3.5 DY-400 Class Transport

A profile of the long-delayed, poorly selling DY-400 class transport (later retooled as the Helsinki class), presented with the successful uprated DY-500 class that became the basis for later Dyson-Yoyodine designs, including specifications for both.

DY-400 (design by Michael Morrisette, based on a concept by Walter M. Jeffries)

DY-500 (design by Rick Sternbach, as adapted and modeled by Roger Sorenson)

The long-delayed DY-400 class finally entered service in 2038. It had been held up for many years due to the failure of its early prototypes. Its partial reversion to the tried and true DY-100 base design represents a throwback to the tried and true; i.e. “what worked before.” It was not perceived as being that much of an improvement over other exiting Dyson-Yoyodine designs, especially with the superior DY-500 upgrade also available. As a result it did not sell very well and had all but disappeared from service by 2045. A retooled version intended for the science and survey role (often referred to as the Helsinki class) was reintroduced in 2055. All six of the DY-400s that were eventually enjoyed moderate success during the Second and Third Earth-Kzin Wars as military intelligence gathering vessels.

Service entry date (old calendar): 2037.

Specifications

Length: 100.6 m
Beam: 36.7 m
Draft: 29.1 m
Mass: 24,500 DWT
Crew: 16
Range: 3 years at 0.35c
Maximum speed: 400,000 km/hr

Uprated DY-500 Class

The uprated DY-500 class was the way that Dyson-Yoyodine had meant to build this class back in the 2020s. Economic concerns had dictated otherwise at the time. The resultant delay actually proved to be a blessing in disguise. It gave Dyson-Yoyodine the chance to incorporate the latest in engine and secondary systems design into the uprated DY-500. The class was intended to be the first production Terran spacecraft equipped with “spinner” drive but these were yanked due to the loss of the Charybdis from the apparent failure of such an engine. Conventional impulse drive engines were fitted instead. Production was boosted by a UESF contract for an intersystem transport, with one out of every three uprated DY-500s going to the UESF. Many were refitted for combat during the Battle of the Sol System in the First Earth-Kzin War and many would also see service during the next two wars. The design would also serve as the basis for the subsequent DY-430 and DY-550 classes.

Service entry date (old calendar): 2038.

Length: 107.6 m
Beam: 32.6 m
Draft: 32.3 m
Mass: 22,500 DWT
Crew: 55
Range: 5 years at 0.35c
Maximum speed: 475,000 km/hr