Additional Testing Facilities

ARA offers a range of additional testing facilities which can be used together or separately to deliver the test requirements of our customers. 

These facilities include:

  • The Balance Calibration Laboratory is used to calibrate all the different types of force and moment balances used in wind tunnel tests.
  • The Mach Simulation Tank is used to calibrate equipment such as nozzles and intakes used in power simulation tests at ARA but also for other companies.
  • The Propeller Test Cell is used for testing large scale isolated propellers and for testing and balancing small scale propellers ready for testing in the TWT.
  • The Small Scale Transonic Tunnel is used to calibrate flow angularity meters and other flow survey probes used in the TWT both for ARA and other companies.

Balance Calibration Laboratory

ARA designs and manufactures balances for customers as well as for use in the ARA wind tunnels. This includes main model balances with load capacities of up to 17,800 Newtons; small store balances with load capacities of 30 Newtons; and sting balances. All of ARA’s manufactured balances are calibrated in the Balance Calibration Laboratory. All balances are calibrated to a very high standard using high accuracy dead-weight loadings.

ARA also offers a calibration service for customer supplied balances. Non-standard balance installations can be accommodated with specialised loading adapters.

All the balance calibration equipment is traceable to UK national standards.

Technical Capabilities

  • Standard equipment used to perform dead weight loadings in the calibration frame, which incorporates pitch and roll levelling mechanisms.
  • Non-standard balance set ups supplied with the necessary specialised loading adaptors.
  • A balance calibration matrix produced from a full set of interactive calibrating load cycles, including first and second order interaction terms.
  • During loading, deflection measurements of the support systems are recorded as standard and checks are continually made to ensure interference free operation of the live elements.
  • For a typical civil aircraft drag model balance, the achieved resolution of ±0.11N (±0.025lbf) in axial force components and ±0.60N (±0.135lbf) in normal force components in static calibration is equivalent to ∆CA = 0.000014 and ∆CN = 0.000075 for a typical qS of 8000N (1800lbf).

Mach Simulation Tank

The Mach Simulation Tank (MST) is used for mass-flow and thrust/drag calibration of through-flow nacelles (TFN), turbine-powered simulator (TPS) nacelles, ducted models and nozzle systems.

This facility is used to support propulsion testing in the Transonic Wind Tunnel (TWT) but is also available for stand-alone tests.

Facility Capabilities

  • Simulated Mach number range from zero up to 1.3
  • High precision thrust measurement with a 1300N (292lbf) axial force capacity
  • High precision mass flow measurement with a binary array of critical flow venturis
  • Plentiful supply of clean, dry, high pressure air delivered by two servo-controlled high pressure airlines with pressures up to 69bar (1000psi).
  • Air supply instrumentation is the same as that used by the Transonic Wind Tunnel (TWT)
  • Control room equipped with all the required data acquisition and health monitoring systems
  • Online data processing and real-time graphical displays
  • Proven data processing programs are available

Propeller Test Cell

The propeller test cell is used for model assembly, systems installation and initial dynamics trial runs prior to installation in the Transonic Wind Tunnel (TWT).

Facility Capabilities

  • Two metered high pressure air supplies for air motors
  • High voltage power supplies for electric motors – pictured motor is 447kW (600hp)
  • Reinforced control room equipped with all the required data acquisition and health monitoring systems
  • Online data processing and real-time graphical displays
  • Good model visibility without compromising safety
  • Economic check-out facility for complex TWT models

Small Scale Transonic Tunnel

The small scale transonic tunnel is a 1:12 scale version of the Transonic Wind Tunnel (TWT). This facility is used for low-cost wind tunnel testing on small models in the early development stages of a new program. It is also used for the calibration of flow angularity meters and other flow survey probes to be used in the TWT.

Facility Capabilities

  • Mach number range from 0.3 to 1.2
  • Incidence range up to 20˚
  • Small strain gauge sting balances
  • Wall mounted half model balance
  • Pressure measurements using ESP modules
  • Provision for Schlieren windows in the test section side walls

Technical Information

  • The test section is 22.86 cm (9 in) wide by 20.32 cm (8 in) high with perforated walls of 20% open area.
  • The tunnel is powered by an ejector driven from the 10bar (145psi) high pressure air reservoir.
  • Supersonic speeds are attained using the flexible nozzle

2-Dimensional Tunnel

The two-dimensional wind tunnel is used to test aerofoil sections at speeds between Mach 0.3 and 0.87. The tunnel test section is 0.2m (8in) by 0.46m (18in). The typical model chord length is 0.127m (5in).

The maximum unit Reynolds number is 55 million per metre. The stagnation pressure ranges between 1.5 and 4.0 bar atmospheric pressure.

The incidence range for models is -11° to +20°.

The 2-Dimensional  tunnel is mainly used for dynamic testing and analysis of helicopter rotor blade section performance. The model is mounted in the Enhancing Rate Pitching System (ERPS) which is used to simulate the rotor blade dynamics to assess: dynamic stall of the retreating blade, and shock-induced separation of the advancing blade. The ERPS is driven at different frequency and incidence rates to simulate the aerodynamics of the advancing and retreating helicopter rotors.

The model is filled with 39 Dynamic Pressure Transducers (Kulites) measuring chordwise pressure distribution which is integrated to give sectional CN and CM.

The 2-D tunnel can also be used to measure the steady-state lift, pitching moment and drag of aerofoil sections.

Contact us

Aircraft Research Association Limited

Manton Lane, Bedford, England MK41 7PF

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