Our heavyweight helicopter equal in the world does not have
In Rostov started production of the most load-lifting rotary-wing car The Russian holding «Helicopt[...]
Handling Qualities Analysis Tool
The handling qualities analysis tool is an integrated MATLAB/GUI-based SW for analytical evaluation of the HQs of aircraft and rotorcraft [27]. The HQ criteria for military helicopters specified in ADS-33 and the HQ and pilot-induced oscillation (PIO) prediction criteria specified for fixed-wing aircraft in MIL-STD-1797A are covered in this toolbox. The input information could be in the form of time histories, state-space models, TF, or frequency response data. It is important that an adequate theoretical/analytical evaluation of HQ is carried out at the design and development stage of an airplane, before thorough evaluation in flight. For this purpose mathematical models are used and experimental evaluations can be made on flight simulators. Table 10.10 gives a brief overview of certain possible HQ criteria to be evaluated for a helicopter. A brief description of some of the tabulated criteria is given next.
10.5.3.1 Hover and Low-Speed Requirements (HLSR)—Pitch Axis Response Criteria
Bandwidth (BW) criterion: It addresses the small amplitude and short-term pitch attitude changes to control inputs. vBW and phase delay tp are determined from the frequency response of the pitch attitude to longitudinal cyclic frequency sweep input. For rate command vBW should be lesser than wBWs and wBw For attitude command
vBW = wBw,. Phase delay criterion: tp = 5<723(2°v^l. v180 is the frequency at which the phase angle is —180°, vBW is the frequency at which the gain margin is 6 dB, and vBW is the frequency at which the phase margin is 45°. These quantities are computed for the given test conditions and are placed on the pitch BW HQ level templates to determine the criteria that meet the levels of HQ.
Dynamic stability (DySt) criterion: These are the natural frequency and damping ratio of the oscillatory mode especially of phugoid and Dutch roll. In hover, these modes are coupled. These parameters are determined from the responses and compared against the pitch axis dynamic stability HQ level boundaries.
Attitude quickness (AQ) criterion: Attitude quickness criterion measures the agility of the rotorcraft. The metrics are дЦ8// and the minimum attitude change.
These parameters are compared on the ADS-33 HQ level boundaries for the target acquisition and tracking task.
Large amplitude (LA) criterion: ADS-33 specifies minimum achievable angular or attitude change; for example, for moderate agility mission test element, Level 1 limit is ± 13°/s and +20/—30° altitude.
