Program package for helicopter flight dynamics Computation

TsAGI’s scientists together with Design Bureau specialists developed the effective program suite for simulating helicopter three — dimensional controlled dynamics. Its high precision and reliability were many times confirmed by long — time operation in solving practical problems. The suite is based on modular principle and it makes possible to package the mathematical models of single — rotor and twin — rotor helicopters of different detalization degree as well as to simulate:

• operational conditions (ground run, takeoff, landing, steady and transient conditions, manoeuvring);
• special conditions (vortex ring, screening surface proximity);
• out — of — limits flight and during failure of the main functional systems.

The mathematical models used in the snite realize a wide possibility range in modern computations of helicopter aerodynamic, aeroelastic and dynamic characteristics, taking account of:

• experimental non — linear aerodynamic characteristics of rotor blades and helicopter fuselage in the whole range of attack and slip angles;
• non — stationary hysteresis phenomena of lift and pitching moment of blade sections;
• bending blade strain in thrust, rotation and torsion planes;
• elastic coupling between blades through swashplate (blades of one rotor can have different mass constant, rigid and geometrical characteristics);
• velocities induced by the rotor in the own plane of rotation and other helicopter lifting components;
• dynamics of flight control system and automatic propulsion control system;
• helicopter wheeled undercarriage motion.

The use of the suggested program package allows computing:

• instantaneous and middle, distributed and total forces and moments acting on lifting and the main load — carrying structural elements (rotor blades and hub, swashplate and guiding hydraulic actuator rods, fuselage, tail fins, wing and undercarriage legs);
• flapping motion in thrust and rotation planes, elastic deformations and hinge moments, dynamic stress state of the rotor blades;
• coefficients of helicopter motion linear equations;
• longitudinal and lateral trim characteristics;
• dynamics characteristics of helicopter tree — dimensional controlled motion.

The program package operates under Windows 2000/XP operating system and its suitable interface ensures efficient input/output of the initial data and computation results.