Search results

The purpose of this paper is to present a method for determining the safe flight boundaries of the asymmetrically loaded airplane in the terminal flight phases. The method is applicable to both, the inherent airplane asymmetries and those asymmetries resulting from the airplane use irregularities, asymmetric stores under the wing being one of the examples. The method is aimed to be used in the airplane design and combat airplane service life support.

The analysis method is based on the comparison of demanded and structurally available flight control displacements. Control surface aerodynamic properties, structurally available flight control displacements and dynamic pressure define control surface authority as the capability of control surfaces to generate the forces and moments needed by the airplane to perform required maneuvers. Demanded flight control displacements are those related to the maneuvering requirements and to those needed to compensate lateral wind and any type of the asymmetric airplane load.

The method results are given in the form of the speed and lateral wind component and are a subset of the total set of airplane safe flight boundaries. The key objective is the improvement of flight safety of the asymmetrically loaded airplane.

The method supplements the safe flight boundaries of the symmetrically loaded airplane, the minimal landing speed being the dominant limitation. This boundary positions method analysis in the domain of linear lift coefficient variation, as the function of the angle of attack permits the addition of control surface displacements required to perform the maneuvers and compensate the asymmetrical loads.

The method combines a simple roll dynamics model, stationary equations of the airplane lateral-directional motion and several numeric analysis procedures to obtain the results. This new combination possesses synergy properties and is implemented as the computer program.

The purpose of this paper is to present the methodology and approach adapted to conduct a wind tunnel experiment on the inverted joined-wing airplane flying model together with the results obtained.

General assumptions underlying the dual-use model design are presented in this paper. The model was supposed to be used for both wind tunnel tests and flight tests that significantly drive its size and internal structure. Wind tunnel tests results compared with the outcome of computational fluid dynamics (CFD) were used to assess airplane flying qualities before the maiden flight was performed.

Extensive data about the aerodynamic characteristics of the airplane were collected. Clean configurations in symmetric and asymmetric cases and also configurations with various control surface deflections were tested.

The data obtained experimentally made it possible to predict the performance and stability properties of the unconventional airplane and to draw conclusions on improvements in further designs of this configuration.

The airplane described in this paper differs from frequently analyzed joined-wing configurations, as it boasts a front lifting surface attached at the top of the fuselage, whereas the aft one is attached at the bottom. The testing technique involving the application of a dual-use model is also innovative.

This paper presents the longitudinal stability analysis of a single tractor propeller airplane LASTA at high engine power settings. This analysis is part of the ongoing process of certifying the airplane for civil use according to the civil regulations CS-23.

The design methodology that is presented in the paper consists of comparing flight test aerodynamic and calculation results. The methods used here are standard and routinely used in flight testing.

Flight testing results indicate that at low airspeeds the cumulative destabilizing effects because of high values of the angle of attack and high power settings are about 6 per cent of MAC. This value is in a very good agreement with published data.

The information presented in this paper are new, and are very specific to this one aircraft configuration. The methods used here are standard and widely used in flight testing.

The information in this paper presents flight test results. There are not many publications in this area.

THE complexity of the problems which are associated with the lateral stability and directional control of tailless aeroplanes was not realized until rather late.

IN connexion with the development of the modern transport aeroplane it is of growing importance to pay proper attention to the take‐off characteristics of these aeroplanes and to consider the means suitable to improve them. For the realization of economically justified air transport two trends have been indicated; both having an unfavourable effect on take‐off performance. These trends are:

THE problem of designing an aircraft so that the pilot is able easily to regain and maintain control following the sudden failure of an engine has been for some years a serious one. It is thought that an elementary description of the aerodynamics of the problem and of the flight tests which are made to assess a particular aircraft may be of interest. The equally important problem of ensuring adequate performance after an engine failure is not discussed here.

Under this heading are published regularly abstracts of all Reports and Memoranda of the Aeronautical Research Committee, Reports and Technical Notes of the United States National Advisory Committee for Aeronautics and publications of other similar Research Bodies as issued

This paper aims to present a new one-variable first-order shear deformation theory (OVFSDT) using nonlocal elasticity concepts for buckling of graphene sheets.

The FSDT had errors in its assumptions owing to the assumption of constant shear stress distribution along the thickness of the plate, even though by using the shear correction factor (SCF), it has been slightly corrected, the errors have been remained owing to the fact that the exact value of SCF has not already been accurately identified. By using two-variable first-order shear deformation theories, these errors decreased further by removing the SCF. To consider nanoscale effects on the plate, Eringen’s nonlocal elasticity theory was adopted. The critical buckling loads were computed by Navier’s approach. The obtained numerical results were then compared with previous studies’ results using molecular dynamics simulations and other plate theories for validation which also showed the accuracy and simplicity of the proposed theory.

In comparing the biaxial buckling results of the proposed theory with the two-variable shear deformation theories and exact results, it revealed that the two-variable plate theories were not appropriate for the investigation of asymmetrical analyses.

A formulation for FSDT was innovated by reconsidering its errors to improve the FSDT for investigation of mechanical behavior of nanoplates.

Understanding the performance and flight envelope of a damaged aircraft is a preliminary requirement to recover the aircraft after damage. This paper aims to provide a comprehensive understanding of wing damage effect on airplane performance, local stability, and flying quality of each trim state inside the achievable flight envelope.

This paper demonstrates the use of attainable equilibrium points which are referred as trim states in order to estimate a damaged airplane manoeuvring flight envelope using a numerical computation method.

Wing damaged airplane manoeuvring flight envelope is estimated for different portions of the wing tip loss. Local stability at each trim condition inside the estimated flight envelope is analysed, and also motion flight modes and flying quality sensitivity to the wing damage are explored.

Local stability and flying quality analysis at each trim condition inside the flight envelope which demonstrate the effect of damage provides a criterion to prioritize the choice of trimmed flight condition as motion primitives for the airplane post‐damage flight and safe landing.