Ultralight 1S 3" BabyTooth (35.5g dry)

By SquishinStix on Dec 31, 2020

16  687  13

This is my fourth build and I have named it "Jameson". My most recent previous build was a lightweight 3S Toothpick3 that quickly became my favorite quad (and still is), so I decided to take that build a bit more extreme and a do an ultralight BabyTooth build.

I started with the 1.5mm BabyTooth frame from FPVCycle. I cut off the minimortal T mount to save weight, and one of the FC mounting points so the AIO board's mini-USB port would fit.

I debated whether to use a true All-In-One board or to use a dedicated VTX and/or receiver. Ultimately, I figured I would be flying this thing in smaller and tighter areas, and wouldn't really need more range provided by a dedicated VTX and receiver, so I decided to go all in on the lightweight aspect and got the BetaFPV 1S AIO with the FRSky receiver and 25mW TX built into the board.

First, I removed the motor plugs from the AIO board to save weight and because direct soldering motors offers less resistance and better performance.

I then soldered the motors to the underside of the AIO board, conformal coated the bottom, and mounted it. I used the shorter stack screws that came with the frame, and only three of them, to further minimize the weight. These were, by far, the smallest pads I've had to solder to before and I was pleasantly surprised and happy with my work. If this had been my first build then I would have ruined something and maybe given up on the hobby altogether!

I then mounted the camera in the canopy (after clipping off two of the three canopy shrouds to save weight) and soldered the camera to the AIO board. I then conformal coated the top of the board.

I then attached the canopy (no need for nuts on the stack screws as they thread into the canopy) and used a ziptie to keep the receiver antenna and VTX antenna vertical and in place.

Finally, I ziptied the power leads to an arm for stress relief and used a single rubber band to both hold down the motor wires and mount the battery. This is an awesome way to mount the battery because the two bands underneath act as a grippy battery pad while the two bands on top hold the pack nice and snug. It ends up being sandwiched between four bands and is really in there snug. Added bonus is that the band holds the motor wires down so no need for tape or additional zipties (less weight, baby!).

Dry Weight: 35.5g
All Up Weight: 47.8g

As KabobFPV states on FPVCycle, it is difficult to get this AUW down below 50g but it makes a big difference vs. the "standard" ~60g weight. I've only flown one pack so far but compared to my only other 1S quad (Mobula6) this thing rips. It's nothing compared to my 3S TP3 but I didn't expect it to be. Where it really shines is safety and sound. This is an order of magnitude quieter than any other quad I've ever flown - even at full throttle nearby it just sounds like a little toy. And for safety, well these motors don't have much torque, the blades aren't spinning that fast compared to other quads, and the entire thing weighs almost nothing. The only way this quad could reasonably cause harm would be a direct hit to the face.

My goal was to get a bit closer to Mr. ShutterBug's dry weight of 33g, but I'm not too far off. Of course, he has a proper VTX on board...the only things I could do to further cut weight would be titanium motor screws instead of steel, REMY stack screws instead of steel, and a custom VTX antenna like he did. I suspect that if I did all of those I could shave off, at most 3g, but likely more like 2.5g. I wouldn't be surprised if I ended up doing the REMY screws and maybe the custom VTX antenna but likely won't bother with the titanium motor screws.

Photos

Discussion

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Mr_Stripes   11 days ago  

How is it with only 3 mounting points? I am thinking of doing the same thing with this board on mine.

SquishinStix   11 days ago 

Rock solid. This thing is so light that it's VERY resilient to crashes. I haven't broken a single thing on it; I've flown probably 40 packs with and crashed on concrete a few times and into trees and grass dozens of times.

Mr_Stripes   11 days ago 

Awesome, I just popped an esc on mine and I'm probably gonna get this board. I have used one in ht past and it had good range for 25 mw. Save weight over the eachine nano vtx that I currently have.

Mr_Stripes   11 days ago 

Also try toilet tanking your battery (mounting it side to side) it makes a difference, especially when you power loop or do a front/back flip.

Amadneon   Sep 23, 2021  

Hi, is the 5A esc output enough to sustain the motor current draw? I want to build an ultralight like you too but im concerned about the esc bottlenecking the motors.

Currently on the market there is no true AIO FC that outputs over 5A except NewBeeDrone's BeeBrain BLV3 and BLV1 which is absurdly expensive, each costing $100 and $90 respectively.

SquishinStix   Sep 23, 2021 

Yes, it is definitely enough. My build peaks at 13A which is only 65% of the rates max continuous, plus the peak current rating is more like 6A (24A total) I believe.

I have flown and crashed this thing a lot and never broken anything. I turtle when I crash even though this build can really only turtle and take off on paved surfaces or VERY short grass.

Amadneon   Sep 24, 2021 

Sweet, i guess im going with happymodel elrs aio for ultimate weight saving. That receiver and 200mw vtx is really alluring.

SquishinStix   Sep 24, 2021 

Awesome! That's a huge step up over the 25mW VTX and SPI receiver on mine!

fw42   Jan 03, 2021  
1

Nice build! Might be able to save another gram or so by not twisting the motor wires but instead cutting them to the exact required length.

SquishinStix   Jan 03, 2021 

I actually did cut them to length with just a little slack that ended up being enough to then twist them four times. But it's literally only about 1/3” of slack.

Joshua_A   Dec 31, 2020  

Nice, whats the thrust/wight ratio on this beast?

SquishinStix   Dec 31, 2020 
1

I can't find any thrust numbers on these motors but my guess is around 4:1 - nothing crazy. My 6S 5" quads are more like 11:1 and my 3S TP3 is similar in feel, but this thing definitely lacks that INSANE punch of those builds. This is, however, loads more powerful than a 1S tiny whoop.

DrewFPV   Dec 31, 2020  
1

That's a nice clean build! I just got a Babytooth and am waiting for my TBS tx module I ordered to be delivered.

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