The Experts below are selected from a list of 441 Experts worldwide ranked by ideXlab platform
L L M Veldhuis - One of the best experts on this subject based on the ideXlab platform.
-
aerodynamic interaction effects of tip mounted propellers installed on the horizontal Tailplane
AIAA Aerospace Sciences Meeting 2018, 2018Co-Authors: Nando Van Arnhem, Tomas Sinnige, T C A Stokkermans, Georg Eitelberg, L L M VeldhuisAbstract:This paper addresses the effects of propeller installation on the aerodynamic performance of a Tailplane featuring tip-mounted propellers. A model of a low aspect ratio Tailplane equipped with an elevator and a tip-mounted propeller was installed in a low-speed wind-tunnel. Measurements were taken with an external balance and surface pressure taps to determine the aerodynamic characteristics of the Tailplane, while the flowfield in the wake of the model was investigated using particle-image velocimetry. The experimental data are supported by CFD analyses, involving both transient simulations of the full-blade configuration and steady-state simulations the propeller replaced by an actuator-disk model. The upstream effects on the propeller time-average and time-accurate thrust and normal-forces are found to be limited for different Tailplane operating conditions. It is shown that for a given propeller rotation direction, the load distribution on the Tailplane is highly dependent on the direction of elevator deflection. The rotation direction of the Tailplane tip-vortex relative to the propeller swirl therefore significantly affects the integral loads on the Tailplane, resulting in differences in the normal-force gradient and elevator effectiveness.
Thomas P Ratvasky - One of the best experts on this subject based on the ideXlab platform.
-
flying qualities evaluation of a commuter aircraft with an ice contaminated Tailplane
SAE transactions, 2000Co-Authors: Richard J Ranaudo, Thomas P Ratvasky, Judith F Van ZanteAbstract:During the NASA/FAA (Federal Aviation Administration) Tailplane Icing Program, pilot evaluations of aircraft flying qualities were conducted with various ice shapes attached to the horizontal Tailplane of the NASA Twin Otter Icing Research Aircraft. Initially, only NASA pilots conducted these evaluations, assessing the differences in longitudinal flight characteristics between the baseline or clean aircraft, and the aircraft configured with an Ice Contaminated Tailplane (ICT). Longitudinal tests included Constant Airspeed Flap Transitions, Constant Airspeed Thrust Transitions, zero-G Pushovers, Repeat Elevator Doublets, and Simulated Approach and Go-Around tasks. Later in the program, guest pilots from government and industry were invited to fly the NASA Twin Otter configured with a single full-span artificial ice shape attached to the leading edge of the horizontal Tailplane. This shape represented ice formed due to a 'Failed Boot' condition, and was generated from tests in the Glenn Icing Research Tunnel on a full-scale Tailplane model. Guest pilots performed longitudinal handling tests, similar to those conducted by the NASA pilots, to evaluate the ICT condition. In general, all pilots agreed that longitudinal flying qualities were degraded as flaps were lowered, and further degraded at high thrust settings. Repeat elevator doublets demonstrated reduced pitch damping effects due to ICT, which is a characteristic that results in degraded flying qualities. Pilots identified elevator control force reversals (CFR) in zero-G pushovers at a 20 deg flap setting, a characteristic that fails the FAR 25 no CFR certification requirement. However, when the same pilots used the Cooper-Harper rating scale to perform a simulated approach and go-around task at the 20 deg flap setting, they rated the airplane as having Level I and Level II flying qualities respectively. By comparison, the same task conducted at the 30 deg flap setting, resulted in Level II flying qualities for the approach portion, and Level III for the go-around portion.The results of this program indicate that safe and acceptable flying qualities with an ICT condition, can be effectively assessed by task-oriented pilot maneuvers. In addition, other maneuvers such as repeat elevator doublets provide good qualitative and quantitative assessments of pitch damping and elevator effectiveness, which are characteristics that correlate well with pilot task ratings. The results of this testing indicate that the FAR 25 zero-G pushover maneuver, which requires no CFR during its execution, may be an overly conservative pass/fail criteria for aircraft certification.
-
nasa faa Tailplane icing program flight test report
2000Co-Authors: Thomas P Ratvasky, Judith F Van Zante, Alex SimAbstract:This report presents results from research flights that explored the characteristics of an ice-contaminated Tailplane using various simulated ice shapes attached to the leading edge of the horizontal Tailplane. A clean leading edge provided the baseline case, then three ice shapes were flown in order of increasing severity. Flight tests included both steady state and dynamic maneuvers. The steady state points were 1G wings level and steady heading sideslips. The primary dynamic maneuvers were pushovers to various G-levels; elevator doublets; and thrust transitions. These maneuvers were conducted for a full range of flap positions and aircraft angle of attack where possible. The analysis of this data set has clearly demonstrated the detrimental effects of ice contamination on aircraft stability and controllability. Paths to Tailplane stall were revealed through parameter isolation and transition studies. These paths are (1) increasing ice shape severity, (2) increasing flap deflection, (3) high or low speeds, depending on whether the aircraft is in a steady state (high speed) or pushover maneuver (low speed), and (4) increasing thrust. The flight research effort was very comprehensive, but did not examine effects of Tailplane design and location, or other aircraft geometry configuration effects. However, this effort provided the role of some of the parameters in promoting Tailplane stall. The lessons learned will provide guidance to regulatory agencies, aircraft manufacturers, and operators on ice-contaminated Tailplane stall in the effort to increase aviation safety and reduce the fatal accident rate.
-
in flight aerodynamic measurements of an iced horizontal Tailplane
37th Aerospace Sciences Meeting and Exhibit, 1999Co-Authors: Thomas P Ratvasky, Judith Foss VanzanteAbstract:The effects of Tailplane icing on aircraft dynamics and Tailplane aerodynamics were investigated using, NASA's modified DHC-6 Twin Otter icing research aircraft. This flight program was a major element of the four-year NASA/FAA research program that also included icing wind tunnel testing, dry-air aerodynamic wind tunnel testing, and analytical code development. Flight tests were conducted to obtain aircraft dynamics and Tailplane aerodynamics of the DHC-6 with four Tailplane leading-edge configurations. These configurations included a clean (baseline) and three different artificial ice shapes. Quasi-steady and various dynamic flight maneuvers were performed over the full range of angles of attack and wing flap settings with each iced Tailplane configuration. This paper presents results from the quasi-steady state flight conditions and describes the range of flow fields at the horizontal Tailplane, the aeroperformance effect of various ice shapes on Tailplane lift and elevator hinge moment, and suggests three paths that can lead toward ice-contaminated Tailplane stall. It was found that wing, flap deflection was the most significant factor in driving the Tailplane angle of attack toward alpha(tail stall). However, within a given flap setting, an increase in airspeed also drove the Tailplane angle of attack toward alpha(tail stall). Moreover, increasing engine thrust setting also pushed the Tailplane to critical performance limits, which resulted in premature Tailplane stall.
-
nasa faa Tailplane icing program overview
37th Aerospace Sciences Meeting and Exhibit, 1999Co-Authors: Thomas P Ratvasky, Judith F Van Zante, James T RileyAbstract:The effects of Tailplane icing were investigated in a four-year NASA/FAA Tailplane Icing, Program (TIP). This research program was developed to improve the understanding, of iced Tailplane aeroperformance and aircraft aerodynamics, and to develop design and training aides to help reduce the number of incidents and accidents caused by Tailplane icing. To do this, the TIP was constructed with elements that included icing, wind tunnel testing, dry-air aerodynamic wind tunnel testing, flight tests, and analytical code development. This paper provides an overview of the entire program demonstrating the interconnectivity of the program elements and reports on current accomplishments.
-
investigation of dynamic flight maneuvers with an iced Tailplane
37th Aerospace Sciences Meeting and Exhibit, 1999Co-Authors: Judith F Van Zante, Thomas P RatvaskyAbstract:A detailed analysis of two of the dynamic maneuvers, the pushover and elevator doublet, from the NASA/FAA Tailplane Icing Program are discussed. For this series of flight tests, artificial ice shapes were attached to the leading edge of the horizontal stabilizer of the NASA Lewis Research Center icing aircraft, a DHC-6 Twin Otter. The purpose of these tests was to learn more about ice-contaminated Tailplane stall (ICTS), the known cause of 16 accidents resulting in 139 fatalities. The pushover has been employed by the FAA, JAA and Transport Canada for Tailplane icing certification. This research analyzes the pushover and reports on the maneuver performance degradation due to ice shape severity and flap deflection. A repeatability analysis suggests tolerances for meeting the required targets of the maneuver. A second maneuver, the elevator doublet, is also studied.
Nando Van Arnhem - One of the best experts on this subject based on the ideXlab platform.
-
aerodynamic interaction effects of tip mounted propellers installed on the horizontal Tailplane
AIAA Aerospace Sciences Meeting 2018, 2018Co-Authors: Nando Van Arnhem, Tomas Sinnige, T C A Stokkermans, Georg Eitelberg, L L M VeldhuisAbstract:This paper addresses the effects of propeller installation on the aerodynamic performance of a Tailplane featuring tip-mounted propellers. A model of a low aspect ratio Tailplane equipped with an elevator and a tip-mounted propeller was installed in a low-speed wind-tunnel. Measurements were taken with an external balance and surface pressure taps to determine the aerodynamic characteristics of the Tailplane, while the flowfield in the wake of the model was investigated using particle-image velocimetry. The experimental data are supported by CFD analyses, involving both transient simulations of the full-blade configuration and steady-state simulations the propeller replaced by an actuator-disk model. The upstream effects on the propeller time-average and time-accurate thrust and normal-forces are found to be limited for different Tailplane operating conditions. It is shown that for a given propeller rotation direction, the load distribution on the Tailplane is highly dependent on the direction of elevator deflection. The rotation direction of the Tailplane tip-vortex relative to the propeller swirl therefore significantly affects the integral loads on the Tailplane, resulting in differences in the normal-force gradient and elevator effectiveness.
Ciliberti D. - One of the best experts on this subject based on the ideXlab platform.
-
A New Vertical Tail Design Procedure for General Aviation and Turboprop Aircraft
2018Co-Authors: Nicolosi F., Della Vecchia P., Ciliberti D.Abstract:A new procedure to evaluate the aerodynamic interference of airplane’s components on the vertical Tailplane has been proposed. It has been developed by solving Navier-Stokes equations in a fully turbulent subsonic flow regime on more than 200 regional turboprop aircraft configurations, with the aim to bring CFD into aircraft preliminary design.
-
A New Vertical Tail Design Procedure for General Aviation and Turboprop Aircraft
EWADE-CEAS, 2013Co-Authors: Nicolosi F., Della Vecchia P., Ciliberti D.Abstract:The paper presents a new procedure to evaluate the sideforce (and hence the directional stability and control contribution) generated by the vertical Tailplane of a typical regional turboprop aircraft in sideslip and with rudder deflection. The evaluation of stability and control derivatives has a deep influence on Tailplane design. To develop a new procedure that correctly estimates the effect of aircraft???s components aerodynamic interference (wing-body sidewash and wake, horizontal Tailplane end-plate effect, rudder deflection), a regional turboprop aircraft geometry has been chosen, with some constraint such as fuselage slenderness, wing and tails positions, and aspect ratios. CFD analyses have been executed on hundreds of configurations. The University's computing grid SCoPE has been useful to solve the Reynolds-averaged Navier-Stokes equations in a short amount of time
-
A new approach in aircraft vertical Tailplane design
'AIDAA Associazione Italiana di Aeronautica e Astronautica', 2013Co-Authors: Ciliberti D., Nicolosi F., Della Vecchia P.Abstract:The paper presents a new procedure to evaluate the sideforce (and hence the directional stability and control contribution) generated by the vertical Tailplane of a typical regional turboprop aircraft in sideslip and with rudder deflection. The evaluation of stability and control derivatives has a deep influence on Tailplane design. To develop a new procedure that correctly estimates the effect of aircraft???s components aerodynamic interference (wing-body sidewash and wake, horizontal Tailplane end-plate effect, rudder deflection), a regional turboprop aircraft geometry has been chosen, with some constraint such as fuselage slenderness, wing and tails positions, and aspect ratios. CFD analyses have been executed on hundreds of configurations. The University's computing grid SCoPE has been useful to solve the Reynolds-averaged Navier-Stokes equations in a short amount of time. Numerical results are presented in a few charts to define the aerodynamic interference coefficients and then a new procedure to design a vertical Tailplane is proposed. This new approach provides a simple relationship among the aerodynamic interference factors and accurate results for turboprop aircraft configurations
-
An Investigation on Vertical Tailplane Design
Università di Brno, 2012Co-Authors: Nicolosi F., Della Vecchia P., Ciliberti D.Abstract:The paper presents a deep investigation on the methodologies to design a vertical Tailplane. Nowadays the most used methodologies in preliminary design to estimate the contribution of vertical Tailplane on aircraft directional stability and control are: the classical method proposed by USAF DATCOM (also presented in several aeronautics textbooks) and the method presented in ESDU reports. Both methodologies derive from NACA world war II reports of the first half of the ’900, based on obsolete geometries, and give quite different results for certain configurations, e. g. in the case of horizontal stabilizer mounted in fuselage. As shown in literature, the main effects on the side force coefficient of the vertical tail are due to the interactions among the aircraft components: the fuselage acts like a cylinder increasing the local sideslip angle, the wing position and aspect ratio have an influence on the airflow near the tail zone and the horizontal tail, depending on position and size, can act as an endplate increasing the side force. In order to better highlight these effects, a different approach using the RANS equations has been adopted. Several CFD calculations have been performed on some test cases (used as experimental database) described in NACA reports and used in the past to obtain the semi‐empirical methodology reported in USAF DATCOM, to verify the compliance of CFD results with available experimental data. The CFD calculations (performed through the use of a parallel supercomputing platform) have shown a good agreement between numerical and experimental data. Subsequently the abovementioned effects have been deeply investigated on a new set of propeller transport aircraft configurations. The different configurations that have been prepared differs for wing aspect ratio, wing‐fuselage relative position (high‐wing/low‐wing), vertical Tailplane aspect ratio (vertical tail span versus fuselage radius) and horizontal Tailplane position respect to the vertical Tailplane (in particular investigation the effect of fin‐mounted T configuration, typical of regional turboprop transport aircraft). For all configurations the computational mesh has been carefully analyzed and prepared. All the CFD analyses will be useful to obtain new curves to predict the above-mentioned effects and to have a more accurate estimation of vertical Tailplane contribution to aircraft directional stability and control
Judith F Van Zante - One of the best experts on this subject based on the ideXlab platform.
-
flying qualities evaluation of a commuter aircraft with an ice contaminated Tailplane
SAE transactions, 2000Co-Authors: Richard J Ranaudo, Thomas P Ratvasky, Judith F Van ZanteAbstract:During the NASA/FAA (Federal Aviation Administration) Tailplane Icing Program, pilot evaluations of aircraft flying qualities were conducted with various ice shapes attached to the horizontal Tailplane of the NASA Twin Otter Icing Research Aircraft. Initially, only NASA pilots conducted these evaluations, assessing the differences in longitudinal flight characteristics between the baseline or clean aircraft, and the aircraft configured with an Ice Contaminated Tailplane (ICT). Longitudinal tests included Constant Airspeed Flap Transitions, Constant Airspeed Thrust Transitions, zero-G Pushovers, Repeat Elevator Doublets, and Simulated Approach and Go-Around tasks. Later in the program, guest pilots from government and industry were invited to fly the NASA Twin Otter configured with a single full-span artificial ice shape attached to the leading edge of the horizontal Tailplane. This shape represented ice formed due to a 'Failed Boot' condition, and was generated from tests in the Glenn Icing Research Tunnel on a full-scale Tailplane model. Guest pilots performed longitudinal handling tests, similar to those conducted by the NASA pilots, to evaluate the ICT condition. In general, all pilots agreed that longitudinal flying qualities were degraded as flaps were lowered, and further degraded at high thrust settings. Repeat elevator doublets demonstrated reduced pitch damping effects due to ICT, which is a characteristic that results in degraded flying qualities. Pilots identified elevator control force reversals (CFR) in zero-G pushovers at a 20 deg flap setting, a characteristic that fails the FAR 25 no CFR certification requirement. However, when the same pilots used the Cooper-Harper rating scale to perform a simulated approach and go-around task at the 20 deg flap setting, they rated the airplane as having Level I and Level II flying qualities respectively. By comparison, the same task conducted at the 30 deg flap setting, resulted in Level II flying qualities for the approach portion, and Level III for the go-around portion.The results of this program indicate that safe and acceptable flying qualities with an ICT condition, can be effectively assessed by task-oriented pilot maneuvers. In addition, other maneuvers such as repeat elevator doublets provide good qualitative and quantitative assessments of pitch damping and elevator effectiveness, which are characteristics that correlate well with pilot task ratings. The results of this testing indicate that the FAR 25 zero-G pushover maneuver, which requires no CFR during its execution, may be an overly conservative pass/fail criteria for aircraft certification.
-
nasa faa Tailplane icing program flight test report
2000Co-Authors: Thomas P Ratvasky, Judith F Van Zante, Alex SimAbstract:This report presents results from research flights that explored the characteristics of an ice-contaminated Tailplane using various simulated ice shapes attached to the leading edge of the horizontal Tailplane. A clean leading edge provided the baseline case, then three ice shapes were flown in order of increasing severity. Flight tests included both steady state and dynamic maneuvers. The steady state points were 1G wings level and steady heading sideslips. The primary dynamic maneuvers were pushovers to various G-levels; elevator doublets; and thrust transitions. These maneuvers were conducted for a full range of flap positions and aircraft angle of attack where possible. The analysis of this data set has clearly demonstrated the detrimental effects of ice contamination on aircraft stability and controllability. Paths to Tailplane stall were revealed through parameter isolation and transition studies. These paths are (1) increasing ice shape severity, (2) increasing flap deflection, (3) high or low speeds, depending on whether the aircraft is in a steady state (high speed) or pushover maneuver (low speed), and (4) increasing thrust. The flight research effort was very comprehensive, but did not examine effects of Tailplane design and location, or other aircraft geometry configuration effects. However, this effort provided the role of some of the parameters in promoting Tailplane stall. The lessons learned will provide guidance to regulatory agencies, aircraft manufacturers, and operators on ice-contaminated Tailplane stall in the effort to increase aviation safety and reduce the fatal accident rate.
-
nasa faa Tailplane icing program overview
37th Aerospace Sciences Meeting and Exhibit, 1999Co-Authors: Thomas P Ratvasky, Judith F Van Zante, James T RileyAbstract:The effects of Tailplane icing were investigated in a four-year NASA/FAA Tailplane Icing, Program (TIP). This research program was developed to improve the understanding, of iced Tailplane aeroperformance and aircraft aerodynamics, and to develop design and training aides to help reduce the number of incidents and accidents caused by Tailplane icing. To do this, the TIP was constructed with elements that included icing, wind tunnel testing, dry-air aerodynamic wind tunnel testing, flight tests, and analytical code development. This paper provides an overview of the entire program demonstrating the interconnectivity of the program elements and reports on current accomplishments.
-
investigation of dynamic flight maneuvers with an iced Tailplane
37th Aerospace Sciences Meeting and Exhibit, 1999Co-Authors: Judith F Van Zante, Thomas P RatvaskyAbstract:A detailed analysis of two of the dynamic maneuvers, the pushover and elevator doublet, from the NASA/FAA Tailplane Icing Program are discussed. For this series of flight tests, artificial ice shapes were attached to the leading edge of the horizontal stabilizer of the NASA Lewis Research Center icing aircraft, a DHC-6 Twin Otter. The purpose of these tests was to learn more about ice-contaminated Tailplane stall (ICTS), the known cause of 16 accidents resulting in 139 fatalities. The pushover has been employed by the FAA, JAA and Transport Canada for Tailplane icing certification. This research analyzes the pushover and reports on the maneuver performance degradation due to ice shape severity and flap deflection. A repeatability analysis suggests tolerances for meeting the required targets of the maneuver. A second maneuver, the elevator doublet, is also studied.
