly work their way through my digestive system my digital slave works on the JU-03 project.

I made drawings this evening for the compressor blades with spot weld folds, and right now the 3D printer is making a 2mm thick cutting template.



Have a nice weekend guys!

/Anders

[slittlewing]

Jan 11, 2024 14:56:13 GMT -5 Johansson said:

I made one of the shaft tunnel flanges tonight.



Instead of a 5 minute laserjob I did a 1.5 hour handjob.

Hmm, that didn´t sound right...



/Anders

A lengthy handjob by anyone’s standards!! Keep up the great work 😁

[Johansson]

Another day, another small step towards a running engine (or a Chernobyl-style meltdown...)



I welded one shaft tunnel flange in place, the one that bolts to the comp diffusor. I will save the NGV side for later since I have not given the hot end any thought yet.



With the compressor blade template made I couldn´t resist making one 1.5mm blade just to see how it turns out. A while ago I bought a small sheet metal bender for jobs like this.



The FD3/64 had radiused blades for its double walled compressor, but for the sake of simplicity I will try straight backswept blades. The inducer height is 75mm and exducer height 45mm, i.e. a constant passage area for the air.



I will spot weld 12 blades at an angle around the compressor backplate, then add the 1.5mm thick coned lid that is yet to be made.



Care must be taken during welding so the bloody thing won´t warp, but if I cross-weld it and let it cool down between the welds I think it will be ok.

/Anders