SAW Case Studies

Improved Torque Measurement for GE Helicopter Engines

GE, US Army leverage key sensing technology from UK-based Transense for new ITEP — T901 engines

EVENDALE, OH – GE Aviation is advancing the state of the art in turbine engine torque measurement technology with assistants from UK-based Transense Technologies to support United States Army modernization. The advanced torque sensor, together with other technologies, will help provide greater power, fuel efficiency and durability for the new turbine engine that GE is developing for US military helicopters as a replacement for the legendary T700 engine.

The new T901-GE-900 turbine is being developed under the US Army’s Improved Turbine Engine Program (ITEP). The primary purpose of the T901 is to upgrade the performance capabilities of the US Army’s Apache and Black Hawk helicopters. In the future, it is also likely to be adopted for other military and civil aircraft, including the Future Attack Reconnaissance Aircraft (FARA), a scout and light attack helicopter being developed by the US Army with the T901 as the powerplant.

Both the Apache and Black Hawk have been in service for a number of decades, during which time extra armour and other equipment have been added, increasing weight. Over the same period performance expectations have also increased, hence the decision to develop a more powerful engine.

The US Army has specified that the new ITEP engine should offer 50% more power (3,000shp or 2,240kW), be 25% more fuel efficient and provide a 20% longer design life over the current engine. This increase in performance will allow the aircraft to meet its performance requirements at 6,000 ft and 35°C (95°F), to be robust and easy to maintain at forward operating bases, and to have high survivability in warfare environments.

The T901 turbine engine has a single-spool core architecture and is designed as a drop-in replacement for the current engine. It should allow easy and low-cost maintenance, while re-engineering of the host aircraft will be minimal.

Under a Technology License Agreement, each T901 engine incorporates Transense Technologies Surface Acoustic Wave (SAW) sensors. SAW sensors provide very fast and high responses of real time torque outputs which together with other technologies used in the engine allows for more precise power application and data logging to improve predictive maintenance to assist in meeting the US Army requirements. The US Army CCDC AvMC partnered with GE to demonstrate the SAW sensor during the Future Affordable Turbine Engine program, which contributed to this integration onto the T901.

Transense Technologies primary business is knowing how to measure rotary torque, strain, temperature, pressure and thrust using Surface Acoustic Wave devices in demanding and hostile environments and has developed the patented non-contact SAW sensor technology. 

Surface Acoustic Waves are a naturally occurring phenomenon, being a sound wave travelling along the surface of a body in motion. In the case for the Transense Technologies sensors, it measures RF resonance waves travelling along a quartz substrate which has the advantages of size being relatively small, light wireless not susceptible to magnetic fields and without the need for batteries. These sensors are used in a wide variety of high-performance applications from aviation and Indy car Racing to wind turbines, robotics and automotive applications both for Electric Vehicles and Electric Power Assisted Steering

Transense Technologies is working on several cutting-edge projects, each of which will advance the state of the art in their respective fields.

GE is expected to provide the first T901 engine to test in 2021 with a flight test airworthiness release in 2023, after which the program will involve fitting 6000 new engines to the Army’s existing fleets of helicopters.

For further information regarding the T901, visit

About GE Aviation

GE Aviation, an operating unit of GE (NYSE: GE), is a world-leading provider of jet and turboprop engines, components, integrated digital, avionics, electrical power and mechanical systems for commercial, military, business and general aviation aircraft. For more information, visit us at Follow GE Aviation on Twitter at  and YouTube

About Transense Technologies

Based in Oxfordshire, UK, Transense Technologies plc (UK AIM:TRT) has developed patent-protected sensor systems and supporting technology for use in a variety of diverse high growth markets. Transense's Surface Acoustic Wave (SAW) wireless, battery-less sensor systems offer advantages over legacy wireless sensor systems enabling Transense to target the torque, temperature and pressure sensing markets. The continuing business within its Translogik division offers a range of tyre testing equipment aimed at fleet managers and tyre service providers.