Stealth Submarine Design

[redboat219]

yes. it is where I inject the air charge for the bladder using a turkey baster pump so I can measure the air volume I need.

How much air does it need?

[southern or]

the WTC contains the entire propulsion system that needs to be sealed off from water. main parts are electric motor, servos, level sensor, battery, battery charge guard, esc, pump, & solenoid valve. it is a RECABS. And out side of the WTC, in the hull, are two compressed air tanks. The bladder is inside a wetted compartment of the WTC. Thank you for the information on stealth. Appreciate the clarification. When I first conceived the hull shape, I was influenced heavily by my favorite airplane-the SR-71 Black Bird.

From one of our trips to the Evergreen Museum. It has been moved over to their space museum and has a D-21 drone with it.

[cliffhanger67]

Thought the conduit cover was a clever idea.
Also like the looks of your hose and connectors.
Where did you find a source for them?
Scott T

The hose is an aquarium air pump aerator. They come in several size and stiffness. I selected the most supple and id that fits best for the fittings. The fittings are from Home Depot used for drip irrigation. They are available in different configurations, T, elbow, straight, plug. To allow easy connect and disconnect, I rounded the sharp barb of the fitting. once I finalized my air system configuration, I ended up gluing every joint to get 100% leak proof.

[cliffhanger67]

How much air does it need?

I fill the bladder 100 cc of air.

[redboat219]

Can you give the dimensions of your air tanks?

[Ralph --- SSBN 598]

100cc = 3.38ounces = 6.102 cubic inches

Example:
cube 2.25"x2.25"x1.25" = 6.33 cubic inches
cylinder 2.5" in diameter by 1.25" long gives 6.1328 cubic inches of volume. (3.14 x (1.25" x 1.25") x 1.25") = 6.1328 cubic inches

Volume of cylinder 3.14 x radius squared x length = volume

[redboat219]

Lets clear things up. Cliffhanger pumps up the bladder using a baster with 100cc of air. To dive the boat a pump sucks the air out of the bladder and stores it in the 2 tanks in the stern section. To surface a valve releases air back into the bladder.
It's those tanks' dimensions that I'm interested in. I want to know how much pressure the pump delivers and the pressure capacity of the tanks.

[Ralph --- SSBN 598]

I do understand.
I was just providing various formulas on calculating volume.
Once the pump pressure is determined, then the volume needed that the pump can pressurize without stalling the pump can be determined.

If there is room, a large pressure tank can be used requiring less pressure from the pump to store the 100cc needed.

The size of the pressure tank(s) can be off set with ballast weight until the tank is neutral.
Then only the 100cc effects the surface/dive trim of the boat.

I was not disagreeing with the system used.
I like to see the engineering others use to make their boats work.

[redboat219]

Simple Boyle's equation. You can compute for pressure and volume.

About using a bigger storage tank, wouldn't you have difficulty re-inflating your bag due to the lower pressure differential?

Yes, it's great to see home engineered solution.

[Guest]

If you use the small diaphragm type compressors generally used with RCABS, RCABS-R, snort etc. The pressure limit is usually about 5-6 psi before they reach their limit. Some of the larger pumps can go up to 15psi, but they tend to be too large to fit in smaller cylinders.

Therefore the limit of depth to blow ballast is about ten feet and if the system is recirculating you will require a reservoir about three times the volume of your dive tank. For boats where the ballast tank makes up about 10-12% of the overall displacement, that kind of volume is usually easily found. More than that can sometimes prove a struggle, and in that case a vented, or partially vented system can be useful.

If you think you're likely to go deeper than ten feet (unlikely except unintentionally), you need to think about using another system which is capable of dealing with higher pressures, or you will need to fiddle about with things like running pumps in series to increase pressure.

[cliffhanger67]

Harpoon sub air volume

Lets clear things up. Cliffhanger pumps up the bladder using a baster with 100cc of air. To dive the boat a pump sucks the air out of the bladder and stores it in the 2 tanks in the stern section. To surface a valve releases air back into the bladder.
It's those tanks' dimensions that I'm interested in. I want to know how much pressure the pump delivers and the pressure capacity of the tanks.

The twin cylinders are elliptical section 1.22x.675, 2.75" long inside dimensions. Originally, I was pressurizing at 14+ psi. however, my pump failed. I bought the same pump. It could not get more than 11 psi. Mostly at 10 psi. Not good enough. I cannot change the space for the pump so I ended up making conformal air tanks to double my total compressed air reservoir. The bladder is 350 cc rated. I am still using about 100 cc of air to surface the boat. The tanks were tested at 20 psi. I placed the new conformal tanks mid ship between the hull ant WTC.

[redboat219]

Cliff can you post photos of your new layout.

"Maligayang Pasko!"

[redboat219]

Possible air tank.
Found this at my local coffee shop. They're whip cream chargers. The originally contained NO2 gas. The cylinders are about 6.3 cm (2.5 inches) long and 1.8 cm (0.7 inches) wide. The walls are about 2 mm (about 1/16 inch) thick . The interior volume is 10 cm3.

[bigdave]

Too small and heavy. I would not even bother unless you used compressed gas. BD