Moebius Skipjack and proposed ballast system

[trout]

More of an exercise of the mind.......
The arms and pads on the servo that you are using do not adjust to the difference the bags will have between fully empty to completely full. So as the bag is full the pads on the arms are pinching and when it is empty there is no contact or influence. Is it even an issue? I don't know.

What if (and this may introduce its own issues) you had two arms, we will call them tension arms, that have a spring that gently pull together. These would be a safety of sorts because on power failure, the gentle pressure from the pads along with WTC compress air would raise the sub. The rods on the servo would be the adjustment of the pads. What do you think? Not necessary (design by committee)?

[DanLew]

More of an exercise of the mind.......
The arms and pads on the servo that you are using do not adjust to the difference the bags will have between fully empty to completely full.
What if (and this may introduce its own issues) you had two arms, we will call them tension arms, that have a spring that gently pull together. These would be a safety of sorts because on power failure, the gentle pressure from the pads along with WTC compress air would raise the sub. The rods on the servo would be the adjustment of the pads. What do you think? Not necessary (design by committee)?

Right. That's why there is still no detailed design proposed. Design by committee is a good thing here. I need ideas, feedback, expertise. A constant compression source to keep the bags in contact with the servo compression arms (whatever) would also be great as a total power loss failsafe as you say.
One helpful bit - the bags don't change that dramatically from empty to full - maybe 3/4" or less of diameter change. When the sub is fully surfaced, the plan is to still have just enough water in the bags that the pitch controller can level the sub.
Thanks for the feedback. Toss in any more ides you have, please.

[Albion]

Note the relief valve should be first item connected to discharge side of pump. If you start pump with the check valve closed you will blow the fittings off and flood the cylinder.

Any positive displacement pump can generate enormous pressure, if momentarily closed in.

one of my old customers manufactured inks, one of the operators figured it was quicker to close the valve for a moment when moving from one container to another, instead of setting the pump on bypass. It's less than a second right! The hose blew high pressure ink in his face, and liberally coated the whole filling area. He was lucky he had eye protection. No safety valve in the system!

[redboat219]

Imagine the look on his co-workers' faces!

[DanLew]

Note the relief valve should be first item connected to discharge side of pump. If you start pump with the check valve closed you will blow the fittings off and flood the cylinder.

Ah....right. Thank you.
Correction made.
Still trying to figure out bag compression system.

[redboat219]

Just want to share something I found surfing. http://www.rigidnsoftmoldtech.com/ch...ild_index.html

The ballast system is rather interesting as it utilizes 2 separate tanks fed by a single water pump.

Ballast Operation:
" The water pump ballast system is what allows this r/c submarine model to submerge. The concept is simple, pump water into the boat to submerge and pump it out to surface. This diagram identifies the various parts of the system.

This submarine needs to float the bow higher than the stern to run on the surface, this is called up bubble trim. Preparing to submerge the forward ballast tank is filled first, bringing the submarine to level bubble. When the forward tank is full, ballast water is vented into the center ballast tank and the boat submerges. Reverse the pump and the boat surfaces at level bubble. When the center ballast tank is empty, the forward tank will drain trimming the boat once again for surface running."

[crazygary]

Possible to have your compression pads hinged, fore and aft,
and spring loaded in a downward fashion. Lightweight springs
should do well at maintaining the hinged pads' contact with
the ballast bags without placing unwanted pressure on the bags.

Just a thought!!

CG

[crazygary]

Always a possibility that the compression pads can be hinged, fore and aft,
and lightly spring-loaded so that they can maintain an even contact with the
ballast bags without placing unwanted residual pressure on them.

Just a thought!!

CG

[He Who Shall Not Be Named]

Could you two POSSIBLY make this thing more complicated!!!!??????........

[Subculture]

[crazygary]

Arrrrgh!! Careful what ye ask for, Matey!! Hah!!

Hey, that looks doable, Subculture!!

CG