A NATO project aiming to develop a next-generation military helicopter is preparing to kick off the first of a series of concept studies that will contribute to the design of the future rotorcraft.

Work on the Next-Generation Rotorcraft Capability (NGRC) programme got under way late last year following agreement between the six alliance members driving the venture and the NATO Support and Procurement Agency (NSPA), which is coordinating the initiative.

nh90-c-bundeswehr

Source: Bundeswehr

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Now the NSPA has launched a tender, running until 1 September, for the first of five concept studies that will inform the design of the eventual medium- or heavy-class helicopter.

Published on 4 July, the request for proposals (RFP) seeks a vendor to conduct research into a “novel powerplant” for the NGRC.

This includes the “transmission, propulsion and flight-control systems accordingly, as well as providing power for onboard systems and accessories/auxiliaries, both in flight and on ground”, says the document.

Although the concept study is focused on a “novel” propulsion system, an advanced gas turbine would meet that definition, it states.

“Any potential conceptual or technological powerplant solutions that go beyond established conventional solutions, whether based on new, emerging technologies or an evolution of existing technologies can be considered ‘novel’.”

This could include a next-generation gas turbine – including the use of sustainable aviation fuel – electric- or hydrogen-powered designs, or a hybrid solution.

The NSPA says the study should be “solution agnostic” and provide a “a comparative analysis” of the potential powertrain technologies available.

It should also assess whether specific powerplant concepts are “more aligned to particular platform transmission and propulsion systems, for example, conventional rotorcraft, compound drive, co-axial [or] tilt propulsion”, it says.

Other critical points for evaluation are the integration of the powertrain with the airframe – including how to manage future upgrades – whether the adaption of a civil rotorcraft engine would provide benefits over a bespoke military solution given the operational differences between the two, and the impact on aircraft capability and performance from each powerplant concept.

Disclosed performance attributes for the NGRC suggest a range of 900nm (1,650km) in combat configuration and 1,080nm in “clean” configuration, endurance of 5h with a full crew and 1t payload, and a cruise speed of “optimally greater” than 220kt (407km/h) or more, “but not less than 180kt”. Maximum take-off weight is planned to be between 10-17t.

An earlier attributes document suggested engines of at least 3,000shp (2,240kW) or above would be required for the NGRC, but the RFP states that “the exact power requirements will be dependent on the overall platform design architecture”.

The “climatic and environmental effects” on each concept should be studied – across a range of operating theatres, including maritime – while further considerations are the mission readiness and vulnerability of each system, while the “detectability” and supportability of the concepts should also be assessed, the document states.

With many of the potential propulsion concepts in the early stages of development, the study should additionally consider what should be the target technology readiness level “to meet the expected NGRC initial operating capability (target 2035) and subsequent upgrades during the lifecycle.”

Any company selected to conduct the study can propose their own powerplant or propulsion system or technologies, the RFP states, “provided that such elements are assessed in a fair and balanced comparison”.

The NSPA anticipates contract award for the study in late 2023, leading to delivery of a final report around six months later.

It plans to release an RFP for the next industry-led concept study – covering the NGRC’s open-system architecture – in August, with contract award before year-end.

The two studies, plus nation-led activities on the concept of operations and technologies, will feed into a fifth stream to develop the “integrated platform concept”. Up to three designs will be proposed by industry, leading to final reports towards the end of 2025.

Six NATO members are involved in the NGRC project – France, Germany, Greece, Italy, the Netherlands and the UK – while Canada is to be admitted from October.

Underpinning the project is the knowledge that hundreds of medium and heavy helicopters operated by alliance members – excluding the USA – will need to be repalced in the coming decades.