Aircraft Performance/Stability & Control Testing
PASSENGER + COMMERCIAL AIRCRAFT
AERODYNAMIC EFFICIENCY & COMPONENT INTERACTION
The Performance, Stability & Control test technique is utilized to fully understand the efficiency and effectiveness of the aerodynamic shape of the aircraft. This includes evaluating the interaction between components such as engine-nacelles/wing and the effectiveness of control surfaces to “steer” the aircraft as the aircraft maneuvers through its intended operational envelope (attitude, altitude, and speed). Within this test technique, Performance Assessment speaks to understanding the attributes of aircraft performance in takeoff, level flight/cruise, range, etc. Whereas, Stability & Control looks at the effectiveness of control surfaces in maneuvering and recovery from changes in flight path, etc.
Within this test technique, Calspan tailors our tests to meet the customer’s particular goals and test objectives. In order to support the aircraft development, test objectives can incorporate many of the following:
- Acquire wind tunnel data required to support full-scale drag polar buildup to validate aerodynamic performance.
- Validate high speed neutral controls for longitudinal and lateral/directional stability.
- Determine the contribution of major components (wing, fuselage, propulsion system, and empennage) to the total aircraft aerodynamic characteristics.
- Determine basic and combined high speed control effectiveness and sizing for ailerons, spoilers, speed brakes, elevators, stabilizer, and rudder.
- Predict wing buffet onset and horizontal tail bending and torsion.
- Alternate components assessments for fuselage, wings, winglet, alternate tail, and alternate wing-body fairing.
- Pressure distributions for loads analysis and CFD validation.
- Examine the effects of different simulated engine mass flow ratios on aircraft drag, wing lift distribution, and determine spillage drag increments for drag buildup.
- Determine engine inlet flow quality at the fan face, both with a clean wing and spoilers deflected.
- Obtain surface flow visualization patterns at cruise Mach numbers.
- Examine Reynolds number effects, particularly high Reynolds/Low Mach Number excursions.
FORCE & MOMENT TESTING
During the wind tunnel test, a number of aerodynamic configurations and components are tested in order to determine their effect on the overall model performance/stability and control through a range of model incidences, Mach, and Reynolds numbers. Calspan measures overall forces and moments on the model by a precision internal strain gauge balance and converted to aerodynamic coefficients (e.g., Lift, drag, pitching moment, etc.). Calspan applies industry standard data corrections to offset tunnel effects (i.e., remove effects of the test not representative to a full-scale aircraft). In addition, techniques Calspan has devised through our years of experience are executed throughout the test to further achieve similarities to full-scale flight.