# Tag Info

100

Wouldn't they be more stable and easier to control than helicopters? No, they would not. Quadcopters don't have any special inherent stability. When you increase power of one of the rotors to pitch, the increasing pitch will not do anything to the power difference and therefore the pitching moment. The advantage of quadcopters is that the rotors can be ...

31

It has (sort of) been done: The company that did this is working on a more useful version. It's important to note that scaling up is extremely difficult in aviation. Model airplanes have performance numbers the full scale folks can only dream about.

19

Quadcopters are not an efficient design -- one large rotor is far more efficient than four smaller rotors. The reason quadcopters became popular is that they are mechanically simpler, safer (due to the smaller rotors) and far easier to control by software. That said, recent advances in machine learning have made so that helicopters can be controlled by ...

19

The three most important factors in passenger air travel are safety, safety & safety. So that is where most of the questions will focus on, and where most of the engineering effort will be put into. Couple of questions: Artificial stability: what happens if the stability circuit breaks down? What happens if one of the motors fails, for instance one of ...

18

Advanced Tactics has also somewhat did it! A video of the first flight of the Black Knight Transformer has been released on Youtube.

17

Almost certainly not. Given the comments specifying a $0.5$ inch radius (blade length,) that means the circumference of the path of the blade tips would then be $$2 \pi \cdot 0.5 \, \text{inches} \approx 3.1415 \, \text{inches} \approx 0.2618 \,\text{feet}$$ To get to the speed of sound (which is approximately $1,126 \,\frac{\text{ft}}{\text{s}}$ at sea ...

17

The most important thing to remember here is the Purpose. For what purpose do you want to use the Quadcopter? That being said , let’s start with the very basic . Required Thrust = ( Weight x 2 ) / 4 In order to choose a motor you need to determine how much weight you are planning to take, and then work out the thrust required to lift the quadcopter .Also ...

17

That drone has fixed-pitch rotors, and that pitch is optimized for thrust, not for autorotation. In the absence of power, those rotors won't autorotate. They will stop rotating 'in the right way' and then start windmilling in the opposite sense. That windmilling will cause drag and some deceleration of the fall, but not of the same magnitude as an ...

14

If a single motor fails, it's not unsafe (supposedly). The 184 is technically an X-8 multi-rotor, meaning that it has four points of thrust, each consisting of two motor-propellers, coaxially aligned—one “tractor” propeller and one “pusher.” This means that if any one of the motors dies, or a propeller disintegrates, the aircraft won’t flip and crash to ...

11

Simple answer. No. A drone with fixed wing propellers such as the one you describe can not autorotate. For autorotation to work the pitch of the blades needs to be variable. At the instant of engine failure, the main rotor blades are producing lift and thrust from their angle of attack and velocity. By immediately lowering collective pitch, which ...

10

Four rotor copters were actually the first copters... Raúl Pateras Pescara, Buenos Aires, Argentina, 1916 Etienne Oehmichen, Paris, France, 1921

9

Scaling up the quadcopter design would make them very large. Only having one (or even two) rotor allows the helicopter to be smaller and even fold up the rotors and remain fairly compact. Since by definition helicopters are supposed to get into more difficult landing areas, increasing the footprint is generally undesirable. Also, the power system would be ...

9

There's a really interesting paper by Manikandan Ramasamy (Hover Performance Measurements Toward Understanding Aerodynamic Interference in Coaxial, Tandem, and Tilt Rotors, Journal of the American Helicopter Society, Vol. 60, 2015) that talks about this question, which is of great interest for multirotor UAS (which, for rotorcraft, is a substantial number of ...

8

The smallest BRS listed here is certified up to 600 pounds (272 kg) of aircraft weight. That should be more than enough for a small jetpack or personal quadcopter. This system weighs about 22 pounds (10 kg), not counting anything required to install it. As GdD mentioned, altitude may be an issue. The FAQ for a Cessna 182 mentions an altitude loss of about ...

8

What are the advantages that quadrocopters have over conventional helicopters? Super cheap flight control achieved via electronic control of individual electric motors. (Basically, it means avoiding the mechanically complex main rotor hub.) Self-cancelling torque thanks to counter-rotating propellers, further simplifying construction. Now, let's look at ...

7

There are three challenges for making a market-competitive full scale quadrocopter. 1) Energy efficiency The quadrocopter is not an energy-efficient design. Helicopters increase their range by using relatively under-powered engines that take a long time to spool up throttle and try to keep it at relatively constant RPM while changing the pitch of the blades ...

7

In a way, this has been done already half a century ago. When NATO decided to try a VTOL strategy, the Harrier was not the only result. There was even a supersonic VTOL fighter, and it used swivelling engine pods at its wingtips, much like the V-22 does today. It was the VJ-101C, developed in Germany and first flown in 1963. VJ-101C in flight. Note the ...

7

The main point of a quadcopter is that it can be controlled by engine power using much simpler fixed-pitch rotors¹. Assuming this construction, you need to be able to separately adjust power of forward and rear set of propellers for pitch control, left and right set of propellers for roll control and clockwise and counterclockwise-rotating set of propeller ...

7

As I am closely working on some of these projects, I think I can answer. Let me start from: if the power fails this is a rather extreme situation, since everyone is including emergency functionality in case the batteries get below a charge guard level, triggering an emergency landing (still powered). So to have the "power fails" scenario that your ...

6

Below is the info about one of the early protoypes by P Moller, author also of the: 'Volantor', now he's head of Freedom-Motors, a company focused on Wankel Rotary Combustion Engines. Moeller built his flying machines with fans driven by Wankel rotary engines, however, it sounds better having electrical engines for lifting and propulsion fans, and some kind ...

6

It's possible, but I would say unlikely. Supersonic propeller tips really mess with efficiency. The tip speed of many aircraft propellers is close to supersonic, and if not properly controlled can exceed the speed of sound, but most models don't get up that fast (and your blade tips don't have to be supersonic to be annoyingly loud). There is a formula to ...

6

I am a career helicopter pilot who enjoys watching the development of drone technology. I can tell you for certain that this aircraft is incapable of autorotation. A parachute would be it's best option for pure simplicity. This would not guarantee a safe landing, just avoid a 'splat'. It is very apparent to me that the number one challenge of the drone ...

5

This question does not belong in this SE, however this cable is for uploading pictures from the SD Card (Supposedly from your drone camera) to your computer via USB. You just plug the SD Card in the end it belongs in and plug it into a USB port on your computer.

5

Use Mark Dela's XROTOR - it will give you the chord and twist distribution over span for a given speed, torque and thrust (well, two out of three). It is based on Larabee's theory (PFD!) for a minimum induced loss rotor. For a practical solution try to design an optimum propeller for the speed and torque of your motors and then try to find something ...

5

Cheap MEMS gyroscopes have been on the market only since maybe 10 years. Before you needed more bulky and expensive gyros. Also, cheap and powerful micro controllers which can process the sensor data quickly enough and can control the speeds of the four motors to stabilize the quadcopter have only been available recently. The third recent innovation was more ...

5

After watching the video the problem he was having was in keeping it horizontal. It appears that the software isn't able to control the unpowered motors. I know absolutely nothing about quads but I'm assuming with a fixed rotor pitch they must use variable voltage to the motor to control everything such as translational movement. I'm also assuming they have ...

5

As commented, a quadcopter is generally flown by a computer. Given command inputs, the computer controls the speed of the four rotors, as shown in the images included in the question. The four rotors give the quadcopter a wide range of maneuverability. This is why quadcopters are currently used in many research applications. They can simulate conventional ...

5

The main reason V-22 uses propellers is efficiency. To get high thrust for power, you need to affect a lot of air and that requires a large propeller. The V-22 has huge propellers, closer to helicopter rotors than typical aircraft propellers. This gives it the static thrust-to-weight ratio of more than 2, so even with one engine out it still has more than 1 ...

5

An important point is that that type of aircraft can't glide in autorotation, as helicopters are able to do in case of engine trouble. It will drop like an stone...

5

There are few examples of three-rotor helicopters. On of them is the Cierva W.1 Air Horse. According to Wikipedia, torque balance, and hence, yaw control 'was provided by slightly inclining each rotor axis to generate horizontal thrust components to provide anti-torque moments. The three rotor configuration was foreseen by Belgian helicopter experimenter ...

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