4L4 fusial thrust engines were advanced sublight drive engines manufactured by Incom Corporation for use aboard X-wing starfighters. As well as the T-65 models used during the Galactic Civil War, these engines were also used on later models such as the XJ3 X-wing, which saw action during the Yuuzhan Vong War.
Four of these powerful engines were mounted on each X-wing, allowing for a maximum speed of 1,300 kilometers per hour in atmosphere, with even higher speeds possible with deflector shields on. In addition, engines of this type were often adapted with a system of etheric rudders, allowing thrust vectoring and enhanced maneuverability. This maneuverability was so increased that pilots likened it to flying a T-16 skyhopper in atmospheric flight.
Next-generation X-wing models, such as the XJ X-wing, were equipped an even more advanced propulsion system—Incom 4j.4 fusial thrust engines. Rated at 300 KTU, these engine units provided even more power than the 4L4s, allowing speeds comparable to that of the RZ-1 A-wing interceptor.
- Star Wars: The Roleplaying Game (As "4L4 fusial thrust sublight engine)
- The Star Wars Sourcebook
- Starfighter Battle Book: X-wing vs TIE Interceptor
- Rebel Alliance Sourcebook
- Rebel Alliance Sourcebook, Second Edition
- Star Wars Sourcebook, Second Edition
- The Essential Guide to Vehicles and Vessels
- The Official Star Wars Fact File 1 (XWI2, T-65 X-Wing Fighter)
- Star Wars: Complete Cross-Sections
- Star Wars Omnibus: X-Wing Rogue Squadron Volume 1
- "X-Wing" TechPlate