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Post by Johansson on Feb 10, 2024 4:09:05 GMT -5
Dam...... that looks epic....  It is pretty massive yes.  I am sitting and trying to draw up a blade press jig in Fusion 360, hopefully the PLA+ is hard enough when held together by screws. |
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Post by Johansson on Feb 10, 2024 5:58:08 GMT -5
The printer has 22 hours of work to do now, I will try a solid PLA+ blade press jig reinforced with steel plated sides and M5 screws. I will make the plunger later if this turns out ok.  I am also reviving the glue experiments, I bought a new kind of glue that might do the trick.  I mean, since gorillas are strong like crazy a glue made out of gorillas has to be strong as well. Simple logic, it is a shame there are so few of us who actually use it nowadays.  /Anders |
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Post by Johansson on Feb 11, 2024 4:30:23 GMT -5
It seems like the gorilla used for this particular glue batch was unhealthy somehow, perhaps some tropical disease? The glue strings (I didn´t put glue in between the parts, only along the edges) didn´t stick very well, that much is a fact.
I will try their epoxy glue next, hopefully they used a new and healthier gorilla for that batch.
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Post by wannabebuilderuk on Feb 11, 2024 4:43:10 GMT -5
It seems like the gorilla used for this particular glue batch was unhealthy somehow, perhaps some tropical disease? The glue strings (I didn´t put glue in between the parts, only along the edges) didn´t stick very well, that much is a fact. I will try their epoxy glue next, hopefully they used a new and healthier gorilla for that batch. Epoxy is your best bet, make sure you rough up the surfaces too uk.gorillaglue.com/guide-to-glue-on-metal/ |
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Post by Johansson on Feb 11, 2024 7:12:37 GMT -5
Another decision I have made is that the turboshaft engine that will power the formula car will be a single shaft engine.
I will use a snowmobile belt clutch fitted on the rotor shaft in front of the compressor wheel, and couple it to a manual car gearbox somehow to get a reverse and ability to choose gearing.
So the turbine wheel will be set up to absorb as much energy as possible, not like a jet when it just needs to power the compressor and make thrust out of the rest. A bit more twist to the blades is needed in other words.
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richardm
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Joined: June 2022
Posts: 413
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Post by richardm on Feb 11, 2024 7:25:36 GMT -5
I Ve worked with "JB Weld Steel" epoxy Around 3000 psi strength Quite strong as long as surfaces are clean and rough. Don't go for 5 minutes epoxy Its faster but never gets as strong as regular epoxy.
Bare minimum of 24 hours curing time double that before you try to tear it apart.
Now about your snowmobile / car gearbox idea. How will you be able to shift the gear box unless the centrifuge clutch is disengaged. I mean won't you have to bring the engine to idle to do that That means a long spool down / waiting time before you can change gear .. But again I might be wrong
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Post by Johansson on Feb 11, 2024 7:31:47 GMT -5
I Ve worked with "JB Weld Steel" epoxy Around 3000 psi strength Quite strong as long as surfaces are clean and rough. Don't go for 5 minutes epoxy Its faster but never gets as strong as regular epoxy. Bare minimum of 24 hours curing time double that before you try to tear it apart. Now about your snowmobile / car gearbox idea. How will you be able to shift the gear box unless the centrifuge clutch is disengaged. I mean won't you have to bring the engine to idle to do that That means a long spool down / waiting time before you can change gear .. But again I might be wrong I´ll let it sit a couple of days before I try to break the pieces apart. No gear shifts while running, the gear choice will mostly affect the top speed. I will probably find a gear that is best depending on the track conditions and stick to that, the ability to reverse is a big bonus. |
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richardm
Senior Member
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Posts: 413
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Post by richardm on Feb 11, 2024 8:59:28 GMT -5
Ok I get it ..How about an automatic transmission? Wouldn't it continually shift it self to the best ratio O may be even better. a CVT transmission no need for the snowmobile clutch then..
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Post by wannabebuilderuk on Feb 11, 2024 9:07:37 GMT -5
I Ve worked with "JB Weld Steel" epoxy Around 3000 psi strength Quite strong as long as surfaces are clean and rough. Don't go for 5 minutes epoxy Its faster but never gets as strong as regular epoxy. Bare minimum of 24 hours curing time double that before you try to tear it apart. Now about your snowmobile / car gearbox idea. How will you be able to shift the gear box unless the centrifuge clutch is disengaged. I mean won't you have to bring the engine to idle to do that That means a long spool down / waiting time before you can change gear .. But again I might be wrong I´ll let it sit a couple of days before I try to break the pieces apart. No gear shifts while running, the gear choice will mostly affect the top speed. I will probably find a gear that is best depending on the track conditions and stick to that, the ability to reverse is a big bonus. Use the whole snowmobile clutch/cvt assembly? Gives you gearing and control then |
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Post by Johansson on Feb 11, 2024 9:29:43 GMT -5
Use the whole snowmobile clutch/cvt assembly? Gives you gearing and control then That is the idea. |
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richardm
Senior Member
Joined: June 2022
Posts: 413
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Post by richardm on Feb 11, 2024 11:18:42 GMT -5
I think you wouldn't need a clutch if you d use a car CVT transmission Maybe just some kind of toothed belt between the engine and the trans
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Post by Johansson on Feb 11, 2024 12:22:47 GMT -5
I think we are talking about the same thing, when I said a belt clutch I meant a CVT transmission just like in a snowmobile. Those are cheap and easy to adjust for the characteristics that the engine need.
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Post by Johansson on Feb 11, 2024 14:24:44 GMT -5
I got a fair bit of work done this weekend, yesterday I drilled and threaded the turbine disc with 40 M6 holes.  A while later.  This will be a big turbine wheel...  I ended up milling a blade press jig from aluminum with a 3D printed insert.  It works just fine, with 6 tons of pressure it profiles the blades just like intended.  Despite its shortcomings in certain areas PLA can take a shitload of pressure like this. The printed layers are pressed into the 3mm stainless sheet so I can feel them with my fingers.  Next up is to build a tool for twisting the blades, I´ll heat the root of the blades before twisting. Cheers! /Anders |
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richardm
Senior Member
Joined: June 2022
Posts: 413
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Post by richardm on Feb 11, 2024 15:22:54 GMT -5
I was talking about an automobile VT www.youtube.com/watch?v=PQHVLH8jVc8. Contains all you need in one package including neutral reverse and differential ( if you go front wheel drive) |
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Post by Johansson on Feb 11, 2024 15:37:14 GMT -5
I´ve never heard of a car with belt drive other than the infamous DAF 66.
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