A research program to reduce interior noise in general aviation airplanes: Noise reduction through a cavity-backed flexible plate

A prediction method is reported for noise reduction through a cavity-backed panel. The analysis takes into account only cavity modes in one direction. The results of this analysis were to find the effect of acoustic stiffness of a backing cavity on the panel behavior. The resulting changes in the noise reduction through the panel are significant

Comparison of theoretical predicted longitudinal aerodynamic characteristics with full-scale wind tunnel data on the ATLIT airplane

An analytical method is presented for predicting the lift coefficient, the pitching moment coefficient, and the drag coefficient of light, twin-engine, propeller-driven airplanes. The method was applied to the Advanced Technology Light Twin-Engine airplane. The calculated characteristics were then correlated against full scale wind tunnel data. The analytical method was found to predict the drag and pitching moment fairly well. However, the lift prediction was extremely poor

Wing mass formula for twin fuselage aircraft

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76666/1/AIAA-46261-468.pd

Peter H. Hovenkamp overleden (1953 – 2019)

Naturali

Surrogate Models and Mixtures of Experts in Aerodynamic Performance Prediction for Mission Analysis

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140436/1/6.2014-2301.pd

Closer look at the flight dynamics of wings with non-elliptic lift distributions

Prandtl’s alternative solution for wings with minimum induced drag opens another route for improving aircraft performance especially at the conceptual design phase. In this work, the lateral-directional characteristics of such wings are studied for a glider use case from a per-spective that focuses on pro verse yaw and handling qualities. The authors propose an aileron design methodology that ensures roll authority and proverse yaw characteristics. The resultsshow that these conditions cannot be satisfied by a conventional Elliptic configuration, whereaswings with non-elliptic distributions provide several solutions. Non-linear flight dynamic mod-els of the configurations that provided maximum proverse yaw were assessed in an engineering simulator and compared against the baseline Elliptic case. Proverse yaw was observed in thesimulation data and pilot feedback indicated improved handling qualities in the non-elliptic cases. However, the inherent directional instability combined with other lateral-directional coupling effects masked the observations from the pilot’s perspective

seasonal abundance of the nearctic gall midge obolodiplosis robiniae in italy and the impact of its antagonist platygaster robiniae on pest populations

The Nearctic gall midge Obolodiplosis robiniae (Haldeman, 1847) (Diptera Cecidomyiidae) infesting black locusts, Robinia pseudoacacia L. (Fabaceae), was detected in Asia in 2002 and in Europe (first in Italy) in 2003. Its distribution in Europe has expanded dramatically, probably favored by extensive distribution of its host plant along the main routes. The results of a 3-yr study on the seasonal abundance of O. robiniae in northern Italy are reported here. O. robiniae can develop three to four generations per year by exploiting plants of different ages and vigor. Overwintering takes place as diapausing larvae and adults emerge in spring. Two generations are completed on mature plants where populations decline in summer. Two additional generations can develop on root suckers from midsummer onward. Pest population densities reach their highest levels in late spring. Gall midge larvae were attacked by various predators, but parasitism by the platygastrid Platygaster robiniae Buhl & Duso was particularly significant. The impact of parasitism by P. robiniae is indicated as a key factor in reducing O. robiniae population densities

A new aircraft architecture based on the ACHEON Coanda effect nozzle: flight model and energy evaluation

Purpose Aeronautic transport has an effective necessity of reducing fuel consumption and emissions to deliver efficiency and competitiveness driven by today commercial and legislative requirements. Actual aircraft configurations scenario allows envisaging the signs of a diffused technological maturity and they seem very near their limits. This scenario clearly shows the necessity of radical innovations with particular reference to propulsion systems and to aircraft architecture consequently. Methods This paper presents analyses and discusses a promising propulsive architecture based on an innovative nozzle, which allows realizing the selective adhesion of two impinging streams to two facing jets to two facing Coanda surfaces. This propulsion system is known with the acronym ACHEON (Aerial Coanda High Efficiency Orienting Nozzle). This paper investigates how the application of an all-electric ACHEONs propulsion system to a very traditional commuter aircraft can improve its relevant performances. This paper considers the constraints imposed by current state-of-the-art electric motors, drives, storage and conversion systems in terms of both power/energy density and performance and considers two different aircraft configurations: one using battery only and one adopting a more sophisticated hybrid cogeneration. The necessity of producing a very solid analysis has forced to limit the deflection of the jet in a very conservative range (±15°) with respect to the horizontal. This range can be surely produced also by not optimal configurations and allow minimizing the use of DBD. From the study of general flight dynamics equations of the aircraft in two-dimensional form it has been possible to determine with a high level of accuracy the advantages that ACHEON brings in terms of reduced stall speed and of reduced take-off and landing distances. Additionally, it includes an effective energy analysis focusing on the efficiency and environmental advantages of the electric ACHEON based propulsion by assuming the today industrial grade high capacity batteries with a power density of 207 Wh/kg. Results It has been clearly demonstrated that a short flight could be possible adopting battery energy storage, and longer duration could be possible by adopting a more sophisticated cogeneration system, which is based on cogeneration from a well-known turboprop, which is mostly used in helicopter propulsion. This electric generation system can be empowered by recovering the heat and using it to increase the temperature of the jet. It is possible to transfer this considerable amount of heat to the jet by convection and direct fluid mixing. In this way, it is possible to increase the energy of the jets of an amount that allows more than recover the pressure losses in the straitening section. In this case, it is then possible to demonstrate an adequate autonomy of flight and operative range of the aircraft. The proposed architecture, which is within the limits of the most conservative results obtained, demonstrates significant additional benefits for aircraft manoeuvrability. In conclusion, this paper has presented the implantation of ACHEON on well-known traditional aircraft, verifying the suitability and effectiveness of the proposed system both in terms of endurance with a cogeneration architecture and in terms of manoeuvrability. It has demonstrated the potential of the system in terms of both takeoff and landing space requirements. Conclusions This innovation opens interesting perspectives for the future implementation of this new vector and thrust propulsion system, especially in the area of greening the aeronautic sector. It has also demonstrated that ACHEON has the potential of renovating completely a classic old aircraft configuration such as the one of Cessna 402

A Systematic Methodology for Populating the Aircraft Thermal Management System Architecture Space

Presented at AIAA SCITECH 2021The aircraft thermal management system functions to provide suitable working conditions for pilot, crew, passengers, and the other aircraft systems. The additional weight, drag and power consumption caused by it greatly influences the performance of the aircraft. However, due to rising heat load of emerging novel aircraft concepts, traditional design approaches which rely on data and empirical equations may not apply to the future thermal management systems. Many existing literature which tried to identify the optimal thermal management system architectures only considered limited architecture space where the candidates were pre-selected in terms of experience or intuition. Therefore, viable but non-intuitive architectures may not be included in the design space. To fill this gap, this paper proposes a behavior-based backtracking methodology to systematically populate the architecture space by enumerating both intuitive and non-intuitive architectures. Thermal management requirements for traditional and novel configurations are used to generate the architectures. By comparing the generated architectures with existing ones, this paper validates that the proposed methodology is capable of generating both intuitive and non-intuitive architectures

The structure of subjective well-being in nine western societies

The structure of subjective well-being is analyzed by multidimensional mapping of evaluations of life concerns. For example, one finds that evaluations of Income are close to (i.e., relatively strongly related to) evaluations of Standard of living, but remote from (weakly related to) evaluations of Health. These structures show how evaluations of life components fit together and hence illuminate the psychological meaning of life quality. They can be useful for determining the breadth of coverage and degree of redundancy of social indicators of perceived well-being. Analyzed here are data from representative sample surveys in Belgium, Denmark, France, Germany, Great Britain, Ireland, Italy, Netherlands, and the United States (each N≈1000). Eleven life concerns are considered, including Income, Housing, Job, Health, Leisure, Neighborhood, Transportation, and Relations with other people. It is found that structures in all of these countries have a basic similarity and that the European countries tend to be more similar to one another than they are to USA. These results suggest that comparative research on subjective well-being is feasible within this group of nations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43699/1/11205_2004_Article_BF00305437.pd