One of the most enjoyable part of our hobby, except flying, is the design of a new model. First of all you define the type of model you would like: small 60 inches glider for pylon racing, semi-scale, starting from a fuselage, thermal sailplane. In all the cases, one difficult step is to choose the airfoil and the planform, and try to calculate different parameters in order to evaluate the performance of your futur sailplane. VISUAERO is a software to assist the modelers during this phase, as you will see in this review.
VISUAERO run on Windows 95 with a hardware configuration starting from a simple 486 processor.
The installation of the software is the standard one. Run a:\setup from Windows 95 and follow the instructions ( destination directory for instance ).
Then to run VISUAERO, click on the corresponding icon. A first picture appears: Click on it and you reach the main screen of the software.
The main screen is dedicated to airfoils: On the left part of the screen, you will find all the information about:
To help multiple drawing the bottom part of the screen propose two types of line: dot and normal line. In addition it is possible to stack several sections or to split the drawing. This option is very interresting to compare differents sections together and see where the differences are.
The drawing take place in a white rectangle on the right side of the screen, with the main information ( thickness, camber, alpha 0, cm 0 ) just below.
From the upper menu "airfoil", you can also calculate intermediate section between 2 base sections. You just have to indicate the number of intermediate sections you want and VISUAERO do the rest. The result is store directly in a file (coordinates), but is also displayed on the screen.
If you decide to display the polar and the airfoil at the same time, be careful, because the choice is not the same.
The polar is just for indication. We cannot compare VISUAERO with the output of XFOIL or other professional software, but it's not the same price !
At the top of the screen, just above the display of the section, you will find several buttoms ( short cuts) allowing to print the airfoil, list the coordinates, print the coordinates.
Forget the buttom to cut the wing. This sofware contain also a module to drive a cut machine (hot wire), but here will be usefulless without the associated hardware.
The normal menu includes all the feature I just listed in addition to several minor others like the use of smooth lines or polygone lines to draw the airfoil, the possibility to introduce a amount of washout.
After 5 minutes of use, you will be more confident, even if there is no user's guide. The interface is very intuitive and friendly.
I noticed several translation mistakes. I'm sure that the author will correct them soon.
An online help is available. It gives you a short explanation about the part you are pointing with the mouse, it's sometimes very useful.
This menu includes all you need to predict the performances of your glider. First of all you need to enter all the dimension of the wing planform, tailplane and fuselage. Don't forget the section you have choose with the previous menu !
The top part of the screen is dedicated to the plane geometry, divided in three boxes:
For the wing you need to know:
Each time you double click on a parameter buttom, a dialog box appears. You enter the value and validate by cliking "OK".
Visuaero deduces the wing area, the aspect ratio and the average chord.
Idem for the tailplane, but this time Visuaero will calculate the area ratio with the wing and the corresponding volume. I noticed that it is not possible to define a multi-taper tailplane like for the wing.
The last box, called "other elements" including airfoil, arm lever, weight, static margin. Visuaero will deduces the optimum aspect ratio, that you can compare to the real one.
On the bottom part of the display is the table containing all the aerodynamical information:
Then from these information, its possible to obtain every king of graph. You just specify what you want as abscissa and as ordinate.
I admit that some combination are absolutely usefulless, but it doesn't matter. It's very confortable to have the possibility to study the effect of one parameter on another.
Of course, you can print each graph on the printer, or look at the value used in the table.
From the upper menu you can also:
I didn't verify if all the formula are correct or not. From the information I have is that these formula come from a special issue of RCM (radio commande magazine) dedicated to aerodynamics, so they should be OK.
Anyway, because I use Visuaero to compare too different model together (for instance same planform with different sections), a potential error (if any) has no effect on the result.
This screen is very close to the previous one, but, in addition, propose to calculate parameters related to electric motor:
No prediction about the vertical speed is calculated by Visuaero: It could be interresting to add this feature for the next release ...
Visuaero is a nice software which really help in certain tasks. One drawback is that the format used for the airfoil database is not compatible with the pseudo standard which seems to be applied world wide, allowing the exchange of coordinates of new sections. A library containing 3000 different sections is proposed in option.
For more information please contact the author of this software: Patrick Medard
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Pierre Rondel.
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