OP
Kimsey0
Guest
What museum is that, Airleron? Sounds like a neat place to work; they must some of the rarest dive gear if that's the case. Speaking of that, what's strange is, I've got this OSS diving video, and the Lambertsen in that video is actually a different model than this other WWII one I"m working on; the one in the video is actually a backpack, made out of perforated sheet metal (containing the counterlung) with a scrubber fastened to the top (just like the one I'm working on) of the perforated case. What's more is, the FFM is different; it's basically a two window WWII us gas mask, unlike the one I'm working on. That must have been Lambertsens very early varient...? Oddly enough, on the cover of the OSS vhs cassette... a picture of the one I'm working on is showing (the one with the bladder around the shoulders/neck)
Annnnyyway, onto the trials;
When I submerged, the WOB was kind of high, and as a result, too much O2 escaped past the FFM, but I found the FFM to actually be loose. The lesson I learned from using this FFM was these masks, are simply not designed to be taken on and off on a whim; once you put it on it's designed to be basically welded to your face temporarily; it's just not practical to take it on and off repetitively, as tight as you have to fasten it, especially, so given that, I can see why Lambertsen made such a complex DSV, you really need a popoff valve, surface valve, waterdrain valve... all that good stuff, for using a FFM like this to be remotely practical. It's amazing just how different an experience it is, than just using a mouthpiece.
Never the less, I submerged for a few moments to check things out, once I got: situated.
Man, what a weird experience. You talk about a different experience to open circuit. The most distinct sensations were, the mask being pressed up against my face (is that how a FFM normally feels?) A strange tugging sensation on my back, as if I was dragging a surface buoy on the back of the LARU; I surfaced, blew out some of the oxygen, then submerged, going a bit deeper. Everything was going OK till my mask was taking on water near the mouth, come to find out, the piece of plumbing i press fit to the ball valve got a bit loose. It took me a while to figure out what happened. But other than that one thing, and the WOB issues, it worked great. I think what accounts for the WOB is, the sodalime was packed extremely tight up against the wall of the scrubber (as, from my understanding, it should be)
unlike last time. I used a dapple plate, and spring to compress the sodalime up against the wall of the scrubber, and I used a 3/8" buna-n o-ring inside, after the first layer of sodalime (similar to the patent prints) to prevent inner diameter channeling. Anyway, I know right off the bat some ways to help the WOB, just drill more holes in the dapple plate
Honestly, just because I got the mask watertight doesn't mean I should start using it yet, think I'll use a mouthpiece next time to add just rebreather testing dynamics to the situation, rather than mask AND rebreather testing. Probably should put the mouthpiece on till I get a highly sophisticated Lambertsen DSV made. I've got the plumbing to a Pirelli WWII ARO as well, need to get it going to have an alternate RB to use in case the MUCH more complex Lambertsent still has issues next time. Lol... the ARO was basically just a can, bag and hose, not much there to troubleshoot. Of course, I'm sure it will have it's limits compared to the Lambertsen.... anyway... see you guys!
