Red Riot

By sharkbyte on Dec 18, 2018

16  654  3

Sub 250gram AUW, that's the purpose, that's the goal.

The european law concerning flying RC will be reformed Q1 2019. Currently living in the US we eventually will go back next year. We will relocate back to Germany and cities over there are more dense then most of US cities. There I wont have the luxury of wide, open, unoccupied spaces nearby. So, I want to come up with a valid build to cater that need, that goal: #sub250

I recetly joined the FPVchat slack server ( great podcast "" originated there) and somehow I came across Larry's (lazd) frames. His site has many original frames which immediately catched my eye. I built a TinyShark first and then spontanously ordered the FeatherLight4. That frame looks gorgeous! It is minimal and has a lot of curves, which not only looks sexy but also makes it structurally more robust compared to the cheap, straight cut Banggood frames.

The FeatherLight4 comes with 15mm and 20mm standoffs and fitting camera mount plates. I really liked the slim look of the 15mm assembly, but it later turned out that to fit everything would be nearly impossible.
The Diatone Mamba stack is the latest hotness in matters of price/performance. It's so cheap I had to try it, especially as the components ticked all my boxes: F4, MPU6000, 4S, BlackBox and the solderpads are great, a little elongated and all located together on one side. The ESC can handle enough amperage and is pretty compact. But, as it turns out not compact enough for the 30x30mm mount. I had to take off some material from the standoffs to make it fit!

After I made sure that the ESC will fit I started mounting the motors and racewire. The motors are only a little heavier then the common 1407 options and I hope(!) they have more grunt in low end speed and maybe are a little more efficient. But, as I could not find any good review and want to experiment with other motors anyway I put some racewire on. Switching motors should be very easy!

I laced the arms with CA glue to prevent delamination as much as possible and covered it up with a red paint pen. I think it looks hot!

For the RX and VTX and wanted to go small and light too. Originally I opted for an already present XM+ but then switched to a R-XSR. I wanted that sweet sweet telemetry and to play around with Lua scripts. The VTX ticks my boxes: light, smartaudio, U.fl antenna connector for the new AXII micro, and it offers more then 25mW if needed. Found it here on rotorbuilds.

The struggle was real. After hours of trying to fit all four components in a 15mm stack height I was close to give in and go with 20mm. I talked to the designer on FPVchat and he offered to hand me down a left over prototype chassis which is longer than the original frame. He initially has designed it as an alternative top and middle plate, joined by a fifth standoff in the back. I didn't like that as it would add even more weight so I only mounted the top. This allows me to take off FC, RX and VTX by unplugging ESC and camera. Voila, the whole top plate comes off.

The next struggle was to arrange RX and VTX and find spots for the antenna. The back rotors are close together as the frame was designed for stretch-x, which I changed to deadcat by flipping the front arms. There was just no space to get zipties attached and(!) the antenna secured from propstrikes. So everything comes through the top plate pretty central of the frame. I already got scolded by members of FPVchat for that, but for the moment it will stay like that and I will see how good/bad it works.

The camera is a leftover from an attempted 5" build. I can shave off 6g if I drop down to a micro eagle or even more with micro swift style cams. I will break this one first. It is pretty exposed, so I'm sure this will happen rather sooner than later.

Overall, this is a tight build and I had lot of fitting to do to get it right. Besides the antenna mount I pretty happy with it!
The quad without props and nuts comes in at 167gram. Now I have to find the perfect battery for sub250 AUW and maybe shave some grams off that piggy!

Please, if you have any questions or suggestions, leave a comment. Haters gonna hate :P



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BloodyLordV   Dec 19, 2018  

That is a nice work. Unfortunatelly I have to bring you nad news. The New EASA regulation states the 250g is the AUW (which means sub 250g with LiPo). If you are interested in how to achive it - check out my jewest build a 6s 4ibch quad which weights only 254g with LiPo. Of you change the ESC and FC to iflight succex mini - you have a 6s 4inch quad under 250g with LiPo (249 g to be exact).

sharkbyte   Dec 23, 2018 

Indeed! Yes, I'm aware that the AUW is 250g. Your 6S build looks very interesting, respect.
I hope to shave of some weight on the frame and to find some 4S battery with a little less weight. Maybe 850mAh.
Thanks for sharing your thoughts!

TheMrJahn   Dec 19, 2018  

Great work, awesome drone!

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