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Re: [AirshipList] Re: Designing Airships - bringing our collective knowledge together
by johannes.eissing
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Hi Andreas and all,
I'd love to contribute. Of course I can't spread everything, since this would be against my work contract. But there's an idea about a tool or two, I'm thinking about for several years, but never found the time to implement. I'll send you the details later.
Keep in mind, there's not "The" airship to be designed for "The" mission. Reqiurements differ widely, and so does the design approach. I think a toolset or toolbox would be more suitable than a one-fits-all supertool. It's cruitial to keep this toolbox simple and clearly arranged, just a set of basic tools. A blacksmith's shop rather than a rocket scientists laboratry.
Exchange of information/data between these modules should be simple, I think an xml based dataset would be great.
To start with the basic tasks you first would need something to collect the requirements. It's important to define if your design is for dynamic positioning, racing or just for floating around, beeing cool (Yes even this can be a requirement). It helps avoiding extra work later on in trying to fulfil a requirement, that was never asked for, or that copes a further requirement.
Then a tool for basic volume, buoyancy distribution and CB (Centre of Buoyancy) assessment. Buoyancy is "The" feature of airships, so this is a key module. It should be based on a SAC (Sectional Area Curve): You do not need to know the shape of the ship yet, but the lift. Or you could import a given shape to compute the buoyancy distribution. See FreeShip! or ArchimedesMB for reference (the latter uses an xml file format). Ballonet design should be placed in this module too. Later, you could use this dataset for the assessmetn of added mass distribution.
Fin size, number and placement would be an extra tool. For a first conceptual design run, it should be based on statistical data, later it could compute simple aerodynamics. (see the "Fin and Rudder Wizard" in FreeSHip!).
Basic weights and CG (Centre of Gravity) assessment could be the next step. My former colleagues used to say "in LTA, WEIGHTS IS GOD!". Weight and CG of the envelope, fins, propulsion should be estimated (ah, I missed the propulsion tool!). Later, mass distribution could be be updated, e.g. with measured weights.
W&B (weights and ballance) data should be based on the "Mass Properties Exchange (MPEX) Format" http://www.dbmass.com/mpex/stdframe.html
Resistance and Propulsion
There are several methods of estimating drag or "resistance" as called in ship design. Quite an issue is the large range of Reynolds numbers, since the friction drag coefficient strongly varies with Re- number. For propeller design there are tools available, so I wouldn't load this toolset additionally. What is missing, is a simplified prop model, giving an efficiency based on disk loading.
Anyway, the most common way to design a ship or aircraft is iterating your findings, e.g. in the so called design spiral. From design stage to design stage, you would need more and more specific tools. But don't make the mistage to start a design with a too specific tool: Start simple. And do not try to optimize automatically. At least not yet, since for now, it's more important to understand the coherences than trying to optimize something you are not fully aware of.
Well, more later,
Best, Johannes
> -----Ursprüngliche Nachricht-----
> Von: "Andreas Grunewald" <airshipworld@...>
> Gesendet: 02.07.08 19:57:55
> An: "Airship List" <airship-list@...>
> Betreff: [rc_airship_regatta] Re: [AirshipList] Re: Designing Airships - bringing our collective knowledge together
> Hey Great to get a reply.
>
> On Wed, Jul 2, 2008 at 2:35 PM, hindemith5 <glade@...> wrote:
> >> Do you think we need a resource that collects the best practices
> and
> >> patterns probably pointing to specific books for further reference?
> >
> > Yes, making such resources available would allow LTA/HTA airship
> > enthusiasts at all levels to design and experiment more productively.
>
>
> Awesome that you think so too. I will set up a Wiki on Airshipworld
> that we can use to start compiling stuff.
>
> >
> >
> >> Do we need an Airship Development Software tool that helps us
> design
> >> airships in a computer aided design approach to have an integrated
> >> development environment....if you would be willing to contribute.
> >> The Development model should be collaborative and the software or
> >> resources and artifacts produced should be available for free as
> >> opensource so that everyone can use them enhance them and modify >
> them.
> >
> > I really like the idea of an open source software for simulating
> > airships, since effects such as "apparent mass" that are important
> for
> > airship design are not always intuitive.
>
> Cool So let's do it. I believe we can create something. As Development
> Language I suggest Java, just because it's platform independendt and
> you can even develop in Groovy, Ruby, Python, Scala, Prolog and put
> that stuff directly into the Java programms.
>
> >
> > I am a graduate student at MIT, and could possily find information
> from:
> > Materials department -- composite materials models;
> > Ocean Engineering department -- hydrodynamic models taking into
> > account fluid drag and inertia forces, buoyancy, weight, mass
> inertia,
> > and elastic forces;
> > Aerospace department -- aerodynamic lift models
> > Earth & atmostpheric science department -- weather patterns
>
> That would be awesome, it would be cool if we could connect to those
> deparments, and maybe interest students to contribute maybe as part of
> their thesis or a project !?
>
> > It may even be worth starting a global club around this topic, named
> > something like OpenAirWare. Any ideas about how to obtain funding
> for
> > such an effort?
>
> I don't have any direct sources and I think we first have to outline
> our plan and start producing something, then get Universities and
> Companies involved who can get a benefit from the Project. Then we can
> approach Google or other large Organisations for Funding. The
> bootstrap has to be done on a shoestring budget. But webspace and dev
> environment are free so it costs only time and idealism right now ;-)
>
> >> Let me know what you think I could envision specialized versions
> for
> >> designing remote controlled airships and passenger airships.
> >
> > It may be worthwhile to try to leverage the free Google SketchUp
> > software for 3D design and visualization, as programs such as
> > SolidWorks are very expensive for non-professionals.
>
> Yes I have thought about Google SketchUp and there is probably a lot
> of other stuff that we can leverage. I am even thinking about using
> the Havok Physics Engine which is available for free from
> http://www.havok.com/content/view/17/30/ this could give us a good
> start.
> As Platform I would suggest the Eclipse Rich Client Platform for its
> high quality and the good framework it provides.
>
> So the Idea is there who is interested to contribute.
>
> Let everyone know. Let's build our own Airship CAD&IDE. (Computer
> Aided Design&Integrated Development Environment)
>
> Regards
>
> Andreas
>
> >
> > Best,
> >
> > Forrest Liau
> >
>
> --
> Editor of Airshipworld
> --------------------------------------------------------
> Visit the Airshipworld Blog at
> http://airshipworld.blogspot.com
> --------------------------------------------------------
> __._,_.___
> Messages in this topic (1) Reply (via web post) | Start a new
> topic
> Messages | Files | Photos | Links | Database | Polls | Members |
> Calendar
>
>
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I'd love to contribute. Of course I can't spread everything, since this would be against my work contract. But there's an idea about a tool or two, I'm thinking about for several years, but never found the time to implement. I'll send you the details later.
Keep in mind, there's not "The" airship to be designed for "The" mission. Reqiurements differ widely, and so does the design approach. I think a toolset or toolbox would be more suitable than a one-fits-all supertool. It's cruitial to keep this toolbox simple and clearly arranged, just a set of basic tools. A blacksmith's shop rather than a rocket scientists laboratry.
Exchange of information/data between these modules should be simple, I think an xml based dataset would be great.
To start with the basic tasks you first would need something to collect the requirements. It's important to define if your design is for dynamic positioning, racing or just for floating around, beeing cool (Yes even this can be a requirement). It helps avoiding extra work later on in trying to fulfil a requirement, that was never asked for, or that copes a further requirement.
Then a tool for basic volume, buoyancy distribution and CB (Centre of Buoyancy) assessment. Buoyancy is "The" feature of airships, so this is a key module. It should be based on a SAC (Sectional Area Curve): You do not need to know the shape of the ship yet, but the lift. Or you could import a given shape to compute the buoyancy distribution. See FreeShip! or ArchimedesMB for reference (the latter uses an xml file format). Ballonet design should be placed in this module too. Later, you could use this dataset for the assessmetn of added mass distribution.
Fin size, number and placement would be an extra tool. For a first conceptual design run, it should be based on statistical data, later it could compute simple aerodynamics. (see the "Fin and Rudder Wizard" in FreeSHip!).
Basic weights and CG (Centre of Gravity) assessment could be the next step. My former colleagues used to say "in LTA, WEIGHTS IS GOD!". Weight and CG of the envelope, fins, propulsion should be estimated (ah, I missed the propulsion tool!). Later, mass distribution could be be updated, e.g. with measured weights.
W&B (weights and ballance) data should be based on the "Mass Properties Exchange (MPEX) Format" http://www.dbmass.com/mpex/stdframe.html
Resistance and Propulsion
There are several methods of estimating drag or "resistance" as called in ship design. Quite an issue is the large range of Reynolds numbers, since the friction drag coefficient strongly varies with Re- number. For propeller design there are tools available, so I wouldn't load this toolset additionally. What is missing, is a simplified prop model, giving an efficiency based on disk loading.
Anyway, the most common way to design a ship or aircraft is iterating your findings, e.g. in the so called design spiral. From design stage to design stage, you would need more and more specific tools. But don't make the mistage to start a design with a too specific tool: Start simple. And do not try to optimize automatically. At least not yet, since for now, it's more important to understand the coherences than trying to optimize something you are not fully aware of.
Well, more later,
Best, Johannes
> -----Ursprüngliche Nachricht-----
> Von: "Andreas Grunewald" <airshipworld@...>
> Gesendet: 02.07.08 19:57:55
> An: "Airship List" <airship-list@...>
> Betreff: [rc_airship_regatta] Re: [AirshipList] Re: Designing Airships - bringing our collective knowledge together
> Hey Great to get a reply.
>
> On Wed, Jul 2, 2008 at 2:35 PM, hindemith5 <glade@...> wrote:
> >> Do you think we need a resource that collects the best practices
> and
> >> patterns probably pointing to specific books for further reference?
> >
> > Yes, making such resources available would allow LTA/HTA airship
> > enthusiasts at all levels to design and experiment more productively.
>
>
> Awesome that you think so too. I will set up a Wiki on Airshipworld
> that we can use to start compiling stuff.
>
> >
> >
> >> Do we need an Airship Development Software tool that helps us
> design
> >> airships in a computer aided design approach to have an integrated
> >> development environment....if you would be willing to contribute.
> >> The Development model should be collaborative and the software or
> >> resources and artifacts produced should be available for free as
> >> opensource so that everyone can use them enhance them and modify >
> them.
> >
> > I really like the idea of an open source software for simulating
> > airships, since effects such as "apparent mass" that are important
> for
> > airship design are not always intuitive.
>
> Cool So let's do it. I believe we can create something. As Development
> Language I suggest Java, just because it's platform independendt and
> you can even develop in Groovy, Ruby, Python, Scala, Prolog and put
> that stuff directly into the Java programms.
>
> >
> > I am a graduate student at MIT, and could possily find information
> from:
> > Materials department -- composite materials models;
> > Ocean Engineering department -- hydrodynamic models taking into
> > account fluid drag and inertia forces, buoyancy, weight, mass
> inertia,
> > and elastic forces;
> > Aerospace department -- aerodynamic lift models
> > Earth & atmostpheric science department -- weather patterns
>
> That would be awesome, it would be cool if we could connect to those
> deparments, and maybe interest students to contribute maybe as part of
> their thesis or a project !?
>
> > It may even be worth starting a global club around this topic, named
> > something like OpenAirWare. Any ideas about how to obtain funding
> for
> > such an effort?
>
> I don't have any direct sources and I think we first have to outline
> our plan and start producing something, then get Universities and
> Companies involved who can get a benefit from the Project. Then we can
> approach Google or other large Organisations for Funding. The
> bootstrap has to be done on a shoestring budget. But webspace and dev
> environment are free so it costs only time and idealism right now ;-)
>
> >> Let me know what you think I could envision specialized versions
> for
> >> designing remote controlled airships and passenger airships.
> >
> > It may be worthwhile to try to leverage the free Google SketchUp
> > software for 3D design and visualization, as programs such as
> > SolidWorks are very expensive for non-professionals.
>
> Yes I have thought about Google SketchUp and there is probably a lot
> of other stuff that we can leverage. I am even thinking about using
> the Havok Physics Engine which is available for free from
> http://www.havok.com/content/view/17/30/ this could give us a good
> start.
> As Platform I would suggest the Eclipse Rich Client Platform for its
> high quality and the good framework it provides.
>
> So the Idea is there who is interested to contribute.
>
> Let everyone know. Let's build our own Airship CAD&IDE. (Computer
> Aided Design&Integrated Development Environment)
>
> Regards
>
> Andreas
>
> >
> > Best,
> >
> > Forrest Liau
> >
>
> --
> Editor of Airshipworld
> --------------------------------------------------------
> Visit the Airshipworld Blog at
> http://airshipworld.blogspot.com
> --------------------------------------------------------
> __._,_.___
> Messages in this topic (1) Reply (via web post) | Start a new
> topic
> Messages | Files | Photos | Links | Database | Polls | Members |
> Calendar
>
>
_______________________________________________
The-List mailing list
The-List@...
http://airshipworld.info/mailman/listinfo/the-list_airshipworld.info
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