"If you have problems running the latest version FlightGear on your Windows system, you may want to try an earlier version with lower graphics requirements (for example 0.9.8)" (Page 85 of Flight Gear Manual for version 3.6)
Flight Gear version 1.0 which this project is based on can be downloaded here:
Download Flight Gear version 1.0 and other older versions.
Older versions of aircraft can be downloaded from that site also.
Flight Gear Windows versions from early versions on
Download your aircraft here - Aircraft-1.9.1 is my source for FG1 aircraft
The Mirage 5 in FG 1 at Tracy Municipal, KTCY. For an early version on Flight Gear, very nice graphics. Running in Linux Mint 18+ under WINE. Note the shadows and shading. HP45 Celeron notebook with 2GB RAM and with integrated Intel graphics.
*System Specifications