Accession Number:

ADA158005

Title:

Use of Hinged Strakes for Lateral Control at High Angles of Attack.

Descriptive Note:

Master's thesis,

Corporate Author:

AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH

Personal Author(s):

Report Date:

1985-05-01

Pagination or Media Count:

164.0

Abstract:

This thesis investigated the feasibility of using a portion of the leading edge LE strake hinged along the longitudinal axis as a roll control device for a high performance aircraft at high angles of attack AOA. A wind tunnel test was conducted to gather static force and moment data for use in a six degree of freedom computer simulation. Asymmetric strake deflections, both dihedral and anhedral, were investigated. The longitudinal coefficients were little affected by strake deflection, but the lateral directional coefficients showed a nonlinear, but repeatable, behavior with strake deflection. Comparisons to be published data indicate that the strakes produce similar behavior for different aircraft designs. Simulations of the aircraft response to the strakes showed that an improvement over current roll performance could be obtained by combining the positive strake deflection with the ailerons up to 38 deg. AOA, after which the strakes alone produced the best roll performance. Sideslip and AOA must be closely controlled or the air-craft will either not roll, or will depart during the roll. The roll performance using hinged strakes at high AOA is compared to roll performance using differential LE flaps. The diffential LE flaps produce comparable roll rates with less sideslip than produced by the hinged strakes. However, the possibility exists of combining hinged strakes with differential LE flaps for improved roll performance.

Subject Categories:

  • Aerodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE