ЭКСПЛУАТАЦИЯ САМОЛЕТОВ-АМФИБИЙ НА ЗАСНЕЖЕННЫХ ПОВЕРХНОСТЯХ

The article deals with known cases of operation of seaplanes and amphibians in the snow-covered surfaces. On the basis of the existing data on the resistance and acceleration acting on the hull of planing snowplane analysis of possible acting on the bottom of the amphibious aircraft weighing 37 tons moving in the snow-covered surface was carried out. Estimates have shown the possibility of the takeoff of such plane while moving in the snow-covered surface. Vertical acceleration and landing hit will not exceed the maximum permissible value if the thickness of the snow cover is not less than 1 meter.Работа посвящена анализу возможности эксплуатации гидросамолетов и самолетов-амфибий на поверхностях, покрытых глубоким снегом. Представлен обзор известных случаев такой эксплуатации. На основании существующих данных по сопротивлению и перегрузкам, действующим на корпуса глиссирующих аэросаней, выполнен анализ возможных нагрузок, действующих на днище самолета-амфибии, близкого по характеристикам к Бе-200, при движении его по снегу. Оценки показали возможность осуществления взлета такого самолета при движении днищем по снегу. Вертикальные перегрузки и посадочный удар при условии толщины снежного покрова более 1 м не будут превышать предельно допустимые

Technical and economic efficiency of the unconventional propulsion units use for civilian aircraft of various purposes

In order to develop a methodological apparatus for assessing various stages of the life cycle of hybrid/electric propulsion units, the existing approaches to estimating the costs of developing, manufacturing and operating aircraft engines of the traditional propulsion units scheme for determining the cost framework and their further harmonization with the technical and economic boundary conditions of new elements in the hybrid/electric SU scheme are considered. The relevance of solving the problems of assessing the technical and economic efficiency and forecasting the cost of hybrid propulsion units is determined. To solve the tasks, a methodological approach to determining boundary conditions and criteria is proposed. Within the framework of this methodological approach, a preliminary assessment of the cost of the main stages of the life cycle of aircraft engines for various variants of traditional propulsion units was made. Based on the estimates obtained, criteria for the economic efficiency of using a hybrid propulsion unit of various capacities for civil aircraft were formed. A computational and parametric analysis of the cost estimation of variants of aircraft engines included in the propulsion unit of the traditional scheme is presented. The role of accounting and management accounting data in economic and mathematical models is determined, which makes it possible to qualitatively reflect the economic efficiency of the life cycle of aviation products

Subgap magnetotransport in

Andreev reflection spectroscopy has been used to probe mutual influence of superconductivity and ferromagnetism in contacts of a low-temperature superconductor (S), Pb, and a half-metallic ferromagnet, La0.65Ca0.35 MnO3 (LCMO). In the contacts, which we distinguish as proximity-affected ones, a few unusual effects have been detected: i) a spectacular drop in the resistance of the contacts at the onset of the Pb superconductivity; ii) excess current and doubling of the normal-state conductance; iii) subharmonic gap structure; and iv) the ratio of the single-particle gap to the Pb superconducting transition temperature is anomalously large. Microscopically, our results can most reasonably be explained assuming a conversion from spin singlet pairs to spin triplets at the S/LCMO interface and a long-range proximity effect