Rocket Fin

Description
Fins are used to aerodynamically control the direction of flight.



Usage

 * 1) There are several ways to invoke the command:
 * 2) * Press the button.
 * 3) * Select the option from the menu.
 * 4) * Double click on a Fin object in the model view.
 * 5) Set options and press.

Fin Type
At the moment, only trapezoid shape fins are supported. This will change as the workbench continues to be developed.

Cross Section
The cross sectional shape of a fin can greatly affect its performance at different speeds, as well as the looks of the rocket. A variety of fin cross sections have been implemented. Fins are created by lofting the root cross section to the tip cross section, so not all combinations of Root Cross Section and Tip Cross Section will produce useful fins.


 * Square. Both the leading and trailing edges are squared.




 * Round. The leading and trailing edges are rounded.




 * Airfoil. Uses the NACA symmetrical airfoil shape (https://en.wikipedia.org/wiki/NACA_airfoil) with maximum thickness at 30% of the chord.




 * Wedge. The trailing edge of the fin is square, converging to a point at the leading edge.




 * Diamond. The diamond shape starts from a point at the leading edge, straight out to the maximum thickness at a point determined by Length 1, and back to a point at the trailing edge.




 * Leading Edge (LE) Taper. The leading edge is tapered to a point as determined by Length 1




 * Trailing Edge (TE) Taper. The trailing edge is tapered to a point as determined by Length 1




 * Taper. The leading edge is tapered to a point as determined by Length 1, and the trailing edge is tapered to a point as determined by Length 2



Through the Wall (TTW) Tabs
Through the Wall fins add structural strength by extending though the outer body tube to an inner body tube such as a motor mount. Instead of attaching just to the outside of the outer body tube, it can be attached at multiple points. As such, tthe height of the tab would be the distance from the outer diameter of the inner body tube to the outer diameter of the outer body tube. Other parameters would vary depending on requirements.



Properties
These parameters are provided for information and have no effect on the design of the component.


 * : Manufacturer when known
 * : Manufacturer part number
 * : Description of the component
 * : Material when known


 * : Defines the shape of the fin. At the moment, only Trapezoidal fins are supported.
 * : The fin height.
 * : The distance from the front of the fin root to the front of the fin tip along the x axis. This may be negative. Setting this value will cause the Sweep Angle to be adjusted.
 * : The angle of the front of the fin, with a vertical front being 0 degrees. This may be negative. Setting this value will cause the Sweep Length to be adjusted.
 * : The cross section shape of the fin at the root, see Options
 * : The distance between the fin leading and trailing edges at the root
 * : Maximum thickness at the root of the fin
 * : Expresses the Fin Root Length 1 and Fin Root Length 2 properties as a percentage of the Fin Root Chord
 * : Usage depends on the Fin Root Cross Section and will apply to a taper length or similar, see Options
 * : Usage depends on the Fin Root Cross Section and will apply to a taper length or similar when multiple values are required, see Options
 * : The cross section shape of the fin at the tip, see Options
 * : The distance between the fin leading and trailing edges at the tip
 * : Maximum thickness at the tip of the fin
 * : Expresses the Fin Tip Length 1 and Fin Tip Length 2 properties as a percentage of the Fin Tip Chord
 * : Usage depends on the Fin Tip Cross Section and will apply to a taper length or similar, see Options
 * : Usage depends on the Fin Tip Cross Section and will apply to a taper length or similar when multiple values are required, see Options
 * : True when a tab for Through the Wall fins is required, see Options
 * : Distance from the front of the fin to the front of the TTW tab
 * : Length of the TTW tab
 * : Height of the TTW tab
 * : Thickness of the TTW tab

Scripting
See also: Category:API and FreeCAD Scripting Basics.

TBD

Tutorials and Learning
TBD