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Post by Johansson on Apr 9, 2024 14:57:07 GMT -5
It is a beautiful engine and installation Andy! I know the feeling when you have tested everything at home and when you hit the race track nothing works any more....
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Post by Johansson on Apr 8, 2024 14:13:20 GMT -5
I upgraded my mill today, for years I have been eyeballing a SAJO UF52 duomill with a drill press style mill head and when I found one for sale that was not on auction (I hate auctions) I just had to buy it. It is more than twice the size of my old mill so I have to rearrange the workshop quite a bit, but I think it will be great when I am finished. The hydraulic press, the rollers and some other stuff that I don´t use very often will be placed in the cold shed. So bear with me until I have everything in order, it will take a couple of weeks before I can continue building my jet engine. Cheers! /Anders
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Post by Johansson on Apr 7, 2024 15:27:43 GMT -5
The workshop is almost empty at the moment, I will get a nice upgrade in machinery tomorrow so I have had to make some space. Stay tuned...
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Post by Johansson on Apr 1, 2024 13:47:52 GMT -5
The ignitor that Andy built for me arrived this weekend, I tested it just now and holy smokes does it give nice sparks! With the uneven spark pattern that I love from "real" gas turbines, awesome! Thanks a lot Andy for helping me out.
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Post by Johansson on Mar 27, 2024 15:57:16 GMT -5
I've seen some turbos with a nylon wear surface in the compressor housing to allow them to self clearance. Might be a bit harder to do on a turbine! I don´t think nylon is the material best suited for the turbine stage. But some spray coated porous ceramic material might work. Thanks for the kind words guys, redneck machining at its finest. *LOL*
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Post by Johansson on Mar 26, 2024 15:28:10 GMT -5
Nice! Best of luck with the maiden run!
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Post by Johansson on Mar 26, 2024 15:07:30 GMT -5
I decided to fix the turbine blade clearance tonight, started off with the air grinder in the tool holder but I soon realised that this will take ages. What to do, what to do? I need a bigger grinder.... Worked like a charm, I used a crowbar to adjust the sanding belt pressure on the blades while grinding. I set the tip clearance to 1.3mm, judging from the looks of it I don´t think I should open it up much further. No more work on the engine before Easter, the weather will be crappy but it will still be a cosy weekend in the cabin with the kids. Cheers! /Anders
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Post by Johansson on Mar 26, 2024 0:11:42 GMT -5
My guess is that it is heat distorsion, tensions in the castings letting go or a combination of both.
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Post by Johansson on Mar 25, 2024 0:22:13 GMT -5
you need an abrasive NGV ring so the turbine can clearance itself That would be nice, perhaps add a diamond dust coating to the blade tips so they wear a track for themselves in the metal.
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Post by Johansson on Mar 24, 2024 2:04:50 GMT -5
The only thing I really am looking forward to in the future is when affordable metal 3D printers hit the market, imagine being able to print aluminum gaskets, turbine blades in inconel, etc etc. Except for that I would rather live in a cart and donkey century. The day we get household metal 3d printers is the day we all can just print a whole engine whilst not lifting a finger lol Wait a second, that would be a horrible scenario! Droves of formerly preoccupied hobbyists aimlessly roaming the countryside, leaving behind them trails of havoc and unwanted pregnancies. Highly likely the beginning of the end of civilization as we know it.
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Post by Johansson on Mar 23, 2024 16:42:02 GMT -5
The only thing I really am looking forward to in the future is when affordable metal 3D printers hit the market, imagine being able to print aluminum gaskets, turbine blades in inconel, etc etc. Except for that I would rather live in a cart and donkey century.
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Post by Johansson on Mar 23, 2024 14:18:18 GMT -5
Not silly at all, I appreciate questions and suggestions from people with know-how in the trade. I am stubborn as hell so I might end up just ignoring them, but I appreciate them none the less. Segmenting the NGV ring is an interesting idea, but it won´t work since it is the support for the engine cover and will have a flange welded to it later. The heat expansion in the NGV will be pretty complex with hot and cold areas but I will try it out and see how it works. The freepower NGV for the bike was made like this and I ran it glowing hot without any signs of damage, during the 306km/h run the Allison C20 turbine wheel rim cracked from excessive heat but the homemade NGV survived. It took two hours to make a set of 12.9 shoulder bolts for the turbine blades. I bought 40 long ones and threaded and cut them to length, now there is a flat surface that supports the blade hole. With the turbine blades properly torqued down I can fit it in the lathe and get the clearance right. I just had to give it another spin before I called it a night, I will probably wear the bearings down before I get a chance to start the engine... Cheers! /Anders
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Post by Johansson on Mar 23, 2024 2:08:25 GMT -5
A very good pointer Richard, I would rather err on the generous side since a rub would probably bend the blades.
Using the calculator a blade will become 1.1mm longer when heated to 700C, and I have no idea if the NGV cover ring will hold the NGV expansion back or not.
Perhaps setting it closer to 2mm than 1.5mm would be wise, as you say John lots of unknowns and the blade segments might settle a tenth or two in the bolt holes when things start to stretch from rotation.
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Post by Johansson on Mar 22, 2024 15:40:51 GMT -5
Another hour in the lathe and the clearance is ok, ~1.5mm with a little variation due to blade height. I will put the turbine wheel in the lathe and trim the blades to a uniform tip radius, a quick job with the air grinder in the lathe tool holder. I´ve also moved the rotor shaft so that it protrudes in the front like it is supposed to do. Time to start making drawings for the flame tube build, another CNC laser project since I refuse to drill the gazillion of holes needed in 1mm stainless. Have a nice weekend guys! /Anders
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Post by Johansson on Mar 22, 2024 0:11:15 GMT -5
LOL..............most of us can only dream of welding as good as you , you make it look easy, which it ain't :-( I´ve done my fair share of thin sheet welding, practice makes....decent. I say stick the lathe in highest gear possible and spin her up 🤣 That is the best idea I´ve heard so far today! It pulls a bit of wind even at the 160rpm setting, might blow the tools off the lathe at 10x that. Imagine the havoc when the NGV works itself free from the chuck and starts bouncing around the walls in the workshop...
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