Re: [PSUBS-MAILIST] Hydraulic Drive Unit

[Coalbunny <coalbunny@vcn.com>]

Carsten, this is a bit off of this subject but relavant- how much would
it cost to build your sub in the US?
Carl


Carsten Standfuss wrote:
> 
> Gary R. Boucher schrieb:
> 
> > Each design is an optimization of purpose based on a very extensive set of
> > tradeoffs.  The engineer's main purpose is to make judgements as to what is
> > important and what is not, what is going to promote the design philosophy
> > and what is not.  Good engineers are going to weigh the merits and balance
> > the pros and cons.
> 
> :-))
> 
> > I hear a lot of talk about propulsion on PSUBS.  I hear some really
> > outlandish proposals.  Most are not feasible, but I seldom discard these
> > ideas, in that I put many of them on the shelf for later consideration.
> 
> :-)))
> 
> > >Carsten Standfuss obviously understands the issues.
> >
> > Carsten apparently is a good engineer and builder.  But, just because he
> > elected to not use hydraulics for his controls does not make, in itself,
> > hydraulic controls a poor decision.
> 
> Right..
> 
> May I should explain how the process on my sub was..
> 
> First step : I decided to have hydraulics for the Thruster and the vales
> and the rudder
> and all outside in the seawater direct on the rudders etc. The reason
> was :  the simple
> hydraulic truehulls. And the compact force hydraulics have. And that I
> get a big pump for free.
> 
> Second we found out :
> That standard hydrauilc motors and cylinder are not seawater resistant
> over longer periods
> and if they failed we can not work on it in the water.. so boat has to
> be back into the harbour
> and than move onshore - just two times 1000 US Dollar for the crane.
> Also the lip-bearing
> of the cylinders and motors are normally designed for inside pressure
> higher than outside..
> 
> - so we decided to put the cylinders inside.
> 
> Third we found out that the 2 x 9 KW Thruster need a big hydraulik oil
> storage tank
> for cooling reason and  a bigger pump - the 30 % performance lost goes
> mostly to head..
> - so we decided to have electric thruster direct in the pipes -
> drill-motor typ- means
> standard electricmotors for deep-drill-holes - allready filled with
> water or oil.
> 
> With all the hydraulics inside it was just a small step - just the
> information that
> strong DC servos available - to keep out the hydraulics complete..
> 
> I use hydraulic on the yard every day - there are many good reason for
> hydraulic
> and Euronaut will have a short hand power hydraulic double action
> cylinder to open the
> 500 pound heavy diver exit hatch - because hydraulic means - hi force
> and compact
> on the place were the action is.
> 
> Just today we make a new concept for the machinery room concept for the
> sub
> - is number 11 or 12.. i think.. Without the hydraulic pump it is
> nessesary
> to re-think some other components there - maybe I can have a small
> workbench there.
> 
> In my first days on Sgt.Peppers I have a lot of trouble with the
> oil filled outside electric thrusters.. so I rebuild them to pressure
> air compensation..
> .. One day the storgae bottle had a bad conection the pressure air goes
> away
> and the motors flooded with water.. .. was freshwater - obviously it is
> much
> more difficult to flood a hydraulic cylinder or motor..
> 
> I personaly think that seawater resistant water-hydraulic can be a very
> nice solution
> - no big deal if you have small leaks.. and if seawater goes inside - it
> will be
> have only a very little effect to all the freshwater inside the system.
> Seawater in
> oil filled system can be a nightmare..
> 
> Be happy - Carsten
> 
> > Gary Boucher

-- 
"You delight not in a city's seven or seventy wonders, but in an answer
it gives to a question of yours, or the question it asks you, forcing
you to answer, like Thebes through the mouth of the Sphinx." -- Kublai
Khan