Skip to main content
20 votes

Why are larger propellers generally more efficient than smaller ones?

Thrust is proportional to the change in momentum of the air passing through the prop - i.e. how much the prop speeds it up. The power required to do this is proportional to the kinetic energy of the ...
Robin Bennett's user avatar
17 votes

Why are larger propellers generally more efficient than smaller ones?

An explanation for why this is can be found in this Aviation.SE answer: Why aren't large, low-speed propellers widely used?, which I'll paraphrase here. The thrust a propeller generates is a function ...
ifconfig's user avatar
  • 6,008
9 votes
Accepted

Why is 900 MHz better for long range than 2.4 GHz?

The strength of an electromagnetic signal will attenuate (decrease in strength) over long distances between the receiver and the transmitter due to the inverse square law, but this phenomenon applies ...
ifconfig's user avatar
  • 6,008
7 votes

Transmit video from drone to laptop via WiFi

You have a few options. One is to switch to a digital video system such as the fat shark bytefrost and do something like this to convert the video to a format compatible with your laptop. Essentially ...
user7379804's user avatar
7 votes
Accepted

What obstacles are there in making ultra long range model aircraft?

So many different issues, I study a lot of the FAA regulations closely but have contemplated this same question a few times. The power and weight of gear is heavy, so to make it all the way around is ...
FunHog.me's user avatar
  • 1,068
6 votes

Why are larger propellers generally more efficient than smaller ones?

Comment number 7 at this link is an excellent source (and fairly trustworthy as it was written by Joshua Bardwell). The main reason specified for the efficiency is that for a given amount of thrust, ...
Drones and Whatnot's user avatar
5 votes
Accepted

First radio transmitter. Taranis X-Lite, X9 Lite or Jumper T8GS?

At this point I would recommend the radiomaster TX16S. It goes for about the same price as the other radios you list but has everything you need to get you going for a very long time. FrSky (Taranis) ...
Flyback FPV's user avatar
5 votes

Why is 900 MHz better for long range than 2.4 GHz?

Besides the purely physical considerations listed in ifconfig's answer, there's another reason, and it has nothing to do with frequency, but with how the signal is encoded and decoded. The Crossfire ...
FlashCactus's user avatar
  • 2,997
4 votes

Transmit video from drone to laptop via WiFi

It is a totally different communications protocol than the 5.8GHz wifi your laptop supports but there are devices for under $30 that let you receive the video on an android phone or a windows laptop ...
nvuono's user avatar
  • 141
4 votes
Accepted

Budget drone capable of lifting 0.5 - 1 kg and flying ~2km radius

The flight you describe is 100% illegal in the US requiring 107/commercial license + BVLOS waiver. BVLOS waivers are very rare, 61 issued searching the DB for "107.31" here: https://www.faa....
FunHog.me's user avatar
  • 1,068
4 votes
Accepted

Transmit video from drone to laptop via WiFi

This is not possible, at least directly. Although the two technologies use the same frequency range, they are very different communication protocols. A possible solution would be to buy a compatible ...
Kralc's user avatar
  • 6,046
4 votes
Accepted

Is there an open source video processing/sensor based follow me technology?

You may want to take a look at dronecode.org, or their supported projects. Especially, PX4 (which was also mentioned in another answer): Getting Started with PX4 Autopilot guide PX4's Follow-Me ...
Dvir Berebi's user avatar
4 votes

Can a flying drone get powered with solar energy?

I don't think anyone has made a multi-rotor fly on solar power yet. Exploring the math for balancing available power against weight, and optimising the motors and rotors for a sufficiently high thrust ...
Robin Bennett's user avatar
3 votes

Are ultrasonic sensors good for obstacle detection?

Ultrasonic detectors are frequently used for obstacle detection on wheeled robots, where a range of 2 or 3 meters is adequate. For a drone, that might not be enough warning - especially for difficult ...
Robin Bennett's user avatar
3 votes
Accepted

How are IMU used to detect orientation with respect to ground?

The core idea regarding the accelerometer is the following: if you take any flight of an object and calculate the average experienced acceleration over the whole flight (ignoring gravity as a factor ...
FlashCactus's user avatar
  • 2,997
3 votes

Can Reinforcement Learning be used for UAV waypoint control?

Reinforcement Learning can be used for UAV control. This video details a method to use RL for quadcopters. In summary, you program a model of your UAV that effectively simulates your drone. You then ...
Krish's user avatar
  • 752
3 votes

Why are larger propellers generally more efficient than smaller ones?

The easiest way to think about this is to remember that drag increases with the velocity squared. A smaller propeller will have to spin faster to achieve the same thrust as a larger propeller, and ...
Fraser Steen's user avatar
3 votes

What technology offers the longest range for RC controls?

If you are not interested in hard, real-time control and can accept some autonomy in the drone, then your best choice is satellite communication. The iridium based modules are lightweight, (45 grams), ...
jpou's user avatar
  • 411
2 votes

What technology offers the longest range for RC controls?

To my knowledge, the most readily available consumer long-range RC control system is the Crossfire ecosystem from Team BlackSheep. It makes use of the 868 MHz/915 MHz band and supports RF transmission ...
ifconfig's user avatar
  • 6,008
2 votes

What technology offers the longest range for RC controls?

The control range depends on the frequency, power and how the transmitter sends the data (the 'mode'.) Power More power gives longer range (much like a brighter light can be seen from further away.) ...
Kralc's user avatar
  • 6,046
2 votes

multi-protocol transmitters -- difference between stm32 4-in-1 and stm32 c2500 only ? [tx16s Vs. tx12]

1> The "4 in 1 chip" does handle more protocols than the CC2500. It has the CC2500, nRF24L01, A7105 and CYR all integrated in one package and allows you to bind with and use Flysky, ...
Kritik Agrawal's user avatar
2 votes

Is there an open source video processing/sensor based follow me technology?

The PX4 open-source flight stack has made some progress on various forms of computer vision. While not exactly turnkey, it’s an active area of development and you absolutely can buy hardware that ...
pion's user avatar
  • 211
2 votes

For an autonomous propeller drone plane, what is the absolute highest it can fly (disregard any laws)?

You're right that the physical limit is the reduced density of air at altitude, but it's a little more complicated. As density decreases planes have to fly faster to generate the same amount of lift. ...
Robin Bennett's user avatar
2 votes

How does Herelink achieve 20km range with 1080P video streaming quality?

Wi-Fi and 2.4GHz are not necessarily the same thing. 2.4GHz is part of the ISM band (Industrial, Scientific, Medical) of frequencies that can be used for short range communications. Wi-Fi is a ...
Kevin's user avatar
  • 501
2 votes
Accepted

How does the Switchblade 300 drone maneuver?

After investigating the very few detailed images available of this loitering munitions UAV, it appears to use ailerons on the front set of wings. I've found one image which shows the underside of the ...
Jacob B's user avatar
  • 5,792
2 votes
Accepted

What kind of drone could be remote controlled over 4km of open water?

Any purpose built machine can make it out that far: https://rotorbuilds.com/build/29119 That is well within the range of hobby grade analog and digital control and video systems. The DJI digital FPV ...
Brydon Gibson's user avatar
2 votes

SIYI HM30: Network Connectivity and Range

There's an equation for working out the curvature of the earth, and how far you can see depending on your altitude. There's a calculator here: https://www.omnicalculator.com/physics/earth-curvature ...
Robin Bennett's user avatar
1 vote

Would appreciate help! What is wrong with the ESC?

Most likely the FC is not arming the ESC for some reason. The best way to solve arming problems is to connect up the VTX and see what warning message BetaFlight is showing in the OSD. Also, in the ...
Robin Bennett's user avatar
1 vote

Problems with drone receiver using BetaFlight

That sounds like betaflight has something the wrong way around, so when it notices a slight tilt, it powers up the wrong motor, which makes the problem worse and causes a run-away feedback loop. There ...
Robin Bennett's user avatar
1 vote

What kind of drone could be remote controlled over 4km of open water?

Probably the most popular drone for taking video (you'll see it a lot on youtube) is the DJI Mavic, and it's specs include: Range: Low Interference (open landscape abundant line of sight, few ...
Robin Bennett's user avatar

Only top scored, non community-wiki answers of a minimum length are eligible