lofi
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Post by lofi on Mar 31, 2020 5:17:55 GMT -5
Really enjoying this thread, thank you for taking the time!
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lofi
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Post by lofi on Jan 5, 2020 15:20:33 GMT -5
Is there a way you can put the scavenge pump inside the tank? Maybe mount it to the inner side of a removable plate or suchlike?
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lofi
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Post by lofi on Dec 30, 2019 13:22:18 GMT -5
Incredible. Thanks for taking the time to document the process.
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lofi
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Post by lofi on Oct 24, 2019 2:47:07 GMT -5
It's not impossible to make a clutch, and well within your tooling/ability. Garage54 on YouTube successfully ghetto-fabbed (and I mean really ghetto) one out of a brake drum and shoes for a Lada recently. youtu.be/o6AF3LiMItsGiven some dimensions to work to, it's something I wouldn't mind having a go at myself and shopping over to you!
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lofi
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Post by lofi on Jun 9, 2019 7:51:53 GMT -5
Nice project, but wouldn't these be better posted to a Github or Bitbucket repository? The forum loses all the formatting and change control is a bit of a nightmare. Plus you'd get all the bug tracker tools, versioning and the entire project would be downloadable rather than a lengthy copy/paste.
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lofi
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Post by lofi on Dec 10, 2018 19:34:22 GMT -5
Hi Anders You've got some interesting discoloration that matches that chowdered seal... While looking over the photos I noticed the cuts in the strengthening webs you made to bring the casting back to flat and it made me wonder if that large diameter casting is distorting under load / heat, causing the front cover to get misaligned, jamming the wheel and also opening up that area letting the seal blow by. I'd put money on the wheel jamming being the cause of the nut unwinding, but that's just a 'hairs on my butt' hunch, to coin a Johnism. Lol! Thinking through Chris' comments on thermal expansion in alloy I thought it worth throwing into the mix of ideas. That casting keeps the front cover in the right place to define the comp clearances, after all. I know I don't comment much, but thanks for the continued updates. I've literally been following your exploits for years now! Hope you get it sorted soon either way Ian
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lofi
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Post by lofi on Aug 2, 2018 9:01:40 GMT -5
Try asking www.youtube.com/user/AgentJayZHe works on J79's and other large engines quite frequently. It's an excellent channel in general with lots of poking inside large jet engines.
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lofi
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Post by lofi on May 13, 2018 6:08:14 GMT -5
Hi John
If I remember correctly, you were struggling to get the fuel to fan out and hit the sides of the vaporiser tubes and were exploring ways the break up the boundary layer in the tube? What about increasing the turbulence of the air entering the vaporizers with some square projections at the entry points? If my understanding is correct, this should slow the flow down, prevent boundary conditions somewhat and aid mixing, which seems to fit with what you're trying to achieve.
The idea stems from research into steam loco exhausts, where proper function is achieved through maximising turbulent mixing in the boundary of the confined jet of exhaust steam into the combustion gases in the smokebox. The goal is to maximise turbulence at the boundary, minimise cylinder back pressure and keeping the jet velocity low.
An excellent PhD paper has been produced on the subject, and contains a lot of historical research into confined jets and turbulent mixing. A late development has been to make the steam exhaust exit square, with four small square projections on the flat sides pointing inwards. Practical tests by a Canadian gentleman testing on a large model suggest it has quite a profound effect. In the same vein, what about diffusing vaporiser tubes? A pain to make, but possibly another tool to slow things down in the vaporisers?
Just a thought that it may be of help to look outside into some different areas of fluid dynamics research. The paper has been published as a book titled The Fire Burns Much Better - its an excellent read.
Reading with interest as always. Apologies if I'm way off the mark!
Ian
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lofi
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Post by lofi on Feb 20, 2018 18:47:04 GMT -5
Such an interesting project, please keep the updates coming. I love that the press has made its way into the house! Can't hide that one...
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lofi
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Post by lofi on Nov 26, 2017 12:58:43 GMT -5
Just musing about your bearing arrangements... If I recall correctly, the clearance between the comp blades and front cover is fairly important to efficiency. As little as possible is desirable. Making a few assumptions: 4" between the comp and turbine, shaft heat soak up to 200 degrees. With the rear bearing being captive and the front being free to move against the preload spring, you'll be seeing about 5 thou of thermal expansion making the comp move forward that much. That's a lot of extra clearance to allow for when cold! With the front bearing captive the comp would be locked in place and the turbine moves as the shaft expands. This isn't important at all on the axial turbine and easy to design for. Another thing to consider is the front bearing is likely cooler, so better able to cope with the axial load, of which there is bound to be some. Something to think about, anyway. Lovely project though - looking forward to more updates /Ian
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lofi
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Post by lofi on Jun 19, 2017 6:15:51 GMT -5
Have a look for motorbike oil pumps. Lots have an integrated relief valve, are designed to be chain driven, and will be happy giving the kind of pressure and flow you want for a small turbo. They're also quite inexpensive second hand /Ian
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lofi
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Post by lofi on Feb 28, 2017 4:40:47 GMT -5
You glorious madmen! Thanks for the video and glad all involved are OK. I'll look forward to the next installment!
Ian
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lofi
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Post by lofi on Feb 17, 2017 7:06:19 GMT -5
Hi Jeff, I thought this might amuse you... I once made a covered wheel in steel, 16" diameter: It was "designed" (hmmmm, that looks right) for suction rather than as a compressor, and I had no means at the time to make curved blades or slots, but it was quite effective. Sorry it's a bit off topic, but I thought you might appreciate my "Scrapheap Challenge" approach as a counterpoint to your lovely precision work! lol Lovely, lovely work on your new carbon wheels, can't wait to see how they perform. Cheers Ian
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lofi
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Post by lofi on Feb 16, 2017 8:28:23 GMT -5
Thanks Jeff. Time for an update! I've finally got the oil pump working properly after the belt and wheels arrived from China: 100psi on full chat with 12v. Not sure what the pressure relief valve is doing as that's a bit high really, but I'll mess with it later. I can fine tune with the PWM box if needed. My new welding helmet arrived too, which should cope with the low amperage TIG operations better. The old one was a bit hit and miss about triggering, so I stopped! Cheers Ian
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lofi
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Post by lofi on Feb 5, 2017 6:41:24 GMT -5
That looks fantastic, Jeff. Are you tempted to make the blades in a similar way?
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