Re: [PSUBS-MAILIST] Re: Compass instruments

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

The reason I want to use also the gyro is : I have them allready..
Had purchase two or three at Ebay for between 30 - 80 euro.. 
Also one elek.Horiziont. - Next step will be an aircraft intercom. 

Alec a fluxgate magnetic sensor can be pretty small - just put
it on top of an small antenna. 

Sgt.Peppers has a diver-compass in front of the dome - but it never
works because of the elec.currents in the bowthruster and the reason
that he was to close to the (steel-) hull. 

The only other thing I can imagine - is a small pressure tight bouy  
on a 5 feet cable with the sensor in - or more for the techs - a
hydraulic mast drives out only if you need a course inout.. 
Change the hull material to GRP will be also a solution.. :-))

regards Carsten


Alec Smyth schrieb:
> 
> I just re-read your message. My first response was in a bit of a rush, as my wife was calling from downstairs that the house was flooding due to the melting snow. But priorities are priorities, and I had to finish my PSUBS message!
> 
> :)
> 
> Anyway, between you and Cliff I'm really indebted for the research. Imagine if I went out and spent a couple of thousand dollars on an electric gyro only to find out what you just said about the 15 minute duration! But my question is this... if you put a fluxgate in the sail, it should work whether you're surfaced or submerged. What's the need for having a gyro as well?
> 
> And less my earlier remark offend Cliff, I do want to mention my objection to an outside can is only a problem on Solo, because I don't have a sail in which to carry it cleanly. In his boat, the idea is perfectly sound. In fact he has been generous enough to share design documentation with me, and I should mention he puts me to shame in every way!
> 
> cheers,
> 
> Alec
> PS: wife is calling to lunch now, gotta go.
> 
> -----Original Message-----
> From:   Alec Smyth on behalf of Alec Smyth
> Sent:   Sat 2/22/2003 12:20 PM
> To:     personal_submersibles@psubs.org
> Cc:
> Subject:        RE: [PSUBS-MAILIST] Re: Compass instruments
> 
> Funny, I wrote that last night and since then changed my opinion about how to attack this one. I am back behind Cliff's proposed approach, except I now envision a small acrylic dome open to the inside of the sub, as opposed to a separate "pod". I'm shooting to put the ez-compass-3 in it together with GPS sensor and a panning micro video camera.
> 
> thanks,
> 
> Alec
> 
> -----Original Message-----
> From:   Carsten Standfuss [mailto:MerlinSub@t-online.de]
> Sent:   Sat 2/22/2003 1:49 AM
> To:     personal_submersibles@psubs.org
> Cc:
> Subject:        [PSUBS-MAILIST] Re: Compass instruments
> 
> Hi Alec, nice to hear from you - I still think that "Solo" is the best
> choise for a name of a selfbuild onemansub ;-) The question is so good
> that I transmit the answer to Psubs...
> 
> I found out that an aircraft gyro need to be compensate all 10-15
> minutes by a .. magnetic compass.. Its not a joke - on smaller crafts
> the pilots do it by hand - fly straight course, same speed and level
> than turn the compensate switch with his eyes looking on the magnetic
> compass.
> 
> On bigger or modern aircrafts this compensation is done automaticly by
> an interlink between the gyro and the magnetic compass.. The reason for
> that is that a ships gyro - which is north stabilzied needs some time
> (hours) before he works properly - and is much bigger and heavier.
> 
> I go this way : An aircaft gyro compensate by hand with the information
> form a pretty small magnetic fluxgate sensor about 1.5 (5 feet) on top
> of the sail at on one of the radio antennas.
> 
> The only question concerned me : Is there a problem with the radio VHF
> antenna and the fluxgate magnetic sensor ?
> 
> See you Carsten
> 
> Alec Smyth schrieb:
> >
> > Carsten,
> >
> > I've finished my power distribution panel and am now getting into the instrumentation for depth, life support, navigation, etc. One of the basic decisions is what to do about a compass.
> >
> > I see two possibilities; Cliff Redus's approach using an integrated circuit outside the hull, or an electric directional gyro inside the hull. I don't like the outside the hull approach because it would imply a hydrodynamic drag and might not even work given the amount of steel around.
> >
> > I remember a month or two ago you were asking about gyros. Did you find anything reasonably priced? D'you know if they can be interfaced to a PLC?
> >
> > thanks,
> >
> > Alec
> 
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