All Questions
73
questions
11
votes
2
answers
728
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?
- 5,898
14
votes
4
answers
6k
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 ...
- 5,642
8
votes
3
answers
2k
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 ...
- 578
14
votes
2
answers
773
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 ...
- 5,898
5
votes
5
answers
149
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, ...
- 2,957
5
votes
2
answers
7k
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.
- 4,412
21
votes
2
answers
767
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
20
votes
4
answers
1k
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.
...
- 1,033
18
votes
4
answers
3k
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 ...
- 2,644
16
votes
3
answers
345
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?
- 271
11
votes
2
answers
3k
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 ...
- 5,898
8
votes
2
answers
14k
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 ...
- 749
8
votes
4
answers
15k
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?
- 5,642
7
votes
3
answers
931
views
What process should I use to ensure my motors are spinning the correct direction when using Betaflight
I heard that a lot of problems occur due to one or more motors spinning the wrong direction. What process should I take to ensure that all my motors are spinning the correct direction if I'm using ...
- 751
7
votes
3
answers
341
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-...
- 5,642
6
votes
3
answers
591
views
What blocks an FPV video signal?
I am interested in long-range range FPV flying. What things block the video signal of a 5.8gHz video transmitter the most?
- 5,642
4
votes
3
answers
790
views
Why do higher voltage batteries need lower KV motors?
I've noticed that higher voltage batteries need lower KV motors, why is this?
user149
3
votes
2
answers
984
views
How do I set up LUA scripts on my OpenTX radio?
I’m looking at how to use LUA scripts and was wondering how to configure them I am OpenTX radio.
Thanks.
More info: at present, I don’t want to write my own scripts, only run scripts that I can find ...
- 4,412
3
votes
1
answer
125
views
What is an Ultimate Air Trap (UAT)?
I am confused about what an Ultimate Air Trap is.
I understand somewhat that its task is to remove the air bubbles in the fuel feed to an engine. But how does it work?
How is it different from a ...
- 85
2
votes
4
answers
439
views
Effect of motor load on ESC?
I know that when a prop is caught on something or is slowed down by something it can put extra strain on the ESC or even burn it out.
If I was using a 2207 motor with an unusually large and heavy ...
- 5,642
14
votes
4
answers
391
views
How to know if a place is a no-drone zone in the UK?
I live in the UK and often hear that a lot of places are "no-drone zones" meaning flying a drone there could get you a penalty.
Is there any database for these zones as often signage isn't clear?
user149
13
votes
2
answers
2k
views
Why is it bad to power up a drone without an antenna on the VTX?
I've heard a few times now that if you power up your drone you have to make sure that you have an antenna on the VTX. Is that true? If so, what will happen if I power up my drone without an antenna on ...
- 445
13
votes
5
answers
7k
views
Why do most drones have upward facing motors?
Most freestyle quadcopters I have seen are specifically designed to fly with the motors facing upward and have the arms of the drone underneath the propellers like this:
As you can see in the picture ...
- 5,642
12
votes
3
answers
5k
views
What does BEC, SBEC, UBEC, and OPTO mean for brushless motor ESCs?
I'm looking to purchase an ESC to go with a brushless motor. Many of the product pages include terms related to a BEC, such as SBEC, UBEC, and Opto.
What do those acronyms mean and how should I ...
- 749
12
votes
2
answers
2k
views
In what situations do puffy batteries pose a risk of ignition?
In this Drones and Model Aircraft SE question, Is it safe to fly LiPo batteries after they get "puffy"?, David O. asked if it is safe to use puffy LiPo batteries.
Gparyani provided an ...
11
votes
5
answers
519
views
How can I safely parallel charge my LiPo batteries?
I have multiple LiPo batteries that I want to charge up so I can get out flying as fast as (safely) possible.
With my existing LiPo charger, how can I parallel charge multiple batteries at once?
- 749
10
votes
3
answers
6k
views
How can I reverse the direction of a brushless motor?
I have a brushless motor on my RC plane. After connecting it to an ESC and testing it I've found that it is spinning in the wrong direction.
How can I reverse the direction the prop is spinning?
- 749
10
votes
3
answers
311
views
How do you build and use a smoke stopper?
What is the right way to build and use a "smoke stopper" device to prevent a short or other improper wiring from damaging your electronics?
Is it different depending on what voltage you are using?
- 1,130
10
votes
2
answers
4k
views
Do propellers layered on top of each other have twice the thrust of one propeller?
If you had two of the same propellers layered on top of each other going at the same RPM, with some space in between, would the thrust be double the amount of a single propeller at the same RPM?
If ...
- 459
10
votes
4
answers
2k
views
Do aerodynamics scale for model aircraft?
If I wanted to make a scale model plane that looked like a real aircraft, could I just scale down all of the measurements of the actual aircraft to make a model aircraft with similar flight ...
- 5,642
10
votes
2
answers
250
views
How do I safely dispose of my LiPo batteries?
I have an old LiPo battery that is nearing the end of its life, how can I dispose of it safely?
user149
10
votes
3
answers
3k
views
How low can I safely discharge a LIPO battery during flight?
What is the minimum voltage I can safely discharge a LIPO battery during a flight?
For example, if I have a 3S LIPO battery, should I be aiming to land my RC plane before the battery gets below a ...
- 749
10
votes
2
answers
112
views
What is a safe amount of time a LiPo pack can be kept fully charged before it is discharged to storage capacity?
Is there any research that shows the actual decrease in capacity/performance/longevity of high discharge current LiPo batteries, like those used in quadcopters, depending on the total time they spent ...
- 494
10
votes
2
answers
470
views
Should Crossfire transmitter antenna orientation match receiver antenna orientation?
I've always heard that you should orient the antenna on the Crossfire transmitter vertically, with the ends pointing up and down. I've also heard that you should do the same with the receiver antenna (...
- 203
9
votes
2
answers
311
views
When flying FPV in a group, what are the best video transmission channels/frequencies to use to avoid interference?
When flying FPV drones in a group setting it is very important to choose appropriate video transmission frequencies so you don't interfere with others that are flying near you. What are the best ...
- 1,130
9
votes
5
answers
153
views
New Prebuilt Drone flipping on takeoff
I have a small quadcopter drone, immediately on takeoff it flips upside down, this happens all the time.
What could be a potential problem?
Edit: It is prebuilt and bought from a shop and has never ...
user149
9
votes
3
answers
6k
views
Do low temperatures damage LiPo batteries?
I'm wondering if low temperatures affect LiPo batteries in any way? Can colder temperatures damage the cells? Can I store my batteries in bat safe box outside, in cold/hot temperatures?
- 579
8
votes
2
answers
917
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
3
answers
229
views
How do you waterproof your electronics?
I fly FPV drones a lot in the winter where it is wet and snowy. What is the best way to protect your equipment from shorting out from water?
- 1,130
7
votes
3
answers
1k
views
How to fix OSD flickering?
I just changed my Diatone R349 flight controller because the old one broke. On my first test flight, I noticed the OSD is flickering very bad, sometimes losing it for more than 1 second, even when not ...
- 343
7
votes
2
answers
1k
views
How to get a licence to fly a drone in the city of Prague for a week?
I would like to take my drone and go fly in the city of Prague - it's super beautiful there during lockdown. (I'm close by anyway so don't worry, I'm staying safe) But -
According to Czech law it's ...
- 173
7
votes
1
answer
328
views
Streaming FPV over WiFi?
I met a guy some time ago running a first person view (FPV) stream over Wifi. He said that the setup didn't use a complete Operations System Interconnect (OSI) network stack and this allowed them to ...
- 295
7
votes
1
answer
100
views
How to restore LiPo-powered aircraft that have not been flown for years?
I have a bunch of relatively inexpensive battery-powered radio-controlled aircraft that I haven't flown in over a year. I haven't flown some of them in over 3 years.
The aircraft are airplanes, ...
7
votes
2
answers
2k
views
Difference between analog and digital FPV systems?
The new DJI digital FPV system and a few other systems are using a digital signal for FPV video. How is this different from a traditional analog signal for FPV drones?
- 5,642
7
votes
1
answer
5k
views
DJI Mini 2 Mapping Capabilities
I planned to buy my first drone to ease my work. Recently, I found the DJI Mini 2, which I can afford to buy. I've already done some research about drone mapping. Based on my findings on the internet, ...
- 73
6
votes
3
answers
3k
views
How to build a buddy box cable for FlySky FS-i6X RC transmitters?
I have a couple of FlySky FS-i6X RC transmitters that I'd like to use to teach my brother how to fly. I've seen other people use "buddy box" cables that connect two transmitters and allow one person ...
- 5,898
6
votes
2
answers
538
views
Do drones with inflight API access for control inputs exist?
I am a software engineer brand new to drones.
I want a drone where I have full access to all of the flight controls programmatically. For example, I can run a python script and once executed, it ...
- 161
6
votes
2
answers
427
views
What are the conditions for LiPo battery damage from undervoltage?
It is widely known that Lithium-polymer cells are permanently damaged if their voltage drops below a certain threshold, around 3.0 volts, but I couldn't find much on the exact conditions and factors ...
- 2,957
6
votes
3
answers
1k
views
How to determine the lowest safe ESC current rating for a drone build?
I was planning to build a quadcopter and was wondering how I should decide what ESC to get. I'm asking about ESC current ratings. I am building a 7 inch drone using 4s with 2306 1900Kv motors. I have ...
- 5,642
6
votes
1
answer
804
views
At what voltage per cell should I store a LiPo?
Some sources say you should store your batteries at 3.85V per cell, other says it should be 3.7V.
My charger (ISDT Q6 Lite) on the "Storage" mode has a thumbs-up mark at 3.7V, probably indicating ...
- 550