UK launches Project Callisto to field affordable engine for one-way UAVs
A small turbojet of the type that the UK MoD wants to develop for one-way UAVs under its Project Callisto. (Janes/Patrick Allen)
The UK Ministry of Defence (MoD) has launched a new effort to field an affordable engine for one-way unmanned aerial vehicles (UAVs).
Dubbed Project Callisto, the effort launched on 6 July 2026 aims to bridge the performance gap between hobbyist, model aircraft engines and higher performance, long-life and more exquisite engines. The initial GBP750,000 (USD1 million) phase will consist of design, development and ground testing (in appropriate engine test facilities) of four prototype engines.
“The engines must be affordable and scalable. Any future scaled production requirement is not included under this competition, and if required shall be subject to a separate procurement,” the MoD said.
As noted in the sources sought notification, the project is split into two lots. Lot 1 Callisto Light is geared at a smaller, less powerful engine rated at 750 N (comparable to a smaller turbojet that powers a large remote-controlled hobby aircraft), and Lot 2 Callisto Heavy is geared at a larger, more powerful engine rated at 1.8-2 kN (comparable to larger turbojet that powers a subsonic aerial target). Tenderers are able to bid for one or both lots.
A contract for this initial phase is scheduled to be awarded on 16 October 2026 to run through to 31 March 2027.
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