To determine the lift force of a helicopter in hover, weighing the helicopter provides a straightforward method, as lift equals weight when hovering. For testing thrust produced by the rotor, methods include using a spring scale or a strain gauge-based force transducer to measure forces accurately. Wind tunnel testing and established aerodynamic calculations are also utilized to validate thrust measurements. Additionally, resources like books on helicopter aerodynamics were shared, although some links were outdated and no longer functional. Accurate thrust measurement and understanding of aerodynamics are crucial for anyone building their own helicopter.