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Yes, and he's a bloody annoying one too! I'm the marketing guy here, and the damned thing is call a SNORT system. Low Pressure Blower is an awful name for this. It sounds weak and pitiful (like some people's marketing skills). I'm off to make L P B a cuss-word - that'll put a stop to his horses doofers!Last edited by Kazzer; 12-06-2010, 05:34 AM.Leave a comment:
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So Chris your starting out in subs and with a sizeable one at that 2.5m of type 21 right? But you did also mention in your post a "cost" is an issue....well to Echo David but in my own words here is why you'll be better off buying off the shelf a Sub driver. I am sure David and Mike that will have something that will fit that beast.
If you buy a subdriver water tight cylinder unit you will have the backing of the best in the business.
see
When people usually see the cost of these things (effective proven parts) they normally embark on what they believe is a cost saving alternative rig of their own. I was guilty of this at the start as are most newcomers. 2 decades and many subs later for myself and clients, economy = proven parts and back up by the manufacturer.
Problem is there are but few effective ways to approach RC subs and many many more ways that all start from the premise of economy but practically end in much higher cost and tears. The internet is littered with the garbage of best low cost intentions towards RC subs and sadly the over opinionated skilled internet trolls that can't and don't build a thing. The best place for information and help amongst guys with a proven track record is right here at the Sub Drivers Forum.
What makes this site different is that its essentially "peer reviewed". You won't find meaningless discussion or reinvented bad wheels or net experts who can't build leading you astray. Posts that head this way are nailed very quickly, the perps publicly flogged, and sent in search of rehab or a wadding pool to play in - sadly there are some of these trolls that are beyond help or reason, like rampant bacteria they search the hobby universe for a host to assist with their many issues that allow them to have the inferiority complex professionally untreated as they steer some other sucker down a black hole of cost and frustration all for the good of playing out some petty little empire building game.
There are unfortunately a lot of bum steers people get when they start out in subs, and I hope you avoid them.
JLast edited by Slats; 12-05-2010, 11:43 PM.Leave a comment:
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Hi David, thanks for the reply, I'll check out your reading recommendations.
.... and yes, I still 'wanna' play.
ChrisLeave a comment:
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And you start it off saying you're complexity and disaster averse!? Man, did you click on the wrong site! This is most assuredly not the hobby for you.
Move along!
You would be much happier some place else!
You don't like noise?! What the hell is wrong with you, anyway?
Regardless of the ballast sub-system you employ, Chris, this is an EXPENSIVE hobby. If you find the RCABS components too expensive, then you will find the gas, pump, LPB, piston, hard-tank, and baking-soda forms of ballast water management too expensive as well.
Find something else to do with your time and limited funds is my recommendation. If you have to justify the price of your hobby, then may I suggest you take up bug collecting, bird watching, or TV watching -- things that won't eat at your wallet. R/c Submarining is not a game for pensioner's on a budget; unwashed losers waving will work for food ... God bless you signs at intersections; Welfare slugs; mechanical morons; nose-picking geek-a-zoids; and people who-do-not-like-noise.
You want to play this game on the cheap? OK. Fine! Check out Mike's Sub Works, Rogue Subs, or some other such dealer who specializes in cheap, half-ass, unsupported crap, allegedly intended for use by those wishing to practice the hobby of r/c model submarining. And, Chris, when that box of crap shows up and you discover that you have no idea what to do with it, ask 'em for help. Go ahead! I double-dog dare ya!
Anyway ... if you have not yet stormed out in a burst of tears and choking sobs, here is some straight forward information for you:
Start with the Cabal Reports presented here.
And read what you can of this, http://vabiz.com/d&e/articles.html
The current stuff at the SubCommittee site is wasted band-width. But, if you can dig out the old stuff --authored by me, Asay, Copeland, Dorey, Broader, Sharpe, Perrott, Berger and other of the 'old crew', then you'll find good reading there.
OK, now to the specifics of your post:
RCABS is simple, but suffers from the need to run another motor, the pump/compressor motor. The end-caps (access points at each end of the WTC) have to be hardened to keep from popping off when the internal pressure within the WTC rises as the bladder is sucked dry of air. The bladder (the element that changes volume to effect displacement change) is not an efficient mechanism for the available space and will not always assume the same shape and position in its inflated and deflated conditions. Unless an inordinate amount of bladder is dedicated to the sub-system then some high freeboard type model submarines will not attain their scale surfaced waterlines. For a given displacement, the RCABS installation takes up more room within the WTC than a gas sub-system.
A gas ballast sub-system (the System is a collection of sub-systems that include propulsion, control, and ballast -- the assembled WTC/SubDriver is The System) comprises a soft ballast tank (soft in that its structure is never exposed to any significant differential pressure), open at its bottom; a vent valve; a gas source; and a blow valve.
The negatives of the gas ballast sub-system is the need to periodically charge the gas supply bottle/tank; the slight weight change as a consequence of gas use; and (for you, Chris) the price of the gas, air-brush propellant (the gas source we recommend).
The positives of the gas ballast sub-system is the assurance of the ability to blow the ballast tank dry regardless of depth; the complete use of the ballast tank volume to effect displacement change; elimination of any high current drawing devices; and the low volume of the sub-system components within the WTC/SubDriver.
The snort is the Low Pressure Blower (LPB) ballast sub system. Mr. Caswell is still a Limy at heart and insists on calling it a 'Snort'. I, however am a real American, I use the American term for this air-dependent ballast blowing sub-system.
As employed by Caswell-Merriman, the LPB is a snorkel fed pump that works to blow dry the ballast tank. The LPB works in parallel with, but is not part of, the gas ballast sub-system.
The LPB can only work when the sail of the submarine is broached, putting the LPB induction inlet above the water into the air. In those rare occasions when you can't plane the boat to broach the snorkel induction, you use the gas ballast sub-system to get the sail above the surface, only then can the LPB/Snort ballast sub-system be employed to finish emptying the ballast tank.
Typically, a Caswell-Merriman SubDriver will have two ballast sub-systems aboard, working in concert: the gas ballast sub-system, and the Snort/LPB ballast sub-system. Even though we're dealing with two independent sub-systems to handle ballast water, the devices take up little internal space. For example, the tiny 1/144 KILO SubDriver easily contains both sub-systems!
Yes. You are thick.
Still wanna play?
David,Last edited by Outrider; 12-05-2010, 01:46 PM.Leave a comment:
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Hello all, I am a newbie to RC Subs and am trying to learn the pros and cons of the various ballast systems. I was planning to build an RCABS system, but have been shocked by the price of the valves. This is a hobby to me, unfortunately I cannot justify the prices. It seems overly complicated too and prone to disaster. Not to mention the compressor noise. This thread has made up my mind that it is not the system for me.
My choice now would be the gas ballast system I think. I would love to hear your learned recommendations for the valves required (vent and blow), and the pumps. There is a lot of interesting discussion and debate, and serious time you gentleman have put in, and to this end, your experience and knowledge will be my guide.
Despite my hours of trawling I am yet to find out what a snort is and what it means to the gas ballast system!!! (Am i thick?). Also, what is LPB?
I thoroughly understand why things are discussed in technical terms, but for a newbie, it gets very confusing!
Could anyone suggest any schematics available for download/purchase?
My project is a 2.5m type XXI. My experience to date is mainly RC warships.
Thanks for your time. Any help/suggestions would be most gratefully received.
ChrisLeave a comment:
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Andy,
I'm outraged, sir ... simply outraged!
How dare you!
David,Leave a comment:
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Mike,
re the pumps too - have been mucking around with target stuff....i.e. WW2 depth charge thrower. I won't give you all the details in case someone takes their eye out trying - so don't.
The RCABS pump and bag combination works a treat too at inflating underneath a threaded clear rod connected to a scale chopper with motor inside. Effectively as a gimmick device on a target carrying a helo you power the chopper up with an ESC with pwr leads connected to the on-board motor being very fine brass on the outside of a clear acrylic rod. The rod goes into a sleeve and can move through a vertical plane raising and lowering the chopper via the RCABS bag pushing the rod up and lowering it via inflation deflation cycles.
Other uses involving RCABS principles of getting air from a chamber (not one with push-rods or equipment) are using the pumps to raise and lower scopes - again a gimmick device only - some like it.
Guess what I am saying is there are many uses for these components.
JLast edited by Kazzer; 12-06-2010, 05:37 AM.Leave a comment:
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Hang on to those things, Mike. Might use them as trim tanks for the bigger SD's. I've got ideas:
A small bag at each end of the SD, with a tiny, small volume peristaltic pump between 'em, and another low volume peristaltic pump feeding/emptying the bags from sea, that sort of thing. Two bags, two small pumps giving the ability to both change weight (hovering tanks) and shift the c.g. (trim tanks).
Keep 'em in stock, Mike -- those smaller bags are solid gold!
David,Leave a comment:
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THAT is more like it John!
Thank you for those few kind words!
I guess it's official now -- RCABS sucks!
Damn! I've still got bladders in inventory! (Shot myself in the foot over them eh!)
Maybe we should have a clearance sale on them?Leave a comment:
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Well done, my young sith-loard-in-training.
David,Leave a comment:
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