|
Post by vance on Dec 12, 2021 19:28:12 GMT -8
I just ordered some tool holders, so I cut one down for this project. Now I can machine the mold.
|
|
|
Post by antique diver on Dec 14, 2021 11:20:40 GMT -8
I recently discovered that the Bendix was originally operated on a 450 psi Oxygen supply in the aircraft. That likely explains the recurring issues I have battled with seeping HP seat at 1800 psi supply. It leaks less and less as tank pressure drops, and is imperceptible by 500 psi. Testing the monster with a 450-500 psi adjustable regulator (hex shaped item at about 4 o'clock from valve) has almost completely solved that problem, but with a some loss in performance at high demand breathing levels. Likely due to small volcano orifice diameter. However, it is still breathing better than ever due to the newly revised diaphragm with increased demand lever throw. More info after I get a chance to try it in the water. Hoping to get a chance soon since the water isn't getting any warmer.
|
|
|
Post by vance on Dec 14, 2021 18:21:32 GMT -8
What kind of in-line pressure regulator is that?
|
|
|
Post by antique diver on Dec 14, 2021 21:20:26 GMT -8
What kind of in-line pressure regulator is that? Aqua Environment model 969, 6000 psi max input pressure, and adjustable discharge from 0-250 from factory. Anodized aluminum body and some internals, also some SS internals. It is not designed for underwater use, but what the heck, neither is the Bendix. I shimmed the main spring, allowing it to deliver 460-500 psi with tank pressures ranging from 200 to at least 2200. Probably will still operate ok with 3000 psi. Not sure how will it will hold up for diving, but at least it will only see fresh water. I have some smaller inline simple regulators, but they were wildly unstable above 250-300 psi. There may be more suitable regs available, but I just happened to have this so it gets the test job for now. www.aquaenvironmentinc.com/pdf/model-969.pdf
|
|
|
Post by vance on Dec 15, 2021 8:58:47 GMT -8
How did the Bendix system regulate the pressure on aircraft? I assume there was some kind of device like the one above, not 450 psig fills in the tanks....
|
|
|
Post by cnotthoff on Dec 15, 2021 9:17:56 GMT -8
What kind of in-line pressure regulator is that? Aqua Environment model 969, 6000 psi max input pressure, and adjustable discharge from 0-250 from factory. Anodized aluminum body and some internals, also some SS internals. It is not designed for underwater use, but what the heck, neither is the Bendix. I shimmed the main spring, allowing it to deliver 460-500 psi with tank pressures ranging from 200 to at least 2200. Probably will still operate ok with 3000 psi. Not sure how will it will hold up for diving, but at least it will only see fresh water. I have some smaller inline simple regulators, but they were wildly unstable above 250-300 psi. There may be more suitable regs available, but I just happened to have this so it gets the test job for now. www.aquaenvironmentinc.com/pdf/model-969.pdf I've used Aqua Environment regulators in air fill systems that I've built. They work well for their intended use. A significant difference between a diving regulator and one not designed for diving is the ability to compensate for increasing ambient pressure. Since that regulator has no ambient pressure ports the perceived pressure it supplies will drop as depth increases. I'm sure this setup will be ok for shallow dives. Be aware of performance at deeper depths. Good Dives, Charlie
|
|
|
Post by antique diver on Dec 15, 2021 11:16:16 GMT -8
How did the Bendix system regulate the pressure on aircraft? I assume there was some kind of device like the one above, not 450 psig fills in the tanks.... Looks like they were mostly using larger diameter light weight tanks rated for the lower pressure. I have seen them in older military surplus stores. There may have been some higher pressure tanks used as well, but I can't confirm that. It does seem logical to use smaller hp tanks in smaller aircraft, and they may have been regulated at the source. Good question.
|
|
|
Post by antique diver on Dec 15, 2021 11:22:49 GMT -8
Aqua Environment model 969, 6000 psi max input pressure, and adjustable discharge from 0-250 from factory. Anodized aluminum body and some internals, also some SS internals. It is not designed for underwater use, but what the heck, neither is the Bendix. I shimmed the main spring, allowing it to deliver 460-500 psi with tank pressures ranging from 200 to at least 2200. Probably will still operate ok with 3000 psi. Not sure how will it will hold up for diving, but at least it will only see fresh water. I have some smaller inline simple regulators, but they were wildly unstable above 250-300 psi. There may be more suitable regs available, but I just happened to have this so it gets the test job for now. www.aquaenvironmentinc.com/pdf/model-969.pdf I've used Aqua Environment regulators in air fill systems that I've built. They work well for their intended use. A significant difference between a diving regulator and one not designed for diving is the ability to compensate for increasing ambient pressure. Since that regulator has no ambient pressure ports the perceived pressure it supplies will drop as depth increases. I'm sure this setup will be ok for shallow dives. Be aware of performance at deeper depths. Good Dives, Charlie Thanks for bringing that up Charlie. I thought of making a vent port for ambient correction, but haven't done it yet preferring to test dive this first. Mostly will be using this rig for 15-30' diving, at least until I develop a bit more trust in the Bendix conversion or dive with a redundant air source. I haven't really thought about where to vent the AE regulator yet. If you get a chance to look over the schematic maybe you could help with a suggestion on that. Thanks!
|
|
|
Post by nikeajax on Dec 15, 2021 13:15:10 GMT -8
One of you two should contact these folks: www.aircorpsaviation.com/wp-content/uploads/P-47_NovDec-2020-Web.pdfThey're restoring a Republic P-47: This is an image of Lt Col Francis S. "Gabby" Gabreski, with the mask dangling down: the other ends would be connected to the diluter... In the first link you'll find an image of a diluter, not the Bendix, but it should still be connected to the same type of air-source!!!! Hope this helps... JB EDIT: It is my understanding that early scuba enthusiasts would use old fire extinguisher tanks as an air source: these were much lower pressure, like 750-psig if I remember correctly.
|
|
|
Post by antique diver on Dec 15, 2021 17:27:42 GMT -8
JB, That's a great link, and included a page showing the fill pressure of the Oxygen storage! I'll try to figure out how to post that page.
See pages 15 and 16.
That is a big help in documenting the stored O2 pressure. Thank you!
|
|
|
Post by nikeajax on Dec 15, 2021 17:43:23 GMT -8
That's why I'm here buddy: putting my nerd-super-powers to work for good! Glad I could help Side note: if you ever get a chance, you should look at some of the crazy engineering that it took to build the P-47. Essentially, it was designed around a supercharger to feed a monstrous engine! JB
|
|
|
Post by SeaRat on Dec 15, 2021 18:49:55 GMT -8
One of you two should contact these folks: www.aircorpsaviation.com/wp-content/uploads/P-47_NovDec-2020-Web.pdfThey're restoring a Republic P-47: This is an image of Lt Col Francis S. "Gabby" Gabreski, with the mask dangling down: the other ends would be connected to the diluter... In the first link you'll find an image of a diluter, not the Bendix, but it should still be connected to the same type of air-source!!!! Hope this helps... JB EDIT: It is my understanding that early scuba enthusiasts would use old fire extinguisher tanks as an air source: these were much lower pressure, like 750-psig if I remember correctly. Eban, you’ve got to read this, especially about the development of the M2 50 caliber machine gun. It is at the back of the article that JB linked to. When I was in the First Med Field Hospital at DaNang, we had a helicopter crew member come in with a wound to his thigh. It turned out that he had been hit, at about 5000 feet, by a 50 caliber machine gun round that had penetrated his helicopters skin, and was lodged in his leg. Luckily, it was almost completely spent, and had only penetrated his flight suit and skin, and lodged just under his skin. Somewhere I have a photo of his X-ray, before the surgeons opened his leg up and removed it. He got his Purple Heart, got the spent bullet, and walked out of the ER with only a small dressing on the wound. John
|
|
|
Post by nikeajax on Dec 16, 2021 9:08:27 GMT -8
I seem to recall hearing that these are constant-flow regulators: is that still the case with a lower IP?
JB
|
|
|
Post by antique diver on Dec 16, 2021 13:24:02 GMT -8
I seem to recall hearing that these are constant-flow regulators: is that still the case with a lower IP? JB The ones we are using are not constant flow regulators, but are Diluter Demand Oxygen Regulators. The one shown on page 15 of the link to the P-47 aircraft is labeled with that "demand" designation. The confusion may have come from the fact that they are also equipped with a manual bypass valve that does provide a free flow of gas in case of regulator failure or lack of enough volume to satisfy the user. The user can manually open and adjust the valve, sending oxygen directly from the 450 psi line, bypassing both the first and second stages and straight into the regulator body cavity and hose. There may actually be some free flow systems in use, but it seems that would waste a lot of precious Oxygen.
|
|
|
Post by nikeajax on Dec 16, 2021 13:31:13 GMT -8
Bill, thanks for that heads up I'm quite glad that I could help you guys with some of my esoterica, make it useful to someone: I wonder if anyone else is aware of this info who has one of these types of regs? I'm hoping that y'all can make these safe for open-water JB
|
|