How to Fly Your Quadcopter Like a Pro: 7 Important Tips

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Image Source: instructables

REMEMBER: You Will Discover 7 MOST Important Tips for Flying Your New Quadcopter or Drone! Number 4 Is Really Interesting! These Tips Helped Over 28,000 Readers!

Flying a quadcopter is much harder than it looks. While people love bragging and showing off their flying skills, new pilots often crash and burn a few times before learning how to really master their flying. The following tips will allow you to fly your quadcopter like a pro in no time.

1. Do Not Go to Manual Mode Too Fast

Manual mode is meant for expert flyers. When in manual mode, the systems put in place to help make flying easier will not provide the extra stability you need. This forces you to either be a great pilot or crash and burn in the process.

Manual mode, should by no means, be engaged unless you really know how to fly your copter. When you feel that it is time for manual mode, choose your practice location safely.

Learn how to fly at low altitudes at first until you understand manual mode, and then start flying higher.

2. Be Very Cautious of Windy Conditions

Wind is the downfall of most copters. If you notice that 10 – 20+ mile per hour winds are outside, you will not want to bring your copter out for flight.

There are some copters that have automatic correction for windy conditions and will adjust for the gusts of wind by altering the motor speeds accordingly.

As a general rule of thumb, you will also want to check the current mode setting of your copter. If the mode is set on indoors, you will want to switch it to outdoor mode for better overall stability and control.

3. Use GPS Mode if Available

More expensive models come with GPS mode. This is a mode that will use GPS to know where the copter is in space.

This is a great feature for precision flying or when you want to take video or images of a specific location and you really want to pinpoint the location on the map.

Furthermore, GPS mode provides great flight advantages that the beginner and advanced pilot will be able to take advantage of from their very first flight.

When in GPS mode, you will be able to take your hands off of the copter and it will balance itself and hover. This is ideal for pilots transitioning to be a pro. When you get nervous or you are unsure of what to do, GPS mode will correct your faults and allow you to take a deep breath before flight continuation.

GPS mode also provides the major benefit of knowing exactly where your copter is located. If a crash does occur, you will be able to find the wreckage much easier if GPS mode is active.

4. Fight Wind Gusts With Caution

You can fight wind gusts with caution. There are some higher end models that allow you to control the pitch of your copter so that you can negate the gusts of wind. This is done through what is called anegative pitch, but it is very advanced.

When wind is coming and you feel yourself losing control of the copter, you will want to fight the wind by pushing against it.

If wind is hitting the left side, you will want to attempt to fly into the wind to counteract the change in direction. The goal is to fight the wind if possible, but you must also know when to put an end to your flight.

As a rule of thumb, you don’t want your helicopter to be too far away from you in the event that wind blows it out of operating range. When possible, keep your helicopter close and land it if the wind is too powerful.

5. Keep Controls Simple

Up, down, left and right are the controls you want to master. Do not waste time trying to do rolls or advanced techniques until you have had months of flight experience. When you want to practice more advanced methods of flight, you should do so in optimal weather conditions. It is never a good idea to try doing a roll or flip for the first time when the weather is bad.

Keep all of your controls as simple as possible so that you can learn to fly the right way.

6. Master Hovering

Those that haven’t mastered flying will find that hovering is very difficult, but it is also very useful.

When you learn to hover, not only will you be able to take better pictures and videos, but you will be able to have full control over your copter.

A few tips on hovering are as follows:

  • Hoover 4 – 5 feet or higher in the air. When hovering too low, you can cause a disturbance from the force of the blades against the ground.
  • Maintain a proper throttle, pitch and roll to stay hovering in the same spot.

Hovering is very difficult and will take some time to master. Many models do not come with a pitch control. Instead, users will have the copter’s system control this part of flight.

7. Learn to Turn Off the Throttle

Crashing comes with the possibility of severely damaging your copter. When the copter crashes, you will want to learn to shut off the throttle as fast as possible.

This will stop the blades from rotating. When the throttle is turned off, further damage is prevented and there is less of a chance that the motors will suffer damage in the process.

While this may not seem like a pro tip, you must learn how to crash because it can and does happen quite a bit. Unfortunately, crashing will occur when you least expect it, so always ensure you are ready to cut the throttle in an instant.

As a pro pilot, you will also want to purchase propeller guards. These guards are small, easy to install and are ideal if a crash occurs. When the propellers are twirling, the guards will keep them from hitting the ground, trees or any other objects nearby.

Propeller guards will also provide you with further reaction time if the throttle is not cut fast or if the copter was pulled out of range by the wind before it crashed.

SOURCE: DRONEBLY

Working of Electric Motor

The electric motor is a device which converts electrical energy to mechanical energy. There are mainly three types of electric motor.

1) DC Motor

2) Induction Motor

3) Synchronous Motor.

All of these motors work in more or less same principle. Working of electric motor mainly depends upon the interaction of magnetic field with current. Now we will discuss the basic operating principle of electric motor one by one for better understanding the subject.

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Image Source : Electrical4u.com

Working of DC Motor

Working principle of DC Motor mainly depends upon Fleming Left Hand rule. In a basic dc motor, an armature is placed in between magnetic poles. If the armature winding is supplied by an external dc source, current starts flowing through the armature conductors. As the conductors are carrying current inside a magnetic field, they will experience a force which tends to rotate the armature. Suppose armature conductors under N poles of the field magnet, are carrying current downwards (crosses) and those under S poles are carrying current upwards (dots). By applying Fleming’s Left hand Rule, the direction of force F, experienced by the conductor under N poles and the force experienced by the conductors under S poles can be determined. It is found that at any instant the forces experienced by the conductors are in such a direction that they tend to rotate the armature.

Again, due this rotation the conductors under N – poles come under S – pole and the conductors under S – poles come under N – pole. While the conductors go form N – poles to S – pole and S – poles to N – pole, the direction of current through them, is reversed by means of commutator. Due to this reversal of current, all the conductors come under N – poles carry current in downward direction and all the conductors come under S – poles carry current in upward direction as shown in the figure. Hence, every conductor comes under N – pole experiences force in same direction and same is true for the conductors come under S – poles. This phenomenon helps to develop continuous and unidirectional torque.

Working of DC Motor Video – Click Here

Working of Induction Motor

Working of electric motor in the case of induction motor is little bit different from dc motor. In single phase induction motor, when a single phase supply is given to the stator winding, a pulsating magnetic field is produced and in a three phase induction motor, when three phase supply is given to three phase stator winding, a rotating magnetic field is produced. The rotor of an induction motor is either wound type or squirrel cadge type. Whatever may be the type of rotor, the conductors on it are shorted at end to form closed loop. Due to rotating magnetic field, the flux passes through the air gap between rotor and stator, sweeps past the rotor surface and so cuts the rotor conductor. Hence according to Faraday’s law of electromagnetic induction, there would be a induced current circulating in the closed rotor conductors. The amount of induced current is proportional to the rate of change of flux linkage with respect to time. Again this rate of change of flux linkage is proportional to the relative speed between rotor and rotating magnetic field. As per Lenz law the rotor will try to reduce the every cause of producing current in it. Hence the rotor rotates and tries to achieve the speed of rotating magnetic field to reduce the relative speed between rotor and rotating magnetic field.

Working of Induction Motor Video – Click Here

Working of schronous Motoryn

In synchronous motor, when balanced three phase supply is given to the stationary three phase stator winding, a rotating magnetic field is produced which rotates at synchronous speed. Now if an electromagnet is placed inside this rotating magnetic field, it is magnetically locked with the rotating magnetic field and the former rotates with the rotating magnetic field at same speed that is at synchronous speed.

Working of Schronous Motor – Click Here

SOURCE : Electrical4u.com

 

 

 

FLIGHT CONTROLLER – BEHIND THE MULTI ROTORS

Multi-rotors are unique in the world of R/C hobbyists. Usually, when it comes to controlling a model boat or plane, the pilot has absolute, precise control over the motor. A nudge of the throttle translates to a proportional increase in RPM. The same is true of input to the rudders, ailerons, flaps, and other parts involved in changing speed or direction.

The distinction with multi-rotors, whether or not advantageous, is that no human is capable of controlling the rotational speeds of three or more motors simultaneously with enough precision to balance a craft in the air. This is where flight controllers come into play.

A flight controller (FC) is a small circuit board of varying complexity. Its function is to direct the RPM of each motor in response to input. A command from the pilot for the multi-rotor to move forward is fed into the flight controller, which determines how to manipulate the motors accordingly.

The majority of flight controllers also employ sensors to supplement their calculations. These range from simple gyroscopes for orientation to barometers for automatically holding altitudes. GPS can also be used for auto-pilot or fail-safe purposes. More on that shortly.

With a proper flight controller setup, a pilot’s control inputs should correspond exactly to the behavior of the craft. Flight controllers are configurable and programmable, allowing for adjustments based on varying multi-rotor configurations. Gains or PIDs are used to tune the controller, yielding snappy, locked-in response. Depending on your choice of flight controller, various software is available to write your own settings.

Many flight controllers allow for different flight modes, selectable using a transmitter switch. An example of a three-position setup might be a GPS lock mode, a self-leveling mode, and a manual mode. Different settings can be applied to each profile, achieving varying flight characteristics.

Getting To Know Flight Controllers

DJI, arguably the dominant player in multi-rotors, produces two models. The Naza-M Lite is a high-quality, easy-to-set up unit with GPS and fail-safe capacities. Its Naza-M V2 is virtually identical, but includes a handful of additional features, such as the ability to daisy chain DJI expansions (a Bluetooth module, for example). Also, it allows up to eight motors, rather than six.

              DJI Naza Lite flight controller

 DJI Naza Lite flight controller

Multiple flight modes are available: GPS lock, altitude lock, orientation mode (moving forward always happens away from take-off point, regardless of craft rotation), and a non-stabilized manual mode.

The Nazas are the ultimate hobby flight controllers, with a multitude of features, optimized ease of use, and relatively straightforward setup. They may, however, no be the best choice for every multi-rotor. Let’s get into why.

SOURCE: TOMSHARDWARE

CFD – HEAT TRANSFER PROBLEMS

For many simulations of real world engineering applications, the predictions of heat transfer properties are as important, if not more important, than the actual flow field. Such scenarios include simulations of heat exchangers, HVAC (Heating, Ventilation and Air Conditioning), combustion/burners, electronics cooling, and many more. In these applications, we are often interested in how heat moves through both the fluid and solid domains, and importantly the transfer of heat across the interface between adjacent domains.

ANSYS CFD is a leader in solving all three modes of heat transfer: convection, conduction and radiation. Deciding which physics to include is critical to setting up an efficient CFD model. For instance, radiation provides a computational overhead but it is a very important heat transfer mode for bodies with high temperatures which radiate to cooler adjacent bodies or to a lower ambient temperature (since radiative heat transfer scales with Temperature4).

This image shows the heat that is convected away from a finned heat exchanger. As indicated by the streamlines, air is flowing from left to right in the image.

 

Conjugate Heat Transfer (CHT) is applicable whenever there are two adjacent domains and we wish to analyze the heat transfer between these domains. These domains can either be solid or fluid domains. One example is the forced or natural convective cooling of a heat-sink attached to active electronics components which generate heat.

As well as heat-transfer across solid-fluid domains, we can also resolve heat transfer across solid-solid domains and fluid-fluid domains. Solid-solid interfaces are used where two solid components are in contact with each other and there is heat flowing between the objects. Although a fluid-fluid CHT system may seem unphysical, it is a valid assumption in some cases, such as a co-flow heat-exchanger where two fluids are separated by a thin wall. In this case, it can be assumed that the heat-transfer across the dividing wall is calculated in the wall normal dimension only (without explicitly meshing the wall thickness), and there is negligible heat flow along the wall.

In all of the above instances, a thermal resistance can be applied to the interface in ANSYS CFD. Such resistances can be used to represent thermal coatings (often used in electronics applications) or badly mated surfaces between adjacent solids (to understand the tolerance of poorly designed connections).

 

This image shows a cross-section through the stream-normal plane of a finned heat exchanger. Heat is input to the system at the bottom boundary condition and is carried through the structure and out into the surrounding air.

For CHT simulations, it is critical to select appropriate boundary conditions that best represent the physical situation. ANSYS CFD provides a wide range of thermal boundary conditions, but also allows users to customise boundary conditions (using UDF’s or CCL Expressions) so that any heat transfer situation can be modeled.

One extremely important aspect of performing accurate CHT simulations is the wall adjacent mesh sizing, as accurately resolving the thermal boundary layer is crucial for producing reliable CHT results. To resolve the thermal boundary layer, an identical approach can used to when we are resolving the viscous boundary layer (for accurate flow separation, pressure drop, etc…), where we create high-aspect ratio prism or hexa elements stacked in the wall-normal direction (protruding into the fluid domain). Within the solid domain, however, there is no need to have such resolution (as there is no convection) so a uniform, coarser mesh can be used.

The use of Conjugate Heat Transfer simulation unlocks a range of simulations that can be performed using ANSYS CFD across industries including electronics, built environment and power generation. With proper training and knowledge, CHT simulations contribute an integral aspect of the Simulation-Driven Product Development approach that is being embraced by innovative designers and manufacturers worldwide. Contact LEAP today if you have an engineering problem where heat transfer is an issue.

Difference Between Gyroscope and Gymbal

GYROSCOPE

A gyroscope (from Greek γῦρος gûros, “circle” and σκοπέω skopéō, “to look”) is a spinning wheel or disc in which the axis of rotation is free to assume any orientation by itself. When rotating, the orientation of this axis is unaffected by tilting or rotation of the mounting, according to theconservation of angular momentum. Because of this, gyroscopes are useful for measuring or maintaining orientation.

Image Source : wikipedia

Gyroscopes based on other operating principles also exist, such as the electronic, microchip-packaged MEMS gyroscopes found in consumer electronics devices, solid-state ring lasers, fibre optic gyroscopes, and the extremely sensitive quantum gyroscope.[citation needed]

Applications of gyroscopes include inertial navigation systems where magnetic compasses would not work (as in the Hubble telescope) or would not be precise enough (as in intercontinental ballistic missiles), or for the stabilization of flying vehicles like radio-controlled helicopters orunmanned aerial vehicles, and recreational boats and commercial ships. Due to their precision, gyroscopes are also used in gyrotheodolites to maintain direction in tunnel mining. Gyroscopes can be used to construct gyrocompasses, which complement or replace magnetic compasses (in ships, aircraft and spacecraft, vehicles in general), to assist in stability (Hubble Space Telescope, bicycles, motorcycles, and ships) or be used as part of an inertial guidance system.

GYMBAL

Gimbal lock is the loss of one degree of freedom in a three-dimensional, three-gimbal mechanism that occurs when the axes of two of the three gimbals are driven into a parallel configuration, “locking” the system into rotation in a degenerate two-dimensional space.

The word lock is misleading: no gimbal is restrained. All three gimbals can still rotate freely about their respective axes of suspension. Nevertheless, because of the parallel orientation of two of the gimbals axes there is no gimbal available to accommodate rotation along one axis.

A gimbal is a ring that is suspended so it can rotate about an axis. Gimbals are typically nested one within another to accommodate rotation about multiple axes.

They appear in gyroscopes and in inertial measurement units to allow the inner gimbal’s orientation to remain fixed while the outer gimbal suspension assumes any orientation. In compasses and flywheel energy storage mechanisms they allow objects to remain upright. They are used to orientthrusters on rockets.[1]

Some coordinate systems in mathematics behave as if there were real gimbals used to measure the angles, notably Euler angles.

For cases of three or fewer nested gimbals, gimbal lock inevitably occurs at some point in the system due to properties of covering spaces (described below).

Difference Between Gyroscope and Gimbal

While there is a connection between a gyroscope and a gimbal, the fact is that the two devices are not identical. In fact, the gimbal is an integral part of the gyroscope. Without the use of the gimbal, the gyroscope would be much less effective.

The best way to understand the difference between a gimbal and a gyroscope is to define the nature and structure of both devices. Essentially, a gimbal is some type or base or ring that is mounted on an axis. The gimbal allows an object that is mounted on the base to move freely in any direction, so that the object remains in a horizontal position regardless of the angle of the base. This freedom of movement makes the gimbal an essential element in many devices that are used to measure momentum and directional orientation.

 

A gyroscope is one of the objects that makes efficient usage of the gimbal. Gyroscopes are composed of a rotor that is configured to spin around a single axis. Surrounding the rotor are one or more gimbals that help the device to maintain proper pitch and thus help to maintain inertia. This means that the gyroscope will often employ the use of both an inner and an outer gimbal in order to function properly. The outer ring of the gimbal configuration pivots around the axis and helps to maintain the level of force. The inner gimbal is mounted within the outer gimbal and pivots on an axis that maintains a consistent perpendicular relationship with the axis of the outer gimbal.

The function of the gyroscope would not be possible without the presence of a gimbal. One excellent example is with aviation. Because the gyroscopes are used to monitor or adjust the roll, pitch, and yaw of angles during flight, the devices are essential to maintaining the force and directional control needed to successfully fly from one location to another. Without the balance created by the gimbal, the gyroscope would not provide this type of data and would serve no useful purpose.

SOURCE :WIKIPEDIA,  WISEGEEK ,

Composite – Prepreg Basics

Take some composite reinforcement, such as carbon fiber mat, lay it out and saturate it with a thermoset resin. What you have then, in the uncured state, is prepreg. Sounds simple? Well, just think about the practical problems – for example shelf life. Resins cure once they have the catalyst or hardener has been added, so how is curing of a prepreg prevented?

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Image Source : EASYCOMPOSITE

There are two approaches, both aspects of the same solution – thermal control.

Prepreg resins are specially formulated so that they cure very slowly or not at all at room temperature. If they are then stored in refrigerated conditions then curing can be halted completely.

The length of time the prepreg can spend at room temperature before partial curing prevents practical use is known as the material’s ‘out life’.

The freezer storage time of a prepreg without affecting practical use when thawed-out is known as its ‘freezer life’ or ‘shelf-life’.

Complex Curing

The second approach is to cure the shaped prepreg product (say a rowing scull) at a high temperature – in a pressurized oven. These special ovens are called autoclaves. Clearly there is a practical limit to the size of oven that can be economically built. The largest of autoclaves can cure massive sections of airplanes.

The curing process can be complex. Here are the instructions for curing a specialized commercial prepreg used for tooling:

30 minutes at 300°F/150°C, then 4 hours 350°F/177°C followed by 6 hours at 383°F/195°C

This kind of process is hardly practical for the average DIY person building a skateboard, but nevertheless prepregs can be used in the home workshop – and the kitchen too as a domestic cooking oven can be used for some home projects.

Voids

When multiple layers of prepreg are required in a structure, then there is a risk of voids being introduced between the layers. For example, aerospace requirements dictate less than 1% void content in composite structures and components.

Vacuum bagging is used during manufacture of the prepreg, but to minmize inter-layer voids then then lamination should also be vacuum bagged if void content is a concern.

Why Use Prepreg?

The convenience of using prepreg is considerable. Prepreg is easy to handle and depending on its ‘tackiness’ it is to place in a mold and sticks in place.

It can be bought ready to use, so there is no resin mixing and no ‘wetting-out’ to be done. This improves the quality and consistency of the finished product (saturating the mat with resin – ‘wetting-out’ – is usually done using a vacuum bag by the manufacturer). For example, aerospace requirements dictate less than 1% void content in composite structures and components. The result is that in the finished product surface blemishes are almost entirely eliminated and weak spots due to resin voids are likewise minimized.

Why People don’t use Prepreg

The key reason is practicality. This can be because the structure is too large for an autoclave, or simply than it is impractical to keep the material in a freezer and on-site mixing is necessary.

Also cost, prepregs generally cost more then the same dry fiber and a similar liquid resin.

In some applications – for example in satellites – any void at all can cause cavitation damage when the structure is itself used in a vacuum and the pressure in the void blows out into space.

The Future of Prepreg

The key problem with prepreg has been the need for the autoclave, making it uneconomic for large structures. However, research into Out-of-Autoclave (‘OOA’) techniques is now starting to change the picture. Using Vacuum-Bag-Only (‘VBO’) curing processes at near-ambient temperatures, we should soon have the technology to make prepreg economic and practical for building airplanes (as opposed to building components).

SOURCE : COMPOSITEABOUT.COM