Pratt & Whitney 3-Stream Engine Architecture Suited to Power Next Gen Military Combat Aircraft

Pratt & Whitney, a division of United Technologies Corp. (NYSE: UTX), has announced it has successfully completed testing of an adaptive three-stream fan in an engine with an F135 core as part of the US Air Force Research Laboratory´s Adaptive Engine Technology Development (AETD) program, the company said.

Successful testing of the three-stream engine architecture demonstrates Pratt & Whitney is well positioned to transition adaptive engine technology to meet future US Air Force requirements for combat aircraft propulsion.

Modern military turbofan engines have two airstreams — one that passes through the core of the engine, and another that bypasses the core. The development of a third stream provides an extra source of air flow to improve propulsive efficiency and lower fuel burn, or to deliver additional air flow through the core for higher thrust and cooling air.

Utilizing a third stream of air that can be modulated to adapt the engine´s performance across the flight envelope means a fighter can have the best of both worlds by accessing an on-demand increase in thrust or smoothly shift to highly efficient operations during cruise. This capability provides an optimal balance for combat scenarios requiring both high-end acceleration and increased range.

The adaptive three-stream fan technology leverages and improves upon Pratt & Whitney´s experience as the only provider of fifth generation fighter engines — the F119 and F135, which power the F-22 Raptor and F-35 Lightning II, respectively.

Pratt & Whitney is a world provider of the design, manufacture and service of aircraft engines and auxiliary power units. United Technologies Corp., based in Farmington, Connecticut, provides high-technology systems and services to the building and aerospace industries. To learn more about UTC, visit its website at, or follow the company on Twitter: @UTC.