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Post by vance on Jun 5, 2020 18:12:04 GMT -8
So, I'm attempting to make an improved Mistral lever ass'y, mainly 'cause I'm missing the OEM lever ass'y on one of my Mistrals, and I really like the HW setup. I've made the base and the two levers, but the problem is clearance. If you try to mod the HW lever ass'y, you'll end up too high. So everything depends on lowering all the components. I've done a few things to get lower, but I'm not sure it'll be enough. The whole thing will probably end up dependent on lever bending. If the diaphragm clears everything enough to get sufficient depression, it'll work. It's in the middle of development, but looks possible. I'll post pics soon.
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Post by vance on Jun 7, 2020 16:05:16 GMT -8
 
The problem is lowering the levers enough to get enough pin depression. |
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Post by nikeajax on Jun 7, 2020 17:34:41 GMT -8
WOW--this is super impressive PY!  JB |
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Post by vance on Jun 7, 2020 17:40:21 GMT -8
It might be a good alternative lever system for the Mistral. I'll just need to refine and bend the levers correctly. I'm confident it'll work.
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Post by nikeajax on Jun 8, 2020 11:01:50 GMT -8
How big is your bending brake? I can't help but think with such long levers it will be more sensitive, I hope?
JB
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Post by vance on Jun 8, 2020 13:13:16 GMT -8
I don't have a sheet metal brake. I'd like one.... I think the longer lever might make it more sensitive. I haven't tried it yet, since the forked part still needs bending for the diaphragm interface, and I don't have a venturi nozzle. What's in the valve is a barb for the O-P hose.
I'm considering silversoldering an adjuster nut to the bottom lever for a set screw adjuster like HWs have.
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Post by vance on Jul 2, 2020 15:51:37 GMT -8
I've been making levers lately. One for Mark's Trieste, and a shortening/rebend for my Titan II mod lever,  and the HW/Mistral mashup. It is interesting for a fly-by-the-seat-of-your-pants guy like me to venture into design or re-design. It's one thing to copy an established part. It's entirely another to venture out onto the limb, so to speak, with modding a part so it might work with what you need. As I've mentioned, I'm not a professional machinist, and I'm nowhere near an engineer. It's interesting how short the Trieste lever is at 26mm-ish, and it isn't a compound setup. You'd think the effort it would need to pull that short lever down against a downstream spring would be astronomical, but it really isn't. However, this started me thinking about off-center levers and whether or not they improve the performance, due to a longer lever, or decrease performance by not taking full advantage of the diaphragm (if that happens?). Any opinions? Facts? |
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Post by SeaRat on Jul 2, 2020 22:46:20 GMT -8
I don't have a sheet metal brake. I'd like one.... I think the longer lever might make it more sensitive. I haven't tried it yet, since the forked part still needs bending for the diaphragm interface, and I don't have a venturi nozzle. What's in the valve is a barb for the O-P hose. I'm considering silversoldering an adjuster nut to the bottom lever for a set screw adjuster like HWs have. Okay, you really don't have a Mistral, but rather a Overpressure Breathing regulator. Why not simply keep the hose-within-a-hose concept, and build on that? Bring it into the mouthpiece, create a receiver nozzle in the mouthpiece, and don't worry about a Mistral nozzle. The Overpressure Breathing concept was actually a better breathing machine, and much quieter, than the Mistral. And. I have both and have evaluated each. The Mistral is great, but the Overpressure Breathing is even better. John |
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Post by SeaRat on Jul 2, 2020 22:50:07 GMT -8
I've been making levers lately. One for Mark's Trieste, and a shortening/rebend for my Titan II mod lever, and this setup. It is interesting for a fly-by-the-seat-of-your-pants guy like me to venture into design or re-design. It's one thing to copy an established part. It's entirely another to venture out onto the limb, so to speak, with modding a part so it might work with what you need. As I've mentioned, I'm not a professional machinist, and I'm nowhere near an engineer. It's interesting how short the Trieste lever is at 26mm-ish, and it isn't a compound setup. You'd think the effort it would need to pull that short lever down against a downstream spring would be astronomical, but it really isn't. However, this started me thinking about off-center levers and whether or not they improve the performance, due to a longer lever, or decrease performance by not taking full advantage of the diaphragm (if that happens?). Any opinions? Facts? Actually, the pressure of the spring is balanced by the air pressure, the interstage pressure, on the other side. It takes very little effort therefore to break the seal upon inhalation. John |
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Post by james1979 on Jul 3, 2020 1:52:03 GMT -8
I don't have a sheet metal brake. I'd like one.... I think the longer lever might make it more sensitive. I haven't tried it yet, since the forked part still needs bending for the diaphragm interface, and I don't have a venturi nozzle. What's in the valve is a barb for the O-P hose. I'm considering silversoldering an adjuster nut to the bottom lever for a set screw adjuster like HWs have. Okay, you really don't have a Mistral, but rather a Overpressure Breathing regulator. Why not simply keep the hose-within-a-hose concept, and build on that? Bring it into the mouthpiece, create a receiver nozzle in the mouthpiece, and don't worry about a Mistral nozzle. The Overpressure Breathing concept was actually a better breathing machine, and much quieter, than the Mistral. And. I have both and have evaluated each. The Mistral is great, but the Overpressure Breathing is even better. John If you decide to go that way, let me know.... I could probably make something with a hose barb and a non return for the the mouthpiece (whichever one you want to use with it.
Respectfully,
James
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Post by vance on Jul 3, 2020 7:45:13 GMT -8
Actually, it is a Mistral. The nozzle is missing, and I had an Over-Pressure barb that I cleaned up on the lathe (hex was rounded). I installed it in this just to see if the threads were ok and to keep track of it.
Interestingly, while on the O-P subject, the Mistral valve body has one very small drilling almost at the pin that regulates the venturi, but the Over-Pressure body has two.
Part of my question is not clear, upon rereading it. If the lever is made long and contacts the diaphragm plate off center, say 1/4"-3/8" or so, will the function of the diaphragm opening the valve be affected (reduced)?
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Post by SeaRat on Jul 3, 2020 9:00:58 GMT -8
Actually, it is a Mistral. The nozzle is missing, and I had an Over-Pressure barb that I cleaned up on the lathe (hex was rounded). I installed it in this just to see if the threads were ok and to keep track of it. Interestingly, while on the O-P subject, the Mistral valve body has one very small drilling almost at the pin that regulates the venturi, but the Over-Pressure body has two. Part of my question is not clear, upon rereading it. If the lever is made long and contacts the diaphragm plate off center, say 1/4"-3/8" or so, will the function of the diaphragm opening the valve be affected (reduced)? What will probably happen is that the diaphragm will tilt, and may not provide the downward motion you desire if the lever impacts off-center. I think you'll loose just a bit of the diaphragm's ability to push downward, and it will try to lay along the entire length of the lever, possibly not giving the downward thrust you want. John |
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Post by vance on Jul 3, 2020 15:47:42 GMT -8
Hmmm. I wish we could put a camera inside to see what happens...
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