Re: [PSUBS-MAILIST] Ambient pressure design considerations

[MerlinSub@t-online.de (Carsten Standfuss)]

Hi Dave .. the only problem I see is the size of the regulator and the
size of the air tank.. 

If you write " small and hydrodynamic as possible" that indicates that
you can change the deep very fast. From 33 feet to 99 feet in how many
second ? And if the regulator or air tank is to small... crunchhh...

regards Carsten 

> Dave Altis schrieb:
> 
> Okay, I've silently observed this list for some time now and I'm ready
> to disclose some of my ignorance to the group in the hope of gaining
> some valuable input.
> 
> My intent is to build a small ambient pressure dry sub for
> recreational use in the fresh water lakes of my area.  The conceptual
> design would be limited (by pressure switch) to a depth of 33 feet
> (aproximately).  I need to keep the sub as small and hydrodynamic as
> possible to minimize power requirements.  The sub will remain slightly
> positive in boyancy and will power-dive using dive planes which will
> be linked via a mechanical mixer to provide both pitch and roll
> control.  A control stick and rudder pedals would be incorporated as
> in an airplane (like flying under water).  If the craft exceeds the
> depth of 33 feet the pressure switch will deactivate the motor thereby
> forcing it to ascend back into its window of operation.  An emergency
> override switch will allow the use of power beyond the 33 ft. limit.
> My plan is to breathe compressed air through a two-stage regulator
> (scuba) with an exhaust duct to carry exhaled gasses to the outside of
> the sub.
> 
> Any red flags yet?
> 
> By exhausting the exhaled air to the outside I hope to minimize
> moisture condensate and CO2 buildup inside the sub, however, I realize
> in order for this to work it is absolutely essential that the air
> pressure inside the sub remain ambient to the pressure outside the
> sub.
> 
> I have to go for now, but I have more questions relative to ambient
> pressure and boyancy to come in another post.  I'm not looking for
> ridicule, but if you have some constructive criticism or see cause for
> concern with my plans thus far, I would value your input.
> 
> Thanks,
> 
> Dave Altis
> 
>