Installed Propulsion Performance

Introduction

A typical civil aircraft is most often propelled by propeller engines or jet engines. More advanced engines such as open rotors (jet engines with fan blades on the outside) are under active development. Whatever means the aircraft uses to propel itself will have significant effects on the airflow around the aircraft. The challenge aircraft designers face is to prevent these effects from disrupting the aerodynamic efficiency or stability and control of the aircraft.

The Role of Wind Tunnels

The airflows emerging from aircraft engines can be very complex and dynamic making prediction with numerical methods very challenging. Wind tunnel tests can provide reliable measurements of propulsion installation performance allowing unexpected effects on drag or stability and control to be detected and any necessary design modifications to be made before flight test.

World Class Capability

ARA offers a one-stop service for our customers starting with the design and manufacture of test equipment followed by calibration in one of our support facilities and finishing with a test program in our Transonic Wind Tunnel. We offer a comprehensive range of test equipment and techniques to provide solutions for all major types of propulsion test.

Propeller Simulation

We have a world leading capability in propeller testing for half-span models built on decades of pioneering work into balance, hub and blade design as well as telemetry and data acquisition.

We offer both single propeller, twin propeller and contra-prop configurations. The propellers are powered by air motors driven by a high pressure air supply.

Our advanced health monitoring system for the air motors and propeller blades is very successful in detecting potential problems before they occur providing significant advances in reliability and productivity.

Our one-stop service includes the manufacture of the rotary balances followed by calibration in our Balance Calibration Laboratory as well as fine-tuning the balancing of propeller assemblies in our Propeller Test Cell.

Jet Simulation

ARA has been a pioneer in jet propulsion testing since TPS units (turbine powered simulators driven by high pressure air) were first developed over 40 years ago.

TPS units allow a high-fidelity simulation of inlet conditions and bypass flow through a jet engine model.

Our one-stop service includes the design and manufacture of the engine models followed by calibration of the assembled TPS units in our Mach Simulation Tank.

Through Flow Nacelles, Ducts and Blown Nacelles

Through flow nacelles and ducts are used to measure the effect due to the presence of nacelles and ducts without any jet effects and  can be installed in both full-span and half-span models in the Transonic Wind Tunnel.

Blown nacelles are powered by a high pressure air supply and are used to measure jet effects.

We offer manufacture of single, double and triple bodied through flow nacelles, through flow ducts and blown nacelles followed by calibration in our Mach Simulation Tank.

A Wealth of Experience

ARA has decades of experience in pioneering propulsion simulation serving aircraft and engine manufacturers from Europe and the US.

Excellent Value and Productivity

Our customers receive a service which provides excellent value - comparable with any of our competitors. Very high levels of productivity with minimal down time are made possible by our advanced health monitoring systems, excellent test program management based on decades of experience and a recent doubling of our high pressure air supply.

Data Acquisition and Processing

Customers who test with us can take advantage of our proven and flexible data acquisition and processing capability. We offer seamless integration of customer supplied code and programs into our in-house data processing suite. We provide full visibility and traceability of our data processing steps giving our customers the highest level of confidence in the data we deliver.

Real-time processing and display of data allows our customers to make quick decisions based on a reliable data set and adapt their test program as required. This enables a more efficient use of tunnel time creating better value for our customers.

Fully corrected and validated data is transferred to customers within minutes of completion of each test run. This allows our customers to analyse their data from the beginning of a test program.

Assured Security of Model and Data

When testing with us, the security of the model and data is assured; we tailor our security measures to suit our customers’ needs. Upon prior request, our highly experienced IT support team can set up Virtual Private Networks (VPN) to permit remote monitoring of test data by customer teams from within and outside the UK.

Flexibility

We operate a flexible service throughout the year to suit the requirements of our customers; we have considerable experience in delivering test programs with 24-hour running.

Technical Information

Propeller Simulation

• Capability to measure blade twist
• Air motor operational range up to 13,000 rpm

Jet Simulation

• TPS unit operational range from 40,000 to 70,000 rpm

Flow Investigation:

• Use oilflow visualisation to investigate surface flow phenomena such as separation bubbles and trailing edge separations
• Use high speed pressure transducers to measure unsteady pressures to investigate regions of separated flow
• Use microphones installed on the fuselage to measure cabin noise

Data Acquisition:

• Up to 220 channels measured at up to 10 data points per second
• Measurement of up to 1000 steady-state pressures recorded at up to 10 data points per second
• 1/rev data acquisition
• Measurement of rotating pressures on propeller hubs and blades