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Automated surfacing mechanism - anyone else know about this type of syst

R/C Submarine modelers

Postby Carcharadon » Tue Feb 24, 2004 7:46 am

I am currently testing a 7 ft. dynamic diving Nautilus. Having lost this sub twice I'm very concerned about losing it again and consequently developed a very simple self surfacing mechanism and I wanted to know if anyone else has heard of this type of system. It's very simple it seems to work but without actually seeing the sub underwater it's hard to tell.

Here's what it does -- -- motionless at the surface the sub sits level. As forward thrust is applied and as the nose is directed down the sub submerges. The sub is now underwater pointing towards the bottom at a slight angle. I'm guessing that the sub is about 15 ft. underwater. Now only forward thrust is on. The sub is traveling underwater and the sub automatically levels out but the tail end now drops. This means that the nose is now pointing up. The sub probably travels 50 ft. underwater but now since the nose is pointing up it breaches to the surface. And maintains a level position again on the surface.

Here's how it (theory) works. In the tail section there is a rubber bladder. It's the size of a small football and it's only holding air at atmospheric pressure. At the surface the amount of buoyancy provided by the air bladder holds the tail end up such that the sub sits in a perfectly horizontal position. In other words the sub is balanced with foam, weights, etc. and the air bladder. Now if I were to take the sub down to 10 ft. (vertically displace using scuba gear) I should observe that the sub is now pointing up slightly. If I take it down 20 ft. it should be pointing up at an even greater angle. This occurs because the water pressure compresses the air bladder consequently making the tail end of the sub heavier thus changing the inclination of the sub to point up. If forward thrust has been applied you can see that since the sub is pointing up it is forced to the surface and breaches. I should mention though that even without forward thrust the sub would float to the surface anyway but at least this method (I think) keeps me from running the nose into the mud at the bottom in about 30 ft. of water. I did do this onetime and the sub was buried into the mud at least 3 ft. it was a real effort to pull it out.

Since I have not been able to actually see the sub underwater and have only seen the result I am guessing that my simple device is working. But I just don't know.

I have since removed the bladder because I did want the sub to travel underwater and only to surface when I wanted it to and not when it wanted to. I just have to be careful about not running the nose into the bottom mud.

But I was wondering if anyone else has ever come across this concept?




Edited By Carcharadon on 1077626151
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Postby Carcharadon » Tue Feb 24, 2004 9:12 am

For those interested here is a short video clip showing the sub to give you an idea of what it looks like. This is its ramming posture, practice for when it takes out a scale ship!

http://home.comcast.net/~tyourk/7foot.html
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Postby Art Broder » Tue Feb 24, 2004 10:23 am

If you use an ESC it probably turns itself off with radio "Loss Of Signal", as when you go too deep. I wouldn't feel comfortable in a deep pond, with a failsafe system that depends on a compressible bladder, which makes your sub heavier, and may not allow you to surface if your drive motor stops from LOS, or catches on weeds, or other hazard. It would be better to have the bladder flat, centered, and able to expand if your boat ends up "dead" on the bottom. This could be accomplished by a failsafe system that activates a CO2 cartridge or an air pump to inflate the bladder on LOS or at a predetermined depth.
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RCABS- It's easy to control your own bladder!
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Postby Carcharadon » Tue Feb 24, 2004 10:43 am

No ESC. I had a gas system, that’s how I got in trouble, thought I could depend on it. It worked great many times only messed up once. It was fun. I'd just sink it to the bottom 20-30 ft, let it sit there, then pop it straight up. Now I don’t need it. I want to avoid anything complicated less to go wrong. Right now no moving parts on the sub. The sub is currently set up so that it will not sink even if I try to send it to the bottom or as close as it will get. It will be under a long time but it just pops up when I take my hands off the controls. I just wish I could see it.
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