Design and lift characteristics analysis of a small single-rotor propeller using parameter iteration implemented in PyCharm

The aerodynamic performance of small single-rotor propellers degrades under low-Reynolds-number conditions (10⁴–10⁵), restricting the endurance, load capacity, and operational stability of micro air vehicles. To address this limitation, this study focuses on developing a rapid, high-precision design method to maximize lift within constrained propeller diameter and specific speed ranges. A complete technical framework comprising “theoretical design–numerical verification–precision manufacturing–experimental testing” is established to maximize lift for micro air vehicles while enhancing engineering practicality.

Based on an improved blade element momentum theory (BEMT), the propeller blade is divided into multiple radial elements, the force conditions of each blade element are calculated, and the overall performance parameters are obtained through integration. Parametric iterative programs are implemented in PyCharm to optimize the distributions of blade chord length and pitch angle to maximize lift. The optimized propeller model is imported into ANSYS Fluent for mesh generation and flow field simulations to validate its aerodynamic performance. A hybrid additive–subtractive manufacturing technique combining stereolithography (SLA) 3D printing with five-axis CNC machining is adopted to fabricate physical prototypes. Lift tests are conducted on a self-built experimental platform to measure the actual lift at various rotational speeds. The theoretical, simulated, and experimental results are compared, and the corresponding errors are analyzed, verifying the effectiveness of the design method.

The results show that 1) the optimized propeller has a diameter of 90.0 mm and four blades. With a constant pitch angle of 35° along the blade span, the chord length gradually increases from 15 to 19.5 mm along the radial direction. Lift grows quadratically with increasing rotational speed, and no obvious flow separation inflection point is observed within the speed range of 8000–12000 r/min. 2) At a rotational speed of 11000 r/min, the theoretical, simulated, and experimental lift values are 1.22, 1.20, and 1.19 N, respectively, with an error of approximately 2.5% between the experimental and theoretical values. 3) The simulation residual values steadily decrease below 10^–3, indicating good convergence. 4) Across the full speed range, the theoretical predictions are generally consistent with the experimental lift data, with errors within acceptable limits.

Based on the improved BEMT, the precise regulation of chord length and pitch angle distributions effectively suppresses flow separation and maximizes lift within the specified diameter (90 mm) and speed range (8000–12000 r/min), thereby overcoming the reduced aerodynamic efficiency commonly observed in traditional propeller designs operating under low-Reynolds-number conditions. The consistency among theoretical calculations, CFD simulations, and experimental tests verifies the accuracy of the proposed design method in predicting the aerodynamic performance of small-scale propellers. The hybrid additive–subtractive manufacturing technique, which combines SLA 3D printing and five-axis CNC machining, meets the requirements for rapid prototyping and high-precision fabrication. The established technical framework provides a feasible and practical approach for the rapid, high-precision design and aerodynamic performance analysis of small single-rotor propellers. It also provides a reference for the design optimization of propulsion components under low-Reynolds-number conditions.