Full models consist of a complete replica of the object to be tested, with scales varying from 1:7 to 1:20. The most common aircraft scale is 1:12.
Full models are extremely suitable for testing an object’s stability and control, drag, aeroelasticity and acoustics. Test objects comprise all types of aircraft, vessels, trains and trucks, buildings and building components.
Depending on the type of test and the tunnel to be used, DNW can accommodate aircraft models with a span of up to 4.5 m in the 8 m x 6 m test section of its LLF in the Netherlands. The maximum model size for other tunnels is smaller, depending on the tunnel dimensions.
Support systems for models can vary from dorsal and ventral stings to stings attached to the rear of an object. In addition to providing the right type of support, the stings are used as ducts for cables and compressed air flow. Selection of the support system used depends on the test objective and required maneuverability during tests, and is always selected in consultation with the customer. The basic classification is:
- Dorsal sting support: Simulation of take-off and landing conditions
- Ventral sting support: Simulation in free air
- Rear sting support: High-speed tests that require minimum interference with the wings
Naturally, the stings have an effect on the flow in the proximity of the support system. However, extensive tests of aerodynamic effects of the support systems result in correction factors that enable us to eliminate the introduced interference.
The NWB tunnel in Braunschweig, Germany, uses a high-precision Model Positioning Mechanism (MPM) to simulate object maneuvers. This mechanism can oscillate a model about its body axis or simulate combined motions.