Frequently Asked Questions
Advanced Aircraft Analysis:
► What is the maximum altitude AAA uses to calculate atmosphere properties?
Our atmosphere model has a maximum of 291,000 ft. AAA will warn you when certain parameters are beyond what can be calculated with AAA methods.
► Is it possible to analyze a radio controlled plane with the AAA program?
Quite a few modules in AAA can be used for radio controlled airplanes. Such as aerodynamics and stability and control. The weights module is not useful and neither is the cost module. Be careful though with low Reynolds numbers. Kansas University students have used the AAA software in the past for radio controlled airplanes.
► Can Advanced Aircraft Analysis (AAA) be used to design Unmanned Air Vehicles (UAV's)?
Yes. AAA can be used for UAV design (fixed wing only). In the next release of AAA even regression coefficients for UAV's will be included in Weight Sizing. Most other AAA modules can be used in the design of UAV's.
► Can I model a joined wing in AAA?
Yes. A joined wing may be modeled using a wing and a canard lifting surface. Twin vertical tails may be modeled between the surface tips as well.
► Is it possible to manipulate AAA to analyze a blended wing-body (BWB) airplane configuration?
You can define a flying wing by indicating there is no horizontal, no V-Tail, no canard and no vertical tail. You can supply fuselage parameters for the part of the blended body that is used as fuselage. We do not have a trim module for flying wings. Weights and S&C derivatives can be used for flying wings.
► It is unclear as to where the factors 36.5 and 0.08 in the help for Cmo_f originate from.
The factor 36.5 is a conversion factor from degrees to radians and the 0.08 per degree is because the graph from which de/da is calculated is based on a CL_alpha of 0.08 per degree (Refer Figure 8.115, Airplane Design: Part VI by Dr. Jan Roskam). See Pitching Moment for a Body of Revolution (pdf) for more details.
► What is the appropriate way to model an engine/nacelle that is buried in the fuselage?
It is best to model the nacelle as a part of the fuselage and not define it separately.
► What is the appropriate way to model an engine/nacelle that is buried in the fuselage?
It is best to model the nacelle as a part of the fuselage and not define it separately.
► It is unclear as to where the factors 36.5 and 0.08 in the help for Cmo_f originate from.
The factor 36.5 is a conversion factor from degrees to radians and the 0.08 per degree is because the graph from which de/da is calculated is based on a CL_alpha of 0.08 per degree (Refer Figure 8.115, Airplane Design: Part VI by Dr. Jan Roskam). See Pitching Moment for a Body of Revolution (pdf) for more details.
► Is it possible to manipulate AAA to analyze a blended wing-body (BWB) airplane configuration?
You can define a flying wing by indicating there is no horizontal, no V-Tail, no canard and no vertical tail. You can supply fuselage parameters for the part of the blended body that is used as fuselage. We do not have a trim module for flying wings. Weights and S&C derivatives can be used for flying wings.
► Can I model a joined wing in AAA?
Yes. A joined wing may be modeled using a wing and a canard lifting surface. Twin vertical tails may be modeled between the surface tips as well.
► Does Advanced Aircraft Analysis (AAA) support SI units?
Yes, AAA supports SI units. When you install AAA for the first time it will ask what your default units are and you can set it to SI. You can always change this inside AAA by going to Setup > Units. You can also temporarily change a unit in the calculator. For instance if you have the engine power in hp, but you have setup your AAA for SI units (it will show power in Watt or KW) then inside the calculator you can click the SI/British button and you can enter the power in HP.
► When using the Transfer Function modules in Dynamics, the Transfer Functions are not displayed in AAA 2.4 as they are in previous versions. How do I view the Transfer Functions?
To display the Transfer Functions as in previous versions of AAA, follow these steps. Go to Help on the menu bar. Then select "About". When the "About AAA" window displays, hit F6 on the keyboard to toggle on the Transfer Functions. This will also turn the Transfer Function display off. The Transfer Functions can be printed (as before) by going to File/Print and selecting "Pring Parameters". This is a known bug and will be fixed in the next release of AAA.
► How do I know where certain variables are calculated?
AAA 2.5+: There is a button that takes you to the calculation.
AAA 2.4 & earlier: The User's Manual contains an Appendix with all variables currently calculated in AAA. The Appendix shows a flow chart on how to find this variable in AAA.
► Can I export my airplane drawing from AeroPack to AAA?
Currently the interface between AAA and AeroPack is only from AAA to AeroPack.
► Will AAA run in a network environment?
AAA can be installed as a Node Locked License: AAA is only valid on the PC the software is installed on; and Floating License: AAA can be used on any computer in the network. The number of floating licenses is set by the WIBU-BOX/U: Universal Serial Bus (USB).
► Is AAA available on Linux?
Not at this time, but we are looking into porting AAA to Linux.
► Is AAA available on UNIX (AIX, IRIX, Solaris)?
No. AAA Version 1.7 was the last version of AAA that ran on UNIX workstations. There are no plans to port AAA back to the workstations. AAA runs under Windows on PC and under window emulators on workstations such as SoftWindows or VirtualPC.
► Will AAA run on the MAC?
Some customers have successfully run Advanced Aircraft Analysis (AAA) software on the MAC using a Windows emulator program. However we have not tested this and do not support AAA on the MAC.
► How does AAA relate to AeroPack?
AAA interfaces with AeroPack, which is an add on software to Shark and Shark FX. The interface is actually file exchange. AAA exports a geometry file and AeroPack can import this file. There is currently no export from AeroPack into AAA. This is planned for a future version.
► What kind of background do I need to use AAA?
We recommend a technical background and knowledge of the airplane design process. In addition, we recommend the textbooks Airplane Design I - VIII, Flight Dynamics I & II, by J. Roskam and Aerodynamics & Performance, by C.T. Lan and J. Roskam be used with the software. These textbooks can be purchased at our On-Line Store.
► What are the Software Minimum System Requirements?
Processor: Pentium
Operating System: Windows 2000, XP
Memory: 32MB
Hard Disk Space: 70MB
Monitor Resolution: 1024 x 768
Output Devices: Windows driven printers and plotters.
► What is included with the software purchase?
AAA node locked or floating license on CD-ROM, printed user's manual, WIBU-BOX:USB and 12 months technical support.
Student License: AAA software and user manual (pdf) on CD-ROM and WIBU Key (USB).
► In the isometric view the airplane is oriented along the X axis. Does this correspond to the Y axis in the conventional coordinate system or is the aerospace practice to orient along the X axis instead of the Y axis?"
The Aerospace convention is to orient the fuselage along the X-axis, not the Y-axis. We just have to be different from the rest of the world. If you remember from the "Concepts Setup" module, that is actually why there is an option to change the view definitions in Concepts.
► What is the benefit of using conics? Should I redraw my airplane using conics?
The use of conics actually dates back to before high-powered CAD programs. It was actually first used on the P-51 Mustang as a way to accurately control cross sectional areas to secure the required effect for lift, drag, stability, and overall performance. They provide a good way of mathematically defining cross sections that are more complex than simple circles or ovals. In terms of drawing an aircraft, the main benefit of conics and polyconic surfaces are the ease of creating and updating the model. Rather than having to create each individual cross section, all you have to do is create the profile lines and then you can numerically define the cross sections. Also, you don't have to worry about unwanted waves developing between your cross sections like you do with Skin surfaces and it is much easier to get proper tangency with adjacent surfaces. For example, when a "Skin Surface" type method is used a "crease" will often appear down the center of the aircraft where the surfaces were not tangent. This almost always happens and is difficult to get out while keeping a symmetric aircraft. By using polyconic surfaces, symmetry and tangency are guaranteed.
Since you already have the model created, there is probably no reason to redraw it until you decide to make changes.
► I have kept on working with Concepts 3D Version 2 (build 579) since my Version 3, SP1 package (build 642) does not correctly display splines and conics of my drawings drawn with the build 579 (some conics look squarish and splines no longer run through the correct original points). So, I am keeping to using Concepts 3D V2 for now, until I find out what the cause of this is and whether it can be corrected. Perhaps CSI has modified the definitions of their splining...?:
The display issue that you are experiencing is a bug that was introduced in Version 3 (Build 624). Basically, Concepts âestimatesâ the shape geometry when displaying it to save system resources. In this case, the estimations are getting too far from the real shape. The math behind the curves are still ok, they are just not being displayed correctly.
To more or less fix the problem in Version 3, go to Edit->Change Resolution and select the "Even Distribution" box. The displayed spline will still slightly miss the control points, but the error is on the equivalent order of 1/10000 of an inch, so unless you are zoomed in VERY close, you cannot see a difference.
CSI is aware of the problem and working to correct it. I have worked a little with the V4 Beta and so far I believe the issue has been corrected to the point where the default display works like V3 does with "Even Distribution" selected. I am not certain about this, however. Even if nothing has changed, the â"Even Distribution" trick would work in V4 as well.
In response to a similar question on their forum, developers at CSI posted this response which provides a more permanent solution: You could also create a Resolutions.ini file to customize default curve and facet resolutions, syntax as follows:
[CurveResolutions]
COARSE=20.0000000000000000
MEDIUM=15.0000000000000000
FINE=11.0000000000000000
SUPER_FINE=4.5000000000000000
VERY_FINE=8.0000000000000000
[FacetResolutions]
COARSE=20.0000000000000000
MEDIUM=16.0000000000000000
FINE=12.0000000000000000
SUPER_FINE=5.0000000000000000
VERY_FINE=7.0000000000000000
Word of caution from David [Concepts developer] - "be careful with this, it can change the faceting of existing files when they are read in"
The file created should be placed in the 'Environ' folder, located in the installation directory.
Changing the value of one of the resolutions to 0.0 actually gets curves and surfaces closer to their control points than the 'Even Distribution' and 'Precise Facets' do. By setting the program preferences to create all new geometry with the resolution that was set to 0.0, the user will not have to individually change the resolution to fix the display. One other thing to watch out for with this solution is that it may significantly slow down the programâs performance, especially for large files.
► What is AeroPack?
AeroPack is a collection of unique drawing tools created specifically for airplane design and drafting that can also read geometric information from the Advanced Aircraft Analysis (AAA) analysis modules. AeroPack is not an independent software, but is an add on to Punch Software Shark and Shark FX, providing increased capabilities for today's aircraft design.
► Does AeroPack support Stereolithography?
Yes. It is an export option.
► Does AeroPack read Auto-CAD files?
AeroPack reads ASCII, DWG, DXF, ACIS and FACET files and also uses IGES for file exchange.
► My browser's padlock icon indicates that your online bookstore is not secure. Is it really safe to submit my credit card information to you over the Internet?
The reason the padlock does not appear is because there are some parts of our online store that are common to our other websites, such as images, formatting, etc. This data is not transferred over a secure connection. Because the page you are seeing contains both encrypted and non-encrypted data, your browser's padlock icon will indicate an insecure page.
If you check your browser's listed properties for our page you will find our valid certificate signed by Equifax and an encryption confirmation. We use strong encryption to protect your information from interception. You can verify this in Mozilla Firefox by double-clicking the padlock icon with the red slash in the lower right corner of the window. In Internet Explorer, you can right-click on the page and go to "Properties." Under "Connection" you should see the encryption information.
We take the security of our customer's data and our computer systems very seriously. When you make an online purchase, we do not store your credit card number, and the card data cannot be intercepted in transit.
► I have a brochure for G.A.-CAD, but do not see it listed on your website. Do you still sell the G.A.-CAD software?
G.A.-CAD, G.A.-HomeBuilt and G.A.-CADlite are no longer available.
► Do you offer educational discounts to students?
Yes! Students can purchase a 12-month node locked license for Advanced Aircraft Analysis (AAA). We allow an academic discounts for Airplane Design I - VIII, Flight Dynamics I & II and Aerodynamics & Performance at our on-line store.
► What is the Technical Support and Upgrade Service?
The Technical Support Service is a contractual service which includes unlimited technical support, bug fixes and software upgrades.
► Do you have errata sheets for your textbooks?
You can download errata sheets for Airplane Design I - VIII, Flight Dynamics I & II and Aerodynamics & Performance in pdf file format.
► What kind of Consulting Services does DARcorporation offer?
DARcorporation has been providing consulting services in the general area of aircraft configuration design and analysis, stability and control and estimation of airplane models for flight simulators and aircraft technical analysis since 1991. In fact, we are the engineering department for several airplane manufacturers. Other services include water tunnel and wind tunnel testing and analysis. For additional information, feel free to contact us.
► Can AAA be purchased through a distributor?
DARcorporation is the sole developer of Advanced Aircraft Analysis (AAA) and related services. We are pleased to offer authorized distributors of AAA in several countries. Please contact one of our fine representatives for questions and pricing options for Advanced Aircraft Analysis (AAA) and related services.