I have been looking at getting myself a FPV racing drone as I need to remove the temptation to hoon my Mavic… I have a friend who has built one himself unsuccessfully so far (mainly due to lack of fine tuning and flying experience) and i really like the idea of effectively picking the parts you want and sticking them together to create your own custom drone. I shouldn’t have any issues with the tuning of the drone but my soldering skills are pretty rusty, from what he has told me some of the soldering can be tricky.
So this brings me onto buying a complete FPV drone (pre assembled) that i can pretty much take out the box and fly. This doesn’t sound as fun but there is a lot less hassle involved and there are some competitive prices out there for prebuilt FPV drones.
What I did was buy a used custom build from eBay. I had it in my mind they would be more complex than they are.
It let me see how it all goes together and gave me a chance to learn to fly it but also modify it etc.
I’ve stripped it down completely, new frame, vtx and FC. Setup smartport telemetry, added leds, buzzer soft mounted motors etc.
Soldering is pretty easy on a 5" quad, it’s something your going to end up doing wether you make your own or buy one.
Key is having a decent iron with correct tip and some good solder.
For me I’d say tuning is the worst part. Betaflight defaults are pretty good but if you do get oscillations, warm motors or twitches it’s quite time consuming analysing traces on blackbox and adjusting filters and PIDs.
It probably didn’t help I was learning to fly and tune at the same time, not ideal.
I’m quite happy with way I’ve went about it and my next one will be built from scratch.
That’s not a bad idea, it would make the purchase a lot cheaper! I am not overly bothered about the soldering, like you said i will just need to get a decent soldering iron with the proper tip. I haven’t soldered anything for at least 5 years
Ok, so here’s my thoughts. My builds include: 4 APM builds, 1 Pixhawk, 3 massively altered Quanum novas, 2 F4s, 1 F7 and a ton of altered bought ones… These are mostly quads a hexes. I also have several ready builds.
What have I learnt from building from scratch:
Watching your own creation fly is the most rewarding thing ever. Total buzz! You just can’t beat that feeling. You have to be brain dead not to crack a smile.
Nothing goes perfect on any build. You’re going to be frustrated often. Be prepared to fault find. Patience is a must. Some builds are quick, some take considerable time. You never know which of these builds you are starting!
Getting clean video transmition is not always easy. Some components are extremely poor quality and highly susceptible to everything from poor power to other onboard transmitters. Nothing cleans then up. Some are really good, but require cleaning of supply power and isolation from interference to make them shine.
Buy the frame first, then carefully plan the insides noting component dimensions, positions of USBs, buttons, displays etc. You will need to access to some components, buttons, displays, connectors etc when the build is complete and not all frames are compatible with all components.
Keep the build simple. It’s tempting to add GPS, sonar, complex VTX technology etc, but your probably not going to use them on a racing quad and will fight to get them to work right. Weight is also important and a heavy quad is not nimble.
Read reviews for parts and check out YouTube before buying to save disappointment.
An electric high powered soldering iron is essential. One with temp display is recommended. You will get used to what temp you require after a while. A large fat tip for soldering high current wiring, large pads and connectors. A small pointed tip for delicate soldering pads and wiring. A solder sucker and wire soldering iron tip cleaner are essential. Good heart is required for clean solder joints, but be careful not to overheat components. Medium high heat and quick action is best. Poor heat and slow action will cause dry joints and often cause overheating of components. Tin lead multicore flux solder is far better than lead free solder, this can be bought on eBay. It penetrates joints and heats better. A gas soldering iron for on-site is useful, but not as accurate to temperature control. Tips don’t last forever on any iron so when you start to notice poor heat transfer chuck it and get a new one. I have 2 A55KJ 60W irons, one for soldering and one for heat shrinking which saves a massive amount of time. Tin both surfaces before making joint.
A meter is essential. Check everything several times before powering up… even USB power. You will at some point unintentionally kill something. Usually an expensive VTx!
Always plan your connections on paper before you start. Make sure you’re writing is tidy.
Setup and programming is often tricky first time round, YouTube is your best friend here (Joshua Bardwell, Painless360, UAV Futures etc).
Tuning sucks, this takes time. Joshua Bardwell has some good tutorials on YouTube to assist and what to look and listen out for in flight and how to adjust PIDs accordingly.
It’s generaly cheaper to buy a prebuilt. Hell of a lot cheaper! Did I say it’s cheaper!
Don’t build a rocket if you can’t already fly! A Mavic is its own pilot and the controls are so dumbed down. You could sit on the controls and probably get some great footage. This is not the case with a racing done.
Make sure you understand kV motor rating, thrust, voltage, RPM, ESC Amps, battery C rating and prop pitch before buying these parts. High voltage, high kV motors and high thrust props usually cause excessive motor heat, hot puffy batteries and poor life expectancy.
Add one component at a time and test when building. Adding everything in one go will make it hard to determine the cause of a fault.
Make sure the flight controller is secured before powering up motors etc. Vibrations from the motors will cause the sensors in the flight controller to go nuts as it merrily vibrates in is unsecured state. Good dampening mounts for the fight controller really help.
A simulator really helps.
There are some great out of the box racing quads out there. You will forgo a lot of pain with one of these. The Diatone Tyrant S 2017 / 2018 is a great starter quad and flies well out off of the box. It is pre tuned and flies at a controllable speed. The Diatone GT2 is also a great quad, but will probably be stuck in a tree in milliseconds if you haven’t flown a racing quad before.
Buying second hand of eBay can be great, buy you may also buy someone’s junk. Intermittent fails are difficult to prove!
I’d always recommend buying a prebuilt first. Learn to fly it. Then build when you know how a quad should fly.
Good equipment is a must. Cheap goggles, high latency washed out poor image cameras, poor remotes etc really don’t make for a good experience or for ease of flight.
Frame quality is important. Flexible frame is bad, brittle low quality frame is bad!
Would I build another quad, of course, but then I am a glutton for punishment!
I could go on all day, so if you want to save on sleeping pills tonight…
There is so much to get your head around, but don’t be put off.
There are some really good guys on YouTube that are well worth a watch as mentioned in my last post.
I recommend looking at components on Banggood (Chinese drop shipper). You can probably get the same items from a UK supplier, but you will pay double for something that they bought from China to sell in the UK. Most Banggood stores will declare low customs value… Try keep order values as low as possible just in case. Postage is free so making multiple orders up to £15 reduces the chance of duty charges. Items are cheap as, so you can get a few items for $15. That said most stuff I order considerably over this arrive with a value of $10 on the customs form (fight controllers, motors, Esc’s etc).
One thing to note when selecting your flight controller and components… There are limited amounts of IO ports (UART and I2C) on a fight controller and this will limit the amount of devices that you can attach to it. Be aware that some IO ports are dual purpose and may not be available to use. One of the UART will be convertible to I2C bus. One may be required for the Receiver. Some may be required for flight controller functionally. So buying enough items to fill all the UARTs will not happen.