NALx2019;S Civil Aviation Programme: Solved and Unsolved Problems

The civil aviation programme, more particularly civil aircraft design and development projects, at NAL has been in progress for more than two decades now. From a modest beginning with the fabrication of a bought -out kit of the Light Canard Research Aircraft (LCRA), to the position now that a two seater ab initio trainer aircraft (HANSA -3)is in x2018;limited series productionx2019;; 14-seater Light Transport Aircraft (SARAS) is in the flight development phase with two prototypes flying and an optimization exercise leading to the production standard aircraft at an advanced stage; design of a 4 / 5 seater multirole general aviation ircraft (NM5) has just been initiated jointly with13; a private industry; and a proposal for the development of a 70 seater regional transport aircraft has been submitted to CSIR as a mega project under the 11th and 12th plan eriods. For an Ramp;D laboratory to reach this stage is commendable to say the least. It would seem that now is an appropriate time to take stock of where we are, what13; are the major technical problems that we have encountered and sorted out (or not!). Study of x201C;technicalx201D; history is as important as x201C;politicalx201D; history in order to learn from mistakes and successes. We therefore discuss a few major technical problems that we encountered in our aircraft projects, how they were tackled in a manner appropriate to a mission mode project and what lessons were learnt

Types of flow on the lee side of delta wings

Delta wings have found wide application in a variety of aerospace vehicles including high performance combat aircraft, supersonic civil aircraft, (proposed) hypersonic aircraft and the space shuttle orbiter. A considerable amount of research work has been carried out over the past three decades and an extensive body of literature is available. The present review focuses attention on the nine possible types of flow that can occur on the lee side of delta wings in a Mach number range which extends from subsonic to hypersonic. The dependence of the flow types on geometrical and freestream parameters has been discussed in detail. The extensive experimental data available has made it possible to obtain a broad physical understanding of the mechanisms underlying the different flow types. However much more work needs to be done to determine the effects of Reynolds number, particularly when either the state of the boundary layer is transitional or when the type of flow is changing from leading edge attached to separated. Computational methods have made spectacular advances in recent years. In particular, solutions of Reynolds averaged Navier-Stokes equations at fairly high Reynolds number have become possible and these computations have captured eight of the nine experimentally observed flow types, including those involving cross flow shock waves and shock-induced separation.13

Types of Flow on the Lee Si-de of Delta Wings

Delta wings have found wide application in a variety of aerospace vehicles including high performance combat aircraft, supersonic civil aircraft, (proposed) hypersonic aircraft. and the space shuttle orbiter. Considerable amount of research work has been carried out over the past three decades and an extensive body of literature is available. The. present review focuses attention on the nine possible types of flow that can occur on the lee side of delta wings in a Mach number range which extends from subsonic to hypersonic. The dependence of the flow types on geometrical and freestream parameters has been discussed in detail. The extensive experimental data available has made it possible to obtain a broad physical understanding of the mechanisms underlying the different flow types. However much more work needs to be done to determine the effects of Reynolds number, particularly when either the.(state of the boundary layer is ransitional or when the type of flow is changing from leading edge attached to separated.13; Computational methods have made spectacular advances in recent years. In particular, solu tions of Reynolds averaged Navier-Stokes equations a t fairly high Reynolds number have become possibte and these computations have captured eight of the nine experimentally ohserved flow types including those involving cross flow shock waves and shock induced separation.13; 13

Stability and Control characteristics of MIG-21 aircraft

This document provides the stability and control derivatives data for the MIG-21BIS aircraft in the form readily usable for control system synthesis. Analytical prediction of the aircraft modes, typical time responses as well as Bode plots in the frequency domain are presented. Longitudinal dynamics data presented in this document supersedes the one provided in NAL PD SE 8501