Current version: 2.3        

This parametric program calculates Nasa Bend and Naca Duct shapes.

The 'NASA Bend' is known as a parametric optimum bending shape for pipe media flow. Variants of the unique shape (red in pictures) can often be seen in Formula 1 air intake ducts for manifold optimization, gas turbine exhaust ducts and race head port runners. It minimizes the shear flow in a bended pipe, by other means turbulence and flow resistance.

The 'NACA Duct' is known as an optimum intake duct shape, originally invented in 1945 for aircrafts. It allows air to be drawn into an internal duct with a minimal disturbance to the flow.
The ramp angle and the curvature profile of the walls creates counter-rotating vortices which deflect the boundary layer away from the intake and draws in the faster moving air, while avoiding the form drag and flow separation that can occur with protruding inlet designs. Common applications are race vehicles and aircrafts.

The Bimotion NASA Bend and Bimotion NACA Duct Excel programs are intended to be used with the Catia V5 3D models. The cad models are parametric and linked to the Excel programs. When ever the Excel program is changed and saved, the cad model described by the Excel plot window will update automatically. The cad models can however be rebuilt to describe any geometry.

The Excel program can also be used as stand alone
without the cad models using print out templates.

The Excel program is compatible with Excel2003 or later. The Catia V5R17 files contains the parametric surfaces shown below.


The unique section shape is dependent on the pipe diameters and bending radius.






The inlet, outlet and mid section can be rotated in order to create complex shapes. Any combinations can be modeled basically.

Catia is a trademark of Dassault Systemes.


 The software package contains:

 - Bimotion_Flow.xls

 - Bimotion_NASA_Bend.CatPart
 - Bimotion_NACA_Duct#1.CatPart
 - Bimotion_NACA_Duct#2.CatPart




Assembled Nasa Bend and Naca Duct

Buy the software package now!
Fast delivery by e-mail






US $:49.00

Order is to be placed from Contact in the menu.
Please specify program, operating system and Excel version
(2003, 2007, 2010 or later)