Preparing to build large drone, would much appreciate your input


#1

Hi,

I´m new to this forum, I´m looking forward to becoming an active user!

I´m preparing to build my first drone and I´ve been reading into the subject for some time now. I´m confortable with hardware and software, and building things.

After some thinking I decided to build a large drone which attracts me more that the smaller and faster race drones. I was thinking to start off with 4 rotors but eventually turn the built into 8 rotors. It would be great if it could lift a decent weight, like 15 to 20 kgs. (one day I would love to build something that could carry me around, but for the time being this is just a distant dream…!)
It would be nice if it could stay in the air 20 minutes or more. I understand it could become costly to build this, and that´s fine (up to a point!). I won´t mount a camera on it immediately but would like to do it later on.
As a controller I was thinking of Pixhawk but I´m a bit lost here. What´s the difference between eg version 2.1, version 4 and the Pixhack? What do you recommend I use?
Also, if I understand it correctly, the Pixhawk is manufactured by different brands. What brand do you recommend I use?
What kind of motors do you recommend for the kind of lift I´m after? What about the ESC? It´s not clear to me how to select the ESC based on the Pixhawk and motors I choose.
Regarding the radio controllers, what should I pay attention to? I would like to buy a remote control that is not too expensive but will serve me now and in the future.
Finally, I was hoping to be able to use Windows as the platform the program the Pixhawk and control the system. Is that recommendable or should I be using Linux?

I would hugely appreciate if you could take the time to write down your thoughts and recommendations. It is my intention to keep you all informed of my built on this platform in order to share the experience.

Many thanks in advance, kind regards,
Arnoud


#2

First off, Welcome.

Before you get into the large drone sized, I’d recommend building something in the middle first. Personally, the 450 frame is a good sized starter, and you can get a basic starter kit with motors, ESCs, and a basic Flight controller. the 15-20kgs is a very lofty goal to start on.

As for how to choose your motors, ESCs to match and battery for flight time, that is something that is easier to set a goal and build around.

As for things to look for, Motors have a rating called KV. Their is a very detailed description, but the short hand is that its rotations per minute based on a single volt when applied with no load. Ususally, the lower the KV, the slower the speed, but you have more torque. This lets you use larger blades, with steeper angles on said blade.

ESCs are are often rated by amperage. A 366kv motor at full load will draw 38 amps. so you get a 40amp ESC, that can burst up to 45 for 5 seconds. This is a bit close for some, but your motors will not run at full load for the entire flight.

Batteries are the same. They have a voltage rating, a mah capacity, and a C discharge. You have to first get the motors, escs and the average power draw to get an idea of voltage and C. then through some helpful premade calculators, determine the power draw and mah drain. This lets you estimate your power draw and flight times.

This is a lot to take in at first, so a premade kit is always a good starter, since everything works and you can tweak as needed. Plus a premade kit is often cheap enough that any learning mistakes dont cost alot. I have a large, heavy lift drone, and breaking a motor often includes an arm, and an ESC, so a minimum of 135 euros. A simple starter in the mid size costs as much, and spare parts are cheap enough that the wallet wont hurt.

Now as for a controller/TX, there is a wide variety, and a good starting point is FrSky.


#3

I started my journey into drones by buying this book: https://www.amazon.co.uk/Build-Manual-Haynes-Owners-Workshop/dp/0857338137/ref=sr_1_2?ie=UTF8&qid=1549924505&sr=8-2&keywords=build+your+own+drone

From reading the above, I build my first quad based around the F450 flame. It flew! Since then I’ve got into building 5" quads (usually with much swearing) and have just built my first hexacopter.

Radio controller - Taranis X9D+ would be my recommendation. It’s bullet proof, upgradable and works.

In terms of OS, I’m typically a Linux or OSX fan, but with this hobby, I’ve found Windows to be the better OS for compatibility.

Good luck with the build, we look forward to hearing about it in future posts :slight_smile:


#4

For what it’s worth I would suggest an S500 Quad as a first build to get used to it without costing to much. It is lightweight and fun to fly. I also recommend Trannis X9D+ or Trannis X7 for radio with X8R reciever on copter (See Adrupilot/copter site for getting telemetry on your Trannis)

As for the Big Bird’s I used the Tarot T8x1000 umberlla which I can get about 18 minutes with a Tatu 10000 battery.

For auto pilot you have lots of choice but for me something in the “Pix” family running Ardupilot or PX4. I used a Pixcube 2.1 with Hero+ gps on the Octocopter.

Cameras and gimbals can get tricky If you don’t want to use a gopro (Blackmagic Design) has 2 camera’s that have an SBUS input.

Here are a couple of large frames
http://tarotrc.com/Product/Detail.aspx?Lang=en&Id=b9acf243-8c5f-43d5-a748-b216fcfdcbba
http://tarotrc.com/Product/Detail.aspx?Lang=en&Id=4166ffb8-2821-4b12-b23a-558fd5d85d7c

Stick to reputable motors (like T-Motor) and ESC’s with PWM, oneshot, or multishot.

See http://ardupilot.org/copter/ and https://px4.io/user-guide-2/ for reference


#5

Dear vwdstriker, GrandFromage and spartan27244,

Many thanks for taking the time to write a response, that’s much appreciated. you’ve given me lots of good ideas and I’m going to need some time to look into them and digest all the information. I think I will start by buying the book GrandFromage suggested, that will surely be very helpful.

I was kind of keen to buy at least a controller so that I can connect it up with my computer and start getting acquainted with the software and programming options. This is why I mentioned the Pixhawk. Am I not right to think that a Pixhawk would serve for whatever I build? Are there any particular reasons why to buy, or not to buy, a Pixhawk controller at this stage?

Thanks everyone. I’ll look into all the info and links given, and come back when I have more questions. I’m sure it won’t be long! :wink:

Best regards,
Arnoud


#6

With that load you’re looking for an octocopter like the Matrice S800 of DJI. It could carry 15kg for a cost of basic set 5000euro


#7

Thanks ernade for the suggestion,

I’m keen on building a drone from scratch (maybe not the first “practice” drone), design it myself to the extent possible, and I’ve always had the feeling that DJI is a bit too commercial for me, if that makes sense.

But I will certainly follow up on your suggestion and check out the Matrice S800 and see if that’s what I should go for. Thanks for the contribution!

Best regards,
Arnoud


#8

Sorry correction Matrice 600