Air Force Research Laboratory's 12' Vertical Tunnel

The AFRL Vertical Tunnel building is constructed entirely of reinforced concrete in a vertical cylindrical shape. It has a 12 ft diameter open test section.A fan is driven by a 1000 hp electric DC motor located at the top of the facility. Air is drawn up through the center open test section and returns down a passageway between the test section and the exterior walls. In the return at the bottom of the tunnel, the air is directed back up through a honeycomb and into the test section. The control room is located on the 2nd floor between the test section and return passage.

 

While the tunnel airflow is vertical, the facility and rig are capable of traditional static testing with both top and aft stings over a range of +/-90° angle of attack and +/-30° of sideslip at airspeeds up to 100 ft/sec. Dynamic capabilities include steady state rotation of the model about the airflow velocity vector (rotary) and oscillatory motion about an individual model body axis (forced oscillation).

 

The dynamic test motion capabilities of the MAT rig are: Conventional static Rotary balance    - View Movie [MPV 1.8M] Forced oscillation Roll    - View Movie [MPV 2.0M] Pitch   - View Movie [MPV 1.9M] Yaw    - View Movie[MPV 3.2M] Combined motion – rotary and forced oscillation    - View Movie [MPV 2.4M] The types of data acquisition available for all of the test motions are: Model six component force and moment Complete model Model Components (body-wing, etc) Control surface deflections Control surface hinge force and moment Model surface pressures Complete model Partial model Control surface deflections Power testing – fixed wing and helicoptor Propeller thrust and torque measured with balance Propeller motor isolated – aero effects measured with balance Dynamic control surface deflections Time histories of force and moment effects Real time control actuation in response to measured forces and moments All of the above capabilities are available for customer use in the testing of their model. The following pictures are examples of test articles utilizing some of these test techniques. To support wind tunnel testing Bihrle offers complete model design and construction services. This produces a lightweight and low inertia model that is constructed for optimum dynamic data acquisition.