Proceedings of the Vertical Flight Society 78th Annual Forum最新文献

{"title":"Drag Performance Degradation Due to Icing of eVTOL (Paper 1202)","authors":"Geoffrey Karli, R. Mckillip, Sihong Yan, J. Palacios","doi":"10.4050/f-0078-2022-17533","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17533","url":null,"abstract":"\u0000 An empirical model was developed to estimate the liquid water content (LWC) and mean volume diameter (MVD) of super-cooled water droplets of an icing cloud based on the torque variation of a single rotor. The model was developed for eVTOL configurations that can actively monitor on-board torque via an electric speed controller (ESC). Experimental data was collected in the Penn State Adverse Environment Rotor Test Stand chamber under various icing conditions. From experimental data, a relationship between torque degradation and LWC was developed. This LWCis coupled to the FAR Appendix C Icing Envelopes to determine an MVD range of possible values. The range discrepancy is resolved by running Blade Element Momentum Theory (BEMT) and the Han-Palacios Correlation (HPC) for a given set of condition and finding the results that best match with the recorded torque. This process is repeated over the flying duration, using the actively incoming torque information from the ESC. Through the coupling of BEMT and HPC, torque degradation due to blade icing can be modeled and predicted. Being able to predict torque degradation means that the time until a critical torque is reached can also be estimated. This estimated time is then relayed to the vehicle as the available flying time in the current cloud environment. The proposed model was verified by comparing experimental data to the predicted values. The BEMT prediction deviated from the constant measured torque value by 6.0%. For HPC verification, 11 experimental cases were compared to estimated results. On average HPC deviated from the experimental cases by 14.8% at 20 MVD and 16.6% at 40 MVD. With the model verified, a blind study was performed using this method. A case that emulates possible flying conditions in a realistic environment was chosen. Torque data was acquired during the icing event. Within 90 seconds of data available during testing, the MVD and LWC were predicted within 1.39% and 20% respectively. Every 10 seconds the prediction for 10 more seconds into the future was compared to the 'blind' experimental data. On average, the prediction overestimated the torque by 6.5%. Based on the final calculations it was determined that 5.25 minutes of flying time was available to this particular rotor operating within this cloud environment. The presented effort introduces and verifies the capability to determine icing cloud conditions and available flight time available based on the proposed approach.\u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"66 6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116368898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fifty Years of Innovation in Performance Limit Indicator: A Success Story of Airbus Helicopters Contribution, to Helicopter Fleet Safety by Simplifying Piloting and Reducing Workload","authors":"S. Germanetti","doi":"10.4050/f-0078-2022-17626","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17626","url":null,"abstract":"\u0000 Since their invention, helicopters were typical flying object that requested very specific competencies to control their flight. The control of the rotors power, delivered by the engine, was subject to multiple indicators that were installed in the cockpit. Depending on the various technologies, engine temperature, turbine rotation speed, and torque are measured; main gearbox torque, or free turbine speed are monitored. The pilot has the responsibility to ensure that none of them are at their limit, depending on the environmental conditions mainly outside temperature and atmospheric pressure.\u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127405601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High Speed and Highly Efficient Rotor Blade Design","authors":"Byung-Young Min, Alexander F. Dunn, Annie Gao, V. Klimchenko, Claude G. Matalanis, B. Wake","doi":"10.4050/f-0078-2022-17457","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17457","url":null,"abstract":"Aerodynamic design of the high speed, highly efficient rotor (HSHER) blade is presented. The main objective was to design a medium-lift utility scale blade with improved high-speed performance and no penalty in hover, suitable for a singlemain rotor operating at speeds between 180 and 200 knots. To accomplish this, a design concept was chosen consisting of an advanced passive blade shape along with an adjustable trailing-edge device. Initial studies using a blade-element solver combined with a genetic algorithm were used to quickly survey large portions of the design space. Next, a CFD-based process was established whereby CREATETM-AV HELIOS was used for high-speed forward-flight simulations while hover performance was addressed using a combination of Star-CCM+ for rapid iterations and HELIOS for more detailed evaluation. While fully-automated optimization was not performed, automation was introduced wherever possible to minimize manual effort and keep the engineering effort focused on high-level strategic decisions that are still somewhat difficult to automate. The final result was a new blade design which showed significant improvements in both high-speed performance (∆L/D ~1) and hover efficiency (∆FM ~0.03) with increased thrust capability.","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127072677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Model Based Blade Attachment Stiffness Evaluation of the MERIT Rotor in Hover with Photogrammetry and Digital Image Correlation","authors":"Verena Heuschneider, J. Sirohi, Florian Berghammer, Amine Abdelmoula, M. Hajek","doi":"10.4050/f-0078-2022-17635","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17635","url":null,"abstract":"\u0000 The paper focuses on the analyses of photogrammetry measurement results on the two-blade, hingeless MERIT rotor with diameter 1.8 m at the two rotor speeds 900 and 1800 RPM and collective pitch angles 0-12◦ in hover and their comparison to simulation results calculated in CAMRAD II. Blade tip displacements in flap, lead-lag, axial, and torsional direction are shown as a function of collective pitch and rotor speed. Radial displacements in flap and lag direction depict the influence of the pitch bearing play and blade attachment. The structural blade model is validated by using static DIC deformation measurements and shows very good agreement. Calculated and measured thrust polars match very well with the use of a free wake model in the simulation. The combination of measured flapping angle and calculated flapping moment gives a stiffness estimation for a virtual flap hinge. The influence of hinge offset and stiffness are shown by parameter adjustment. Flap deformations of the rotating blades leave a tip flap offset of less than 1 mm in average, which corresponds to the statically measured effect of the bearing play at the blade tip. The study shows that photogrammetry is a valuable tool to identify and tune parameters of a numerical model.\u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"2013 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127353445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Large Eddy Simulation of the Wakes of Three Urban Air Mobility Vehicles","authors":"Denis-Gabriel Caprace, A. Ning","doi":"10.4050/f-0078-2022-17471","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17471","url":null,"abstract":"\u0000 Recent advances in urban air mobility have driven the development of many new VTOL concepts. These vehicles often feature original designs and futuristic shapes. Due to their novelty, the wake characteristics of such aircraft are unknown. However, large wake-induced velocities, should they exist, may be dangerous for any other vehicle evolving in their close proximity. Therefore, improved knowledge about the wakes of VTOL vehicles is needed to guarantee the safety of urban air mobility operations. In this work, we study the wake of three VTOL aircraft in cruise by means of large eddy simulation. We present a two-stage numerical procedure that enables the simulation of long wake ages at a limited computational cost. The analysis of our simulation results reveals that the wakes of rotary vehicles feature larger wake vortex cores than a typical airplane wing. The vortex circulation decay is also faster due to the self-induced turbulence generated during the wake roll-up. Finally, we introduce a model of the vortex circulation distribution that fits the numerical measurements with satisfactory agreement across space and time, and can be used to evaluate induced velocities.\u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130198953","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comprehensive Simulation for eVTOL Aircraft-Diagnosing Coupled Airframe-Propulsion Dynamic Instabilities","authors":"F. Brenner, J. Goericke, Patrick J. O'Heron, L. Gomez, M. Hasbun","doi":"10.4050/f-0078-2022-17534","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17534","url":null,"abstract":"\u0000 The design, development, and testing of an eVTOL aircraft requires multiple physics-based simulation applications to address technical challenges and optimize the configuration for stringent mission requirements. While existing rotorcraft simulation and analysis tools are utilized for the analysis of eVTOL configurations, the adoption of an electrified propulsion system introduces new challenges. These tools are tailored for analysis of coupled system dynamics including elastic structures, airloads, and wake interactions, but are lacking capability for detailed electrified drive system dynamics. As a result, the dynamics of the electric drive system are often analyzed separate from the flight and structure dynamics. This can cause important coupled interactions to be overlooked and require costly latestage design changes. This paper describes and demonstrates the coupling of GT-SUITE, a detailed electric propulsion modeling and analysis tool, with the comprehensive rotorcraft analysis tool, FLIGHTLAB. The objective of coupling these applications was to provide eVTOL analysis capabilities that enable improved designs in terms of mission range, operation capabilities, and flight safety. The successful coupling of these applications was demonstrated with lift and cruise propellers based on the Uber Elevate configuration. \u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131979157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fatal Rotorcraft Accidents for a Ten-Year Period","authors":"A. Taylor, J. Pellettiere","doi":"10.4050/f-0078-2022-17500","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17500","url":null,"abstract":"\u0000 The Federal Aviation Administration implemented regulations and guidance material to protect occupants in the event of a rotorcraft crash. These rules apply to all newly developed rotorcraft. There has been a recent push to develop similar standards for the existing fleet and for the newly constructed rotorcraft. Two major areas of concern are injuries and fatalities resulting from either blunt force trauma or post-crash fire. To understand the effects of these two factors on survivability outcomes, the National Transportation Safety Board accident database was queried for rotorcraft accidents from January 1, 2009 to December 31, 2018. During this period, a total of 1489 accidents occurred, and after refinement, 187 listed fatal. Of the fatalities, blunt force trauma was by far the greatest cause. Though thermal injuries resulted in fewer fatalities, post-crash fires were still a frequent occurrence and protective measures should be put in place for both. \u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132181450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimizing Battery Life in Conventional Helicopters: Selection, Charging, Storage, and Maintenance","authors":"Mike Neus, Jerome Powell, Collin Zreet","doi":"10.4050/f-0078-2022-17646","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17646","url":null,"abstract":"\u0000 Conventional helicopters are equipped with a main battery to provide power for many situations including pre- and post-flight operational checks, engine starting, and emergency in-flight backup power. Historical field data indicates the average replacement interval for main batteries on commercial helicopters are on the order of 1,000 Flight Hours. This makes main batteries one of the most frequently replaced non-consumable items on fielded helicopters. Other industries, such as renewable energy and space flight, show us much longer lifetimes are possible. This paper discusses the factors that influence helicopter main battery service lives for Absorbed Glass Mat (AGM) and Lithium Iron Phosphate (LFP) battery types. The most common main battery failure modes and their causes are discussed. Considerations for battery selection during system design, associated charging algorithms, storage, and periodic maintenance requirements are identified. These factors and knowledge of battery failure modes are used to provide guidance to optimize AGM and LFP main battery life. \u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130916560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Robotic Hummingbird versus Quadrotor: a Flight Dynamics and Gust Response Comparison","authors":"David A. Coleman, Moble Benedict","doi":"10.4050/f-0078-2022-17444","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17444","url":null,"abstract":"The paper discusses an experimental effort aimed at quantifying and comparing the relative flight dynamics and gust response of a two-winged, biomimetic, hover-capable robotic hummingbird (RH) with wing kinematic modulation methods for flight control, against those of a quadrotor (QR) with the same mass, inertias, and motor and battery mass fractions as the robotic hummingbird. Comparing the linear flight dynamics models, the RH model had 2–3 ×greater translational aerodynamic coefficients along the longitudinal and lateral axes, and rotational aerodynamic coefficients of similar magnitude but opposite sign about these axes. The pitching moment response to longitudinal velocity was similar in the two, while the rolling moment response to lateral velocity was 3.5 × greater in the RH model. Control authority in the longitudinal dynamics was found to be greater in the QR, though this was attributed to mechanism limitations in the RH. The lateral and direction control authority was 1.3 and 4.3 × larger respectively in the RH model. Both vehicles were subjected to a gust in the laboratory. Although the average total movement of the RH was greater than the QR, when the gust speed was non-dimentionalized by the tip speed, the RH had a lesser response. Further, the pitching response was similar between the two, but the rolling response was ≈ 2 × greater in the RH. Finally, the error between the measured and modeled vehicle responses as a function of wind gust velocity was quantified, which generally increased, especially so for speeds > 5 ft/s. The rotational acceleration equations contained the greatest errors. These results suggest that the linear flight dynamics models are not valid for relatively moderate excursions from hovering flight.","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126751944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Operations Study on a Multimodal Transport using Cargo eVTOL Aircrafts and High-Speed Rail","authors":"Yu Ito, Haruki Tsuge","doi":"10.4050/f-0078-2022-17593","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17593","url":null,"abstract":"\u0000 This study discusses how cargo eVTOL operations can collaborate with high-speed rail (HSR) in the context of rapid freight delivery. Operational aspects of eVTOL and HSR is discussed to reveal that their combination will enable a flexible and economic rapid delivery. Although HSR logistics have not been largely introduced in Japan so far, collaboration between a long-undergoing development project regarding HSR - the free gauge train (FGT) - could have synergy with eVTOL logistics. The discussion here also shows how the operational design will be affected by local constraints and social features.\u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123159262","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}