X-Class on a Budget - Parts List

March 13, 2019

Inspiration

X-Class Drones are huge Racing Drones. Building bigger Drones make it easier for Spectators to see them. This ultimately makes for a much better Racing experience then small Drones do.

I see great potential in them and want to build my own. However, I'm on a tight budget.
My build won't use the highest quality components, but will still be flyable.
In this post, I will list what parts I ordered and why specifically I ordered them.

I've had some inspiration by these X-Class Builds.

X-Class by Travis Brann

Picture by Travis Brann https://www.facebook.com/travis.brann.9

TL; DR Shopping List

This is the list of the parts I ordered. I didn't test anything and just made assumptions about them.

Some of the links are affiliate links.
TypePartPrice
MotorsRacerstar 4114 Motors$80
ESCs4x UndergroundFPV Kamikaze Extreme ESC$140
Batteries4x 1550mAh 4s Battery5" Racing Batteries
Propellers6x MAS 13x12$60
FrameRealacc X210 Bottom Plates$40
FrameAluminium Arms 20x20, 1.5mm thick$20
Misc
ScrewsSteel Screws4$
Capacitors4x 1000uF 50v Panasonic EEU-FM1H102$10
Standoffs2x10 25mm Standoff6$
Motor Mounts4x Carbon Fiber Motor Mount$10
Power ConnectorAS150 Connector$10
CanopyLumenier QAV X Canopy$10
10 AWGBattery Cable$3
14 AWGESC Cables$3
16 AWGMotor Cables$15
Misc4x M5/M8 Bolts and nuts$5
Subtotal$416
Normal Drone Parts
FlightControllerBrainFPV Radix$55
VTXUnify$30
CameraRuncam Eagle$35
ReceiverCrossfire$35
AntennaTBS Triumph SMA$20
Total561$

Total Price: 561$


Parts

The rest of this post will tell why I ordered these components.

Batteries

The Batteries, one of the more expensive parts an X-Class Racers has.
Not having to buy new batteries instead, using batteries I already have saves a lot of money.

That's why I am planning to use my 4S-Batteries in series (and parallel) to power my X-Class Rig.
With 4 Batteries I can make an 8s 3000mah Battery.

4S 1500mAh Batteries

Advantages with 8S

  1. Already have 4S Batteries I can use
  2. I couldn't find motors with higher KV for such a low price.
  3. ESCs can handle it

DIY Frame

The next expensive thing would be the frame. Most good frames cost over 100$.
Cutting an Open Source frame is also rather expensive. So I will DIY my frame out of components we can all get for cheap.

My frame is inspired by an X-Class Frame that Travis Brann built.
It consists of two Realacc X210 Bottom plates sandwiching two aluminium tubes. The electronics will then be put into a QAV X Canopy.

Arms

The arms are 20x20mm, 1m Aluminium Square Tubes. They are cheap, can be found in most hardware stores and are flat, so I don't have to mess with the alignment.

Other Options were carbon arms, but they lose strength as soon as you drill into them.

Aluminium frame

Motor Mounts

The motor mounts are DIY Mounts. Carbon plates from China, the rest consists of 3D Printed parts and Aluminium standoffs.

Motor Mount

Motors

The Racerstar 4114 400kv for only 20$ a piece was the cheapest motor I could find. With "decent" quality. https://www.banggood.com/Racerstar-Racing-Edition-4114-BR4114-400KV-4-8S-Brushless-Motor-For-600-650-700-800-RC-Frame-Kit-p-1124370.html

With only 400kv it will probably not perform very well on 6S. That's why I went with 8S. If you find a better motor with higher KV, let me know.

Sidenote: It fascinates me that they are even cheaper than standard 5" Racing Motors.

Propellers

The expensive part.

Master Airscrew 13x12

The Master Airscrew 13x12 is considered the Gold Standard for X-Class Drones.

MAS 13x12

https://www.masterairscrew.com/collections/x-class-drone-racing

Other Option

  • HQProps 12x6. Better suited for those weak motors but are not released yet.
  • HQProps 13x10 also not released.
  • MAS 3X 13x12.
  • Two blade propellers, if the motor is too weak.

You should probably get the newer MAS 13x12 3X. They are a lot better for this application.

Flight Controller

You could take any Flight Controller but keep in mind X-Class rigs have a lot of vibrations and need a good Gyro.
Unless you want to mess with filtering, here are some good options for Flight controllers with less noise / good filtering.

  • Helio, dedicated F3 Chip with awesome filters.
  • BrainFPV, Bosch Gyro, less susceptible to noise
  • FlightOne, no experience, but they have very good filters

brainFPV Logo

In the end, I got the older BrainFPV RE1, due to a friend having a spare one.

Also, I will power those electronics with a separate second battery, so the voltage supply stays consistent and does not get affected by voltage ripple of the battery.

Capacitors, lots of them!

Capacitors are an essential component in racing drones. More capacitance is always better. It helps reduce noise and enables a longer life of components.

Since this system runs with a max of 33.6V, a 35V Capacitor just won't cut it. A Capacitor should always have at least a 20% margin for Voltage Spikes.
Also, size is no concern on an X-Class, I’ve sourced some 50V 1000uF Panasonic from a local retailer.

I should probably cover the legs with solder or an extra cable since they will carry a lot of current and will probably melt otherwise.

50V Capacitors 1000uF Panasonic Low ESR 50V Capacitors 1000uF

ESCs

UndergroundFPV Kamikaze Extreme ESC

This is the UndergroundFPV Kamikaze Extreme ESC.
It handles up to 8S and should be able to handle the current of a 400kv Motor with 3 Blade Props.
https://www.undergroundfpv.com/products/kamikaze-extreme-32bit-escs

UndergroundFPV makes special ones

V2 was a Wraith 32 metal v2
V3 is a Furling 32 Metal, similar to the tekko32 metal

Most ESCs get manufactured by Airbot. Maybe they put special components on there. Nobody knows...

Alternative (none is rated for more than 6S)

Holybro Tekko 32 F3 Metal

Alternatives

https://www.racequadgear.de/ExUAV-Lighting-70A-4-8S-Dshot1200-ESC

Power Distribution Board

As PDB I will use a Copper Sheet which I found in a dead power supply. I went with AS150 Anti Spark Connectors as Battery Connector.

Cables

  • 10AWG Battery Cable
  • 14AWG ESC Cable
  • 16AWG Motor Cable

Copper Power Distribution Board

Conclusion

I hope to be able to finish this build as soon as possible. Currently, I'm still waiting for parts.

Follow me on Instagram or Facebook where I post further updates about this project.

About Pascal Luginbuehl
  • FPV Drone Racing

  • Hacker / Maker

  • Web Developer

More about me...