Burt's Awesome E90 Re-build Journal (w/Raceflight FC+ESC)


Over time, my Awesome E90 got to this:

  • Raceflight Millivolt FC
  • Eachine Minicube 4in1 ESC
  • Racerstar 1103 motors
  • Boldclash F-02 separated cam
  • FrSky XM+

I’m calling this done at v1.0.

But, it’s bothered me that I haven’t used my RF Spark ESC all this time, so with the advent of the latest RF1 beta (v295), I’m hot to rebuild this now. My only reticence is the lack of 3S motors, but I can upgrade those if/when I get some.

Everything will be the same for now, except the ESC being replaced with my Spark. I’m going to tight-and-tidy, so we’ll see how I do. At the moment, we’re here:


Here’s my plan… from bottom (frame) up, shown left-to-right:

  • Frame
  • R111XN on bottom (fitting a component on the backside of the rx into one of the holes in the frame so it’s mostly flush)
  • Spark with only two posts
  • (wiring)
  • Millivolt
  • top plate
  • VTX

I think this will be as low-profile as I can get it. I’m in conversation with @NotFastEnuf to make a shell out of canopy materials so that I could install a board below the frame, most likely the ESC, and then make the top even lower profile. If low enough, then I can run slightly larger props since they wouldn’t run into the stack. That might be v3, since I’d prob want larger motors to run the larger props, and moving the ESC to the bottom would take another teardown.


Struggled late last night with soldering wires to the Spark. Since I decided to NOT go with the pin sockets, I was soldering on the bottom side of the Spark (shown above), but those solder joints are hard to melt into! I presume it’s more of the Spark having so much copper, that heat wicks away so quickly, but pretty much every joint that I soldered onto the board is ugly.

I mean really ugly.

This isn’t just on those pins for ESC signals, but also on the motor pads. I even had a challenge removing a solder bridge between two motor pads… so peculiar, unlike all the other boards I’ve been soldering now.

Anyone know of clear technique adjustments for boards like this? I want to lean on @denovich, but I also don’t want to (imagining myself as a gnat is not pretty) so I’m going to ask for anyone else’s input as well.

Pics when I get home. You gotta see how ugly things are… it’s just bad.


Soldering the Bolt is even worse.

Use a bigger tip, if you have one.
Make sure your tip is “wet”, a tip with no solder on it is a very poor conductor of heat.
Crank up the heat, it’s less than ideal but you gotta do what you gotta do. I normally solder at 300C, but will put it at 400+ if need be.
Tin the pads.
Tin the wires.
A little flux on the pads helps (not too much, because it takes heat to boil it off)
Solder them together. Grounds will be the worst.

My TS100 battery powered iron is surprisingly better for heavy soldering than my bench iron. I think because the cartridge style tip does a better job of heat transfer than the slip on tips with the separate heater.


+1 for the bigger tip. I have a fine tip on my bench iron, but it is just about useless for soldering esc or motor wires. I use a butane iron with a wedge tip and it handles it much better. You want to be able to get in and out quick with the heat.


Tonight’s progress. From the I’m-Growing-To-Dislike-Satellite-RXs school of thought… I still think I can bind a Spektrum satellite whenever I want, but I seem to be having ongoing issues with that. Plus, I installed the transmitter between the frame and ESC, so it’s In There™. Instead of tearing down again, I soldered satellite wires to the top of the FC where the TX wires were soldered, and bound the satellite with a totally different FC while still installed in this quad. #hack

Low Profile Enough?

Without Battery 44.86g

With 325mAh 2S Batter 72.13g


Now with cam, behold my foam craft fu… all for NOT having props in my FPV view.


yeah buddy!