FILE PHOTO: The logo of Airbus Group is seen on the company's headquarters building in Toulouse, Southwestern France, April 18, 2017. REUTERS/Regis Duvignau/File Photo

LONDON (Reuters) - Rolls-Royce RR.L and Airbus AIR.PA have signed a deal to collaborate on development of the UltraFan, a new engine that is intended to 25 percent more fuel efficient than the earliest version of the Trent engine, the British company said on Wednesday.

The companies, already long-term partners on projects such as the A350 passenger jet powered by the Trent XWB engine, will work together on aircraft architecture to test the engine and on maximizing its efficiency.

“It is great to have Airbus expertise to further strengthen our ability to deliver this important development program,” said Andy Geer, chief engineer on the UltraFan, said in a statement.

Rolls-Royce is looking to UltraFan to secure its long-term future. In the shorter term it is focused on fixing problems with its Trent 1000 engines on Boeing's BA.N 787 Dreamliner planes, where some parts have been wearing out sooner than expected.

Some of the funding for the testing phase on the UltraFan will be provided by Clean Sky 2, a European Union research program focused on developing technology to reduce emissions, the companies said.

Rolls-Royce added that UltraFan is a “scalable” design, meaning it will be suitable for widebody or narrowbody aircraft. Currently Rolls only makes engines for widebody jets.