There is one for FS9, it may work in FSX:


http://www.simviation.com/fs2004military51.htm


3 files to download:


FS2004 North American Aviation XF-108 "Rapier" The XF-108 was designed as a Mach 3 long range interceptor primarily to escort the XB-70 Valkyrie. It got as far as the mockup stage before the project was canceled. This model is based on the mockup configuration and has the usual FS9 animations, transparent canopies, and a specular color shine. The 2D panel and VC are based on a photo of the front panel of the mockup. The sound file is from a tape of a actual GE J-93 engine. By Paul Clawson. 3.1MB

Update XF-108 "Rapier" This update has a sound file not included in the orginal upload (XF108.zip). Absence of this file can cause FS9 to close when the 108 hits Mach 1. By Paul Clawson. 178K

FS2004 XF-108 Updates. Updates the wonderful XF-108 by Paul Clawson, above. this update corrects the way the plane flys. I also added improved afterburner effects and smoke effects. Alternative panel included to give better forward view, . try it and see which one you like best. Bob Chicilo. 402K