scholarly journals Actuator Design and Flight Testing of an Active Microspoiler-Equipped Projectile

2017 ◽  
Vol 139 (11) ◽  
Author(s):  
Dooroo Kim ◽  
Laura Strickland ◽  
Matthew Gross ◽  
Jonathan Rogers ◽  
Mark Costello ◽  
...  
Keyword(s):  
Lateral Acceleration ◽  
Shock Interaction ◽  
Frequency Data ◽  
Flight Trajectory ◽  
Flight Testing ◽  
Flight Tests ◽  
Smart Weapons ◽  
Control Authority ◽  
Computational Fluid Dynamics Cfd ◽  
Actuator Design

Actively controlled gun-launched projectiles require a means of modifying the projectile flight trajectory. While numerous potential mechanisms exist, microspoiler devices have been shown to be a promising control actuator for fin-stabilized projectiles in supersonic flight. These devices induce a trim force and moment generated by the boundary layer–shock interaction between the projectile body, rear stabilizing fins, and microspoilers. Previous investigations of microspoiler mechanisms have established estimates of baseline control authority, but experimental results have been restricted to cases in which the mechanism was statically deployed. This paper details the design and flight testing of a projectile equipped with a set of active microspoilers. A mechanical actuator is proposed that exhibits unique advantages in terms of robustness, simplicity, gun-launch survivability, and bandwidth compared to other projectile actuator mechanisms considered to date. A set of integrated test projectiles is constructed using this actuator design, and flight experiments are performed in which the microspoilers are oscillated near the projectile roll frequency. Data obtained from these flight tests are used in parameter estimation studies to experimentally characterize the aerodynamic effects of actively oscillating microspoilers. These predictions compare favorably with estimates obtained from computational fluid dynamics (CFD). Overall, the results presented here demonstrate that actively controlled microspoilers can generate reasonably high levels of lateral acceleration suitable for trajectory modification in many smart-weapons applications.

Modeling and flight testing of wing shaping for roll control of an unmanned aerial vehicle

2015 ◽  
Vol 3 (4) ◽  
pp. 192-204 ◽  
Author(s):  
Michael A. Thamann ◽  
Suzanne Weaver Smith ◽  
Sean C.C. Bailey ◽  
E. Brady Doepke ◽  
Scott W. Ashcraft
Keyword(s):  
Numerical Model ◽  
Unmanned Aerial Vehicle ◽  
Flight Testing ◽  
Flight Tests ◽  
Autonomous Flight ◽  
Roll Control ◽  
Modeling Process ◽  
Aerodynamic Properties ◽  
Aerial Vehicle

In this paper, an approach is described to implement autonomous (waypoint tracking) flight in a testbed airframe, which uses wing twist for roll control. These flights were performed using an existing commercial autopilot. Aileron effectiveness was identified as a parameter that could be modified to maintain roll control during autonomous flight. A modeling process was then developed to calculate the aileron effectiveness for a wing shaping demonstrator aircraft utilizing numerically determined aerodynamic properties. Simulations and flight tests with the testbed aircraft were performed that demonstrated suitability of the approach for autonomous flight. In-flight aileron doublets were used to validate the aileron effectiveness predicted by the numerical model, which matched within 7%.

Fixed-wing approach techniques for complex environments

2015 ◽  
Vol 119 (1218) ◽  
pp. 999-1016
Author(s):  
P. R. Thomas ◽  
S. Bullock ◽  
U. Bhandari ◽  
T. S. Richardson
Keyword(s):  
Complex Environments ◽  
Flight Tests ◽  
Qualitative And Quantitative ◽  
Alternative Approach ◽  
Potential Benefits ◽  
Quantitative Understanding ◽  
Control Authority ◽  
The Stability ◽  
Glide Slope ◽  
Space Requirements

AbstractThe landing approach for fixed-wing small unmanned air vehicles (SUAVs) in complex environments such as urban canyons, wooded areas, or any other obscured terrain is challenging due to the limited distance available for conventional glide slope descents. Alternative approach methods, such as deep stall and spin techniques, are beneficial for such environments but are less conventional and would benefit from further qualitative and quantitative understanding to improve their implementation. Flight tests of such techniques, with a representative remotely piloted vehicle, have been carried out for this purpose and the results are presented in this paper. Trajectories and flight data for a range of approach techniques are presented and conclusions are drawn as to the potential benefits and issues of using such techniques for SUAV landings. In particular, the stability of the vehicle on entry to a deep stall was noticeably improved through the use of symmetric inboard flaps (crow brakes). Spiral descent profiles investigated, including spin descents, produced faster descent rates and further reduced landing space requirements. However, sufficient control authority was maintainable in a spiral stall descent, whereas it was compromised in a full spin.

Modelling, Analysis and Flight Testing of a Military Turbofan Engine Under Windmilling Conditions

2019 ◽  
Author(s):  
Budharaju Balaji ◽  
N. Om Prakash Raj ◽  
Mahesh P. Padwale ◽  
G. P. Ravishankar
Keyword(s):  
Present Model ◽  
Operating Conditions ◽  
Time Dependent ◽  
Flight Testing ◽  
Flight Tests ◽  
Turbofan Engine ◽  
Safety Critical ◽  
Proposed Model ◽  
Modelling Analysis ◽  
Flight Envelope

Abstract Flight testing of a military low bypass turbofan engine involves multitudes of tests to ensure the Engine - Aircraft compatibility across the flight envelope. One of the safety critical tests is to conduct In-Flight restart of the engine. Detailed planning and careful execution is mandated for a single engine aircraft. Accurate modelling of sub-idle performance characteristics of the engine during windmilling conditions enables better prediction of engine behavior during in-Flight shutdown and restart. Typically, Engine manufacturer provides a Performance Cycle Deck (PCD) to predict and assess the performance of the engine across the flight envelope for all throttle positions. However, the PCD does not include sub-idle behavior. The present work focusses on developing a torque based engine behavior model which enables prediction of time dependent fan and compressor characteristics during sub-idle operations. The proposed model is divided into two parts. The first part deals with deceleration characteristics during engine shut-off and spool down, and the second part deals with the acceleration characteristics during spooling up and engine restart. In-flight spool-down (a quick relight without windmilling) restart data obtained through flight tests was used to validate the present model. The model is intended to be used for future flight tests which include windmill restarts under various operating conditions. The model is expected to accurately predict the correlation between aircraft speed and engine windmilling rotor speeds for arriving at a windmill restart envelope for the aircraft.

Flight Simulator as a Tool for Flight Control System Synthesis and Handling Qualities Research

2009 ◽  
Vol 147-149 ◽  
pp. 231-236 ◽  
Author(s):  
Tomasz Rogalski ◽  
Andrzej Tomczyk ◽  
Grzegorz Kopecki
Keyword(s):  
Control System ◽  
Control Systems ◽  
Flight Control ◽  
Flight Simulator ◽  
Flight Control System ◽  
Aircraft Control ◽  
Flight Testing ◽  
Flight Tests ◽  
Control Laws ◽  
Handling Qualities

At the Department of Avionics and Control Systems problems of aeronautical control systems have been dealt with for years. Several different kinds of aeronautical control systems have been designed, prototyped and tested. These control systems are intended for general aviation aircraft and unmanned aircraft. During all research projects computer simulations and laboratory tests were made. However, since in some cases such tests were insufficient, in-flight tests were conducted leading to a series of reliable results. The in-flight tests were made with the use of M-20 Mewa aircraft (autopilot for a GA aircraft) and PZL-110 Koliber aircraft (control system for UAV and indirect flight control system for a GA aircraft). Nevertheless, in-flight testing is very expensive and problematic. To avoid some problems appearing during in-flight tests and their preparation, a simulator – which is normally used for professional pilot training – can be used. The Aviation Training Center of the Rzeszów University of Technology possesses the ALSIM AL-200 MCC flight simulator. We have started preparing this simulator for the research. It is possible to control the simulated aircraft with the use of an external control system. The solution proposed enables testing the aircraft control algorithms, indirect control laws (e.g. control laws modifying handling qualities), as well as testing and assessment of the students’ pilotage skills. Moreover, the solution makes it possible to conduct tests connected with aircraft control, crew management, crew cooperation and flight safety. The simulator allows us to test dangerous situations, which – because of safety reasons – is impossible during in-flight testing. This paper presents modifications to the simulator’s hardware and additional software, which enable the described research.

Flight Testing the ADS-33E Cargo Helicopter Handling Qualities Requirements Using a CH-53G

2013 ◽  
Vol 58 (1) ◽  
pp. 1-11
Author(s):  
Marc Hoefinger ◽  
Chris L. Blanken
Keyword(s):  
Flight Test ◽  
Flight Testing ◽  
Flight Tests ◽  
Handling Qualities ◽  
Design Standard ◽  
German Army ◽  
The U.S

Flight tests with a German Army Sikorsky CH-53G helicopter were performed to evaluate the applicability and repeatability of the U.S. Army's Aeronautical Design Standard (ADS)-33E-PRF cargo helicopter handling qualities requirements. The objectives were to corroborate earlier findings and to propose modifications if deemed necessary. The CH-53G was chosen because it is the largest helicopter operated by the German Army, and its dedicated role is cargo and troop transport. The quantitative criteria and the associated boundaries as specified in the standard were largely confirmed. Several flight test maneuvers were revised and tailored. Generally, the heights for performing the near-earth maneuvers were increased. The time/tolerances experienced were borderline desired/adequate or adequate.

scholarly journals Design of a Fluidic Actuator with Independent Frequency and Amplitude Modulation for Control of Swirl Flame Dynamics

Fluids ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 128
Author(s):  
Amrit Adhikari ◽  
Thorge Schweitzer ◽  
Finn Lückoff ◽  
Kilian Oberleithner
Keyword(s):  
Flow Control ◽  
Large Scale ◽  
Combustion Process ◽  
Precessing Vortex Core ◽  
Flame Dynamics ◽  
Efficient Combustion ◽  
Control Authority ◽  
Swirl Flame ◽  
Actuator Design ◽  
The Impact

Fluidic actuators are designed to control the oscillatory helical mode, called a precessing vortex core (PVC), which is often observed in gas turbine combustors. The PVC induces large-scale hydrodynamic coherent structures, which can considerably affect flow and flame dynamics. Therefore, appropriate control of this structure can lead to a more stable and efficient combustion process. Currently available flow control systems are designed to control the PVC in laboratory-scale setups. To further develop these systems and find an approach applicable to the industrial scale, a new actuator design based on fluidic oscillators is presented and studied in this paper. This actuator allows for independently adjusting forcing frequency and amplitude, which is necessary to effectively target the dynamics of the PVC. The functionality and flow control of this actuator design are studied based on numerical simulations and experimental measurements. To verify the flow control authority, the actuator is built into a prototype combustor test rig, which allows for investigating the impact of the actuator’s forcing on the PVC at isothermal conditions. The studies conducted in this work prove the desired functionality and flow control authority of the 3D-printed actuator. Accordingly, a two-part stainless steel design is derived for future test conditions with flame.

Design improvement of air deployable parachute for high altitude launch ofpayload based on investigationand experimentation

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mahendra Pratap ◽  
Anil Kumar Agrawal ◽  
Subhash Chandra Sati ◽  
Arun Kumar Saxena
Keyword(s):  
High Altitude ◽  
Theoretical Investigation ◽  
Design Methodology ◽  
Cfd Analysis ◽  
Flight Tests ◽  
Content Type ◽  
Design Changes ◽  
Canopy Area ◽  
Theoretical Investigations ◽  
Computational Fluid Dynamics Cfd

Purpose The purpose of this paper is to improve the design of a solid square canopy of a parachute. The design improvements are brought out by providing minor slits in the canopy area. Proper designing of the parachute was carried out using theoretical investigation coupled with experimentation. This parachute is designed for launch of sonobuoy from fixed wing aircraft. Design/methodology/approach Literature review was carried out on the design of such parachutes for the launch of a sonobuoy from a high altitude to the water entry. Computational fluid dynamics (CFD) analysis provided the value of the coefficient of drag for the slit-cut square canopy parachute, with and without sonobuoy for different lengths of the slit. Besides the theoretical investigation, experimentation was also carried out to validate the design. Findings The experimentation was carried out on 58 and 75 gsm fabric canopies with the slit edge plain-cut with thermally sealed edges, stitched and strengthened. In the case of plain-cut slits on the canopy made of 75 gsm fabric, no tearing of the slit edge was observed in dynamic and flight tests. Research limitations/implications The present work has been carried out considering various assumptions and limited trial data specific to precision drop of 9 kg payload. The work can be adopted for bigger parachute for dropping of higher payloads. Originality/value Lab strength test, track dynamic and flight trials were conducted to acquire useful data for the present analysis. Besides the theoretical investigations and CFD analysis inherently based on numerous assumptions, experimentation was carried out as the sonobuoy deployment conditions are full of uncertainty. Dynamic and airdrop tests were conducted for this reason to determine design changes in the slits, both at the material level and on improvisations.

Online Four-Dimensional Flight Trajectory Search and its Flight Testing

2005 ◽  
Author(s):  
Shinji Suzuki ◽  
Yutaka Komatsu ◽  
Satoshi Yonezawa ◽  
Kazuya Masui ◽  
Hiroshi Tomita
Keyword(s):  
Flight Trajectory ◽  
Flight Testing ◽  
Trajectory Search

scholarly journals Numerical Calculation of Effect of Elastic Deformation on Aerodynamic Characteristics of a Rocket

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Laith K. Abbas ◽  
Dongyang Chen ◽  
Xiaoting Rui
Keyword(s):  
Lift Force ◽  
Normal Force ◽  
Center Of Pressure ◽  
Aerodynamic Characteristics ◽  
Force Distribution ◽  
Pitching Moment ◽  
Flight Trajectory ◽  
Aerodynamic Coefficients ◽  
Computational Fluid Dynamics Cfd ◽  
Drag And Lift

The application and workflow of Computational Fluid Dynamics (CFD)/Computational Structure Dynamics (CSD) on solving the static aeroelastic problem of a slender rocket are introduced. To predict static aeroelastic behavior accurately, two-way coupling and inertia relief methods are used to calculate the static deformations and aerodynamic characteristics of the deformed rocket. The aerodynamic coefficients of rigid rocket are computed firstly and compared with the experimental data, which verified the accuracy of CFD output. The results of the analysis for elastic rocket in the nonspinning and spinning states are compared with the rigid ones. The results highlight that the rocket deformation aspects are decided by the normal force distribution along the rocket length. Rocket deformation becomes larger with increasing the flight angle of attack. Drag and lift force coefficients decrease and pitching moment coefficients increase due to rocket deformations, center of pressure location forwards, and stability of the rockets decreases. Accordingly, the flight trajectory may be affected by the change of these aerodynamic coefficients and stability.

scholarly journals Numerical Investigation on Handling Stability of a Heavy Tractor Semi-Trailer under Crosswind

2020 ◽  
Vol 10 (11) ◽  
pp. 3672 ◽  
Author(s):  
Qianwen Zhang ◽  
Chuqi Su ◽  
Yi Zhou ◽  
Chengcai Zhang ◽  
Jiuyang Ding ◽  
...  
Keyword(s):  
Lateral Displacement ◽  
Aerodynamic Characteristics ◽  
Lateral Acceleration ◽  
Yaw Rate ◽  
Body Dynamics ◽  
Crosswind Stability ◽  
Computational Fluid Dynamics Cfd ◽  
Multi Body ◽  
The Relationship ◽  
Lateral Area

Due to the large lateral area of the trailer and variable road conditions, the handling stability of a heavy tractor semi-trailer under crosswind is very important for road safety. In this present work, numerical simulation is performed to study the crosswind effects on handling stability of a tractor semi-trailer. The aerodynamic characteristics of the tractor semi-trailer under different crosswind were computed by computational fluid dynamics (CFD). Then, mathematical models to reveal the relationship between the aerodynamic forces and crosswind were constructed to serve as inputs of the multi-body dynamics to analyze the handling stability under crosswind. The performance of crosswind stability is evaluated by the response of lateral acceleration, yaw rate and the lateral displacement. The lateral acceleration and yaw rate were decreased by a maximum of 14.6% and 16.5% compared to the truck without the deflector, which showed that the crosswind aerodynamics and stability were obviously improved.

Sign in / Sign up

Export Citation Format

Share Document