How to build a 2S pepperFIISH pocket rocket — Shopping list & Recommendations

By | July 28, 2017

Recently I have been asked for my recommendation for a super lightweight pocket rocket. At the time of writing there are no stock lightweight RTF 2S copters I can recommend. You will have to assemble it on your own, luckily you can buy all the needed parts, there is no need to assemble circuit boards on your own. In the end you end up with ~280g thrust on a 27g + 17g (battery) = 45g quadcopter (6.3:1 thrust to weight ratio).

For a decent flying and durable copter I would recommend BR1103 motors. I have used the old racerstar motor design in the past, but unfortunately it looks like it is not in stock anymore… I have updated my frame design to the newer BR1103B motor mounts. The 070x motors I have tested in the bast used brass bushings instead of real ball bearings. In combination with poorly balanced flange you will end up with a short lifetime and maximum vibrations :-\ This is why I recommend 1103 motors.

The other parts are quite obvious, use a tinyFISH FC (or clone), a 2S ESC from furiousFPV (based on my tinyPEPPER2 design), 56mm props, a frame of your choice and Turnigy nano 2S 300mAh batteries:

Shopping List

3D printed parts

Due to changes to the mounting pattern this frame design is only for BR1003B motors!
With this new design you can save some weight by using foam and rubber bands for battery fixation instead of the 3d printed holder. In case you want to use different motors I have a similar design for you: One for 070x motors (with rubber tabs) and one for the older BR1103 motor design.

Assembly

Start by soldering the power cables to the FC input pads. Next, add power and signal connections between the FC and ESC. Connect the input pads of the stepdown to the Lipo Vout pads of the FC and connect the 3.3V output to the camera/vtx combo. I had to add a 47uF capacitor to the 3.3V pads of the step down in order to get the camera to work. You can use any 47uF  capacitor rated for at least 10V for this, I used a SMD multilayer capacitor in the 0805 size.

Use a M2 drill bit and cut the thread into the camera holder. Next, take four screws, the spacers, the FC, the ESC, and the camera holder. The 2mm spacers go between frame and ESC, the 3mm ones belong between ESC and FC. Screw everything together.

Take the motors and mount them to the frame. Make sure to use screws with the right length, they should not touch the motor coils! I used some nice and lightweight titanium screws instead of the ones that came with the motors. Add some low strength threadlocker to the motor screws (I use the purple Loctite 222).

Cut the motor wires to the appropriate length (keep some extra) and solder them to the ESC tabs. Those motor wires are really fragile. The best way to strip the isolation is to cut the wire a bit longer, overstretch/expand the isolation, cut the isolation and apply some heat to it. The isolation is made from heatshrink tubing and will shrink on heat exposure. This exposes the wire you want to solder. Do not use wire stripper/cutter tools as they might leave cut marks on the thin motor wire which cause it to break on vibrations.

Insert the camera into the holder and add a shortened zip tie as protector cage. Now finish up the quad by adding sticky foam on the bottom and mount the battery using some rubber bands.

Setup

Start by binding your TX to the receiver by pressing the bind button during powerup. Do the normal bind procedure you are used to. Now it’s time to proceed with the configuration — Fire up the betaflight configurator. Please note that the FC will not run on USB power, you will have to connect the battery as well. Do not let it run on the lipo for long time, the camera will drain a fully charged battery within less than 40 minutes…

The most important thing you will have to do is to set the FC orientation to the right value! Depending on how you mounted the FC, it is +/-45° or +/- 135°  rotated (yaw axis)! Set and doublecheck it by viewing the 3d model of your copter, it should follow all your turning motion. If you screw this up the copter will end up in your ceiling on the first arming — been there, done that…

Check your motor ordering and fix it by using resource remapping. Verify the receiver functions properly in the input tab. That’s it. For me the copter flies quite good with the stock PID settings.

Just in case you want to use a buzzer on this FC with bf 3.1.7 make sure to apply the appropriate fix.

You finished your 2S pepperFIISH? I would be happy to see and share a picture on my blog!

Happy flying!

5 thoughts on “How to build a 2S pepperFIISH pocket rocket — Shopping list & Recommendations

  1. Pingback: DIY : 2S pepperFIISH pocket rocket | HelicoMicro.com

  2. Jaapp

    Great! This tipped me over the edge. Definitely building this.

    I’m having a hard time sourcing the M2x14mm screws thought. Even the link you provided doesn’t have them larger than 12mm. Any tips where I can get a hold of there 14mm once’s?

    Thanks for this great blog!

    Reply
  3. Firlefanz

    Such a wonderful quad! Can’t wait to find a solution to get the esc in Europe (Germany) without huge shipping costs.

    Reply
  4. Shane

    I have been having problems getting my transmitter (Taranis Plus) to work with my Pepperf1sh. I suspect in my initial setup (first time using betaflight) I might have messed up some settings. Could you send me the proper settings for the configuration, port and receiver screens? Screenshots would be fine.
    Thanks.
    Shane

    Reply
    1. fishpepper Post author

      Just flash it again and set full erase. This will restore the stock settings which should work 😉

      Reply

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