Installed Store Loads

Introduction

Installed stores are items like fuel tanks and missiles which are carried by the aircraft externally on pylons or in internal weapons bays. The presence of these stores changes how the air flows around the aircraft and therefore how the aircraft handles. Because stores are designed to be released, the shape of an aircraft can alter significantly during a mission. It is vital for the safety of the aircraft and crew that the effect of store release on the aircraft aerodynamics is understood.

The Role of Wind Tunnels

The very complicated nature of the airflow around an aircraft with stores and support mechanisms attached means that wind tunnel tests remain an important part of most store integration programs. The position and structure of shock waves and flow separations around and between the stores remain a very challenging area for computer simulation. As in all areas of aircraft development, computers play an increasingly important role in store design and integration but in most cases are not yet powerful enough to provide the level of confidence needed to proceed to flight test.

Wind tunnel tests provide the large quantities of high quality data needed to validate the computer simulations throughout the aircraft’s operational envelope with a speed and reliability that even the most powerful of today’s computers cannot yet match.

A typical test involves the design and manufacture of the stores – and possibly the parent aircraft – followed by a wind tunnel test where a sequence of different store configurations is tested. Some of the typical measurements made during such a test are listed below:

• Change in aircraft handling characteristics due to the presence of stores before and after release
• Aerodynamic loads on stores, store and launcher assemblies and store and pylon assemblies
• Carriage behaviour of stores mounted in tandem, side-by-side or in other configurations
• Effect on adjacent stores due to store release

The measurement of aerodynamic loads on stores and store assemblies is obtained using purpose built force and moment balances installed inside each store. In addition, the overall loads on the parent aircraft are measured with a main model balance installed inside the parent aircraft.

World Class Capability

ARA offers a one-stop service for customers starting with the design and manufacture of stores and balances followed by gauging and calibration of balances and finishing with a test program in our Transonic Wind Tunnel. We have a world leading capability in the manufacture of stores, support mechanisms and balances completed to the very highest standards including bespoke stores with free-floating seeker heads and with spring-loaded free-floating canards or fins.

A Wealth of Experience

We have over 25 years experience testing for numerous store integration programs including Tornado, Jaguar, Harrier, Nimrod, Hawk, Typhoon and the F-35. We have considerable experience in serving international customers and can respond quickly to requirements for out-of-scope tests at short notice.

Excellent Value and Productivity

Our highly experienced test teams deliver excellent test program management combined with rapid model reconfiguration to a superb standard to provide our customers with an efficient and productive service which provides excellent value.

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. 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.

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

Model Attitude:

• Incidence range: -10˚ to +40˚
• Sideslip range: ±40˚
• Roll range: ±180˚

Data Acquisition:

• Up to 220 channels measured at up to 10 data points per second
• Measurement of several hundred steady state pressures recorded at up to 10 data points per second