Blended Wing Body

[Pavan Soni]

Hey there, I am a rookie when it comes to designing. So if any of you guys can help me out in building a Blended Wing Body Aircraft in VSP. Every help is appreciated. thank you

[Mark Moore]

Pavan,

Here are my recommendations.

1) If you already know and are comfortable with Catia - by all means use it to create geometries of interest (after determining what analysis methods you will use to understand the internal packaging, aerodynamics, mass properties, control, propulsion, and mission analysis.  You will need analysis tools for all these areas.  For a conceptual design study you want to choose analysis methods that are relative simple and fast, to let you analysis and optimize geometries quickly (but not with tremendous accuracy, which can occur later - after an initial investigation of the design choices).

2) If you don't know how to use Catia then why in the world would you spend 6 of the next 9 months trying to figure out how to use that highly detailed CAD geometry tool to perform relatively simple geometry problems that VSP was specifically designed to do (far faster and better for conceptual design than Catia).

3) I uploaded the N2A Hybrid WIng Body geometry model as a starting point for your analysis; look in the VSP Hangar.  This is a public geometry based on the prior MIT SAX-40 conceptual design study.  Playing with this geometry will help you quickly understand how you can use VSP to run a vorlax lattice induced drag analysis, get wetted areas to do a parasite drag build-up, etc.  You can easily modify this geometry to meet your needs.  In particular you will be interested in figuring out how to package hydrogen tanks in a Hybrid Wing Body structure to best make use of the large volume that exists in HWB designs.  Hydrogen tanks will take a LOT of volume - and HWBs have a lot of volume to offer.  You can use VSP to do internal packaging studies extremely quickly - everything from tanks to seats to cargo pallets.  Look in the VSP Hanger for the seat and pallet components which can easily be INSERTED in any geometry.

4) Go to the NASA NTRS website.  Do a search for Hybrid Wing Body and see the hundreds of reports that already exist.  Then be much more specific in your search to find the conceptual design studies that have already been done to guide you on how you should do your study.  In particular look for the MIT SAX-40 study.  Look for reports from Guynn or Nickol, who have done many conceptual design studies of HWBs.  In particular look for the Scaling Study done by Nickol.  Look for hydrogen HWB studies, which have also been done.  Always look for reports that show what others have done first, so you can understand what they have done, and make sure you do at least as good as they have done before you. 

This gives you tons of information as a starting point.  What I would expect from you is to make the effort to watch the videos on the VSP website that give a quick and easy tutorial of how to use it.  I would expect that before you ask a question on how to do relatively simple things with VSP that you look for those answers in the VSP manual that is provided, as well as comments on the Google discussion group, as well as the Wiki. 

But if you love to bang your head against the wall, by all means spend the next 6 months learning Catia so that you can then spend the last 3 months of this effort frantically figuring out what you will do with that single geometry you created (instead of the hundreds of different geometries you could have generated and analyzed in the same time with VSP).  If you just throw your geometry into a CFD tool - then that isn't design.  So figure out what information you need, and whether you even want to run any CFD analysis.  CART-3D is an easy way to show CFD analysis results - Rob has provided a complete tutorial on the Wiki to guide you on how you can in less than an hour have CFD results of a HWB geometry such as the N2A model.  But you will need to get access to CART-3D software, which I don't know if you can get.

Make the effort to understand all the needs that you will have to get this conceptual design study done; figure out what unique value you want to add to the existing knowledge that exists; and figure out what you are most interested in so that you can focus your efforts on that one portion of design (i.e. do you like controls, structures, aero - because you won't have time to do an excellent job on everything).  Researchers have been studying the HWB for 20 years,

After you have done your best to figure all this out.  Rob and I are happy to help - but after you have done your part.

Good luck,

Mark

On Sun, Feb 24, 2013 at 2:20 PM, Pavan Soni <pavan...@gmail.com> wrote:

Hey there, I am a rookie when it comes to designing. So if any of you guys can help me out in building a Blended Wing Body Aircraft in VSP. Every help is appreciated. thank you

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[Nelson Brown]

Recently I've been helping with the archiving of X-48B/C flight test
data at Dryden. Not sure if there's anything in there of significant
interest to the design community (that hasn't already been published.)

If you think of something interesting or valuable that is missing from
the existing reports, please send me a suggestion.

Nelson

[Mark Moore]

Thanks for this offer.  The X-48 has been doing some great research into understanding the difference in control of Hybrid Wing Bodies vs conventional transports with a sub-scale demonstrator.  While I have the X-48 exact geometry, it is proprietary to Boeing, so I haven't uploaded it to the VSP Hanger.  If Pavan is specifically interested in understanding and analyzing the control issues of HWBs, he would do well to look at all the research that has been conducted with the X-48.

One note I would add - if you look at the N2A HWB model I posted, it has a LOT of sections to the wing (i.e. 34).  This is way more than I would suggest any student use for a design study.  A total of 5 or 6 sections would correctly capture the shape well for a packaging study, and permit a much easier optimization and investigation.  The N2A model that I posted was attempting to be a highly accurate representation of a CAD geometry, and therefore many sections were used to most accurately capture that data.  This shows the inherent trade-off the aircraft designers must face (and choose) depending on what question they are attempting to answer; is it critical to capture the nearly EXACT geometry (as when using higher-order CFD methods where a slight difference can result in a huge drag difference - potentially).  Or is a parametric investigation being performed with simplier methods that aren't high enough fidelity to even notice small geometric issues.

Thanks again for this offer - and keep publishing such great data sets to help understand new vehicle concepts.

Mark

[Michael Kruger]

Hi Mark.

I enjoyed reading the guidance on the design process you gave above. I am unfortunately one of those who basically spent half of my Masters being frustrated with a high-end CAD package. My study-leader basically insisted that I use that program. My research essentially consists of that 'packaging' problem that you speak of and I would have saved SO MUCH time if I could have used VSP.

Regards

Michael