The approach for achieving the research objectives was to utilize the unique capabilities of NASA’s NF-15B-837 aircraft to allow the adjustment of the nozzle-area ratio and/or canard positions by engaging the ILTV research control laws. The ILTV control laws provide the ability to add trim command biases to canard positions, nozzle area ratios, and thrust vectoring through the use of datasets. Datasets consist of programmed test inputs (PTIs) that define “trims” to change the nozzle-area ratio and/or canard positions. The trims are applied as increments to the normally commanded positions.
A LaNCETS non-linear, six-degrees-of-freedom simulation capable of real-time pilot-in-the-loop, hardware-in-the-loop, and non-real-time batch support was developed and validated. Prior to first flight, extensive simulation analyses were performed to show adequate stability margins with the changes in lift distribution and plume shape. Additionally, engagement/disengagement transient analysis was also performed to show manageable transients.
This work was done by Cheng Moua of Dryden Flight Research Center. For more information, download the Technical Support Package (free white paper) at www.techbriefs.com/tsp under the Mechanics/Machinery category. DRC-009-039