## Abbreviations  
**Nomenclature**: **Description**  
\(P\) [HP] & Power  
\(S_{FC}\) [kg/HP/h] & Specific fuel consumption  
\(N_{GG}\) [%] & Gas generator shaft speed  
\(N_{TP}\) [%] & Free turbine shaft speed  
\(T_{3.max}\) [K] & Inlet turbine maximum temperature  
\(F_{C}\) [kg/h] & Fuel consumption  
\(T_{3t}\) [K] & Inlet turbine temperature  
\(F_{f}\) [kg/s] & Fuel flow  
\(V_{B}\) [mm/s] & Vibration  
\(P_{IM}\) [bar] & Oil pressure  
\(T_{IM}\) [\({}^{\circ}\)C] & Oil temperature \begin{tabular}{l l} \(T_{q}\) [Nm] & Torque \\ \(T_{qs}\) [Nm] & Torque set \\ \(P_{2t}\) [bar a] & Compressor outlet total pressure \\ \(T_{2t}\) [K] & Compressor outlet total temperature \\ \(T_{0}\) [\({}^{\circ}\)C] & Test cell air temperature \\ \(DP\) [mbar] & Differential pressure \\ \(P_{45t}\) [bar a] & Free turbine outlet total pressure \\ \(h_{a}(T)\) [kJ/kg] & Air enthalpy polynomial function \\ \(s_{a}(T)\) [kJ/kg] & Air entropy polynomial function \\ \(h_{g,it}(T)\) [kJ/kg] & Ideal gases enthalpy polynomial function \\ \(s_{g,it}(T)\) [kJ/kg] & Ideal gases entropy polynomial function \\ \(x_{g,it}\) [\(-\)] & Ideal gases mass participations \\ \(x_{a,ext}\) [\(-\)] & Air excess mass participations \\ \(M_{af}\) [kg/s] & Mass air flow \\ \(\pi_{Cl}\) [\(-\)] & Overall total pressure ratio \\ \(\pi_{Tt}\) [\(-\)] & Turbine total pressure ratio \\ \(G_{f}\) [kg/s] & Gases flow \\ \(\eta_{Cl}\) [\(-\)] & Compressor total adiabatic efficiency \\ \(\eta_{Tt}\) [\(-\)] & Turbine total adiabatic efficiency \\ \(\eta_{Te}\) [\(-\)] & Thermal efficiency \\ \(\rho_{s}\) [kg/m\({}^{3}\)] & Density \\ \(V\) [m/s] & Velocity \\ \(A\) [m\({}^{2}\)] & Cross-section \\ \(P_{1t}\) [bar] & Compressor inlet total pressure \\ \(l_{Cl,it}\) [kJ/kg] & Compressor total specific ideal work \\ \(l_{Cl}\) [kJ/kg] & Compressor total specific actual work \\ \(l_{Tt,id}\) [kJ/kg] & Turbine total specific ideal work \\ \(l_{Tt}\) [kJ/kg] & Turbine total specific actual work \\ \(h_{2t,id}(T)\) [kJ/kg] & Total specific ideal enthalpy for station \"2\" \\ \(h_{1t}(T)\) [kJ/kg] & Total specific enthalpy for station \"1\" \\ \(h_{2t}(T)\) [kJ/kg] & Total specific enthalpy for station \"2\" \\ \(h_{3t}(T)\) [kJ/kg] & Total specific enthalpy for station \"3\" \\ \(h_{45t}(T)\) [kJ/kg] & Total specific enthalpy for station \"45\" \\ \(P_{TP}\) [kW] & Free turbine shaft power \\ \(L_{HVf}\) [kJ/kg] & Fuel lower heating value \\ \(T_{1t}\) [K] & Compressor inlet total temperature \\ \(P_{3t}\) [bar a] & Turbine inlet total pressure \\ \(T_{4t}\) [K] & Turbine outlet total temperature \\ \(T_{45t}\) [K] & Free turbine outlet total temperature \\ \(\Delta N_{GG}\) [\(\%\)] & Different percentage of gases generator shaft speed \\ \(N_{GG,co}\) [\(\%\)] & Corrected gases generator shaft speed \\ \(N_{CG,no}\) [\(\%\)] & Cases generator shaft speed (data manual) \\ \(\Delta N_{TP}\) [\(\%\)] & Different percentage of free turbine shaft speed \\ \(N_{TP,no}\) [\(\%\)] & Corrected free power turbine shaft speed \\ \(N_{TP,na}\) [\(\%\)] & Free power turbine shaft speed (data manual) \\ \(\Delta P\) [\(\%\)] & Different percentage of engine power \\ \(P_{co}\) [kW] & Corrected engine power \\ \(P_{ma}\) [kW] & Engine power (data manual) \\ \(\Delta F_{\rm C}\) [\(\%\)] & Different percentage of fuel consumption \\ \(F_{C,co}\) [kg/h] & Corrected fuel consumption \\ \(F_{C,ma}\) [kg/h] & Fuel consumption (data manual) \\ \(\Delta T_{3t}\) [\(\%\)] & Different percentage of inlet turbine temperature \\ \(T_{3t,co}\) [K] & Corrected inlet turbine temperature \\ \(T_{3t,ma}\) [K] & Inlet turbine temperature (data manual) \\ \(\Delta S_{FC}\) [\(\%\)] & Different percentage of specific fuel consumption \\ \(S_{FC,co}\) [kg/kW/h] & Corrected specific fuel consumption \\ \(S_{FC,ma}\) [kg/kW/h] & Specific fuel consumption (data manual) \\ \(\Delta\eta_{te}\) [\(\%\)] & Different percentage of thermal efficiency \\ \end{tabular}