Advanced UAV Aerodynamics, Flight Stability and Control

10 Framework for the Optimisation of a Helicopter Rotor Blade with an Approximate BERP Tip: Numerical Methods and Application

Catherine S. Johnson, Mark Woodgate and George N. Barakos

School of Engineering, University of Liverpool, UK

School of Engineering, University of Glasgow, UK

10.1 Introduction

10.1.1 BERP Blade

The BERP blade has a ‘paddle‐shaped’ tip due to a forward displacement of the planform (creating a notch), followed by sweep, as shown in Figure 10.1. It is a benchmark design because of its improved performance in forward flight, winning it a world speed record for helicopter flight (Perry et al. 1998). Some CFD analysis was carried out for this blade in order to find the specific reasons for its improved performance, and to analyse what happens in the flowfield around it (Brocklehurst and Duque 1990). However, at the time, computational power was limited and today, higher fidelity CFD methods are available. The aim of this chapter is to apply CFD and optimisation methods to investigate if further performance enhancements can be obtained by fine‐tuning specific features of the BERP tip. At the same time, the methods outlined in Chapter 9 are applied. A brief history of the BERP blade development is presented below.

Figure 10.1 Definition of the parameters of the BERP‐like blade.

The BERP tip was designed for high‐speed forward flight without ...