The importance of HQs in aircraft design has been recognised in a series of critical technology projects related to the European Civil Tilt Rotor/Wing aircraft, launched in the EC’s Framework V Programme. UoL has been involved in two of these projects, RHILP and ACT-TILT, examining Level 1/2 and also Level 2/3 handling qualities criteria.

The aim of this project is to optimise handling qualities for future TR/W aircraft through a systematic review of HQ requirements, filling the outstanding critical gaps through theoretical analysis, supported by piloted simulation, and designing novel control and display functions that ensure Level 1 behaviour throughout the OFE.  The 4 primary objectives are;

  1. Contribute to Tilt Rotor/Wing handling qualities design guide, with supporting S/W analysis tools.

  2. Develop design methodology for integrating handling qualities with load alleviation and carefree handling control functions.

  3. Develop new (control/display) concepts for perfecting tilt rotor handling qualities, with special emphasis on,

  1. Steep approaches and departures and low speed, near earth operations in a degraded visual environment (e.g. airport movements, search and rescue, military nap-of-Earth)

  2. Precision manoeuvres in the conversion corridor (e.g. terrain following, aerial refuelling),

  3. High speed cruise and manoeuvring (e.g. emergency manoeuvres)

This structure aligns with the Work Packages presented below.

WP1: Modelling and Simulation

The incorporation of low-speed, unsteady, interactional aerodynamic effects (e.g. fountain flow, ground vortex/empennage), derived from new 3-D FLIGHTLAB components, will provide the basis for simulating realistic disturbances experienced by these aircraft during take-off, landing and low-speed manoeuvring close to the ground.  Improved loads modelling is also required to account for blade flexibility and different rotor hub types. These modelling improvements will be incorporated into a generic family of TR/W aircraft (small (XV-15, 5-7 tonnes), medium (existing RHILP/ACT-TILT, 10-12 tonnes) and large (new, 20-30 tonnes), where required, conceptual HQ models will be created to locate approximately the HQ boundaries for new parameters (e.g. 2nd order transfer function for pitch/flight path control, with variable rate overshoot, velocity command response type for low speed manoeuvring).

WP2 Handling Qualities (Mission analysis, Criteria Review and Gap Closures)

Military missions will be included in the review and a new emphasis will be given to requirements for flight in degraded visual environments (DVE). New criteria for pitch/flight path manoeuvring and control in conversion and aeroplane modes will be developed. A multi-segment approach and landing mission task element will be developed, along with appropriate display functions to examine HQs in such potentially high workload situations. The WP will also include the development of complementary design parameters for HQs and load suppression.

WP3 HQ Toolkit development

Dynamic response criteria form a significant part of a handling qualities requirements manual/design guide.  To ease the process of analysis in the project, a SIMULINK-based toolkit will be created that takes inputs from a linearised model or from the nonlinear FLIGHTLAB model and generates the HQ parameters automatically based on user defined conditions.  The output of this WP will be the HQ Toolkit.

WP4 Control/Display Functions for Level 1 HQs

This WP will examine ways of perfecting the HQs through integrated control-display augmentation (especially for flight in degraded UCE when display augmentation is likely to be essential), providing carefree handling functions to suppress loads and protect against flight envelope exceedances. The work will also examine ways in which the pilot’s controls need to be back-driven to provide important feedback cues to the pilot.  Further details of the control aspects can be found here.