Tehllama 5" Floss 2.1 Ultralight Racer

By tehllama on Dec 10, 2017

4  707  3

This was intended to be an extremely lightweight and responsive racer capable of flying flat out for 2 minutes, or cruising hard for three on a 4S 1000mAh battery. This setup worked so well, I had to get another one.

Overall budget in current form is a really impressively low figure, as is the weight achieved without many really expensive parts. I was actually able to cobble this together over Black Friday sales at under $200, and achieve an AUW under 400g with battery, which is astonishing since I've spent more on every other quad I own, yet not gotten anywhere close to the performance envelope for tight courses that reward agility.

In current form, this one has transformed into a 'stanced' setup with the surviving 5" boomerang arms up front, and replacement 6" arms out back. This setup is surprisingly effective for racing and minimizing propwash as the rear props see very clean air in negative AoA maneuvering. No other changes have been required - just moved to a better cheaper camera, and I now run T5046C props, but that's it.

Now that Serge and the boys have figured out how to make a better version of this for $200 on the Floss3.0 frame, I honestly suggest you buy that one instead... but if you're on a super-tight budget (to the point where cheaper frames and Racerstart electronics are on the docket), this might be a useful reference - if so, do spring for the RCX H2205's ($9 ea), a decent receiver, and a Micro Arrow or Caddx F1/2 Micro (1)

Photos

Part List

Frame

HyperLite Floss "V2.1" Race Frame 5mm Arms 5" (28 builds)
Pirofliprc.com
$44.99

Flight Controller

Cicada AIO F4 30A ESC - FPV FlightClub (2 builds)
Fpv-flightclub.com
$64.00

Motors

4 x RCX H2205 2633kv Motor (8 builds)
Getfpv.com
$51.96

Propellers

DALPROP T5046C Cyclone (2 CW 2 CCW) (394 builds)
Pirofliprc.com
$2.99

FPV Camera

RunCam Sparrow Micro (66 builds)
Getfpv.com
$29.99

FPV Transmitter

Eachine VTX03 Super Mini 5.8G 72CH 0/25mW/50mw/200mW Switchable FPV Transmitter (423 builds)
Banggood.com
$12.22

Antenna

Pagoda FPV Antenna (17 builds)
Race412.com
$3.00

Receiver

FrSky XM+ SBUS Mini Receiver (1534 builds)
Getfpv.com
$16.99

Batteries

G+PLUS 1000mAh 14.8V 4S 70C Li-Po Battery (4 builds)
Pirofliprc.com
$14.49

Radio

FrSky Taranis QX7 ACCESS 2.4GHz RC Transmitter - Choose Your Color (253 builds)
Racedayquads.com
$129.99

Goggles

Flysight FPV Goggles 5.8Ghz Diverity Video Goggles SPX02 40CH Wireless RC Drone Racing Goggles with HDMI in and PIP Function DJI
Amazon.com
$398.00

Video Receiver

ClearView 5.8 Ghz Pro Receiver - ClearView Factory Direct
Clearview-direct.com
$549.95

Radio Module

iRangeX IRX4 Plus 2.4G CC2500 NRF24L01 A7105 CYRF6936 4 IN 1 Multiprotocol STM32 TX Module With Case (5 builds)
Banggood.com
$36.99

Battery Charger

ISDT SC-608 150W 8A MINI Smart LCD Battery Balance Charger AU Warehouse (14 builds)
Banggood.com
$54.27

Soldering Iron

TS100 Portable Programmable Smart Soldering Iron (258 builds)
Racedayquads.com
$58.99

Backpack

RAID Pack II
Atstacticalgear.com
$219.99
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Discussion

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slodsm   Dec 10, 2017  
1

Outstanding looking build man. I recently finished a ghost with a very simple setup that came in AUW at 396 with a 1300 tattu and let me tell you, it's the lightest quad I've built and the performance is so ridiculous that I am still trying to learn to use it all. I've got a floss 2.1 that I finished last night at work but no scales and there is no grass within 100 miles of me at best so I won't weigh or test fly til I get back home but hopefully it too comes in around that weight, then I can decide which I like better.

I'm torn on skipping out on the VTX SA control as well and may end up swapping out the RX to an RXSR and adding it in but other than that, I'm completely happy.

tehllama   Sep 06, 2018 

Having ran this thing quite a lot (and crashed it quite a lot) - I don't miss VTX SA control. At races (where I leave the Band and Power output alone), it's much faster to just peck away at the button and know from the display that it's on the right channel. The Eachine VTX03 is remarkably good (does run a bit hot in desert summer weather), so if you're feeling left out, don't. I do have full VTX SA on other quads, and still find myself manually pecking buttons because it's just as fast.

tehllama   Dec 10, 2017  

Weight and cost savings decisions I may eventually regret:
Skipping Telemtry and VTX SmartAudio control (I had a TBS Unify and XSR Receiver, but concluded that saving 5g and $15 to sneak under a specific threshold would be worth it - therefore XM+ and VTX03)
RCX H2205 2633KV V3 Motors - they're pretty light (26g with long wires), but not as light as advertised. The eventual goal is to move to ZMX Finx23 2205 2622kV motors.
Not running a Lumenier AXII - for cost reasons (+3g) I went with a U.FL to RP-SMA pigtail and went with my favorite Pagoda antenna, the Race412 Nano. This is a really durable setup, but prop clearance is an issue (which could be easily solved by by an AXII and a Brain3D mount for it)
Running a smaller 440uF main battery capacitor (along with 220uF cap for the 5V rail). I may want more capacitance on main battery to even out VBAT to the ESCs, but having a small capacitor on the 5V rail may mask those issues significantly.

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