VSP is a CAD program used by NASA for rapid preliminary design. Until recently it was available to the public on a limited basis… had to sign licensing forms, no further redistribution… and no release to non-US nationals.

OpenVSP is a parametric aircraft geometry tool. OpenVSP allows the user to create a 3D model of an aircraft defined by common engineering parameters.

It’s now been released for general consumption. I’ve not used it, but it’s reportedly very easy to learn and use, and is designed for preliminary conceptual aircraft design. I’m told that it does well at creating watertight meshes, and outputs in a Rhino format.

OpenVSP

An AIAA paper describing VSP is here: Aircraft Conceptual Design Using Vehicle Sketch Pad

Sadly, I don’t see a big fat collection of actual NASA-produced conceptual aircraft designs for downloading, but I suppose some of them will make it out at some point.

www.openvsp.org