[PSUBS-MAILIST] auto pilot

[Stephen Fordyce via Personal_Submersibles]

Hi Hank,
A pretty basic thing, but do you have enough air supply?  Ie. perhaps you
will need quite a bit of water leaking in to actuate the flow switches.
Which needs quite a bit of buoyancy, and since you are at test depth you
have a whole lot of extra ambient pressure to compensate for. Ie.
your 10.7cu ft cylinder at 1500PSI will hold air to displace about 1000cu
ft on the surface, but only 35cu ft at 300m depth.  If that's what you're
using, I think you will be ok ;).

Another consideration is that for the sake of a few minutes extra before
the test, it may be worth a couple of minor considerations in case the
auto-surfacing method fails.  (ie. find a spot in the lake where there is a
flat bottom at desired depth, leave a lifting ring attached/sticking up so
that a cable could later be attached to it for lifting a fully flooded sub,
etc.).

Cheers,
Steve

On Sun, Mar 5, 2017 at 10:27 PM, hank pronk via Personal_Submersibles <
personal_submersibles at psubs.org> wrote:

> Alan,
> Yes I have opted to exhaust my air supply into the MBT's, if I put a
> timer on the solenoid valves to close them, it may not lift if the sub is
> in a snag of some sort.  I want full lifting power.  The solenoid valves
> will be piped into the existing air feed for the MBT needle valves.  I will
> have the needle valves set to feed the air slowly.  I expect Gamma to be on
> the surface before the air is spent.  I am attaching a 5\16 nylon rope to
> the sub and lowering it 5 lbs heavy, so I could haul it up if I had to.  If
> my timer fails and the sub does not surface, I can also simply lower the
> sub another 50 feet or so and the outside  pressure valve will send power
> to the  solenoid valves.
> Hank
>
>
> On Saturday, March 4, 2017 10:49 PM, Alan via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
>
> Hank,
> when the valve opens, is it going to stay open & continually send air
> in to the ballast tanks? Also you mention an external pressure sensor
> to avoid going too deep; are you sending it down on a rope or autonomously.
> Alan
>
> Sent from my iPad
>
> On 5/03/2017, at 2:49 PM, hank pronk via Personal_Submersibles <
> personal_submersibles at psubs.org> wrote:
>
> Hi All,
> I am in the middle of building a remote surfacing system for my subs since
> I seem to be to cheap to go to a pressure chamber.  My system operates from
> a dual industrial timer that powers two solenoid valves, one is redundant.
> The solenoid valves take regulated air to operate an air cylinder that
> actuates a 2,500psi ball valve.  The system also incorporates two float
> switches, one fore and one aft in case water gets in before the one hr test
> is complete.  There is also a internal pressure sensor in case there is an
> air leak, the sub will surface.  There is also an external pressure sensor
> that will prevent the sub diving past the desired pressure test depth.
> Have I missed anything?
> Hank
>
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