Introduction: Designed for the RD-17 series of drone helicopters, the TS-421 is a light turboshaft engine capable of generating 421kW (564.5 shaft horsepower).
Configuration: The TS-421 uses the trombone configuration common on small turboshaft engines like the Allison Model 250 series. In this configuration, air compressed by the compressor is ducted rearward around the system, then turned around 180 degrees at the combustor. Combustion products expand through the two-stage high-pressure turbine, connected to the compression system by the HP shaft, then through the two-stage power turbine. Exhaust gases are turned ninety degrees before exiting radially.
Construction: The compressor and turbine inlets use advanced steel and magnesium alloys to improve the pressure ratio and operating temperatures, allowing increased efficiency. Although the weight is also increased, this increase is smaller than would have been possible with conventional steel and magnesium alloys.
Turboshaft: 2 HP stages, 2 shafts, 6-stage axial and 1-stage centrifugal compressor, 2 power turbine stages
Maximum turbine inlet temperature: 1000 degrees C
Pressure ratio: 9.9:1
Frontal area: 0.572m
Power-weight: 5.6kW/kg (3.4hp/lb)
Fuel consumption: 0.425kg/kW/hour
Oil consumption: 0.0225kg/hour
Power: 421kW at 35000rpm