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12 votes
2 answers
1k 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?
ifconfig's user avatar
  • 6,008
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 ...
Jacob B's user avatar
  • 5,792
8 votes
3 answers
3k 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 ...
TheSimpliFire's user avatar
15 votes
2 answers
1k 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 ...
ifconfig's user avatar
  • 6,008
5 votes
5 answers
201 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, ...
FlashCactus's user avatar
  • 2,997
5 votes
2 answers
13k 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.
Drones and Whatnot's user avatar
21 votes
2 answers
875 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?
David O.'s user avatar
  • 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. ...
anonymous2's user avatar
  • 1,043
18 votes
4 answers
5k 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 ...
Hannes Hultergård's user avatar
16 votes
3 answers
593 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?
Pᴀᴜʟsᴛᴇʀ2's user avatar
11 votes
2 answers
5k 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 ...
ifconfig's user avatar
  • 6,008
9 votes
4 answers
26k 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?
Jacob B's user avatar
  • 5,792
8 votes
2 answers
19k 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 ...
Daniel Ballinger's user avatar
7 votes
3 answers
562 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-...
Jacob B's user avatar
  • 5,792
7 votes
3 answers
1k 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 ...
tavis's user avatar
  • 751
6 votes
4 answers
872 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?
Jacob B's user avatar
  • 5,792
4 votes
3 answers
1k views

Why do higher voltage batteries need lower KV motors?

I've noticed that higher voltage batteries need lower KV motors, why is this?
user avatar
3 votes
1 answer
449 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 ...
Atharva's user avatar
  • 85
3 votes
2 answers
1k 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 ...
Drones and Whatnot's user avatar
2 votes
4 answers
597 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 ...
Jacob B's user avatar
  • 5,792
14 votes
4 answers
424 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?
user avatar
13 votes
2 answers
3k 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 ...
David O.'s user avatar
  • 445
13 votes
5 answers
9k 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 ...
Jacob B's user avatar
  • 5,792
12 votes
3 answers
7k 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 ...
Daniel Ballinger's user avatar
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 ...
End Antisemitic Hate's user avatar
11 votes
5 answers
1k 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?
Daniel Ballinger's user avatar
11 votes
3 answers
9k 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?
Daniel Ballinger's user avatar
11 votes
2 answers
5k 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 ...
Gabriel Kusiak's user avatar
10 votes
3 answers
432 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?
5zero7rc's user avatar
  • 1,130
10 votes
4 answers
3k 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 ...
Jacob B's user avatar
  • 5,792
10 votes
3 answers
4k 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 ...
Daniel Ballinger's user avatar
10 votes
2 answers
269 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?
user avatar
10 votes
2 answers
2k 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 ...
Michał Trybus's user avatar
10 votes
2 answers
606 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 (...
Yorb's user avatar
  • 203
9 votes
5 answers
169 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 ...
user avatar
9 votes
2 answers
436 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 ...
5zero7rc's user avatar
  • 1,130
9 votes
3 answers
9k 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?
Ziem's user avatar
  • 579
8 votes
3 answers
255 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?
5zero7rc's user avatar
  • 1,130
8 votes
2 answers
419 views

How to keep my prop from flying off my motor?

After finally getting every piece on my plane to work, another piece decided to be a problem. Great. My problem is pretty much already summed up in the title, my prop keeps flying off my motor, and I ...
Ceramicmrno0b's user avatar
8 votes
2 answers
1k 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 ...
mr_guy99493's user avatar
7 votes
3 answers
4k 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 ...
ifconfig's user avatar
  • 6,008
7 votes
2 answers
1k 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 ...
Adam Johnston's user avatar
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, ...
mrm9719's user avatar
  • 73
7 votes
2 answers
2k 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 ...
nykon's user avatar
  • 173
7 votes
1 answer
713 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 ...
Carel's user avatar
  • 295
7 votes
1 answer
108 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, ...
End Antisemitic Hate's user avatar
7 votes
3 answers
2k 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 ...
JoRouss's user avatar
  • 343
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?
Jacob B's user avatar
  • 5,792
6 votes
1 answer
163 views

Help finding ESC for brushless motor

I'm very very new to hobby electronics however I have studied a bit about basic electronics in school. I have four EMAX 0802 Brushless Motors and I want to drive them with an Arduino Nano. I know that ...
James McGreivy's user avatar
6 votes
3 answers
1k views

Spray painting a drone, what to look out for?

I don't really like the colours on my drone and found a few bright spray paint colours around my house. I would like to spray paint my drone, but I obviously do not want to damage any parts of my ...
user avatar

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