Which drone do I need for my camera, what do I need to pay attention to when building my drone? Which motors fit on this frame? Which battery do I need? Does it all fit together like this?
We receive these and similar questions every day.
In this guide we want to share our experiences, tips and tricks to help in successfully putting together your first drone.
!! New !! – Configurator – Step by step to the right multicopter setup
We have received a lot of positive feedback about our guides. Many customers have already implemented our tips and recommendations and were able to realize their own multicopter. In order to be able to help interested parties even better, we have created various configurators with which suitable setups can be put together piece by piece. The configurator automatically checks whether z.B. the propellers fit on the frame or whether the selected motor can be operated with the desired voltage. This way you can avoid wrong purchases and achieve optimal results.
Three different configurators have been created for better clarity. The first two are configurators for Tarot Quadcopter as well as Tarot Hexacopter frames. The third configurator is aimed at commercial customers and contains the complete T-Motor range of larger motors, carbon propellers and controllers.
Benefit also from a discount when buying multiple items.
Updated on 18.03.2020
Table of contents – DIY of a drone
1. Drone Definition:
1.1 What is a drone?
1.2 Drone / Multicopter / FPV Racing / Quad? What is the difference?
Often the question arises: what is the difference between an FPV guide and a pilot guide? Drone and a Multicopter and is a Quadcopter something else again?
Multicopter means from the term that it is a model with multiple rotors, so it can be a Tri, Quad, Hexacopter or Octocopter act. How these models look exactly and are built up we explain in the point 2.1. The term is thus generally held and does not designate an exact design.
Especially in the English-speaking world "drone" Synonymous with both military and model aircraft, where the term "multicopter" is used rather rarely used. The press has now taken this up and refers to all types of model multicopters and toys as "drone". Also more and more manufacturers advertise their product as a drone. At the beginning of this development, many modelers were critical of this trend because they feared that a hobby and free product would now be associated with military products.
Due to the increasing popularity of FPV Racing or also FPV Drone Racing However, the term is now more and more characterized by the idea of sports. Since these are often international events, the term "drone racing" also dominates there. FPV Racing means smaller models (mostly quadcopters with a diameter of less than 30cm), which are very strongly motorized and are flown purely via the camera image. The pilot permanently wears FPV goggles and flies the model from the pilot’s perspective instead of by sight. The competition is flown with several pilots on a course marked out by obstacles and markings.
Mini Quad and Mini / Micro FPV Racer are particularly small FPV racers which can also be used indoors.
2. Which drone suits me / my intended use?
The article described here focuses on building and assembling a video copter, i.e. a drone intended for image and video capture. Of course, the procedure can also be transferred to a drone without a camera or a drone with a different payload.
If you want to build a FPV racer, you can use some of the basic calculations and tips as a guideline, but the procedure for putting it together is different, which is why we will cover the topic of putting together an FPV racing drone in a separate article.
2.1 What types of drones are there?
The main feature to distinguish the type of drone is the number of motors / propellers used. The number of motors is then equally name-giving for most models:
2.1.1 Quadcopter:
The type that is seen most often is the quadcopter, which is often also called a quadrocopter. This term is derived from Latin (quadrum is the square). As the name suggests, the quadcopter has four motors and four propellers aligned on a single plane. The logical consequence of this arrangement is a quite stable flight behavior. Two motors opposite each other rotate counterclockwise, or in the opposite direction. rotate clockwise.
There are two different designs. The X-design (the motors are arranged in an X ) and the + Type of construction (motors are arranged in a +). The disadvantage of the + design is, however, that when a gimbal is mounted, the front arm is in the way and may interfere or even be visible in the picture-Variant used. Disadvantage of all quadcopters is that there is no failsafe at all. If one motor fails, this inevitably means a crash, as the remaining three motors can no longer stabilize the drone.
Quadcopter in X Design and quadcopter in design
2.1.2 Hexacopter
Another type of multicopter represents the hexacopter. The syllable Hexa comes from the Greek and stands for the number six. A hexacopter is therefore a drone with six motors and six propellers. Here, too, all motors are arranged on one plane. Due to the higher number of arms, motors and propellers, the total weight of the drone is usually higher. This in turn leads to a higher possible payload and to a smoother flight behavior, in comparison to the quadcopter.
Often in connection with hexacopters is spoken of an increased redundancy. This is to be understood in this way: If one has a higher number of motors and propellers available and uses a special flight control system, then in the event of a failure of one motor, this failure can be compensated for with the help of the other functioning motors. As with the quadcopter, there is also an X and an I design, whereby the I design is hardly ever used because of the arm in the picture.
hexacopter in X Design and Hexacopter in I Type
2.1.3 Octocopter (Flat 
and X8 (Coax design)
and X8 (Coax design)If the number of motors should be even larger we are in the area of the Octocopter. The syllable Octo comes from the Greek language and stands for the number eight. Accordingly, we are dealing with a mulitcopter with eight motors and eight propellers.
With a Flat 8 sind again all motors mounted on one plane. Four motors rotate clockwise and four motors rotate counterclockwise. Again, there is the possibility that the arms in a V or a I are arranged, whereby the V-construction form is clearly more frequently found. Usually octocopters are muliticopters with a rather large frame.
The disadvantage of a Flat 8 is the enormous space requirement because the arms must be accordingly large, so that the propellers do not graze. Sizes of over one meter are not uncommon here. This type of drones are therefore often used in the professional field. Due to the large number of motors we have here again a particularly quiet flight behavior and large payload possibilities. The principle of redundancy mentioned earlier is also given here in conjunction with the correct flight control system. A typical application would be, for example, the transport of a large camera for recording purposes.
As a special form there is therefore the X8 which has a Coaxial design that means that per arm one motor is mounted on the top and one on the bottom, whereby the propellers (and the motor) of the bottom motor point towards the ground. So basically it is two quadcopters mounted on top of each other. Advantage is the space saving as only the dimensions of a quadcopter are needed. Disadvantage is a loss of efficiency because the propellers are fully in each other’s airflow. Also the calculation of the propellers is not so trivial. Another problem is that the lower propellers make a retractable landing gear problematic and may also obscure the camera image in some circumstances.
Octocopter Flat 8 in V and I design as well as X8 in coaxial design
Special forms – Tricopter and Y6:
In addition to the models mentioned so far, there are also some special models that have evolved over time but are rather special models or are intended for special applications.
As a special feature here z.B. a tricopter, i.e. a model with only three motors. These models were used more frequently, especially in the early days of multicopter development. For stabilization, this variant uses a movable tail motor, which is then swiveled and also controlled by the flight controller.
Based on the tricopter, there is also a coax variant, namely a Y6 as well as an IY6.
The Y design has four motors at the front, the I has two. The I type is rarely seen in the picture due to the annoying double motors, but the Y6 is still being used by some providers.
Y6 Copter in IY and Y design
2.2 What are the applications?
The reasons and motivations for choosing a drone are incredibly diverse.
In general, a distinction must be made between private and business or. professional purposes must be separated.
In the private sector, hobby pilots usually opt for a drone, as they are either enthusiastic about FPV sports or want to make landscape shots in the form of photos and videos of your region or but on vacation.
In the professional field, great results can also be achieved in terms of video recordings. Photographers as well as the film industry like to use drones to shoot aerial shots, commercials or film clips. Often enormous savings can be realized here, since a helicopter employment can be renounced.
Other industries such as architects, realtors, surveyors and surveyors can also benefit from aerial technology. In this way, real estate and property areas can be explained to the customer from a different perspective.
Furthermore, all technical facilities such as high-current pylons and wind turbines can be safely controlled from the ground with the help of a drone.
Another important contribution to safety can be made by drones in operations of the police, fire department and THW (German Federal Agency for Technical Relief).
Drones also play an important role in research and science. Many institutes, universities and colleges have already been researching this for quite some time.
Even in the midst of nature there is a wide range of applications for drones. Whether in agriculture to control pests, such as the corn borer, which is controlled with the help of ichneumon wasp larvae distributed by the drone at regular intervals in a field, to use in hunting grounds to track down wild boar damage.
Also associations and honorary office use drones increasingly. A particularly good example is clubs that use drones equipped with thermal imaging cameras to detect fawns so that they can be brought to safety before a farmer mows them down.
The areas of application for drones are incredibly diverse. For almost any purpose a drone can be built and then used.
However, it is always important to handle a drone responsibly and carefully to avoid endangering others in any case.
3. How hard is it to build a drone? – Can I use the whole thing at all?
The desire to build a drone yourself or. The desire to assemble a quadcopter by themselves is awakened and many interested people are confronted with the question at the beginning: Can I do all this at all??
In general, there is a lot to be said for doing it yourself: It’s fun, you can repair and replace parts yourself in an emergency, for example after a crash, and you can decide for yourself exactly which components you want to use.
Of course, a hobby workshop or a basement is a good prerequisite and brings in many points, especially in terms of space and the availability of machines and equipment with certain advantages, especially if z.B. a larger self-build is planned.
Nevertheless, drones in the form of kits and the additional necessary components such as motors, controllers, propellers, etc. can also be purchased, . can be assembled well and flown afterwards even without these prerequisites. A work table and some space are perfectly sufficient.
Help if you are stuck at home or unsure is now available, especially due to the increasing popularity of the hobby, many.
We recommend: Always prefer to ask and inform yourself, for example, if you are not sure about the connection of components. Unfortunately it is so that by a small carelessness an expensive damage can develop.
In general, we as dealers are always happy to advise on the selection of components both before the purchase. Even after the purchase, customers are welcome to contact us with questions.
There are also many YouTube videos and tutorials on the Internet, which can be very helpful, especially for technically more complicated products. A good and meaningful video, which shows step by step the procedure is far ahead of a manual on paper. Furthermore, there are very recommendable blogs and forums that deal with almost every conceivable product. Just google it once.
In any case, flying with like-minded people in a club is also useful. There you can quickly overcome hurdles together with friends and learn a lot from others.
We wish you much joy in your new hobby!
4. Which components are installed in a drone?
At this point, we would like to give a brief overview of the components installed in a drone. In the later course of construction, the components are individually illuminated in detail.
The basis for all other components is the Frame or also called frame. It serves to attach the components sensibly and also contributes significantly to the appearance of the drone. A frame should be stable and light. For this reason, many frames are now made of carbon.
Another important component of the drone are the installed Motors. So-called brushless motors are used in multicopters. The selection of motors is now enormous and ranges from a few grams heavy micro motor to motors with over 1kg dead weight.
On the motors Propeller mounted. The number of propellers corresponds to the number of motors. However, with the propellers you have to make sure that, for example, with a quadcopter there are always two left-turning propellers and two right-turning propellers and that they are mounted correctly. Propellers are available in many different materials. Inexpensive propellers are made of ABS, nylon or GRP compounds, high-quality (and larger) propellers are made of carbon.
Under one controller or an ESCs is an electronic component, which sends signals in a special sequence to the installed motors, so that they rotate. One controller is used per motor.
In order to supply the drone with energy, a battery is neededn Battery needs. Become almost exclusively LiPo (Lithium Polymer) batteries used. At this point, it should already be pointed out that responsible handling, as far as storage and use is concerned, is absolutely necessary.
To control the drone requires a Flight control or. of a flight controller. The main task of this component is to stabilize the drone and to control the motors and controllers.
The Receiver has the task to receive the signals of the remote control and to forward them to the flight control.
Gimbal with camera. A gimbal is a frame in which the camera is mounted. The gimbal stabilizes the camera during the flight so that shake-free images are possible. There are also models which can be additionally controlled by remote control, so that the pilot can turn and pan the camera during the flight.
Furthermore, some other components are needed, which make the flight of a drone possible, but are not directly "on board". To mention here would be a Remote control, a Charger and for example a FPV monitor or a FPV goggles.
5. What other tools do I need?
The main tool used to assemble the frame is a screwdriver (mostly Allen). Also a pair of pliers, tweezers and a side cutter are helpful to hold something in place or to shorten a cable or a cable tie.
Almost inevitable is also a soldering iron with accessories. The soldering work is relatively simple because often only cables must be soldered together or a cable is soldered on a circuit board. Nevertheless absolute beginners should first practice on a pair of "sacrificial cables" before ggfs. the new brushless controller is damaged by too much heat or incorrect use.
Especially with screwdrivers you should pay attention to quality, if you build something often. Nothing is more annoying than a scratch in the carbon frame or a screw that has been unscrewed because the screwdriver did not fit 100% or the pliers do not close properly.
It does not have to be a workshop trolley from Hazet or Gedore 
A solid basic equipment of screwdrivers, pliers as well as soldering iron, tweezers etc. are completely sufficient.
Also a small hot air gun facilitates with more frequent work the shrinking of components with shrink hose clearly.
6. Step by step assembly of a video drone
6.1 Define the purpose of use and set the budget:
6.1.1 What exactly do I want to do with the drone??
At the beginning there is a clear definition of the purpose of use. Is it merely a "taster excursion" into the world of multicopters? Maybe I am already a fixed wing pilot and would like to try something new? Or am I looking for a professional solution for a specific application??
6.1.2 – 10 points to define my intended use:
For us, the motto is: the drone must fit the user and the purpose of use.
For this reason we have come up with a 10 point catalog. The customer should deal with these 10 points in order to be clear about what he personally wants or wants to do. so that we know what kind of drone we are allowed to offer.
Let’s start with Dimensions of the drone. Here it requires a few considerations how the drone should be transported later on. Should this be transported in a special case or loose? Must this possibly. foldable, so that it fits for example in the trunk of the car? Where do I store the drones safely at home??
The maximum takeoff weight: Here it must be clarified exactly whether a certain weight or a limit must be kept. For example, due to current developments, the 2 kilo limit should be pointed out.
Which Payload in grams should be made possible? At this point it must be considered with which additional components the user would like to equip the drone immediately or also in the future. Here, for example, a gimbal and a special camera are mentioned quite classically.
Type of payload: For some users, the payload goes beyond the addressed and classic components like a gimbal and a camera. In agriculture, for example, a box of ichneumon larvae with a certain weight must be included in the payload. Many different payload components are conceivable.
To suit the intended use or personal preferences, there is the point of Desired features and special options. 6-axis stabilization is now standard, but the customer might want GPS, good image stabilization in the form of a gimbal, an electric landing gear and a carbon frame, for example. In addition, accessories in the form of a remote control are desired and existing components should continue to be used. This point is very important in order to equip the drone sensibly and comfortably for the user.
The Frequency of useDo I use the drone very often, for example daily or several times a week on the job or do I fly only now and then and can choose the time of flight in the final effect? This point is also very important, for example if the components are subject to heavy wear and tear so that spare parts can be purchased if necessary.
Especially if the drone is to be used frequently or commercially and corresponding values and expensive camera equipment has been installed is the point of Reliability particularly important. Here, for example, a model and components with a high degree of reliability can be used from the outset. Furthermore, safety systems such as autonomous landing in case of low battery or return to home (RTH) in case of a connection failure can be integrated.
For many applications, the setup of the drone often revolves around the point of the Desired flight time. For example, you need the number of minutes x to fly a certain distance or area with one battery charge. Furthermore, perhaps a certain range or flight distance is necessary.
The principle Upgradeability: Would you like to. Initially still without gimbal and camera start should still think carefully before buying, whether this might not be a possibility in the future. Better one dimensions the threat for the beginning her something over and has then later nevertheless still the possibility for an additional payload to decide. This can then, if possible, be implemented relatively unproblematic.
Another important point is the Budget. How much can I or do I want to spend on the drone? Possibly. certain preferences? For example, I want very good engines if possible, but am happy with a less expensive frame. We have summarized all these considerations in a 10 point catalog which forms a basic framework and on the basis of which first preliminary considerations can be made.
10 points to define the application purpose of a drone
- Dimensions:
- Maximum takeoff weight:
- Desired payload in g:
- Type of payload:
- Desired features / special options:
- Frequency of use:
- Fail-safe:
- Desired flight time:
- upgradeability:
- budget:
6.2 Are components already in place or is it starting from "zero"?
Here is of course again to distinguish whether one enters very freshly into this hobby or evtl. is already modeling.
In this point must be weighed naturally always whether it makes sense to continue to use the components or whether one should rather be changed to better suitable products.
A charger (if sufficient from the data) is usually very durable and can be z.B. are often still used.
Even a remote control that was previously used for model airplanes or helicopters usually offers enough channels to be used without any problems. In any case, it should already be a 2.4Ghz model. Alternatively, there are z.B. also from Frsky very good transmitters and inexpensive transmitters with which many functions can be covered.
With batteries, on the other hand, it should always be checked whether they really fit the application or whether a new acquisition is not more sensible to use the full potential of the drone. It is z.B. it makes little sense to try to plan the new 1 meter octocopter around a pair of small 5 year old 3S lipos, here you would simply limit yourself too much and make unnecessary compromises right at the beginning.
6.3 Which remote control do I need?
On the subject of suitable remote control, you can certainly write a separate article, we will only briefly discuss the possibilities here and focus more on the pure multicopter.
If we assume the pure flight function without additional options, a transmitter with at least 6 channels is sufficient for the beginning.
If camera, FPV, dropping, landing gear, are to be added, of course a larger transmitter is desirable. We use very gladly remote controls of Frsky here there are already very inexpensive qualitatively high-quality transmitters which do not need to be afraid also the price comparison with clearly more expensive models.
For beginners would be z.B. the Q X7 is a possibility:
FrSky Taranis Q X7 in the color black
Or alternatively the Taranis X9D+ or the X9D+ in the Special Edition:
FrSky Taranis X9D+ Special Edition 2019 with ACCESS in the color Carbon Fiber
If you want to learn more about FrSky remote controls, we recommend our very detailed FrSky product guide. There all Frsky Taranis remote controls are presented in detail. In addition we offer always current tables, which compare the individual features of the remote controls (z.B. Number of switches, special functions, scope of delivery. ), so that the decision in the selection is considerably facilitated.
6.4 How much thrust is needed at all for a drone to fly?
In contrast to a model aircraft, a drone must always take off vertically, and the frame does not provide any lift. Therefore, it is not surprising that a much higher thrust-to-weight ratio is needed.
What is a thrust-weight ratio at all??
The thrust-to-weight ratio indicates how much thrust is available in relation to the weight. So with a weight of 2kg and a thrust of 2kg the ratio would be 1:1. With a weight of 2kg and a thrust of 4kg, the ratio is 2:1, etc.
From a ratio of slightly above> 1:1 you would theoretically take off and could hover (external influences like wind, etc. once faded out). However, this is still not sufficient for a climb with reserves. For a videocopter you are well advised with the rule of thumb 2:1, d.h. there should always be at least twice as much thrust as takeoff weight available.
Innovations in the field of brushless motors and LiPo battery have made today’s drones flyable in the first place. There are two points to consider which are due to the operation with a battery: First, in contrast to a man-carrying kerosene-powered airplane or helicopter, the ratio does not increase further due to the emptying tank, but actually decreases, since during the flight the voltage of the battery gradually decreases until the shutdown limit is reached. On the other hand LiPo batteries are also dependent on the outside temperature. In a cold environment these are less powerful. And of course, weather influences such as z.B. Wind plays an even greater role in a model than in supporting aviation.
Rule of thumb for the thrust-to-weight ratio of video drones:
As a rule of thumb, a thrust-to-weight ratio of at least 2:1 is recommended for a videocopter.
6.5 Can I oversize my drone??
This is a question we also receive very often. While browsing our website, z.B. found a large 810 or 900 Tarot frame which is visually very pleasing to the customer. After we have clarified the purpose of the pan, it turns out that a much smaller model would actually be perfectly adequate, since z.B. at first no and later only a small action camera is to be transported.
In principle, you can also use a 10kg octocopter to transport a GoPro with gimbal, but you buy yourself a few disadvantages.
On the one hand, a frame of this size has to be of a stable construction, which inevitably entails a certain dead weight. This automatically requires larger motors, propellers and controllers. In order to operate the whole thing, larger batteries are needed, which of course also require a suitable charger in order to be charged in a reasonable time.
A jump into a larger copter class therefore entails all sorts of things.
Our recommendation is therefore always a certain reserve with to plan around if necessary. to cover future applications as well, but we would not recommend a complete overdimensioning.
Apart from the additional budget, you may also have other disadvantages. Here also the legal conditions are to be mentioned, so that the customer with a too heavy Copter would limit itself under circumstances strongly in the use, without this would be necessary.
6.6 Our tip: Always start with the payload / application:
After we have already gained a good overview based on the 10 points, a rough picture of what our drone "must" be able to do and which features would be desirable already arises automatically.
Our recommendation is to always start with the payload or the desired application, here the car purchase is a good comparison. If I need a lot of trunk volume, a station wagon or SUV is more suitable than a convertible.
The planned payload gives us above all also other important basic data, which are to be considered, like z.B. ggfs. a necessary ground clearance to mount a desired gimbal, space requirements for additional components such as sensors, rescue parachute, dropping device, etc.
7. Sample calculation of a drone based on a practical example:
In order to make the whole topic more tangible, we now assume that we have a customer inquiry which was supplemented accordingly to this data in the customer meeting:
Sample data for our example:
- Dimensions: no matter
- Maximum takeoff weight:<5kg
- Desired payload in g: ca. 500g-700g
- type of payload: Gopro camera with gimbal
- Desired features / special options: RTH, carbon frame, FC with GPS, electric landing gear, FPV transmission and gimbal controllable
- Frequency of use: hobby pilot
- Failsafe: if possible hexacopter desired
- Desired flight time: at least 15 minutes
- Upgradeability: should be given
- Budget: max. 1500 Euro for everything (incl. Remote control and accessories)
Based on this information, we can now make all further calculations to assemble the appropriate components. We have chosen a relatively common example to cover as many points as possible so that the considerations can also be applied to your own setups.
7.1 The first thoughts about the setup:
But now to the construction of the actual drone. From the application purpose and of course to a certain extent also from the budget, the first step in the direction of a self-built drone now arises.
From our application definition we know z.B. Well, that the transport in principle would be no problem and we must remain from the weight but in any case under 5kg. A gimbal should be mounted and an electric landing gear is desired.
We know that in all calculations at least the 700g desired payload must be taken into account and that we now have a maximum of 4.3kg available for the actual copter.
For the further steps there are now different procedures. Since we can of course fall back on the experience of various previous setups, we already have an idea of what would come into question for this customer and do not have to start from scratch with the calculations.
Often the customer has also specified a certain component such as z.B. A frame, engines, etc. in mind and would like to use them. Of course we are happy to comply with this request, as long as a suitable setup can be calculated.
But let’s assume that all possibilities are open and only that a hexacopter frame is desired:
From our thrust rule of thumb, we know that for max. 5kg 10kg thrust would be optimal to achieve a ratio of 2:1. Whether we have to fully utilize the limit or whether the frame will be significantly lighter is not yet known at this point, we have only determined the key points once.
Using the key data, we now work our way through the components to calculate the optimal setup.
However, we are first faced with a problem
We know the maximum weight and the required thrust, but we have no idea if the whole thing can be realized or not. whether there are suitable components with which such a drone would then be flyable or whether we would then be significantly above the weight limit with a suitable battery.
Also in the other direction we don’t know if maybe a suitable setup could be realized already with 3kg and we don’t need that much thrust at all.
Of course it is also clear that for 10kg thrust very probably other motors are needed than for 6kg thrust and the weight of the motors in this case also differs and influences our total weight accordingly.
So we have established that there are several dependencies between the components which can all influence each other, a classic circular relationship.
So what to do?
Our recommendation is to first look at known setups to get a rough feeling for which components are used for the desired application and what these components can do. weigh.
Also rummaging in our Complete sets is very helpful here. Evtl. there is already a setup that meets our requirements and suits us?
Once you have looked at some frames and motors it quickly becomes clear what a frame of a certain size ca. and how many grams of thrust a motor with 100g own weight can achieve, this helps us to better narrow down the components and makes it easier for us to search later on.
The selection of a setup for multicopter is not a linear process:
It is also important to note that the whole procedure is not a linear process, but often several passes are needed to find the most optimal solution, as there may be some differences between the two. only during the consideration shows that another component may fit better, or important points otherwise could not be met.
7.1.1 payload considerations:
We assume in our consideration once that a GoPro Actioncam is already present and only a suitable Gimbal is needed.
For our example, we decided to use a GoPro gimbal from Tarot.
Tarot TL3T01 GoPro Gimbal
With Gimbal and GoPro (and some reserve for cables etc.).) we are now at approx. 300g. The remaining 400g the customer would like to plan as reserve around ggfs. to use telemetry sensors and additional modules or to be able to use a larger camera for a change.
For other payloads such as z.B. Thermal imaging cameras or drop mechanisms (z.B. corn borer) other starting points apply of course. Important factors besides the weight, however, are above all the mounting position and the required ground clearance.
7.1.2 The choice of the design and the frame:
The frame is the basic construct and also significantly determines the weight of the complete drone, on the one hand by its own weight, but also by the components that automatically fit this frame and their weight.
To take up the vehicle analogy again, it makes a difference whether I’m looking for suitable tires and an engine for a Smart or whether the components are to be mounted on a truck.
In this guide we will not go into special shapes like Tricopter or Y6, but rather concentrate on the most common variants.
From manufacturer to manufacturer, the construction of a multicopter frame of course always differs slightly, but the following basic construction can be found in most models:
The Frame or also Frame usually consists of two frame parts Centerplates which form the top and bottom of the frame. Between the centerplates the arms are mounted with mounting blocks. For models with foldable arms, there are then still holding blocks or joints which lock the arms in the respective position. Some frames have a distribution board directly integrated in the centerplates, so it is basically one big board which provides soldering points for the distribution of the voltage. On other frames a distributor board is used otherwise.
Tarot models offer two rails at the bottom which can be used as a mounting rail for the use of a gimbal or the mounting of a battery pack. With other manufacturers, the gimbal is also directly screwed to the lower centerplate.
The end downwards is a landing gear. Most models rely on two arms with skids (tees) on the bottom, as this solution is easier to land than z.B. with three or four single legs.
Since the specifications for our sample Hexacopter, carbon and electric landing gear were we here in any case already once a good starting point.
At this point it makes sense to look at the market to see what frames are available that meet these requirements. Many frame manufacturers have also often already published valuable data such as.B. the pure frame weight the maximum mountable propeller size, diameter from motor to motor, ground clearance with extended landing gear, and sometimes even recommendations for a setup or information on the maximum payload.
To stay with our example we have now looked at different frames and found the following hexacopter frames:
Tarot TL6X001 Hexacopter
Here it quickly becomes clear that this is a relatively large model. The pure frame diameter is already just under one meter and the weight is 2.3kg. Also the maximum propeller size of 18 inches (ca. 45cm) make the later dimensions clear. Together with our planned payload, we are now already at a weight of 3kg without further components. The experienced drone builder will probably already recognize at this point that this frame is a number too large for the desired application purpose. The Beginner found after a Google search some videos and construction reports with this frame which transports up to 3kg payload and was at a takeoff weight of about 10kg.
It is not yet clear if we will be able to keep the 5kg limit, but as mentioned in the point Oversizing described above, it makes sense to check if there is a more efficient solution.
So let’s look further.
We liked the design of the frame from Tarot, on further searching we have now found a small model with just under 70cm frame diameter and 780g frame weight:
Tarot 680 Pro Hexacopter
The electric landing gear is not included with the frame itself, but we found it among the accessories as a retrofit kit:
Tarot TL65B43 – Electric landing gear conversion kit
The conversion parts add another 90g to the bill which brings us to a pure frame weight of approx. 870g lie. With the further search we found out that GoPro Gimbals are mounted on this frame with pleasure, the whole looks thus already once well and the frame seems in any case stable enough for our project.
Let’s summarize briefly at this point:
Hexacopter design ✔
Carbon frame ✔
Electric landing gear ✔
Designing the frame for the desired payload ✔
Ground clearance for mounting the gimbal ✔
7.1.3 Choosing the right drive for our drone:
7.1.3.1 – A: Preliminary considerations and technical background:
So now we come to the next important points: How do I lay out the rest of the drive to match the frame and the desired payload or. my resulting total weight from?
What variables can we influence when selecting a drive??
Before we get into the selection of the drive components a little digression is necessary.
Also with the choice of the drive there are again variables which are subject to mutual dependencies.
Variables that can be influenced by us are:
Voltage of the used battery (measured in volts)
Propeller diameter (measured in inches)
Motor speed (speed without load, measured in kv)
Weight of the components used (measured in g)
This results in the following assessment variables for us, on the basis of which we can evaluate the respective composition:
Maximum thrust and thrust in hover (measured in g or kg) => Measured variable to check if our setup is operational
Efficiency of the propulsion system (measured in thrust (g)/ Watt) => Metric to check if our setup is working efficiently.
However, a big advantage is that the manufacturers have already done a lot of the work for us and publish measurement data on the motors.
First of all it is important for us to evaluate the maximum thrust to make sure that the motor is suitable for our project. Only in the next step we will think about the efficiency and the optimization of the flight time (it would be for us z.B. not helpful to know that a motor may achieve very good efficiency, but unfortunately cannot even deliver 50% of our needed thrust at all).
From example setups we have seen that for our Tarot frame the takeoff weight was usually always between 3-3.5kg. Let’s plan some reserve and assume 4kg. With a thrust-weight ratio we would thus be at 8kg of required thrust (if we had no clue at all we could also go with the maximum, i.e. 5kg of weight, or. 10kg thrust plan). To achieve 8kg thrust with 6 motors we now simply divide the total thrust by the number of motors to get the maximum thrust per motor:
8000g / 6 motors = 1333.33 g required maximum thrust per motor
How to calculate the required thrust per motor?
Required total thrust / number of motors = single thrust per motor
Or converted to calculate the total thrust for a desired engine:
Number of motors * single thrust = total thrust
In order to narrow down the choice of motors, we now roughly sort out which motors are out of the question on the basis of the thrust values. is already clearly too large.
The weight of the engines and propellers is usually directly related to their power values. So we will z.B. not find a motor that can produce twice the thrust for the same weight (and equal or better efficiency values), so we can influence the weight variable only indirectly. It is important to note that the 2:1 is only an empirical value and not set in stone. Even a setup with 1.85 or 1.9 can be flown without problems. it can be deduced that an engine with z.B. 1300g thrust does not have to be sorted out directly, especially since we do not yet know the exact take-off weight.
Based on the measured data of each motor we get an overview which (reasonable) combinations of motors, propeller and voltage there are to achieve a desired amount of thrust.
Example measurement data of a T-motor MN3510 with 700kv
Here is an example of the measurement data of a T-Motor MN3510 700kv motor, by which we will explain all the necessary values in detail:
On the left is the model type and KV number, then the different voltages measured (11.1V and 14.8V) and the propeller sizes measured in each case with the power ratings and temperature at different measurement points.
So basically it is two tables one below the other one for 11.1V and one for 14.8V.
Before we get into the selection, a short note about the calculations:
Relationship of volts, amps and watts:
Often we receive requests like:
I am looking for a motor with xxx watts, do you have something like that??
As many may still know from physics lessons, the electrical power is calculated from the product of voltage and current (P = U * I)
Let’s take the following line from the table above:
14,8V T-motor 13×4.4CF 50% 4.7A 70 Watt 730g 4300 RPM
We are looking for Watt(P) = 14,8V * 4,7A
With the values used we get 69.56 watts which is rounded to the 70 watts given by T-Motor.
The power (Watt) is always a product of voltage and amperes and is not a constant output quantity. So a motor has at a certain load (here in the example 50% thrust with a 13 inch propeller) a power of 70 watts, when using another propeller, other % thrust, etc. the performance is again completely different.
When looking through the motors in our store, it is noticeable that there are several versions of some models, which at first glance appear to be the same in terms of weight and dimensions, which differ only in the KV number (of the MN3510 mentioned in the example, there are z.B. a 700kv, 630kv as well as 360kv version).
What does KV mean for brushless motors?
For example, a motor with 700 KV turns 700 revolutions per minute per volt. It is always the no-load speed without load.
When running on 4S Lipo (16V) such a motor would have an idle speed of 16 x 700 = 11200 rpm.
So the KV number indicates with which speed the motor would run per volt (and without load). To make the whole thing clearer, we can take a look at a simple example: Let’s assume that there is another model of the above mentioned motor, which now has not 700kv but 350 KV.
When operating at 16V we would now have the following speed: 16 x 350 = 5600 rpm. To reach the same speed of 11200 rpm we would have to run this motor with 32V (32 x 350 = 11200 rpm).
7.1.3.2 User question: What does z.B. 13×5.5 for a propeller?
propeller are always given as diameter x pitch. Both values are in inches. So we are talking about a propeller with a diameter of 13 inches and a pitch of 5.5 inches. The diameter seems obvious to everyone but what exactly is the pitch?? The pitch corresponds to a distance a propeller would travel in one revolution in a solid material. A higher gradient therefore provides a higher speed, but this also requires more torque (power).
7.1.3.3 User question: What does CW and CCW mean for propellers??
In multicopters, propellers are always used as CW and CCW variants, d.h. there are propellers that turn left and right. This has the goal to balance the torque of the motors ( because z.B. in contrast to a helicopter there is no tail rotor). A quadcopter uses two CW and two CCW propellers, a hexacopter three CW and three CCW propellers, etc.
If you want to know more about this, you can find more information in the following article in our encyclopedia: Choice of the right propeller in glossary (link will be added)
We have now established that there is a difference between the voltage (variable we can influence) and the motor speed (variable we can influence) there is a connection and that there are several possibilities to achieve a certain speed. How does the Propeller size (last variable we can influence) together with the others?
If you take a look at the measured data for an engine, you will see that with a larger propeller the thrust as well as (unfortunately also) the wattage increases accordingly, that is also plausible, but how does it look with an increasing KV number?