Frequent Questions
78 questions
14
votes
4
answers
7k
views
Why are larger propellers generally more efficient than smaller ones?
In almost every case, long-range drones use larger propellers than other drones that don't need to travel very far or don't need to fly for very long. I have heard that a major reason for this is ...
- 5,802
12
votes
2
answers
2k
views
What does KV mean on motors?
I've seen ratings on brushless DC motors like this one for something called KV. What does that rating mean?
- 6,073
9
votes
3
answers
4k
views
Alternatives to LiPo batteries
LiPo is often the first choice of battery due to its high discharge rate and high specific energy (100 - 265 Wh/kg), defined as its energy per unit mass.
In terms of these two characteristics, what ...
- 588
15
votes
2
answers
2k
views
What is circular polarization in antennae?
I've seen references to left-hand (LHCP) and right-hand circular polarization (RHCP) with respect to antennae, especially in reference to mushroom antennae. What's the difference between the two ...
- 6,073
5
votes
5
answers
237
views
What are the available solutions for creating complex user-defined UAV behavior in autopilots?
Most freely available autopilot-enabled flight control hardware and firmware for hobby/consumer-grade UAVs seem to have a rather fixed feature set. There are usually varying degrees of stabilization, ...
- 2,997
5
votes
2
answers
18k
views
How can I configure a servo in Betaflight?
I’m looking to make a drone capable of deploying a parachute, so I need a servo release mechanism.
How can I configure a servo and map it to a switch in Betaflight?
Thanks.
- 4,432
21
votes
2
answers
980
views
Is it safe to fly LiPo batteries after they get "puffy"?
Some of my LiPo batteries got "puffy" after a few months. Is it still safe to fly them, or should I safely dispose of them?
- 445
21
votes
4
answers
2k
views
Why do multirotors usually have four propellors?
I've observed that hover-capable drones almost always have four propellers. There are helicopters of course, which have two, but in general, the vast majority of UAVs seem to go with four propellers.
...
- 1,053
18
votes
4
answers
7k
views
How does a quadcopter yaw?
I've always wondered how a quadcopter actually yaws, when all propellers are horizontal. I know that two of the motors spins faster, but I don't understand how that generates thrust in the horizontal ...
- 2,674
17
votes
3
answers
730
views
How do you figure out which motors to use for your UAV?
There are a ton of electric motors on the market. Is there a mathematical formula or some other means of figuring out which size of motor you will need for your airplane, helicopter, or drone?
- 281
11
votes
2
answers
6k
views
Can circularly and linearly polarized antennae be used together for FPV?
I have a few spare antennae of mixed polarizations I'd like to be able to reuse for my FPV gear.
Is there anything I need to know about incompatible configurations of mismatched polarizations ...
- 6,073
9
votes
4
answers
35k
views
At what current should I charge a LiPo battery?
I have several different LiPo batteries which I use with my drones, many of them are different voltages and different capacities. How do I know at what current I should charge my drone LiPo batteries?
- 5,802
8
votes
2
answers
2k
views
Control opentx transmitter from pc?
is a standard way to control a physical aircraft by connecting a frsky transmitter to a PC?
I do NOT want to use the transmitter to control a flight Sim etc.
I'd like to write autopilot software ...
- 141
8
votes
2
answers
23k
views
Why do brushless motors have 3 wires compared to 2 wires on a brushed motor? [closed]
I'm familiar with regular DC motors, which is what brushed motors appear to be. They have fixed stator magnets, rotor coils connected to the shaft and two brushes that power the coils at the right ...
- 759
7
votes
3
answers
673
views
What is antenna gain?
As I understand it, generally, a higher gain antenna will result in a longer range and better reception for FPV flying. What is antenna gain? What makes a low-gain patch antenna different that a high-...
- 5,802