Selecting the optimum battery for a multi-rotor unmanned electric helicopter (multicopter)
The study deals with selecting a rechargeable battery mass that ensures maximum flight duration for an electric multicopter in hover mode, taking into account the changes in the electric motor energy conversion efficiency. As a result of studying a refined model that takes into account the changes in energy conversion efficiency, we discovered that using a relative battery mass between 1 and 2 leads to achieving the maximum flight duration in hover mode. The relative mass value corresponding to the maximum in time greatly depends on how rigid the speed-torque characteristic of the engine is, and depends on the thrust-to-weight ratio to a lesser degree. Taking into account the energy conversion efficiency of the engine does not really affect relative battery mass values that are determined using the integral and differential criteria. We can recommend designers to use the values we obtained for the relative battery mass.
 Andres. Optimal Battery Capacity. 2011, April 12, 9 p. URL: http://api.ning.com/files/aFMLPsgnHmZXdNMAY8PM0KekqE4uAQSMx2C*usF6KDpKiqpO4L9-hrUKYBsS-xtRMqo-K4GR5TPsM2Isq56oMw__/battery_capacity.pdf
 Neitzke K.-P. Rotary Wing Micro Air Vehicle Endurance. Proceedings of the International Micro Air Vehicle Conference and Flight Competition IMAV 2013. September 17-20. Toulouse, France, 2013, pp. 16-25.
 Sverdlov S.Z. Vestnik Vologodskogo gosudarstvennogo universiteta - Bulletin of the Vologda State University, 2015, no. 5/15. Available at: http://www.uni-vologda.ac.ru/~c3c/articles/FLIGHT%20DURATION%20OF%20THE%20ELECTRIC%20UNMANNED%20HELICOPTER.pdf
 Ovchinnikov I.E. Ventilnye elektricheskie dvigateli i privod na ikh osnove (malaya i srednyaya moshchnost) [AC converter-fed motors and drives based on them (low and medium power)]. St. Petersburg, Korona-Vek Publ., 2006, 336 p.
 Xia Ch.-l. Permanent magnet brushless DC motor drives and controls. John Wiley & Sons, Singapore Pte. Ltd., 2012, 320 р.
 Sverdlov S.Z. Inzhenernyy zhurnal: nauka i innovatsii - Engineering Journal: Science and Innovation, 2016, iss. 11. Available at: http://dx.doi.org/10.18698/2308-6033-2016-11-1551
 Traub L.W. Range and Endurance Estimates for Battery-Powered Aircraft. Journal of Aircraft, 2011, no. 48 (2):703-707. DOI: 10.2514/1.C031027
 Traub L.W. Optimal Battery Weight Fraction for Maximum Aircraft Range and Endurance. Journal of Aircraft, 2016, vol. 10, no. 03. DOI: 10.2514/1.C033416
 Johnson W. Helicopter Theory. Princeton University Press, 1980 [In Russ.: Johnson W. Teoriya vertoleta. In 2 vols. Moscow, Mir Publ., 1983].