Multirotor Sizing Methodology with Flight Time Estimation

This paper addresses the need for sizing of rotors for multirotor vehicle applications such as personal air transport, delivery, surveillance, and photography. A methodology for the propeller and motor selection is developed and augmented with flight time estimation capabilities. Being multirotor-specific it makes use of the platform’s simplicity to rapidly provide a set of off-the-shelf components ready to be used in the vehicle. Use of operating points makes the comparison process fast, precise, and tailored to specific application. The method is easily implemented in software to provide an automated tool. Furthermore, clearly defined input and output parameters make it also usable as a module in other multicriteria optimisation algorithms. The new methodology is validated through comparison with a consumer-grade drone and the calculated results are compliant with manufacturer’s specification in terms of maximum hover time.

Influence of Cutting Environment on Tool Life

The issues of cutting environment and a suitable choice of cutting conditions by drilling are the main subjects of the article. Attention is paid to the application of the drilling process into the carbon steel. Analysed were the phenomena that adversely affect the tool life. The article demonstrated solutions how to remove these adverse effects. The multicriteria optimisation of input factors (cutting fluid concentration, cutting speed) for a defined target function (tool life) was applied. The measured values were subjected to mathematical–statistical analysis (ANOVA). Based on the implemented experiment and study of this issue, we determined the combinations of input factors, which achieved minimal values of target functions. Based on the implemented experiment and study of this issue, we also determined the combinations of input factors, which achieved minimal values of target functions. Based on this allegation, the most appropriate combination of the following input factors was proved: concentration 6.3 % and cutting speed 100 m/min.