National Aerospace Laboratories Institutional Repository

    Comparison of the graphitizabilities of heat-treated coal tar and its mesophase pitches

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    Formation of graphitizing carbons via a mesophase13; was first reported by Brooks and Taylor [I]. Owing to13; the inherent structural order of the mesophase, it may13; be anticipated that the graphitizability of carbon from13; its mesophase would be higher than that of the same13; carbon, heat-treated from the isotropic phase. How-13; ever, it has been reported by Yamada et al. [2] that the13; graphitizability of some mesophase microbeads is not13; good. With the view to obtain quantitative estimates13; of the graphitizabilities of a graphitizable carbon and13; its mesophase, X-ray diffraction studies on identically13; heat-treated coal tar (CT) and its mesophase (MP)13; pitches have been carried out. Details of the prep-13; aration and metallographic characterization of the13; MP pitch have been published elsewhere [3].13

    Flight Simulation Of HS-748 With And Without Rotodome Part-4 : Handling Qualities And Dynamic Responses

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    The Mathematical And Data Used In Off-Line Simulation Of The Rotodomed Aircraft Have Been Described In Detail In Part-1 . The Issue Related To The Rolls Royce Engine Simulation Studies Have Been Presented In Part-2 . The Formulation Of The Aerostatic 'Model And Its Verification Has Been Discussed In Part-3 . In This Report, The Results Of The Handling Qualities And Dynamic .Responses Of Both The Basic And The Aew Are Presented. The Results Are Discussed Within The Proposed Restricted C.G. Envelope And Speed Limits Of AEW

    Calibration of Fuel Rotameters (Piston Engine)-HAL-1990

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    This report provides details of calibration of fuel flow rotameters carried out in the Piston engine overhaul section of ache Hindustan Aeronautics Limited.Bangalore-560 017 . The calibrated results have been tabulated and are also shown graphically

    Software for bus monitor

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    Software for Bus Monitor (SOBUM) is a package developed for13; MIL-STD-1553B based on Intel's Microprocessor Development System (MDS). SOBUM, consisting of modules in ASM 86 and PASCAL 86 when used with proper hardware interface can transfer the bus messages to the RAM in real time. SOBUM is then used in the off-line analysis of the message traffic on the bus. It displays or prints the data gathered in very useful and interpretive formats

    Dynamic and aeroelastic analysis of a trasnport aircraft

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    The dynamic and aeroelastic characteristic of a transport aircraft has been established using MSC/NASTRAN. Correlation of the dynamic characteristics of the aircraft obtained from analysis with the Ground Vibration Test results of the aircraft is studied. The doublet lattice method has been used to estimate the appropriate unsteady air loads generated on the lifting surfaces of the aircraft. In an attempt to realize the realistic flutter margins, the analysis results of the aircraft for the control surfaces rotational modes have been tuned to the Ground Vibration Test results after establishing the first cut analysis results. Flutter analysis of the complete aircraft has been carried out by both PK and KE methods and the critical flutter velocities have been evaluated. The flutter margins for the aircraft are established with respect to the FAR 25 requirements. All the considered aircraft configurations have been found to satisfy the FAR 25 requirements and have been subsequently cleared from flutter criteria with substantial flutter margins

    Design & Development of Bridge Deck Plate Using Composite Materials and sandwich Construction : Concluding Report

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    This report brings out the gist of the work carried out under the project entitled "Design & Development of Bridge Deck Plate Using Composite Materials & Sandwich Construction" sponsored by R & D Estt. (Engrs.), DRDO, Pun

    Wind tunnel test studies on 1/7 scale NALLA-1 model

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    Wind tunnel tests comprising of flow visualization and measurement of forces and moments have been carried out on a 1/7 scale model of the NAL Light Aircraft -(NALLA-1) and its variants in the open circuit wind tunnels at the Indian Institute of Science, Bangalore. Aerodynamic characteristics of the model derived from these tests are presented in this report

    Eigenstructure Control: A flight vehicle handling qualities design tool

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    With the development of high reliability sensors, computers and actuators, it is now possible to build flight vehicle control systems with extraordinary performance. Indeed full authority fly-by-wire flight vehicles using feedback controllers can substantially mask the basic airframe dynamic characteristics and consequently its performance limitations. These technology developments in turn have brought into focus the role of multivariable control system design methods to evolve complex multi-loop systems using multiple sensors and control effectors. Multivariable control techniques are now being demonstrated in experimental flight research programs. It is thus reasonable to expect that these methods will be used in flight vehicle control design of production aircraft as increased sophistication in airframe design and performance is sought. Among the many control techniques available for such design, Eigenstructure Control techniques offer some unique advantages since the flight vehicle handling qualities requirements originate in the modal control framework. The present study explores methods to adapt this method for deriving practical flight control laws

    Application on system identification techniques to Tejas flight test data

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    Tejas, the Indian Light Combat aircraft, is a fly-by-wire aircraft with relaxed longitudinal stability that provides for enhanced agility, high maneuverability and performance. The aircraft is presently undergoing extensive flight test trails and the flight data gathered is being used by various design groups to evaluate aircraft systems, performance and aerodynamic characteristics. This paper gives an overview of the application of system identification techniques to Tejas flight test data for validation and update of the aircraft aerodynamic database. The aerodynamic characterization is carried out using two different approaches i) point model identification, and ii) coefficient level matching. Typical results are presented from both the approaches along with the time history plots from the flight updated aero database. The main purpose of this paper is show to how system identification techniques can lead to accurate determination of aerodynamic characteristics from flight test data

    Fault toleranat neuro/neuro-fuzzy controllers for aircraft auto landing with actuator failures and severe winds

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    In this talk, we will cover some recent work carried out in our group for developing intelligent flight controllers which can handle failures and also flying under severe winds. Using neural networks and also fuzzy neural networks the controllers are able to handle actuator failures and able to perform similar to those under normal conditions. Specifically, we will look at 1. Neural-aided controller 2. Fuzzy-neural aided controller and 3. Adaptive back stepping neural controller architectures for handling failures under severe winds for an aircraft auto-landing problem. The results indicate that good fault tolerant capabilities can be provided for existing controllers without adding more complexities and computational overhead
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