SU-Primo (2S)

By Flight&Dice on Apr 30, 2019

12  743  7

Update 7/16/2019:
Added Eskimo hood on camera held on with small rubber band.  Wrapped arms with silicone tape, sealed ends with ring of UV cure adhesive to keep from peeling back.  Swapped linear antenna for circular polarized, supported by foam and UV cure adhesive to maintain angle.  Added o-rings to camera screws for better camera angle retention.  Setup global variables on X-lite to put compensated throttle curve adjustment on a slider, (helpful in finding what works best, I'm no expert but I recommend recording the values you like and setup a switch for 2 or 3 configurations depending on flight style).  Throttle cut for basement flying tonight.  The new AUW with 2S 450mah is about 76 grams.

Update 6/21/2019:
Changed to 2S 450mah battery and back to 65mm props.  8 minutes of hot laps in the basement moving pretty quick and around 40% throttle, battery was down to 3.65v per cell.  I like the responsiveness and punch of 3S, but these motors just can't handle what I want to do with them.  I'm downgrading this to 2S for now.

Update 6/16/2019: Complete rebuild, 10 grams heavier and better range.  V080x frame, 2-4S 12A iFlight Succex Micro F4 Stack, 9000kv motors, XM+ Receiver, Eos2 camera, Azure 2.5x4x3 props.  6-1/2 minute cruising basement flight.  VTX does get hotter than most, performs ok so far.  Camera mounting with a stack needs to be revisited. Flight is smooth and quiet, never needed more than 40% throttle indoors. Should get it out later this week.

Update 5/28/2019: Trying the sailfly-x props, flew 8 minutes, cells ended at 3.6v each. Good control. They have a less parabolic leading edge and rougher surface finish than the Kingkong 65mm props. And I noticed the edges are flat instead of sharp. I'm going to use them as beater props.

Update 5/27/2019: So after shredding my props on the coffee table, I didn't fly this one for a while. Plugging it in today, no Betaflight... After 20 minutes, discovered that the boot button was depressed against the frame. Added soft mounts under FC, and had to change the battery settings back from defaults of 1v max per cell. Weird. But after remounting FC, had a 9+ minute basement flight that got me smiling again. Batteries were down to 3.3v per cell tho.

This is the blending of a 3S whoop powertrain with a toothpick style ultralite. Probably best served as a tiny backyard racer.
I found the camera mount for the Mobula camera to be a hassle. I would recommend the Caddx Eos2 (edit: RunCam Racer Nano, plus new mount) instead, frame kit includes a nice Eos2 mount. Trashcan VTX mounts with a separate accessory, designed to go along with kit. 7700kv a must for 3S on Happymodel F4Pro V2.0. (edit: 9000kv for GEPRC/BetaFPV AIO 2-4s FC).
A bit of tiny soldering required to land camera wires on FC board. The canopy is really nice and has multiple areas to run antennas out of. I zip-tied the power leads to the arm to keep them out of the props. Then wrapped the arms with silicone self-fusing tape to protect receiver whip and motor wires. (I include a link below for what it looks like, just buy from hardware store).
Weight all-in with battery was 62 grams, lose the silicone tape and it was just shy of 60.
Maiden flight last night in basement due to wet conditions. Battery charged to 4.1V per cell, cruised around in stability mode for just shy of 5 minutes. Everything came down cool, just VTX was a bit warmish. Typical amp draw around 1.5A. Good throttle response, but had to limit short punchouts to 2.5A to keep from smashing thru the ceiling. Plenty of power, my instant favorite micro. Will try some ACRO outside when the yard dries up.
I left default PIDs on FC.

Update 5/5/19: Cruising basement speeds on 3s charged to 4.2v per cell, 300mah. 8 minute flight, cells each around 3.7v. Motors just a tad warmer than room temp.
Another 3s 300mah lipo charged the same, performed a whole bunch of mini-basement punchouts, 2.5 amp max. 5 minute flight, cells each around 3.9v. Hit ceiling, canopy absorbed it, protecting camera. Everything still looks mint.

Pronounced Supreme-oh, AKA 'leg blender'.
Do not attempt to wear shorts when operating this vehicle. Pajamas are pre-approved for morning flights only. Some peak amperage limitations may apply. Consult your local guru about 12amp service, 200mw VTX, and full range receiver.

Photos

Part List

Frame

Primo (2 builds)
Gnarlyfpv.com
$19.00

Flight Controller

CrazyBee F4 Pro V2 1-3S Brushless FC (FRSKY)
Gnarlyfpv.com
$41.99

Motors

1102 7700kV 2-3S Motors (X4) LITE NEW ITEM (3 builds)
Gnarlyfpv.com
$41.99

Propellers

65mm Bi Blade Props (1mm hub) (2 builds)
Gnarlyfpv.com
$1.99

FPV Camera

Camera/VTX Combos & AIOs for Whoops & Micros (17 builds)
Racedayquads.com
$24.99

Batteries

RDQ Series 11.4V 3S 300mAh 45C LiHV Micro Battery - XT30
Racedayquads.com
$9.24

Batteries

Happymodel 300mAh 3S HV Stick Battery Pack NEW ITEM (2 builds)
Gnarlyfpv.com
$9.00

Misc Parts

Silicone Self Fusing Tape - 1" x 12 yds, Red (2 builds)
Uline.com
See Site
Show stores (3)

Discussion

Sign in to comment

Jeremy Chotto   May 02, 2019  

nice build I am running 3s on mine now to. I lowered the kv to 9000 and getting really low amp draw and good flight time. I was going to get those motors but still wanted a little higher kv to give me 2s performance. also was very unsure of the 7700kv cause could not find them elsewhere and happymodel told me themselves 9000 was the lowest kv they were going to make.

Flight&Dice   May 02, 2019 

I was thinking the same thing. Couldn't choose, so I bought both lower kv sets and 2 frame kits. Was actually copying your build for strictly 2s, but built the 3s setup first. The motors are the same build quality, and there does appear to be a difference in the windings. If I have time in the coming months, I'll try to post a video of each.

Wayno-san   May 07, 2019 

I tested one of the 9000Kv motors and it was closer to 8000Kv; I wouldn't be surprised if they were the same motor, LOL. It was only sample size of one and I don't really plan on re-testing since I believe others have been running 3s on the 9000Kv and the boards seem to be holding out fine. Let me know if you find evidance to the contrary. Peace!

sergetania   May 01, 2019  

Nice pick!👍
Love the tape you got on the arms! Does it stay stuck?

Flight&Dice   May 01, 2019 
1

So it is not sticky, just rubber feeling. The more you stretch to wrap something, the stronger the bond. But if the bond is weaker you can peel it back easily and retry multiple times. Typically works better if you wrap around twice.

sergetania   May 01, 2019 

Thanks! I really like the hockey stick tape because it sticks really well but it is just black cloth. This one is colored and kind of shiny.

Jodie Froster   May 01, 2019  

Sick AF.

Guides & Reviews

Jun 21, 2021

AirbladeUAV has done it again and this time they've brought long range to the 5" class! Based on the popular Transformer Mini, the new Transformer 5" Ultralight adopts a lot of the same design philosophies with larger props and more payload capacity. It can fly upwards of 20 minutes on a 4 cell Li-Ion battery pack and in ideal conditions it's got a range of over 4 to 5 miles. In this guide I'll walk..

Read more
Mar 04, 2021

With the release of the DJI FPV Drone cinematic FPV has become a lot more accessible, but you certainly don't want to crash a $750 drone! The QAV-CINE Freybott is a compact, lightweight cinematic FPV drone that can take a hit and keep going. It's a lot safer to fly indoors and around people. With a naked GoPro or the SMO 4k you can capture some great stabilized footage. In this guide I'll show you..

Read more