Hello everyone,,
I am trying to understand the math/mechanics behind efficiency (not so much performance)
I have a little hubsan X4 that comes a 380mah, 3.7 volt, 4wh battery (I do not have the c rating) that runs for 5 min before it teeters out
I purchased some replacement tri blade props and the flight time reduced to 30 secs.
I would like to understand everything that errored here (for someone looking for efficiency). I would of thought that the additional prop would provide more lift and as long as I was not doing tricks, I could expect additional flight time.
This hypothesis was quickly proven very incorrect.
Is there a formula calculating weight to blade area efficiency requirements?
Where can someone look to to get a very good understanding of the mechanics of prop efficiency?
Math for energy consumption
Math for energy consumption
Last edited by Lincon on Thu May 16, 2019 6:34 am, edited 1 time in total.
Re: Math for energy consumption
Hi,
i will try to explain some of the questions (even with my not so good english).
1) the more blades a prop has, the less efficient is he. The opitmal pro is a one blade (yes ... there are some with counterwight) mostly used on sailplanes.
http://jasta99.de/include/images/userga ... g_1670.jpg
2) the bigger the props (diameter) with the same amount of pitch -> the more efficient he is. -> but also needs more torque to drive
3) The Hubsan has an optimized propulsion system. The motor is optimized to drive the props. If you add another blade you also need more torque -> the motor is not able to deliver this torque and gets hot (so burns more energy). With some bad luck you will burn your motors.
Conclusion: If you like more flight time you have to use bigger props (diameter), not more blades. You also have to ensure, that your drive train is able to deliver the required torque. In the case of the Hubsan -> I think you have to exchange the motors and use bigger props (if that fits).
hope you understand what i mean.
Jens
i will try to explain some of the questions (even with my not so good english).
1) the more blades a prop has, the less efficient is he. The opitmal pro is a one blade (yes ... there are some with counterwight) mostly used on sailplanes.
http://jasta99.de/include/images/userga ... g_1670.jpg
2) the bigger the props (diameter) with the same amount of pitch -> the more efficient he is. -> but also needs more torque to drive
3) The Hubsan has an optimized propulsion system. The motor is optimized to drive the props. If you add another blade you also need more torque -> the motor is not able to deliver this torque and gets hot (so burns more energy). With some bad luck you will burn your motors.
Conclusion: If you like more flight time you have to use bigger props (diameter), not more blades. You also have to ensure, that your drive train is able to deliver the required torque. In the case of the Hubsan -> I think you have to exchange the motors and use bigger props (if that fits).
hope you understand what i mean.
Jens