Citrus Crimson

By steezebe on Apr 12, 2020

4  204  3

My last build was based on a Milwaukee M18 (5S) drill battery, a proof of concept that I am applying to a large VTOL fixed-wing project (more to come on that). While it did function (and rather well as a trainer or beginner setup) the high inertia, weak 3D prints, along with my elementary piloting skills, proved to be too limiting for continuous use, and after the third quad crashing in an epic yardsale, I decided it may be time to try a more traditional approach for freestyle applications. So, to bridge the gap while I work on the VTOL system, I have decided to apply what I've learned in the last project and put together a normal 4S 6inch quad.

Of course, I will also be using it as another testbed, and will utilize the PX4 firmware, which I will be leveraging in the larger build for waypoint an AI functionality. To support waypoints, I printed a custom "recliner" mount for the GoPro, GPS antenna and receiver, using 3M VHB adhesive for the GPS, and while I'm not sure I like PETG as a plastic for drones, it's all I have at the moment. I'm looking to get carbon fiber parts made that should do better, but I have no idea where to get them cut. It also works, so, yeah...

The bottom has racewire LEDs, which help keep the arms clean, and looks sexy as hell. I also just decided to keep the blue clips on for now, since I couldn't come up with a solution I liked more. Ideas???

Given the massive prop size to body ratio (6.1in props), the thing floats at zero throttle, and is super smooth as well... I'm quite surprised. I also love the auto-take-off, position hold and waypoint functions PX4 lets me do, as I'm still not the LOS or FPV pilot that you see on youtube.

I Hope someone finds this build inspiring, or gives them ideas for their next build-- Let me know what you think!



Sign in to comment

Jodie Froster   Apr 13, 2020  
 I thought about telling you all the things you listed (as lessons from the last build) on your last post, but learning is a big part of the fun in this hobby. Since you asked for feedback, I have a few things for you. 
 Lets talk strain relief. Assume that you will crash, repeatedly. Any circut boards you leave outside your carbon frame WILL break in crashes (and sometimes the ones inside, if you crash hard enough). Make room for things to move a little when they crash. Antenna mounting: lash the antenna to the frame somewhere, such that the strain encountered in a crash doesn't get applied to the junction between the antenna and the board it is serving. 
 Lets talk skill gains. There will come a point where you aren't crashing every flight or three, and it's not necessiary to add the weight, or inherant cost, of an action camera stuck to the quads "forehead" like a unicorn horn. Maybe get to a point where you can intentionally fly in a manner that you enjoy, without crashing, for a few batteries before you strap expensive stuff onto the "danger zone" outside the carbon frame.
     The blue clips could be replaced with zip-ties (they don't rattle around and create gyro noise), or gaff tape. 
     I love that you made a quad that ran on power tool batteries, and if you were making something with bigger props, flown exclusivly with waypoint missions, it might still be worth your time. I know it's a lot of dead weight, but I love the safety factor, and the convenience as far as charging goes. I admit, I considered doing what you did when I was first learning about this hobby. I decided the extra plastic weight was too signifigant to justify the time investment designing a 3d printed adapter for quads to use them. I wish I had gone foreward with it, like you did, just for the satisfaction I would have gotten from designing the prints. I lived vicariously through your post, so thanks!
     By the way, your solder joints are VERY nice.
     Full honesty: your current build is packed so tight that you will likely loose several boards in a hard crash (concrete, asphalt, steel). On the other hand, your handling charistics should be stellar. 
     Those motors and ESC's are top notch! 
     Are you running ardupilot, or INAV on this beast? 
     I can't wait to see what you come up with next :)
     If this were my bird, i'd ditch the gopro & gps antenna. I'd get taller standoffs, mount the reciever in the frame, and print a camera bracket (since your carbon side plates won't work with the taller standoffs)
     p.s. Catalyst Machineworks will cut carbon for you.
steezebe   Apr 13, 2020 

Appreciate the kind words, and thanks for the machineworks reference!
Agreed on the learning curve with this. I wanted to try stuff I haven't seen before, and this build was no different. Which antenna are you referring to to lock down? If it's the 5.8 loli-pop, I agree completely; I just couldn't come up with a better option.
I also assume you're referencing the radio receiver board being the vulnerable circuit board? The valuable stuff in the main stack is pretty well guarded?
It is a pretty tight build, mostly dictated by the compact frame.
You pretty much summed up my approach: once I get comfortable with the flying characteristics and put together the VTOL project I referenced, I will probably upgrade to an HD camera like the Caddyx Tarsier, improve the guards around the stack, ditch the lounge chair entirely, put the battery on top and have a proper speed quad.
The firmware is the PX4 FMUv2 based on the nuttx RTOS, similar to ardupilot. It's programmed with QGroundControl, which is a little meh, but overall I like it. I am also very, very happy with the Kakute F7 FC.

Jodie Froster   Apr 13, 2020 

You nailed it, the reciever board, and the vtx antenna. I just picked up a tarsier, i'll let you know how that goes when all my parts get here (who knows how long it will take...corona delay).
Happy flying!

Guides & Reviews

Jun 21, 2021

AirbladeUAV has done it again and this time they've brought long range to the 5" class! Based on the popular Transformer Mini, the new Transformer 5" Ultralight adopts a lot of the same design philosophies with larger props and more payload capacity. It can fly upwards of 20 minutes on a 4 cell Li-Ion battery pack and in ideal conditions it's got a range of over 4 to 5 miles. In this guide I'll walk..

Read more
Mar 04, 2021

With the release of the DJI FPV Drone cinematic FPV has become a lot more accessible, but you certainly don't want to crash a $750 drone! The QAV-CINE Freybott is a compact, lightweight cinematic FPV drone that can take a hit and keep going. It's a lot safer to fly indoors and around people. With a naked GoPro or the SMO 4k you can capture some great stabilized footage. In this guide I'll show you..

Read more