Accession Number:

AD0904090

Title:

Buffet Dynamic Loads during Transonic Maneuvers

Descriptive Note:

Final rept. Mar 1970-Dec 1971

Corporate Author:

MCDONNELL AIRCRAFT CO ST LOUIS MO

Personal Author(s):

Report Date:

1972-09-01

Pagination or Media Count:

292.0

Abstract:

This report describes an empiricaltheoretical study program to develop a first generation method for predicting the buffet dynamic loads and fighter aircraft responses that occur during transonic maneuvers. The prediction method applies to wing upper surface loads acting on the airplane and the induced aircraft dynamic responses. Wind tunnel tests of a 10 scale model of the YF-4E aircraft were used a enhance understanding of the buffet mechanism for lifting surfaces and to obtain data needed to deduce the surface load formulas. A first test phase Series I gave oil flow and tuft information regarding flow on the upper wing surfaces. A second test phase Series II was used to acquire both steady and fluctuating pressure and strain data as well as acceleration response. The fluctuating pressure data were converted to power and cross-power spectra and a mathematical model was formulated to describe the amplitude and the spatial and spectral distributions of the pressures on the wing. The mathematical pressure description was then used as the forcing function in a dynamic response computer program to assess the structural response. The method described in this report is intended for preliminary aircraft design computations of transonic aircraft buffet dynamic loads and responses. The salient feature is the mathematical description of the nature of buffeting flow over a lifting surface. This feature is generally applicable to prediction of aircraft structural dynamic responses.

Subject Categories:

  • Aerodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE