## 2 Specifications
\begin{table}
\begin{tabular}{c c c c} \hline
**Parameter** & **Value** & **Impact** & **Notes** \\ \hline Additional twist & \(\geq\)8 deg/R, pitchward & Performance & This requirement was determined using investigations on the main rotor of the Bo105. \\ \hline Cross section & Shape: NACA23012 Chord: 267 mm & Aerodynamic performance & This parameter comes from the reference rotorcraft, the Bo105. \\ \hline Activation temperature of the SMA & \(\geq\)90 \({}^{\circ}\)C & Power consumption Subsystems thermal protection & The lower limit of this parameter was set to avoid undesired activations caused by high environmental temperatures. Given a maximum environmental temperature of 25 \({}^{\circ}\)C for the tests planned in the project, this limit was fixed in view of future flight demonstrations, characterized by operational temperatures in the range of [\(-\)50, +80] \({}^{\circ}\)C. \\ \hline Maximum temperature of the heating source & \(\leq\)180 \({}^{\circ}\)C & Power consumption Subsystems thermal protection & This limitation is strictly related to tighter safety requirements because the source used to heat the SMA is hosted within the blade, with modest heat transfer capabilities. \\ \hline Power supply & \(\leq\)600 W & Power consumption & This parameter is driven by the test plants. \\ \hline Safety factor for all structural parts of the blade (SMA excluded) & \(\geq\)2 & Structural integrity & This requirement comes from the test facility’s safety restrictions. \\ \hline Allowable stress in the SMA & \(\leq\)700 MPa & Structural integrity & The high level of allowable stress is strictly related to the necessity of generating enough martensite phase during the pre-load task. This value does not take into account fatigue problems since the present application was conceived for WT and WhT tests. \\ \hline Mass distribution & \begin{tabular}{c} Center of gravity within the 1 st quarter of the chord \\ \end{tabular} & Stability & This constraint is linked to the stability requirement, especially for rotary tests. \\ \hline WT speed & \(\leq\)25 m/s & Structural integrity & The speed limitations are strictly related to the above requirement for a safety factor greater than 2. \\ \hline WhT speed & \(\leq\)120 rpm & Structural integrity & \begin{tabular}{c} The same location are strictly related to the above requirement for a safety factor greater than 2. \\ Although these values lead to lower loading conditions than the nominal one occurring at a speed of 44.4 rad/s, they allow us to appreciate the trend of the impact of aerodynamic and inertial loads on the structural integrity and actuation functionality. \\ \hline Thermocouple sensor & \begin{tabular}{c} Maximum temperature \(\geq\) 400 \({}^{\circ}\)C \\ \end{tabular} & \begin{tabular}{c} Safety \\ Level of activation \\ \end{tabular} & \begin{tabular}{c} The maximum detectable temperature is well over the maximum expected temperature of 180 \({}^{\circ}\)C. \\ \end{tabular} \\ \hline Inclinometer measurement range & \begin{tabular}{c} Range no smaller than \\ [\(-\)45,+45] deg \\ accuracy \(\leq\)0.1 deg \\ \end{tabular} & \begin{tabular}{c} Performance \\ measurement \\ \end{tabular} & \begin{tabular}{c} The measurement range is compliant with expected \\ twist and flapping rotations well below +/\(-\)20 deg. \\ The accuracy limit is about 1 order lower than the minimum twist expected by each bay (1 deg). \\ \end{tabular} \\ \hline Strain sensor measurement range & \begin{tabular}{c} Range within \\ [\(-\)2000,+2000] \(\mu\varepsilon\) \\ Minimum strain \\ (absolute value) \(\geq\) 5 \(\mu\varepsilon\) \\ \end{tabular} & \
\begin{tabular}{c} The measurement range and the minimum strain \\ detectable will be discussed in the modeling section \\ against the twist produced by the preload and the most severe load condition. \\ \end{tabular} \\ \hline Cabling and routing &
\begin{tabular}{c} All the cabling must \\ exit from one edge of \\ the demonstrator \\ \end{tabular} & Logistic & This requirement is strictly related to the interfaces of the test facilities that allow the cable to pass only through one edge of the prototypes. \\ \hline \end{tabular}
\end{table}