richardm
Senior Member
Joined: June 2022
Posts: 413
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Post by richardm on Jan 13, 2024 18:37:21 GMT -5
How thick is the compressor back plate you're planning to spot weld on? By spot welding are you meaning resistance welding?
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Post by Johansson on Jan 14, 2024 2:50:40 GMT -5
How thick is the compressor back plate you're planning to spot weld on? By spot welding are you meaning resistance welding? It is 2.5mm think, and yes I will use resistance welding. Spot welding might be a bad interpretation, it is what we call it in Sweden.  |
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richardm
Senior Member
Joined: June 2022
Posts: 413
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Post by richardm on Jan 14, 2024 7:09:14 GMT -5
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Post by Johansson on Jan 14, 2024 13:09:11 GMT -5
I spent a good couple of hours in the shed today while the female part of the family were in town spending my hard earned money on trinkets and clothes made by East Asias finest slave labour. On the table are most parts needed to make the diffuser plate, not shown is a strip of aluminum that will be rolled into a ring where the axial guide vanes will sit.  Here the core parts are welded together and the bolt circle holes are drilled.  Some countersinking later and it looked like this.  To get the outer ring (the vaneless diffuser floor) perfectly centered around the compressor wheel I bolted everything together before welding it.  Lots of welding, I had to take a few breaks to let the air cooled TIG handle cool down.  Here are the parts so far, I made a new blade template for the "right" blade backsweep.  I will try a 45 degree backsweep with 12 blades for the compressor, not much theory to back this up but it looks about right. I can easily make a new one later with a different backsweep, that is the beauty with the steel hub design. Cheers! /Anders |
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richardm
Senior Member
Joined: June 2022
Posts: 413
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Post by richardm on Jan 14, 2024 17:10:53 GMT -5
Progressing swiftly! Funny how females spend a lot of money for a little fun while we can have months of fun in our caves on a few dollars worth of metal!
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Post by racket on Jan 14, 2024 19:48:24 GMT -5
Hi Anders
Lookin' good :-)
Heh heh ......Whats that little comp wheel out of , I hardly noticed it , its so small by comparison .
Cheers
John
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Post by Johansson on Jan 15, 2024 0:21:51 GMT -5
Progressing swiftly! Funny how females spend a lot of money for a little fun while we can have months of fun in our caves on a few dollars worth of metal! To be honest if my Anna and two girls spent as much as I do on hobby related stuff we would all be living under a bridge by now...  Hi Anders Lookin' good :-) Heh heh ......Whats that little comp wheel out of , I hardly noticed it , its so small by comparison . Cheers John Thanks! Don´t you recognice it? It is a TV94 compressor, the one I thought was huge when I started building JU-01. |
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Post by racket on Jan 15, 2024 1:01:01 GMT -5
Hi Anders
OH !!!! but it was such a big comp wheel , I thought all my birthdays had come at once when I got my hands on one :-(
Heh heh , that piddly little comp sent you along at >300kph ....................mmmmmm, thats food for thought.
Cheers
John
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Post by Johansson on Jan 15, 2024 16:27:36 GMT -5
It would be really interesting to find out how fast the JU-02 powered bike would go, but it would also be interesting to live long enough to meet my grandchildren so I don´t know... The job for the evening was to make the compressor blades.  1.5mm mild steel is really pleasant to work with, stainless is a pain in the ass in comparation.  After scribing the top and bottom lines I folded them on the sheet metal bender.  An hour and a half later and I had all 12 blades made.  To find the correct blade angle for all 12 blades I made a quick jig in the rotary table, I turned it in 30 degree increments and scribed the lines around the compressor bottom plate.  Next up is to make the flat pattern for the coned lid that will sit on top of the blades, it is cold as an eskimoe´s asscrack outside so I might very well spend a couple of more evenings in the workshop this week.  Cheers! /Anders |
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Post by andym on Jan 15, 2024 17:10:42 GMT -5
Hi Anders, its coming together very fast..... going to be speacial |
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Post by Johansson on Jan 16, 2024 0:32:02 GMT -5
It is pretty straightforward jobs working on sheet metal parts this size, making progress on castings with hundreds of work hours invested in it takes a much more delicate approach. Not long now until I have the compressor assembled so I can give it a spin on the shaft and see if it wants to move some air. This kind of engine would actually be something that could be cobbled together in a week at a Scrapheap Special episode, if one could happen to find a pair of suitable bearings laying around and some spray nozzles. |
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Post by Johansson on Jan 16, 2024 14:35:30 GMT -5
A little bit of work done on the compressor tonight, I cut out material for the cone for the compressor lid in 1.5mm mild steel.  The flat sheet cut out.  Adding a third dimension to it.  A little welding later.  I mocked up the compressor and took some photos, I need to make custom electrodes for the spot welder to reach all the way in.  Some fine tuning on the blades to get the edges perfectly in angle, and a wack or two on the lid to even out some areas. Then it is ready to be welded.  It actually looks like something that belongs in a gas turbine, even more so when I have the centrum cone made.  The exducer end, it should be pretty windy here once I get it up to 10.000rpm...  Cheers! /Anders |
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Post by andym on Jan 16, 2024 14:43:57 GMT -5
Looking good |
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Post by racket on Jan 16, 2024 19:07:18 GMT -5
Hi Anders
The comp is looking like the real thing :-)
What colour are you going to paint it ??
Cheers
John
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Post by Johansson on Jan 17, 2024 0:30:42 GMT -5
That is a very good question, need to think about it.
How are the inducer and exducer ends "sealed" against the comp cover on these double walled compressors? I will assume that there will be a degree of wobble no matter how carefully I weld the comp together, so some fancy labyrinth seal is not possible to make.
Perhaps it isn´t all that important, the centrifugal force takes care of the incoming air so it won´t sneak away where it doesen´t belong?
And, is there a reason to keep the comp cover very tight against the compressor lid? I´d prefer a more generous 10-15mm spacing and then tightening the gaps at the inducer/exducer area.
/Anders
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