A Practical Method to Estimate the Aerodynamic Coefficients of a Small-Scale Paramotor

• Main Authors: Razvan-Viorel MIHAI, Radu Calin PAHONIE, Ioana-Raluca EDU
• Format: Article
• Language: English
• Published: National Institute for Aerospace Research “Elie Carafoli” - INCAS 2014-12-01
• Series: INCAS Bulletin
• Subjects: paramotor; aerodynamic coefficients; 6 DOF; Two-Step Method
• Online Access: http://bulletin.incas.ro/files/mihai__pahonie__edu__vol_6_iss_4.pdf

There are few aircraft other than lighter-than-air vehicles that have the payload carrying capability, short field take-off, and slow speed ranges afforded by a powered parafoil. One very interesting aspect of the powered parafoils or paramotors, is their tendency to fly at a constant airspeed whether it is climbing, descending, or flying straight-and-level. Not only are the aircraft speed stable, but they have pendulum stability as well, due to the mass of the airframe suspended significantly below the canopy. This allows the aircraft to maintain a safe roll attitude and effectively turn in a coordinated manner when the steering pedals are deflected. One of the challenges of flying these aircraft is the necessity of controlling altitude with thrust, and direction with asymmetric drag. The paper presents a practical method to estimate the aerodynamic coefficients of a small-scale paramotor in order to obtain a suitable mathematical model for the aerial vehicle. Thus, a reduced state linear model based on a simplified nonlinear six degree-of-freedom model (6 DOF) is described. The autonomous control relies on the paramotor dynamics. And those equations depend on the aerodynamic coefficients. The task in this paper is to record the data of steady state flight regime, and to process it offline. Therefore, the system identification of the small-scale aerial vehicle can be done using the Two-Step Method, resulting an efficient six degree-of-freedom mini-paramotor model. The current work will permit the implementation of the control architecture in order to achieve the autonomous control of the small-scale paramotor through waypoints.