The aim of the paper is to validate the analytical–numerical analysis method regarding the operating regime of the propellers of a quadcopter. The research aims to mark the flow areas whose numerical results differ from the experimental ones and to investigate the possible reasons for the discrepancies between the values. The paper presents the determination of the air velocity produced by the rotational movement of a quadcopter propeller for a stationary position of the drive motor. The velocities were determined both experimentally at various points located below the propeller plane using hot-wire anemometric probes and numerically using a time-lapse simulation with a rotating sliding table. The numerical simulations carried out consisted of the determination of the time variation of the velocity distribution developed by the propeller in the rotational movement for the different operating (power) cycles of the engine. In addition, a technique that utilizes reverse engineering to determine the propeller profile, the anemometric probe calibration, and the average velocity values measured at various points below the propeller plane for engine operating regimes that range from 60 to 90% are also presented.

Recently, additive manufacturing (AM) processes have expanded rapidly in various fields of the industry because they offer design freedom, involve layer-by-layer construction from a computerized 3D model (minimizing material consumption), and allow the manufacture of parts with complex geometry (thus offering the possibility of producing custom parts). Also, they provide the advantage of a short time to make the final parts, do not involve the need for auxiliary resources (cutting tools, lighting fixtures or coolants) and have a low impact on the environment. However, the aspects that make these technologies not yet widely used in industry are poor surface quality of parts, uncertainty about the mechanical properties of products and low productivity. Research on the physical phenomena associated with additive manufacturing processes is necessary for proper control of the phenomena of melting, solidification, vaporization and heat transfer. This paper addresses the relevant additive manufacturing processes and their applications and analyzes the advantages and disadvantages of AM processes compared to conventional production processes. For the aerospace industry, these technologies offer possibilities for manufacturing lighter structures to reduce weight, but improvements in precision must be sought to eliminate the need for finishing processes.

A miniaturized on-board platform for optic sensors stabilization is the proposed concept developed and tested by a multidisciplinary team of engineers under a UEFISCDI (the Executive Agency for Higher Education, Research, Development and Innovation Funding in Romania) research funding. The need for a UAV to capture images and give in-depth information of ground objects is fulfilled by the developed three-axial stabilized optical system. Modern techniques, technologies and state-of-the-art electronics are employed in the design process � by use of CAD, FEM and CFD software for multiple potential configurations trials; in the manufacturing endeavourwith 3D printing and CNC machining, as well as for software and hardware implementation and simulation testing- by use of robust control algorithms and adaptive control methods. The selected exterior shell of the optical system was derived under dimensional constrains imposed by the aerial platform, for aerodynamic efficiency and structural strength. The electric motors were selected for reliability and endurance under: weight and dimensional constraints.