Universiteit Leuven has a rotor diameter of 20 mm and is expected to produce about 1000 W. Aircraft Safran-backed French startup Turbotech is developing a 73-kW (98-shp) turboprop with a recuperator to improve efficiency from 10 to 30%, for a brake specific fuel consumption similar to a piston engine, but 30 kg lighter at 55 kg (120 lb) and without cooling drag. Direct operating costs, Turbotech says, should be reduced by 30% due to more diverse fuels and lower maintenance with a doubled time between overhaul at 4,000 h. Targeted for high-end ultralight two-seaters and unmanned aircraft, it will be slightly more expensive than a competing Rotax 912 but should be as competitive over its life cycle. For a VTOL two-seater, a 55 kW turbogenerator would weigh 85 kg with fuel for 2.5 h of endurance instead of 1 ton of batteries. A demonstrator ran in 2016-17 and ground-testing began in the second half of 2018 before flight testing in the second half of 2019 and first delivery in the first half of 2020. The final assembly line was created in Toussus-le-Noble Airport near Paris, for a 1,000-engine annual output by 2025. A 30% efficiency is equivalent to a g/kWh fuel consumption with a 42.7 MJ/kg fuel. The TP-R90 turboprop or TG-R90 turbogenerator can output and burns of jet fuel per hour in cruise. Czech PBS Velká Bíteš offers its 180 kW (241 HP) TP100 turboprop weighing 61.6 kg (135.8 lb) for ultralights and UAVs, consuming 515 g/kWh (0.847 lb/hp/hr). This is equivalent to % of efficiency with a 42.7 MJ/kg fuel. Miami-based UAV Turbines developed its Monarch RP (previously UTP50R) recuperated turboprop for around -gross weight aircraft, to be tested on a TigerShark UAV. On 10 December 2019, the company unveiled its Monarch Hybrid Range Extender, a 33shp (25kW) hybrid-electric demonstrator based on its Monarch 5 turbine unveiled in September, weighting for the engine and for the whole system. Hybrid vehicles When used in extended range electric vehicles the static efficiency drawback is less important, since the gas turbine can be run at or near maximum power, driving an alternator to produce electricity either for the wheel motors, or for the batteries, as appropriate to speed and battery state. The batteries act as a "buffer" (energy storage) in delivering the required amount of power to the wheel motors, rendering throttle response of the gas turbine irrelevant. There is, moreover,