DOCSLIB.ORG

Aerodynamic Characteristic Analysis of Multi-Rotors Using a Modified

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Aerodynamic Characteristic Analysis of Multi-Rotors Using a Modified Trans. Japan Soc. Aero. Space Sci. Vol. 52, No. 177, pp. 168–179, 2009 Aerodynamic Characteristic Analysis of Multi-Rotors Using a Modified Free-Wake Method By Jaewon LEE,1Þ Kwanjung YEE2Þ and Sejong OH2Þ 1ÞResearch Institute of Mechanical Technology, Pusan National University, Busan, Korea 2ÞDepartment of Aerospace Engineering, Pusan National University, Busan, Korea (Received November 23rd, 2008) Much research is in progress to develop a next-generation rotor system for various aircrafts, including unmanned aerial vehicles (UAV) with multi-rotor systems, such as coaxial and tandem rotors. Development and design of such systems requires accurate estimation of rotor performance. The most serious problem encountered during analysis is wake prediction, because wake-wake and wake-rotor interactions make the problem very complex. This study analyzes the aerodynamic characteristics based on the free-wake method, which is both efficient and effective for predicting wake. This code is modified to include the effect of complex planforms as well as thickness by using an unsteady 3D panel method. A time-marching free-wake model is implemented based on the source-doublet panel method that assigns panels to the surface and analyzes them. The numerical wake instability, the most critical problem for analysis, is resolved by adopting slow start-up and by including viscous effects. Also, the instability due to wake interference in tandem rotor analysis is resolved by configuring the initial shapes of the multi-rotor wake as that of a single rotor wake trajectory. The developed code is verified by comparing with previous experimental data for coaxial and tandem rotors. Key Words: Multi Rotor, Time-Marching Free-Wake, Unsteady Panel Method, Wake Instability Nomenclature 1. Introduction c: blade chord An anti-torque system is redundant in a multi-rotor heli- Cd: rotor overlap area copter, such as one with tandem or coaxial rotors. The sub- Cp: pressure coefficient stantial advantage of a multi-rotor system stems from the Cp0 : incompressible pressure coefficient elimination of the tail rotor, which usually consumes an CP: rotor power coefficient additional 5% to 10% of the main rotor’s power. On the CT: rotor thrust coefficient other hand, the mechanical complexity and associated para- d: horizontal distance between rotors sitic drag are believed to be major disadvantages, which D: diameter of rotor disk have made this configuration relatively unpopular so far. H: vertical separation between rotors However, the absence of a tail rotor allows lowers the num- M: mach number ber of helicopter accidents associated with the tail rotor, and rc: vortex core radius enables a more compact configuration than conventional R: radius of blade helicopters. Hence, due to its compact size and lift ability, Re: Reynolds number the multi-rotor system is seem as a viable alternative in t: maximum airfoil thickness UAV or micro-air vehicle (MAV) design.1) In response to vrel: relative velocity increasing needs for compact multi-purpose UAVs, the dual V: velocity rotor system has been chosen in this work. As shown in À : circulation Coleman’s comprehensive review2) of experimental and : induced power factor analytical studies of coaxial rotors, studies during the : doublet 1990s relied heavily on experiments, with a few theoretical : collective pitch angle analyses. Moreover, there is still a long unresolved issue : source about whether or not the coaxial rotor configuration is more rotor: rotor solidity efficient than the conventional rotor system. Detailed aero- È: velocity potential dynamic characteristics, such as wake structures and inter- : azimuth angle rotor interactions, have never been fully understood for wake: wake age coaxial rotor configurations. However, recent advances in computational techniques have enabled modeling of such complex aerodynamics with good confidence. Leishman and Ananthan3) established the Blade Element Momentum Theory (BEMT) for a coaxial Ó 2009 The Japan Society for Aeronautical and Space Sciences Nov. 2009 J. LEE et al.: Aerodynamic Characteristic Analysis of Multi-Rotors Using a Modified Free-Wake Method 169 rotor and solved the local air loads over the upper and lower intends to develop a code for analysis of a multi-rotor UAV rotors. The BEMT does not require the assumptions for the system based on the vortex wake method. The developed induced power factor () and induced power interference method favors analysis of complex wakes generated by factor (int), which are essential for the simple momentum rotors, and also includes the effects of rotor thickness. The theory. Validation of BEMT with Harrington’s experi- current study considers an unsteady source-doublet panel ments4) has shown good agreement. With the limited test method coupled with a time-marching free-wake model. data available, Leishman and Ananthan3) have compared In the single-rotor case, the concept of a finite-thickness- the spanwise airloads of BEMT for a coaxial rotor with bladed rotor was presented by Ahmed and Vidjaja,9) who the results of a Free-Vortex Method (FVM).5) Although dif- used a source/sink distribution over the blade surface and ferences were evident when compared in detail, the agree- a doublet distribution over the camber surface inside the ment between BEMT and FVM was found to be reasonable. blade. However this study used source and doublet distribu- Based on 2D theory, BEMT has the remarkable advantage tions over the blade surface. To improve the calculation of very low computational cost, while it has limitations in efficiency for wake-induced velocity, the doublet panel with analyzing flight regimes such as forward flight, for which constant strength representing the wake is replaced by an 3D effects are important. One research that used full equivalent vortex trapezoid. An important issue regarding 3D theory, was by Bagai and Leishman5) for analysis of codes using a time-marching free-wake model is resolution multi-rotors using the potential theory-based vortex wake of wake instability in hover. This paper focuses on resolving method with pseudo-implicit predictor-corrector method. this, issue and the interaction of rotor wakes. The Karman- Another study by Wachspress and Quackenbush6) used the Tsien compressibility correction is applied in order to cor- constant vorticity contour method. Although these studies rect the compressibility effect over the calculated pressure have proved successful and computationally efficient, the coefficient. The Table-lookup method, which is usually used methods use a vortex lattice description of the blade and supplementary in codes that do not account for viscous cannot predict thickness effects. Moreover, complex config- effects, is used for estimating power of the rotor system. urations of blades with variations in the sectional airfoil For UAVs or model rotors, due to the difference in the have rarely been considered. Due to the relative motion of Reynolds numbers between the analysis and the tables for the rotors, multi-rotor analysis using Navier-Stokes (NS) 2D airfoil aerodynamic data, the Reynolds number scaling based methods requires a complicated grid topology and law is used to estimate rotor power. involves significant difficulties in pre- and post-processing. Validation of results for multi-rotor configurations from One instance of a multi-rotor study using a NS-based developed code has been carried out by comparison with method was by Kim and Brown,7) who numerically ana- available experimental data.4,10) The trajectory of the tip lyzed the performance of a coaxial rotor in hover, steady for- wake in the present method is compared with the experi- ward, and level flight conditions, using a Vorticity Transport mental data of Nagashima,11) and Brown.7) The effects of Model (VTM) based on a time-dependent computational the tandem rotor vertical separation (H=D) and horizontal solution of the vorticity conservation form of the NS equa- distance (d=D) are investigated thoroughly. tion. The simulation results provided a detailed analysis of the differences in performance and the wake behavior of 2. Numerical Analysis the single and coaxial rotor systems. Another application of an NS-based method to a coaxial rotor was by Ruzicka To account for the effect of thickness and the complex and Strawn.8) They described efforts at modeling coaxial platform, this work uses a source-doublet panel method, rotor aerodynamics using the Reynolds-averaged, Navier- which is usually used in fuselage or full aircraft analysis Stokes (RANS) solver Overflow 2. The VTM, which is of fixed-wing aircraft. In addition, this work uses a time- formulated assuming incompressibility, is a partial CFD marching free-wake model, which is excellent in reproduc- scheme with NS for the near blade region, but RANS is a ing rotor wake. The problem in applying the time-marching fully viscous CFD scheme. When using a convection algo- free-wake model is wake instability. The following sections rithm and an adaptive-grid system, VTM was more efficient describe the solution to this problem, as well as the numer- than regular CFD analysis using the NS equation. However, ical method used in the multi rotor analysis code. it is still computationally inefficient compared to potential 2.1. Source-doublet panel method theory based panel methods. If flow is considered to be incompressible and irrota- Vortex wake methods represent less diffusive numerical tional, the continuity equation reduces to the Laplace equa- schemes that accurately reproduce the wake and are more tion. The general solution of the Laplace equation is given efficient than NS codes. They are still used widely for heli- as a sum of sources () and doublets (), distributed over copter aerodynamic analysis. However, as mentioned previ- the body surface and its wakes: Z ously for the Vortex Lattice Methods (VLM), which repre- À1 1 1 sent a blade as vortex lattices, the existing vortex wake È ¼ À n^ r ds 4 body r r methods also have limitations in accounting for rotor com- Z 1 1 plexity, including thickness variation and airfoil change by þ n^ r ds þ È1 ð1Þ location, such as found in UH-60 rotor blades.
Load more

Recommended publications
  • WHIRLYBIRDS, U.S. Marine Helicopters in Korea
    WHIRLYBIRDS U.S. Marine Helicopters in Korea by Lieutenant Colonel Ronald J. Brown U.S. Marine Corps Reserve, Retired Marines in the Korean War Commemorative Series About the Author ieutenant Colonel Ronald J. LBrown, USMCR (Ret), is a freelance writer, a high school football coach, and an educa- THIS PAMPHLET HISTORY, one in a series devoted to U.S. Marines in the tional consultant. The author of Korean War era, is published for the education and training of Marines by several official histories (A Brief the History and Museums Division, Headquarters, U.S. Marine Corps, Washington, D.C., as part of the U.S. Department of Defense observance of History of the 14th Marines, the 50th anniversary of that war. Editorial costs have been defrayed in part With Marines in Operation by contributions from members of the Marine Corps Heritage Foundation. To plan and coordinate the Korean War commemorative events and activi- Provide Comfort, and With ties of the Sea Services, the Navy, Marine Corps, and Coast Guard have Marine Forces Afloat in Desert formed the Sea Services Korean War Commemoration Committee, chaired by the Director, Navy Staff. For more information about the Sea Services’ Shield and Desert Storm), he commemorative effort, please contact the Navy-Marine Corps Korean War was also a contributing essayist for the best-selling book, Commemoration Coordinator at (202) 433-4223/3085, FAX 433-7265 (DSN288-7265), E-Mail: [email protected], Website: The Marines, and was the sole author of A Few Good www.history.usmc.mil. Men: The Fighting Fifth Marines. After almost four years KOREAN WAR COMMEMORATIVE SERIES active duty from 1968 to 1971, Brown returned to teach- DIRECTOR OF MARINE CORPS HISTORY AND MUSEUMS ing high school for the next three decades; intermittent- Colonel John W.
    [Show full text]
  • Effectiveness of the Compound Helicopter Configuration in Rotorcraft Performance Increase
    transactions on aerospace research 4(261) 2020, pp.81-106 DOI: 10.2478/tar-2020-0023 eISSN 2545-2835 effectiveness of the compound helicopter configuration in rotorcraft performance increase Jarosław stanisławski Retired doctor of technical sciences [email protected] • ORCID: 0000-0003-1629-4632 abstract The article presents the results of calculations applied to compare flight envelopes of varying helicopter configurations. Performance of conventional helicopter with the main and tail rotors, in the case of compound helicopter, can be improved by applying wings and pusher propellers which generate an additional lift and horizontal thrust. The simplified model of a helicopter structure, consisting of a stiff fuselage and the main rotor treated as a stiff disk, is applied for evaluation of the rotorcraft performance and the required range of control system deflections. The more detailed model of deformable main rotor blades, applying the Galerkin method, is used to calculate rotor loads and blade deformations in defined flight states. The calculations of simulated flight states are performed considering data of a hypothetical medium class helicopter with the take-off mass of 6,000kg. In the case of both of the helicopter configurations, the articulated main rotor hub is taken under consideration. According to the Galerkin method, the elastic blade model allows to compute blade deformations as a combination of the blade bending and torsional eigen modes. Introduction of additional wing and pusher propellers allows to increase the range of operational speed over 300 km/h. Results of the simulation are presented as time- runs of rotor loads and blade deformations and in a form of disk distribution plots of rotor parameters.
    [Show full text]
  • Micro Coaxial Helicopter Controller Design
    Micro Coaxial Helicopter Controller Design A Thesis Submitted to the Faculty of Drexel University by Zelimir Husnic in partial fulfillment of the requirements for the degree of Doctor of Philosophy December 2014 c Copyright 2014 Zelimir Husnic. All Rights Reserved. ii Dedications To my parents and family. iii Acknowledgments There are many people who need to be acknowledged for their involvement in this research and their support for many years. I would like to dedicate my thankfulness to Dr. Bor-Chin Chang, without whom this work would not have started. As an excellent academic advisor, he has always been a helpful and inspiring mentor. Dr. B. C. Chang provided me with guidance and direction. Special thanks goes to Dr. Mishah Salman and Dr. Humayun Kabir for their mentorship and help. I would like to convey thanks to my entire thesis committee: Dr. Chang, Dr. Kwatny, Dr. Yousuff, Dr. Zhou and Dr. Kabir. Above all, I express my sincere thanks to my family for their unconditional love and support. iv v Table of Contents List of Tables ........................................... viii List of Figures .......................................... ix Abstract .............................................. xiii 1. Introduction .......................................... 1 1.1 Vehicles to be Discussed................................... 1 1.2 Coaxial Benefits ....................................... 2 1.3 Motivation .......................................... 3 2. Helicopter Flight Dynamics ................................ 4 2.1 Introduction ........................................
    [Show full text]
  • Open Walsh Thesis.Pdf
    The Pennsylvania State University The Graduate School College of Engineering A PRELIMINARY ACOUSTIC INVESTIGATION OF A COAXIAL HELICOPTER IN HIGH-SPEED FLIGHT A Thesis in Aerospace Engineering by Gregory Walsh c 2016 Gregory Walsh Submitted in Partial Fulfillment of the Requirements for the Degree of Master of Science August 2016 The thesis of Gregory Walsh was reviewed and approved∗ by the following: Kenneth S. Brentner Professor of Aerospace Engineering Thesis Advisor Jacob W. Langelaan Associate Professor of Aerospace Engineering George A. Lesieutre Professor of Aerospace Engineering Head of the Department of Aerospace Engineering ∗Signatures are on file in the Graduate School. Abstract The desire for a vertical takeoff and landing (VTOL) aircraft capable of high forward flight speeds is very strong. Compound lift-offset coaxial helicopter designs have been proposed and have demonstrated the ability to fulfill this desire. However, with high forward speeds, noise is an important concern that has yet to be thoroughly addressed with this rotorcraft configuration. This work utilizes a coupling between the Rotorcraft Comprehensive Analysis System (RCAS) and PSU-WOPWOP, to computationally explore the acoustics of a lift-offset coaxial rotor sys- tem. Specifically, unique characteristics of lift-offset coaxial rotor system noise are identified, and design features and trim settings specific to a compound lift-offset coaxial helicopter are considered for noise reduction. At some observer locations, there is constructive interference of the coaxial acoustic pressure pulses, such that the two signals add completely. The locations of these constructive interferences can be altered by modifying the upper-lower rotor blade phasing, providing an overall acoustic benefit.
    [Show full text]
  • Historical Perspective September 2011 11
    Helicopter heroes It was 50 years ago that a prototype helicopter first flew and a legend was born—the CH-47 By Mike Lombardi urrently serving on the front lines The advantage of this unique design Just as earlier Chinooks proved of the global fight against terror- allows for low load-per-rotor area, elimi- themselves in wartime, the D model Cism, the CH-47 Chinook is the nates the need for a tail rotor, increases has played a key role for U.S. and epitome of the innovative tandem-rotor lift and stability, and provides a large allied troops in the deserts of Iraq helicopter designs produced through range for center of gravity. and the mountains of Afghanistan. the genius of helicopter pioneer Frank The HRP was followed by the U.S. The highly modified MH-47 series is Piasecki, founder of the company that Navy HUP/UH-25, the first helicopter to operated by the U.S. Army Special would later develop into the Boeing incorporate overlapping tandem rotors, Operations Forces. operations near Philadelphia. and the U.S. Air Force CH-21, a long- When the Chinook first flew in 1961 The CH-47, having been continuously range helicopter transport designed for Boeing Magazine wrote: “There is a modernized, has provided unmatched use in the Arctic. saying in the aviation industry that you capability for U.S. and allied troops since Piasecki stepped down in 1955 as can tell a winner by its appearance. The hard work and dedication of the Boeing its introduction 50 years ago this month.
    [Show full text]
  • Ka-50 Attack Helicopter Acrobatic Flight
    24 EUROPEAL'J ROTORCRAFT FORUM Marseilles, France -15th_l i 11 September 1998 ADOS Ka-50 Attack Helicopter Acrobatic Flight Serguey V. Mikheyev, Boris N. Bourtsev, Serguey V. Selemenev Kamov Company, Moscow Region, Russia I. Introduction The Ka-50 attack helicopter is intended to act against both ground and air targets. High maneuverability of the Ka-50 helicopter provides lower own vulnerability in combat. Aerobatic t1ight demonstrates maneuverability of the helicopter. This is effected by validity of the key solution in the helicopter designing. KAMOV Company helicopter experience concentrates in the Ka-50 attack helicopter. The Table No.1 lists basic types of the serial and experimental helicopters which have been developed by K.AJ\10V Company within the 50 years period. This paper consists of presentations on the following subjects: basic technical solutions and aeroelastic phenomena; examination of test t1ight results; maneuverability features; means of aerobatic t1ight monitoring and analysis. 2.Basic technical solutions and aeroelastic phenomena It is very important to have a substantiation of aeromechanical phenomena. This is feasible given adequate mathematical models making possible to explain and forecast : natural frequencies of structures; loads; aeroelastic stability limits ; helicopter performance . KAL'v!OV Company has developed software to simulate a coaxial rotor aeroelasticity [1,2,4,5]. Aeroelastic phenomena to be simulated are shown in the Fig.2 as ( 1-7) lines in the following way: ( 1) - system of equations of rotor blades motion ; (2) - elastic model of coaxial rotor control linkage ; (3) - model of coaxial rotor vortex wake; (4,5,6)- unsteady aerodynamic data of airfoils; (7) - elastic /mass I geometry data of the upper/lower rotor blades and of the hubs.
    [Show full text]
  • Graduation Project September 2020
    ISTANBUL TECHNICAL UNIVERSITY FACULTY OF AERONAUTICS AND ASTRONAUTICS PERFORMANCE CALCULATION FOR HELICOPTER BLADE UNDER HOVER CONDITION GRADUATION PROJECT Hüseyin DİKEL Department of Aeronautical Engineering Thesis Advisor: Assis. Prof. Dr. Özge ÖZDEMİR SEPTEMBER 2020 i ISTANBUL TECHNICAL UNIVERSITY FACULTY OF AERONAUTICS AND ASTRONAUTICS PERFORMANCE CALCULATION FOR HELICOPTER BLADE UNDER HOVER CONDITION GRADUATION PROJECT Hüseyin DİKEL (110150005) Department of Aeronautıcal Engineering Thesis Advisor: Assis. Prof. Dr. Özge ÖZDEMİR SEPTEMBER 2020 iii Hüseyin DİKEL, student of ITU Faculty of Aeronautics and Astronautics student ID 110150005, successfully defended the graduation entitled “PERFORMANCE CALCULATION FOR HELICOPTER BLADE UNDER HOVER CONDITION” which he prepared after fulfilling the requirements specified in the associated legislations, before the jury whose signatures are below. Thesis Advisor: Assis. Prof. Dr. Özge ÖZDEMİR .............................. İstanbul Technical University Jury Members: Prof. Dr. Metin Orhan KAYA ............................... İstanbul Technical University Prof. Dr. Zahit MECİTOĞLU ............................... İstanbul Technical University Date of Submission : 07 September 2020 Date of Defense : 14 September 2020 v To my big family, iii iv FOREWORD Önsöz bölümünün içerisindeki metinler 1 satır aralıklı yazılır. Tezin ilk sayfası niteliğinde yazılan önsöz ikisayfayı geçmez. Tezi destekleyen kurumlara ve yardımcı olan kişilere bu kısımdateşekkür edilir. Önsöz metninin altında sağa dayalı olarak
    [Show full text]
  • Identification of Coaxial-Rotors Dynamic Wake Inflow for Flight Dynamics and Aeroelastic Applications
    42st European Rotorcraft Forum 2016 IDENTIFICATION OF COAXIAL-ROTORS DYNAMIC WAKE INFLOW FOR FLIGHT DYNAMICS AND AEROELASTIC APPLICATIONS Felice Cardito, Riccardo Gori, Giovanni Bernardini Jacopo Serafini, Massimo Gennaretti Department of Engineering, University Roma Tre, Rome, Italy Abstract This paper presents the development of a linear, finite-state, dynamic perturbation model for wake inflow of coaxial rotors in arbitrary steady flight, based on high-accuracy radial and azimuthal representations. It might conveniently applied in combination with blade element formulations for rotor aeroelastic mod- elling, where three-dimensional, unsteady multiharmonic and localized aerodynamic effects may play a crucial role. The proposed model is extracted from responses provided by an arbitrary high-fidelity CFD solver to perturbations of rotor degrees of freedom and controls. The transfer functions of the multihar- monic responses are then approximated through a rational-matrix approach, which returns a constant coefficient differential operator relating the inflow multiharmonic coefficients to the inputs. The accuracy of the model is tested both for hovering and forward flight by comparison with the wake inflow directly evaluated by the high-fidelity CFD tool for arbitrary inputs. 1. INTRODUCTION ing the need for a tail rotor and its associated shafting and gearboxes. Due to the improved performance they may provide, coaxial rotors are expected to become a common solu- While coaxial rotors have been investigated since the tion for next-generation rotorcraft.
    [Show full text]
  • A Numerical Workshop for Rotorcraft Concepts Generation and Evaluation Pierre-Marie Basset, Philippe Beaumier, Thomas Rakotomamonjy
    CREATION: a numerical workshop for rotorcraft concepts generation and evaluation Pierre-Marie Basset, Philippe Beaumier, Thomas Rakotomamonjy To cite this version: Pierre-Marie Basset, Philippe Beaumier, Thomas Rakotomamonjy. CREATION: a numerical work- shop for rotorcraft concepts generation and evaluation. Rotorcraft Virtual Engineering Conference, Nov 2016, LIVERPOOL, United Kingdom. hal-01384197 HAL Id: hal-01384197 https://hal.archives-ouvertes.fr/hal-01384197 Submitted on 19 Oct 2016 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Rotorcraft Virtual Engineering, Liverpool, 8-10 Nov. 2016 CREATION: a numerical workshop for rotorcraft concepts generation and evaluation Pierre-Marie Basset, Philippe Beaumier, Thomas Rakotomamonjy ONERA – The French Aerospace Lab, FRANCE [email protected] Abstract. C.R.E.A.T.I.O.N. for “Concepts of Rotorcraft Enhanced Assessment Through Integrated Optimization Network”, is a multidisciplinary computational workshop for the evaluation of rotorcraft concepts. The evaluation concerns both flight performance and environmental impacts (acoustics, air pollution/fuel consumption, etc.). The CREATION workshop must allow the evaluation of any rotorcraft concept whatever the level of details of the description data initially available. Therefore the tool must cope with the preliminary conception problems.
    [Show full text]
  • Rotor Diameter
    Scaling Up Success The SB>1 Defiant Joint Multi-Role Technology Demonstrator challenges Sikorsky and Boeing to grow the integrated X2 technologies By Frank Colucci peed and range improvements The SB>1 Defiant JMR Technology Demonstrator scales up Sikorsky X2 rigid coaxial rotor sought by US Army Aviation drove compound helicopter technologies to achieve speed, range and agility far better than SSikorsky, Boeing and their Defiant conventional helicopters. (Sikorsky graphic) team to scale up technologies flown on the 6,000 lb (3 t) X2 and 11,400 lb The MPS summary of FVL-M teams, Sikorsky Innovations vice (5.2 t) S-97 to the 30,000 lb (14 t) class performance includes cruising president Chris Van Buiten previously SB>1 Joint Multi-Role Technology speeds greater than 230 kt (426 stated, “Raider is risk-reduction for JMR.” Demonstrator (JMR-TD). A Systems km/h), vertical takeoff at 6,000 ft/95˚F Sikorsky and Boeing teamed Integration Laboratory (SIL) for Defiant (1,800 m/35˚C) density altitude and up on the SB>1 Defiant in January came on line in December and a a combat radius of 229 nm (424 km) 2013. Boeing program co-director Transmission System Test Bed will run with four crew and 12 troops. The 250 Pat Donnelly said, “When we put in 2016. The JMR-TD due to fly in 2017 is kt (463 km/h) Defiant answers the this together, we were certainly very based on a 2013 Mission Performance specification with rigid coaxial rotors, sensitive to the scaling issues of the Specification (MPS) for a medium-size an integrated tail propeller, optimized X2 technology.
    [Show full text]
  • Xtreme, and Often Exceptionally Far Away from What a Pilot May Experience, Even in Extreme Circumstances
    Frontierswww.boeing.com/frontiers SEPTEMBER 2011 / Volume X, Issue V treme measures XTesting structures to the breaking point helps ensure Boeing products are safe PB BOEING FRONTIERS / SEPTEMBER 2011 1 BOEING FRONTIERS / SEPTEMBER 2011 On the Cover Pushing the limits Structural engineers with Boeing Test & Evaluation don’t necessarily like to go around breaking things, but often they do. Their 24 job is to make sure Boeing products such as jetliners, fighters and helicopters can be operated safely, and that means testing to the limit—and beyond. On any given day, Boeing structural labs are supporting testing requirements throughout the company. COVER IMAGE: SCOTT TEALL, LEFT, AND ANDY BAUGH OF BOEING TEST & EvaLUation prepare AN F-15 FOR fatigUE TESTING IN ST. LOUIS. BOB FERGUSON/BOEING PHOTO: CLOCKWISE FROM LEFT, PHILLIP JORDAN, MattHEW DUNCAN AND CatHERINE METTLACH ARE part OF THE TEAM CONDUCTING FULL-SCALE fatigUE TESTING ON AN F-15 IN ST. LOUIS. BOB FERGUSON/BOEING Ad watch The stories behind the ads in this issue of Frontiers. Inside cover: Page 6: Back cover: “787” is part of a series This ad recognizes Corporate citizenship of ads that reinforces the efforts of Dreamflight, refers to the work Boeing’s partnership with a U.K. charity that Boeing does, both Japan, a relationship takes seriously ill and as a company and that began more than disabled children, without through its employees, 50 years ago. The their parents but under to improve the world. campaign features the the care of a team This ad illustrates art of calligraphy, a of doctors and health Boeing’s commitment symbolic tradition of care professionals, to initiatives that Japanese culture that on a memorable nurture the visionaries communicates not only words but a deeper vacation to Orlando, Fla.
    [Show full text]
  • Aircraft Designations and Popular Names
    Chapter 1 Aircraft Designations and Popular Names Background on the Evolution of Aircraft Designations Aircraft model designation history is very complex. To fully understand the designations, it is important to know the factors that played a role in developing the different missions that aircraft have been called upon to perform. Technological changes affecting aircraft capabilities have resulted in corresponding changes in the operational capabilities and techniques employed by the aircraft. Prior to WWI, the Navy tried various schemes for designating aircraft. In the early period of naval aviation a system was developed to designate an aircraft’s mission. Different aircraft class designations evolved for the various types of missions performed by naval aircraft. This became known as the Aircraft Class Designation System. Numerous changes have been made to this system since the inception of naval aviation in 1911. While reading this section, various references will be made to the Aircraft Class Designation System, Designation of Aircraft, Model Designation of Naval Aircraft, Aircraft Designation System, and Model Designation of Military Aircraft. All of these references refer to the same system involved in designating aircraft classes. This system is then used to develop the specific designations assigned to each type of aircraft operated by the Navy. The F3F-4, TBF-1, AD-3, PBY-5A, A-4, A-6E, and F/A-18C are all examples of specific types of naval aircraft designations, which were developed from the Aircraft Class Designation System. Aircraft Class Designation System Early Period of Naval Aviation up to 1920 The uncertainties during the early period of naval aviation were reflected by the problems encountered in settling on a functional system for designating naval aircraft.
    [Show full text]