Questions about aircraft which use four rotors to provide lift.

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### Formula relating propeller torque to lift

I'm trying to find a formulas that relates lift to torque on the rotor shaft. Torque, angular velocity and power are related by the following relationship: $P=\tau \omega$. I am especially interested ...
536 views

### Could a quadcopter fly if its propellers were encased in cylindrical tubes?

Picture a standard quadcopter, with regular old propeller guards, which are generally just circles around the propellers. Now, take the propeller guards and stretch them so that they're cylinders ...
1 vote
133 views

### Can a tail-sitter drone like the XFY-1 Pogo aircraft have any advantage over a classic quadrocopter

I looked at a few rc models of the xfy-1 pogo plane and wondered why there weren't more drones in this setup, some seemed very agile. I think this concept can be refined. of course, the contra-...
9k views

### How do I compute thrust of a rotor disk and the necessary power to drive it??

as it seems, this question has been asked a few times here so please forgive me for asking again. If I have 50 BHP shaft power available at 5000 RPM and 106 N.m torque, then can I convert it to 200 ...
158 views

I am trying to create a simplified model of a heavy-lift drone payload at different altitude during hover mode. I tried to derive it simply by considering that the thrust, $T$ is equal to the weight ...
546 views

### Can quadcopter-like UAVs ever get significantly quieter? Any candidate technology?

note: this question is old (2016) but so far remains unanswered. Perhaps innovations have improved on the noise even since this was first posted. The light weight quadcopter and hexacopter UAVs that ...
457 views

### If the Quadcopter is a MIMO Nonlinear System, How Can it be Controlled using PID?

I know that it is very common to control quadcopters using PID algorithms. I'm just wondering if it isn't a problem that the system is highly nonlinear as well as having multiple inputs and outputs. ...
1 vote
1k views

### Calculating the Thrust vs RPM Relationship of a Brushless DC Motor

hope everyone is doing okay. I am conducting a project with my friends for an Unmanned Aerial Vehicle. We are first using MATLAB - Simulink to design and simulate the quadrotor. We completed the ...
4k views

### Is possible to stick two '2-blade' propellers to get multi-blade propeller?

Does propeller blades' airflow interfere with each other blades and decrease overall thrust? Should I consider high pitch propeller for this purpose? My purpose: I'm looking for a 20-inch four-blade ...
4k views

### Do quadcopter propellers break the sound barrier?

I recently bought a quadcopter and noticed every time I fly it there is this weird buzzing noise. I have heard this noise on other quadcopters around the same size as mine(4in by 4in). On an airliner ...
240 views

### Can I fly this six motor drone? [closed]

My body weight; 70kg, Drone weight; 50kg, Props length 0.7m, 6 motors (2hp each), Total weight 120kg, Total horsepower 12, Each motor runs 3000rpm, Please can I fly it. Thanks!!! drawing of the drone
179k views

### Why haven't quadcopters been scaled up yet?

Why are quadcopters not flown by human pilots yet? Wouldn't they be more stable and easier to control than helicopters?
1 vote
128 views

### Is the total lift of a quadcopter the sum of the lift from each propeller?

In this diagram each rotor R1,R2,R3,R4 has an individual lift force of 490 N. All combined, does the total force on this aircraft equal to 1960 N? The aircraft in question is similar to a quadcopter.
1 vote
71 views

### Can a quadcopter fly stable while its all 4 motors from different manufacturers?

What if we used 4 motors which all are from different manufacturers? Will it fly/hover ? All 4 brushless motors have same kv and dimensions. Like 2204 2300kv .
298 views

### How is the required motor power calculated for a quadcopter?

I've been trying to find the required motor power for a quadcopter. I first calculated drag power and then I made a linear trend line for motor power against motor weight. I made the motor power 1.5 ...
2k views

### How to calculate optimal prop diameter, pitch, torque and power coefficient given required thrust?

this is my first post here, so bear with me if this isn't the right place. I'm coming here from Stack Overflow, and this seemed to be the most relevant Stack Exchange for my question. So, I'm ...
1 vote
1k views

### Must quadcopters have the same propeller sizes?

I was flying quads today and it just suddenly popped up into my mind — do the propellers all have to be the same size in quadcopters? Mine are, but What if two propellers were larger and the other two ...
2k views

### Could a tilt quadcopter use turbofan engines?

I was wondering whether having a quad tiltrotor would allow for the use of turbofan engine rather than turbo prop. I read on another question that the V-22 uses turbo prop as it is easier to balance, ...
1 vote
130 views

### What's the smallest 3-blade propeller for this motor? [closed]

I've got a 15470 brushless 35kw motor from China How do I find the smallest 3-blade propeller I can use for this motor? Here are it's specs, Max Power: 35KW Max Amp: 400A Max RPM: 8500 Max Volt: 120v ...
1 vote
222 views

### Quadcopter: would putting 3 blades on the same level and the other blade below the first three work?

Most quadcopters have their propeller blades all on the same level, or in some cases, a pair of blades placed a little above the other pair. However, I was wondering if three propellers of a ...
1 vote
190 views

### Compute Thrust from RPM and Induced Velocity

I'm attempting to calculate the difference in thrust in a secondary propeller operating in the wake behind a primary propeller, in the context of a trailing quad-copter following a leading quad-copter ...
1 vote
474 views

### What disadvantages does flying a drone close under a ceiling have?

If I want a drone (quadcopter) to be flying always under a surface and close to this surface (i.e: under a table 5cm away from the surface), which are the disadvantages this would have in the lift ...
571 views

### What are the failure mode(s) for flying cars in case of power loss?

There seem to be lots of plans (and even some working prototypes) for various autonomous flying cars and flying taxis. Most of these seem to be based on vertical take-off using some variety of an ...
534 views

### Can quadcopters still fly with propellers at an angle?

Can quadcopters still fly with propellers at an angle? By this I mean like the whole motor mounts will be situated along a certain slope (so as to be neither horizontal nor vertical). UPDATE I meant ...
36k views

### How to calculate the required motor power and rotor size with respect to the weight of quadcopter?

I want to build a quadcopter but don't have any idea about motor and rotor size selection. Is there a formula or equation to use? What are other things that need to be considered? Trial and error ...
317 views

### Why hasn't anyone tried making two propellers facing upwards and the other two facing downwards? [closed]

Within a quadcopter, I know usually it's all the propellers facing upwards or all of them facing downwards. Why hasn't anyone tried making two propellers facing upwards and the other two facing ...
566 views

### quadcopters — should the propellers/motors all be at the same height

In quadcopters (or in any other drones), must the propellers/motors all be at the same height, or can there be symmetric height differences (like for eg, two of the motors at the "back" are elevated ...
268 views

### Is the rotor described in this Kickstarter new?

A NewAtlas story linked to a Kickstarter for a the "Whisper Drone" that shows a CAD model of a rotor that the Kickstartee-aspirant has apparently 3D-printed and flown (four of) on a quadcopter. I ...
5k views

### What‘s the thrust of two stacked propellers?

Let‘s say that you have two identical propellers and each is powered by their own motor and together they produce a thrust of 1 kN. How does the thrust change if instead of operating them side on side ...
1 vote
1k views

### Calculating the maximum altitude of a drone [duplicate]

Is there an equation to find the maximum altitude that a drone or quadcopter can fly to ?
376 views

### Can quadcopters save energy by flying in formation?

If two or more quadcopters are aligned, would the effect of drag due to the lead quadcopter's slipstream lead to measurable energy savings? And if so, how would one determine the optimal distance ...
1k views

### Does the direction of rotation of the propeller affect the direction of the thrust generated?

Does changing the direction of rotation of the propeller from clockwise to anti-clockwise change the direction of thrust it generates?
7k views

### Can a passenger drone perform auto-rotation?

(Source) The Dubai Drone is an Ehang passenger drone planned to start commercial services in July 2017. If there is a failure, can such an electric multi-copter auto-rotate a landing? I'm wondering,...
743 views

### How is the flight of a tricopter controlled?

For a quadcopter, diagonally opposite rotors have the same speed and direction which causes it to hover, and adjusting the speed of the rotors give the three basic movements of a flying object, i.e. ...
1k views

Quadcopters, by virtue of software-piloting rather than human-piloting, are capable of new modes of flight. I've seen one in which the machine maintains altitude despite the loss of two rotors by ...
1k views

### Is quadcopter design scalable? [duplicate]

I've been recently introduced to the world of mini aircraft, specifically, quadcopters - building them, flying them, calibrating them (apparently, it's such an important point that it deserves its own ...
290 views

### Could a quadrotor use a main gas powered rotor with small electric rotors for attitude control?

Here is my idea of heavy lifting quadcopter. (Although it is not a quad copter anymore because of the center rotor) Have a big coaxial fixed pitch rotor at the center. The rotor is gasoline fueled. ...
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2k views

### Can quadrotors be used for commercial passenger flights? [duplicate]

Recently, I have been conducting research on more efficient means for vertical lift transportation. One direction I was thrown in was the use of a quadrotor system with vector thrust and artificial ...
1 vote
180 views

### Could this propeller work on a quadcopter and decrease the sound? [closed]

I came across a video yesterday that showcased a propeller design that looked very interesting. I am a regular drone flyer and I constantly look for exciting things to try out. Would this design in ...
517 views

### How can this single-prop drone maintain stable (rotating) attitude and position?

The short BBC news item and video The drone designed to fly on one propeller shows the flight of something that looks like quadcopter missing three of its propellors and motors. It continuously ...
1k views

Quadcopters use both direct and contra-rotating propellers to be able to turn and to balance the torque caused by the each of the propellers. Propeller performance measurement: When testing the ...
3k views

### What is the weight of ballistic recovery systems?

How much does a Ballistic Recovery Systems parachute system weigh? I wouldn't want to use a personal quadcopter or jetpack without one. I wonder if they could be made small and light enough for a ...
229 views

### What happens if one or more rotors are stopped during autorotation on a quadrotor?

I get the basics of autorotation when it comes to a helicopter in unpowered flight, but it's a bit unclear to me when it comes to quadrotors. My objective is to cover some directed horizontal ...
367 views

### How is propeller thrust vector accurately expressed for airplanes and multirotors? [closed]

For propellers, as the airspeed increases thrust decreases. Is the airspeed component taken as a vector quantity perpendicular to the propeller? If that's true, then it's quite easy to visualize in ...
141 views

### Just got a quadcopter, and not sure about a piece that came with it [closed]

My apologies if this is the wrong forum, but I have seen hot questions about drones/quad-copters from here in the past. I received a quadcopter recently (X5C Explorers), and it has a piece I can not ...