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ALL the performances as well as the strength of an aeroplane are reduced by overloading or increase in gross weight. But, apart from the strength considerations, the maximum take‐off weight permissible for the aeroplane probably determines the final limit of overloading, because the aeroplane must at least fly off the ground into the air.

THE desired qualities for high performance in take‐off were enumerated and discussed in Part I of this article, while certain suggestions were made in Part II, whereby the limiting take‐off weight of modern seaplanes could be increased without adversely affecting the air performance. So far no reference has been made to either atmospheric or sea conditions. In this country there is, on the average, only one dead calm day every three weeks, so that in practice a take‐off is seldom made in flat calm water and in no wind. Before leaving this subject therefore it is desirable to examine the performance of a seaplane in take‐off when there is a wind and to determine the probable effect of wind on the liimting take‐off weight.

New industries are created from the pioneering activities of a few firms. These firms generally face great uncertainty and risk, but also stand to benefit from early mover advantages due to the preemption of resources. Based on an empirical analysis of a diverse set of consumer and industrial innovations introduced in the U.S. over the past 100 years, we find that entrants during the pre-firm take-off stage (termed Creators) have higher survival rates than later entrants that enter between the firm and sales take-off (termed Anticipators), and both of these entrant types have higher survival rates than firms that enter after the sales take-off (termed Followers). Notably, survival rates for Creators and Anticipators do not depend on entry time within the cohort group, i.e. what matters is whether an entrant enters before or after the take-off, not whether it entered first in its cohort. Our results indicate that there is no real option value in waiting when one considers survival as a performance measure, which bodes well for firms interested in creating new industries.

The purpose of the paper is to analyze changes in the selected characteristics of an aircraft aided by a ground-based system using magnetic levitation (MAGLEV) to support safe take-off.

The analysis of the mass characteristics of the main aircraft units with conventional constructing solutions was carried out in this paper. It allowed determining the mass of these units and verifying the obtained results on the basis of the known examples. Thanks to such an approach it was possible to determine the mass of the aircraft modified for the requirements of the ground and on-board system for support of the aircraft safe take-off and landing (GABRIEL) system taking into account the change in the weights of the modified units (fuselage, wings, power unit, landing gear, etc.). The weight of the aircraft in its basic version was determined on the basis of the common knowledge and methods described in the scientific literature which are based on the statistical analysis. The weight of the modified units for the needs of the GABRIEL system was determined on the basis of similar formulas taking into account the constructional changes in the airframe. The thrust required of the power unit was determined on the basis of the analysis of the steady state of the horizontal flight for the calculating aerodynamic characteristics determined by conventional methods. The characteristics in the take-off phase were determined solving the equation of motion of the aircraft influenced by the aerodynamic, electrodynamic forces and the forces that come from the power unit.

The preliminary analysis shows that the take-off aid system that uses the phenomenon of MAGLEV is possible to be created using the present-day technology. However, the costs of its realization would make it economically unproved. But it could increase safety and reduce harmful influence on the environment caused by taking-off and landing aircrafts.

The analysis was carried out only for one chosen version of the solution which according to the author has the greatest chance to succeed. At the present-day state of the art, it seems problematic to use the proposed system to aid landing.

The work shows a practical possibility to implement the proposed solution. The results of the analyses are a separate point for further research of similar systems.

The work presents one of the aspects of the potential application of the innovatory conception of take-off and landing aid of transport aircrafts by the ground-based system using the MAGLEV technology.

This paper aims to study the short take-off characteristics and longitudinal controllability of FanWing. As a new structural plane, it has achieved great success at the air shows, but the existing literature is mostly on feasibility and prototype study while little on short take-off performance analysis and controllability. Thus, the paper will do some research on those two aspects.

This paper focuses on a certain type of a 3.5 kg FanWing and builds the longitudinal model based on its structure characteristics and operation principle. Its take-off process is simulated and the longitudinal control law is designed.

The short take-off performance and the large load characteristic are verified. To attain a better short take-off performance, several factors that influence the take-off distance are researched, and the optimal no-load take-off distance 5 m is obtained when the elevator deflection angle is −30°, the center of gravity is 0.42 m and the cross-flow fan rotation speed is 2500 r/min. The longitudinal controllability is verified through simulation. And without variable cross-flow fan rotation speed control, the longitudinal control of FanWing is the same to that of the conventional aircraft.

The presented efforts provide markers for designing the fan wing aircraft that would have better performances. And the control of FanWing is similar to that of a conventional airplane.

It is proved that FanWing can offer a better take-off performance through reasonable configuration. The paper also offers a useful reference on the control of FanWing.

IN the mathematical treatment of the take‐off problem it was formerly difficult to define any general relationships for the airscrew thrust. This difficulty was avoided usually by assuming certain mean values, such as, for example, 1 • 1 to 12 kg/h.p. for the static thrust and by using this value in the calculation. This procedure is incorrect in that the airscrew thrust is assumed to be constant for a given output and so ceases to be suitable as a governing factor. As we have shown in a previous article, it is now possible to estimate the static thrust more accurately and by appropriate engine design the static thrust can be made to satisfy the necessary demands within wide limits [11]‡ This makes it possible to adopt new viewpoints in the treatment of the take‐off problem, which it is proposed to examine.

IN the last issue of this journal it was shown that the take‐off performance of seaplanes can be influenced greatly by design without adversely affecting the air performance. The various factors to be considered in an estimation of the take‐off performance were enumerated and typical curves of effective thrust, T', reaction drag, DR, and air drag, Da were given for a weight well below the limiting take‐off weight. It is shown in this part of the paper that there are two critical speeds and that failure to take off occurs at the lower of these speeds in some seaplanes and at the higher in others.

IN connexion with the development of the modern transport aeroplane it is of growing importance to pay proper attention to the take‐off characteristics of these aeroplanes and to consider the means suitable to improve them. For the realization of economically justified air transport two trends have been indicated; both having an unfavourable effect on take‐off performance. These trends are: