Inverted 75mm

By pcfranco05 on May 24, 2020

4  107  0

Inspiration from quad66 and from Albert Kim, see links below:
https://www.youtube.com/watch?v=jmAFZa89pdY&t=165s
https://rotorbuilds.com/build/22094

Specs:
Motors: 0802 19000kv
FC: f3 crazybee flysky
Props: gemfan tribade 40mm
Frame size: 75 mm
Weight: 24 grams (no battery)

Info:
I saw this inverted type whoop and wanted to give it a shot! I had a tough time deciding if I wanted to make a 65mm inverted whoop or a 75mm inverted whoop, but I eventually went with the latter version due to larger props being more efficient (and my 65mm frame and props still making its way oversees from bangood). It weights around 24 grams without the battery, but I could definitely lose a gram or two by picking a lighter frame, making the motor wires shorter, and soldering the motor wires directly to the board. I took the parts directly from the vwhoop frame and installed them on the trashcan frame, due to laziness and not wanted to mess up the soldering on the motors. Overall, I am happy with the build and think purchasing the vwhoop for the parts are more than worth the $53 dollars spent on it.

Camera Mount:
Mounting the camera was a little tricky at first, but I decided I would rather my build be more protected then lighter. To make the mount I used two zip ties, a rubber band, and some dental floss. I wrapped the two zip ties threw two holes on the outer most part of the frame. I then used dental floss to pull the lens forward, to keep it in place because the zip ties are holding it back. I tried to use heat shrink instead of the rubber band, but for me the rubber band was working better. I left the zipties a little longer than they have to be to protected my rx and vtx. Having them be that extra length also help the drone with turtle mode.

Other Adjustments:
The motor plugs are in an odd position, and the props may cut motor wires if not carefully placed! I was able to slide on an extra rubber peice that hold the fc on one of the stands to make the wires be a little further from the props. Other adjustments I made to the frame include adding some foam to the bottom of the fc for protection against the ground, and some foam to the battery holder to make sure the batteries don't eject when crashing.

Software and Battery:
I put 48 khz jesc on it and just got rpm filtering working on it (Betaflight 4.1.1), did not really notice a difference in flight performance but I am using old batteries that came with my eachine trashcan. Once those batteries and the batteries from the vwhoop wear out, I will probably switch to at bt2.0 connector. I was getting around 2 minutes and 45 seconds on old 300mah batteries and new 250mah batteries. I am hoping new 300 mah batteries and an unpgraded connector will get it to over 3 minutes. I am using 26 awg wire for the battery lead beacuse that is what it came with, but that probably needs to be shortened and upgraded to 22 awg wire. Still working on the tune, but that will also be attached below.

Leave any questions and suggestions below!

diff all

Betaflight / CRAZYBEEF3FS (CBFS) 4.1.1 Oct 26 2019 / 12:15:47 (83ac98cfb) MSP API: 1.42 / FEATURE CUT LEVEL 2

batch start
defaults nosave
mcu_id 001e001c5734571820323031

name: Inverted

feature -MOTOR_STOP
aux 0 0 2 1525 2100 0 0
aux 1 2 3 1600 2100 0 0
aux 2 35 5 1775 2100 0 0
set gyro_sync_denom = 4
set gyro_lowpass2_hz = 325
set dyn_lpf_gyro_min_hz = 260
set dyn_lpf_gyro_max_hz = 650
set rssi_channel = 14
set fpv_mix_degrees = 10
set dshot_bidir = ON
set motor_pwm_protocol = DSHOT300
set motor_poles = 12
set vbat_min_cell_voltage = 280
set vbat_warning_cell_voltage = 290
set vbat_scale = 110
set vbat_divider = 10
set ibata_scale = 2350
set yaw_motors_reversed = ON
set small_angle = 180
set pid_process_denom = 1
set osd_vbat_pos = 2401
set osd_rssi_pos = 2104
set osd_tim_2_pos = 2369
set osd_flymode_pos = 2412
set osd_current_pos = 2422
set osd_mah_drawn_pos = 2391
set vcd_video_system = NTSC
set flysky_spi_tx_id = 1000
set flysky_spi_rf_channels = 42,59,63,18,90,148,118,106,96,81,51,110,100,36,47,143
set name = Inverted

profile 0
set dyn_lpf_dterm_min_hz = 91
set dyn_lpf_dterm_max_hz = 221
set dterm_lowpass2_hz = 195
set iterm_relax_type = GYRO
set iterm_relax_cutoff = 10
set p_pitch = 80
set i_pitch = 25
set f_pitch = 90
set p_roll = 80
set i_roll = 25
set p_yaw = 90
set f_yaw = 0
set angle_level_strength = 100
set horizon_transition = 80
set level_limit = 70
set d_min_roll = 0
set d_min_pitch = 0

rateprofile 0
set roll_rc_rate = 71
set pitch_rc_rate = 71
set yaw_rc_rate = 71
set roll_expo = 40
set pitch_expo = 15
set yaw_expo = 40
set roll_srate = 80
set pitch_srate = 76
set yaw_srate = 80

save

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