For classroom demonstrations and student investigations into the behavior of fixed-wing aircraft and wing performance during take-off, flight and landing. The apparatus is an open-circuit wind tunnel with a model aircraft suspended in the working section. The model is supported by linkages that allow it to move vertically and to pitch about the quarter chord point independently.
The working section is transparent and the aircraft model is clearly visible through a large window. The operator flies the aircraft manually using a fly by wire control column and throttle. These are positioned directly in front of the window and are arranged as typically found in a light aircraft, providing realistic simulation of flight and the effect of the control surfaces. To fly the aircraft, the operator uses the throttle lever to increase the tunnel airspeed. When the airspeed reaches a certain level the aircraft may be made to ‘take-off’ by drawing the control column slowly back. A digital display shows Pitot pressure (air velocity) in the working section, attitude, altitude, and lift force on the aircraft along with tail plane angle. Air enters the working section through a honey comb shaped flow straightener. The throttle controls the air speed in the tunnel by regulating an axial flow fan downstream of the working section. The change in air speed in the wind tunnel simulates the effect of increasing the change in air speed of a real aircraft due to a change in thrust from the propeller. The control column is linked to the ‘all-flying’ tail-plane of the aircraft. Pushing the column forward or pulling it back changes the angle of the whole tail-plane. The control column differs from that of a normal aircraft in that it has no lateral control of the aircraft: it has no rudder on the tail-plane and may only move up or down.
The control column is designed in such a way that it can be hold at any tail plane angle position so that the angle of the tail plane can be set to any setting. Small tufts cover the port wing of the aircraft. These show the direction and quality of airflow over the wing surface, to show separation and stall. Using the optional Smoke Generator, the smoke enhances flow visualization. An adjustable weight allows the student to set the center of gravity of the model to different positions from fore to aft of the quarter chord point. A scale below the weight indicates the position. This enables students to derive the trim curves and identify the neutral point. To find the lift characteristic of the aero foil, students link the aircraft to a load cell and vary the angle of attack.
Experiments
A variety of practical demonstrations, ‘hands-on’ flight simulations and student investigations into the behavior of fixed-wing aircraft and wing performance, including:
- Practical investigation of longitudinal stability and control of the aircraft to demonstrate behavior during take-off, level flight and landing.
- Measurement of the lift curve for the wing up to and beyond stall.
- Students can adjust the center of gravity of the model to alter its trim. They can then plot trim curves and determine the neutral point.
- Determination of the effect of speed on attitude for level flight and stall.
- Demonstration of phugoid motion in terms of altitude via software (software is optional).
- Short period oscillation due to sudden disturbance can be shown by the change of
incidence via software (software is optional).
