The C-130J is the newest version of the Hercules and the only model still in production. Externally similar to the classic Hercules in general appearance, the J-model features considerably updated technology. These differences include new Rolls-Royce AE 2100 D3 turboprops with Dowty R391 composite scimitar propellers, digital avionics (including head-up displays (HUDs) for each pilot), and reduced crew requirements. These changes have improved performance over its C-130E/H predecessors, such as 40% greater range, 21% higher maximum speed, and 41% shorter takeoff distance. The J-model is available in a standard-length or stretched -30 variant. As a cargo and airlift aircraft, the C-130J's crew includes two pilots and one loadmaster (no navigator or flight engineer), while specialized USAF variants (e.g., AC-130J, MC-130J, HC-130J) may have larger crews, such as navigators/Combat Systems Officers. The U.S. Marine Corps KC-130J uses a crew chief for expeditionary operations. The C-130J's cargo compartment is approximately 41 feet (12.5 m) long, 9 feet (2.74 m) high, and 10 feet (3.05 m) wide, and loading is from the rear of the fuselage. The aircraft can also be configured with the "enhanced cargo handling system". The system consists of a computerized loadmaster's station from which the user can remotely control the under-floor winch and also configure the flip-floor system to palletized roller or flat-floor cargo handling. Initially developed for the USAF, this system enables rapid role changes to be carried out and so extends the C-130J's time available to complete taskings.