3 Inch "Scratch Build" Log


We need some super smart guys to build diy esc’s so we can build them at home. Then we smoke 'em, we can swap out burnt components and keep going. Kinda like our Scisky FETS!


We can do that with commercial ones too, so long as you can diagnose and identify the failed components. I sorted out a Babyhawk esc with a missing diode on the motor out circuit by stealing one from a dead frsky xm+ rx.


I do like the Speedix 20A escs, run d-shot600 fine and are pretty small and light.
Here’s a pic with weights, including the wires they come with, compared to a Bullet 6A.


So if we can identify the smoked components, it is just a matter of replacing, not buying new?
Digi-Key or the like I presume.
Sounds easy enough
I’ll make sure to hold on to my scraps then!
In your experience @Chaotix
Are there the “usual suspects”?


I’d think with something running high currents like escs, each would need assessed on its failure and whether is worth replacing a number of components versus the assumed reliability of a whole new one. Mosfets would be high on the list along with big caps. Guess work here :wink:


Sorry to exhume up an old thread but @NotFastEnuf are you still flying this bad boy? I was thinking of building something similar for LOS flying but with a scratch built tubular frame. Aiming to get the frame around 15gr and getting the weight under 250gr. I’d be safe running a 12a ESC by the look of it?


Ha! I have some carbon fiber tube on my desk for the same kind of project! I’m planning a 3d printed hub and motor mounts to simplify assembly and repairs. Hope to get to that project asap so I can share files for the mounts and hub assemblies. Of course I will be adding canopy and fpv :):stuck_out_tongue_winking_eye:

As for your question of esc… I suppose that depends on the motors and prop size. But I have run up to 5" props on 4s with “older” 2400ish kv motors on 12a - you should be fine! Hope to see you involved in the upcoming tube frame builds!!! Sick light build weights are possible there … it’s the future of ultimate performance!!! I hope/intend to make it easy/accessible for anyone to try!!


Thanks buddy. Yeah, I have some cheap 1806 2400kv and I’m into building tubular quads now after reading the epic thread on RCgroups (you should check it out if you haven’t and speak to @Ian444 as he has some microish builds with tubes and skinny arms). I’ve got a 160mm tubular built and I have 2 x 200mm and 1x 190mm builds on the horizon with various motor sizes. Just wanted something different so going to stick some 3" props on the 1806 as you did and this looks like fun.

I’d love to get involved but I don’t have anything to offer really! I followed a great build from the members of that thread and all in all it’s quite simple of you like making things. I ended up using a B-03 Pro board, Sliverised of course, with some 1306 4000kv, DALT4045 props, 20a Racerstar ESC and 700mah 65c lipo. Frame was super easy to make but I hand cut everything which takes time. It ended up being around 21gr I think due to the epoxy and the wooden dowels but it really is sturdy and weighs 129gr without battery (super heavy ESC!). I’m not sure if that’s light for a 4inch quad?
I’ll keep an eye on what you come out with as it normally is quite fantastic :smile:


That’s beautiful! Yes ian’s work and the thread is the inspiration for my upcoming project. I’ve quite a history working with carbon fiber back from my fixed wing days constructing jets and gliders from scratch and would follow plans as provided there with no problems … but that would leave out alot of guys who don’t have that skill set. It is an advanced build. I’d like to take the same approach but make it more component based with printable parts. We’ll see how it goes. Will be my biggest design challenge to date keeping strength high and weight low.

If you go 4s on 3" with 1806 … you can expect a little over 300 grams of thrust per motor from the most aggressive props available. That will pull well under 10 amps. Very efficient setup but a little low on power. 4" brings amp draw closer to 12 to 15 amps and thrust near 400 grams. I honestly think 1806 is the perfect candidate for a 5s or 6s setup on 3". Wouldn’t that be progressive!!! I would try mine on 5s but I reduces the escs to 10a in an effort to save weight. Lol. They are the ones usually used in a 2" build so probably not a good idea. Lol


that thing looks SICK! :slight_smile:


We’re gonna get you into a tube frame build qlp if I can pull off my plans. Will make it easy and cheap to assemble one! Perfect for line of sight!


what size electronics are you planning to go with 20x20? or 30.5x30.5?


Haha, maybe I’ll be stupid enough to try 5"! I may see if there are any 15a ESCs that take 5s but have a small form factor. I can’t wait to make it up but got to get through these twins not going down in the evenings.:sweat:

I’ll drop into your other thread just see what you’ve got cooking and update this one of anybody cares. I think your plans are ambitious and your idea in making it available to everyone is great. And keeping it cheap will be a great factor, it’s actually the primary reason I made a carbon build as it works out cheaper in the long run buying manufactured frames. As always NFE, you’re doing some great work!

Thanks but in comparison to some of the other guys’ builds mine is iron age while theirs are positively futuristic. :smile:


nothing wrong with the classics bro. By the time I finished any of my builds there were they already outdated. lol


I’d like to make it fit both. First, I just need to crank out a couple brushless boss frames, a few canopy designs, print/assemble/mail out prototypes for review & feedback on the various designs in the works, survive Christmas, and occasionally sleep. Lol oh yeah… and fly. Can’t forget to fly!