Today we checked the maximum thrust for the motor with our first-try propeller (32" x 12). We've built a wood-made arm in balance with a load cell, connected to an Arduino Nano, providing real-time information about the load. Of course, we first calibrated with a dynamometer for several points and the relationship seemed "very linear". In the end we got 41 kgf as maximum thrust... This is not enough thrust for our design since 41 x 6 = 246 kgf. We estimate a total weight (with the pilot) around 200 kg, thus in this case we would hover at 80% of max thrust. We want to be between 50% and 70% of maximum thrust because that's the range where the motor is most responsive for a not-so-bad consumption..
I believe we have to change propellers to a 40"diameter, keeping the same pitch. Ok, let's contact China again during the dawn.
Olá irmão. Que show. Também tenho vontade de fazer um. Será que você poderia compartilhar que motores e que bateria você utilizou? Comprou no Alibaba? Será que vonsigo adaptar o vontrolr do Fimix8SE para controla-lo? Obrigado. E parabéns! drcrisroos@gmail.com
Cadu: This is a pleasure for me to read a comment with a so valuable content. I agree 100% with you about how important is to know that margin for the reasons you described; that's why we spent time to find that max thrust building an apparatus. As soon as we have the new propellers we will test it again and get the new max thrust. Then, with the total weight estimate we will get the new margin. I will let you know. Thank you very much!
Hi Marcelo. Amazing project! Your hovering to max thrust margin will determine how fast the vehicle will be able to react to a attitude change and consequently your flight quality. Your margin and max thrust will define the max roll angle that you can still bring the drone back to hovering, therefore, very very important to safety. This is usually not a problem for small drones but becomes relevant for heavy and high rolling inertia vehicles. Would be interesting to calculate that before your flight. How is your motor and ESC margin to go for the 40" prop? Cheers.
Jeanette: I wonder as well. I will be happy if the maximum thrust will be increased from 41 kgf to 50 kgf (it means 22% of increasing). But I will be VERY happy if it goes up to 55 kgf because, in this case, we will be hovering at 60% of the maximum thrust (and the "magic range" from literature is to stay between 50% and 70% of the max thrust).
I wonder how much the 40” diameter propellers will increase in maximum thrust.