I need to build a multirotor with 5.6Kg of take-off weight. Is it better to build a quadrotor with bigger motors or a hexcopter with smaller motors?
For the quad I’m thinking of using Xing 4214 motors at 6S (13" props) and for the hex I’m thinking on using T-Motor F90 at 6S (7" props).
Think again your motor choice… You have to choose a motor-propeller combo able to lift your multi rotor at 50% power or less.
They should be able to lift around 50% according to the datasheets.
Gotcha, any motor suggestions?
The quad will have no redundancy, so any failure is catastrophic. But it is more efficient.
The hex has limited redundancy and may be able to land with one motor/ESC failure.
Octo has good redundancy but getting even less efficient (smaller prop sizes or the frame has to be enormous)
If the payload is expensive, or the risk of damage to people/property is non-zero then consider a Octaquad (X8 coax). Not as efficient as a quad but vastly improved redundancy.
My philosophy is as follows:
If you won’t be flying near people/property and/or the payload isn’t expensive - quadcopter is the best. Most efficient and cheapest
If you will be flying near people/property and/or the payload is very expensive (more than the aircraft) - X8 is the best. Lose efficiency, but it has the most redundancy and minimal footprint.
Personally not a fan of Hexacopters for projects as my experience has shown that their redundancy cannot be 100% trusted (and they spin after loss). Plus, they are relatively large for their propeller size. If you build an X8 the size of a hexacopter in terms of wheelbase (i.e. bigger props), you can probably get the same amount of flight time and payload capacity with the increased redundancy. Only downside is the additional cost.
1 Like