This is an updated version of a story first published on February 26.

Rolls-Royce on Wednesday revealed plans for a new generation of engine designs to replace the current Trent family. The first, called Advance, would reach the market by the end of this decade, burning at least 20 percent less fuel and emitting 20 percent less CO2 than the first generation of Trent engine. The second, dubbed UltraFan, would enter service by 2025 and use a geared design and a variable-pitch fan system capable of delivering at least a 25-percent improvement in fuel burn and emissions.

Both engine designs resulted from ongoing research and development investment of approximately £1 billion ($1.67 billion) a year, which Rolls-Royce spends across its aerospace and non-aerospace businesses.

The designs will feature architecture and technology improvements, all currently at an advanced stage of development, that include a new engine core architecture to deliver maximum fuel-burn efficiency and low emissions; a CTi fan system featuring carbon/titanium fan blades, and a composite casing that reduces weight by up to 1,500 pounds per aircraft; and advanced ceramic matrix composites designed to resist heat more effectively.

Rolls-Royce’s planned new engines – announced ahead of any potential “platforms” – reflect recent trends in powerplant evolution that include steadily increasing propulsion efficiency through the use of larger-diameter fans, higher bypass ratios and smaller engine cores that offer better thermal efficiency, according to large civil engine strategy and future technology executive vice president Simon Carlisle. He conceded the absence of an immediate application, but noted that Rolls-Royce has engaged in talks with the industry. “To some degree, we've started conversations as part of normal discussions about future requirements,” he said.

The engines could enter service powering updated versions of current designs; Airbus and Boeing have launched re-engined variants of the A320 and 737, respectively, while Boeing has chosen the new General Electric GE9X for new 777 derivatives and Airbus considers re-engining options for its A330 and A380.

Rolls-Royce has withdrawn from the partnership with Pratt & Whitney known as International Aero Engines, whose V2500 became an option on the A320. Large civil engines president Eric Schulz acknowledged an aspiration to return to the single-aisle market “with conviction,” while Boeing explores the market for a longer-range medium-size jetliner to replace the 757, the airplane that launched the predecessor to the Trent—the RB211-535.

The Advance, expected to run in 2015 as a Trent XWB-based demonstrator, served as the basis for the RB3025, submitted to power the Boeing 777X and revealed by a senior Rolls-Royce official last year as the genesis for a “radically different” new-generation engine that “probably” would not carry the Trent name.