Accession Number:

ADA374308

Title:

Elementary Model of Nose Gear Retraction and Oleo-Pneumatic Strut Compression

Descriptive Note:

Major rept.

Corporate Author:

GEORGIA INST OF TECH ATLANTA

Personal Author(s):

Report Date:

1999-08-06

Pagination or Media Count:

28.0

Abstract:

Landing gear systems have two major non-linear components that need to be modeled in order to fully represent a complete landing profile, the extension actuator and the oleo-pneumatic strut. In order to test the equations of motion, the components were put together as part of a system similar to the F-15 nose gear. Working Model tested the geometry, yielding a geometry specific force time diagram that compares well to experimental results. A real systems actuator follows a control system input, which is designed to follow a force displacement path. The equations governing a typical actuator are integrated to compare two models a simplified model and one that assumes no leaking nor compressibility of the fluid. The strut acts as a spring mass system, with a non-linear spring and a damper proportional to the square of the velocity. The strut equations of motion are formulated as well as the constraints for both constant velocity and a simulated drop test. These equations are also integrated to show either a force displacement or time displacement diagrams. The results are then compared to the expected values for each type of test, showing data consistent with experimental and other computational methods.

Subject Categories:

  • Aircraft
  • Hydraulic and Pneumatic Equipment

Distribution Statement:

APPROVED FOR PUBLIC RELEASE