Lil Billy v2 (Tadpole 3")

By sfonkter on Nov 17, 2020

6  666  2

Rebuild of Lil Billy using more reliable parts!

  • Armattan Tadpole 3"
  • 1404 3700kv
  • 25amp F7 AIO
  • JESC RPM filtering and 48khz
  • Dry weight: 99g
  • AUW: 156g

A rebuild of my Armattan Tadpole 3". It was my first quad build and I chose motors with a KV that was too high for 4s.
The original Lil Billy ran 1204 5000kv motors and a 16x16 13amp ESC... on 4S. Not a good combo. Burnt out 3 motors and maybe the ESC before realizing the KV was too high.

Lil Billy V2 is running larger 1404 motors on 3700KV and an AIO 25amp whoop board. MUCH better. Way less battery sag, better flight times, and extended punch-outs are no longer a gamble.

I had originally chosen the 5000kv motors based on 2.5" Tadpole builds without realizing the larger propellers would be harder on the motors, causing them to burn out one by one.
Also, Armattan's own pre-built 3" uses 5000kv motors. I've found that it's right on the edge, where it will work fine, but if you go too hard you risk burning something up. It's just not reliable, and I don't want to do any throttle cuts. 3700kv is very conservative and a little lower than I wanted, but after flying it I think it's perfect! It still screams.

Other changes include 3D printed arm guards and Minimortal T holder from Brain3D, a VTX/RX sled from Tiny'sLEDs, and a custom Crossfire RX antenna. I made a "Medi(um)mortal T" from the stock dipole that comes with CRSF receivers. It's slightly larger than the Minimortal, but gets much better range.

You can see the larger 1404 motors compared to the 1204 motors in one of the pictures, as well as the VTX/RX mounting sled.
Just a tip: if you think you might want to use one of the VTX/RX mounts then plan ahead for it, because once you've soldered to the through-holes it's really difficult to get the pins soldered on. I managed it but it was way harder than it should have been and isn't pretty.

Overall it's a cleaner, more reliable quad!

Dry weight (with props, battery straps): 99g
AUW (4S 450mah CNHL Ministar): 156g

So it's a bit chonkier than the original Lil Billy (Dry weight of 80g). I think most of it comes from the larger 1404 motors and 3D printed protection. However, I don't rememer if I weighed the original with props and battery straps, so they are probably closer in weight than that. I also intentionally left the battery lead extra long on v2 so I can try different batteries.

I don't think I'd change a thing about Lil Billy v2. That being said, I would like to try out higher KV motors (maybe 4500kv or so) just to see if there is a big difference.

Here's a quick one pack DVR edit. I was using a heavier 650mah pack which doesn't fly quite as good as the 450's. It was super windy, you can see how much I have to compensate at the beginning. My hands were also freezing so it takes me a min to get warmed up. The sunset just looked too good so I chose this pack despite.
I forgot to mute the audio, so it's just really loud static.

I'm not running a capacitor, but after watching DVR I think it would help with lines in the video. You can see the breakup at high throttle.

Prop selection
I've tried a bunch of different props, and these are my favorite:

  • Emax Avan 3024
    These are my favorite right now. I get good flight time and good punch out. They feel really good. Very durable and almost always bend back into place.
  • Gemfan Windancer 3028
    I really like these, too. I'll have to switch back and forth between these and the Avans to decide which I prefer. Not quite as durable as the Avans, but they still last.
  • Gemfan Hurricane 3016
    These are very low pitch and don't have quite the punch that the others do, but I feel like they have a bit more control. I would use them for very tight spaces. Not as durable as the others.



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Fractalengineer   Nov 17, 2020  

Damn that thing looks mean from the DVR; snaps right off on demand :O
Also your flying style is giving me heart attacks; like getting on collision courses and avoid last good for my little heart lol
Glad to see someone still using fast rates though :P

sfonkter   Nov 18, 2020 

Well I wish I had the guts to go to a park and dive some buildings like that guy on that SD card you found!

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