[Terje]

Nope, I got nothing from Lauka. Put flying in general on the back burner for the winter, figure I’d try BetaFlight 4.0 when it comes out…

[Terje]

I would definitely go with the mini-tri. Small form factor, and nicely behaved 🙂

[Terje]

Just mount the tilt mechanisms on a 15 degree wedge and see if it makes a difference.

[Terje]

One mount is mirrored, that’s the whole difference. Standard works also, but not as pretty 🙂

Kevin_Erik, isn’t it time you invest in a 3D printer?

[Terje]

The Bicopter does not like propwash at all. Try going forwards while descending. The lean/drift is most likely to come from the wind. The Bicopter does not like wind either 🙂

[Terje]

Looking at https://github.com/betaflight/betaflight/blob/master/src/main/target/OMNIBUSF4/target.c

const timerHardware_t timerHardware[USABLE_TIMER_CHANNEL_COUNT] = {

#if defined(OMNIBUSF4SD) || defined(EXUAVF4PRO)
DEF_TIM(TIM10, CH1, PB8, TIM_USE_PWM | TIM_USE_PPM, 0, 0), // PPM
DEF_TIM(TIM4, CH4, PB9, TIM_USE_PWM, 0, 0), // S2_IN
#else
DEF_TIM(TIM12, CH1, PB14, TIM_USE_PWM | TIM_USE_PPM, 0, 0), // PPM
DEF_TIM(TIM12, CH2, PB15, TIM_USE_PWM, 0, 0), // S2_IN
#endif

DEF_TIM(TIM8, CH1, PC6, TIM_USE_PWM, 0, 0), // S3_IN, UART6_TX
DEF_TIM(TIM8, CH2, PC7, TIM_USE_PWM, 0, 0), // S4_IN, UART6_RX
DEF_TIM(TIM8, CH3, PC8, TIM_USE_PWM, 0, 0), // S5_IN
DEF_TIM(TIM8, CH4, PC9, TIM_USE_PWM, 0, 0), // S6_IN

DEF_TIM(TIM3, CH3, PB0, TIM_USE_MOTOR, 0, 0), // S1_OUT D1_ST7
DEF_TIM(TIM3, CH4, PB1, TIM_USE_MOTOR, 0, 0), // S2_OUT D1_ST2
DEF_TIM(TIM2, CH4, PA3, TIM_USE_MOTOR, 0, 1), // S3_OUT D1_ST6
DEF_TIM(TIM2, CH3, PA2, TIM_USE_MOTOR, 0, 0), // S4_OUT D1_ST1

#if defined(OMNIBUSF4SD) || defined(EXUAVF4PRO)
DEF_TIM(TIM5, CH2, PA1, TIM_USE_MOTOR, 0, 0), // S5_OUT
DEF_TIM(TIM4, CH1, PB6, TIM_USE_LED, 0, 0), // LED strip for F4 V2 / F4-Pro-0X and later (RCD_CS for F4)
#else
DEF_TIM(TIM5, CH2, PA1, TIM_USE_MOTOR | TIM_USE_LED, 0, 0), // S5_OUT
#endif
DEF_TIM(TIM1, CH1, PA8, TIM_USE_MOTOR, 0, 0), // S6_OUT
DEF_TIM(TIM1, CH2, PA9, TIM_USE_NONE, 0, 0), // UART1_TX
DEF_TIM(TIM1, CH3, PA10, TIM_USE_NONE, 0, 0), // UART1_RX
};

Motors 1 and 2 (S1_OUT, S2_OUT) use timer 3 and motors 3 and 4 (S3_OUT, S4_OUT) use timer 2, so you should be fine.

[Terje]

No.

Use the latest official Betaflight.

Use David’s CLI dump (or my diff).

And you’re done.

[Terje]

(Re-post)

No. I installed Betaflight 3.5.1 on the RCExplorerF3 (prior to installing the KakuteF4v2). Here is the diff:

# diff
# Betaflight / RCEXPLORERF3 (REF3) 3.5.1 Sep 2 2018 / 03:22:27 (890d0e0b9) MSP API: 1.40

board_name RCEXPLORERF3
manufacturer_id
resource MOTOR 1 B00
resource MOTOR 2 A04
resource MOTOR 3 NONE
resource MOTOR 4 NONE
resource SERVO 1 A07
resource SERVO 2 A08
mixer CUSTOMAIRPLANE
mmix 0 1.000 1.000 0.000 0.000
mmix 1 1.000 -1.000 0.000 0.000
servo 2 900 2100 1585 100 -1
servo 3 900 2100 1420 100 -1
servo 4 1050 1950 1500 100 -1
smix 0 2 2 100 0 0 100 0
smix 1 2 1 -100 0 0 100 0
smix 2 3 2 100 0 0 100 0
smix 3 3 1 100 0 0 100 0

feature -ANTI_GRAVITY
feature TELEMETRY
beeper -ON_USB
serial 1 32 115200 57600 0 115200
aux 0 0 0 1300 1700 0 0
aux 1 1 1 900 1300 0 0
aux 2 2 1 1300 1700 0 0
aux 3 28 0 1725 2100 0 0
set gyro_lowpass_hz = 90
set acc_trim_pitch = -6
set acc_calibration = -12,17,47
set mag_hardware = NONE
set baro_hardware = NONE
set rssi_scale = 41
set rc_interp_ch = RP
set min_throttle = 1015
set motor_pwm_rate = 2000
set align_board_yaw = 270
set current_meter = ADC
set ibata_scale = 336
set ibatv_scale = 336
set servo_pwm_rate = 250
set deadband = 5
set yaw_deadband = 6
profile 0

set dterm_lowpass_type = BIQUAD
set dterm_notch_hz = 260
set anti_gravity_gain = 1000
set iterm_windup = 50
set yaw_lowpass_hz = 50
set throttle_boost = 0
set p_pitch = 60
set i_pitch = 45
set d_pitch = 60
set p_roll = 45
set i_roll = 20
set d_roll = 15
set p_yaw = 40
set i_yaw = 20
set d_yaw = 60
set f_yaw = 0
rateprofile 0

PS: Don’t use the gemfan 5152 on the bicopter, they will just make it crash faster. Use HQ 5x4x3 or KingKong 5x4x3 instead.

[Terje]

Yes I couldn’t leave good enough alone.

Got the kit, put a KakuteF4v2 AIO in it (Because life just wasn’t complicated enough) and put the impossible tilt on it. Lesson learned: Motors and servos need to be on different timers to work, so it does matter which motor outputs you assign to what. Since the AIO won’t fit with the USB sticking to the front or back, I drilled a hole in the side plate – I know, it is sacrilege (David forgive me, for I have drilled 😉

Hovers great in my living room – It’s going to rain in Denmark for the next 9 months or so, but will test properly when the weather allows.

Bicopter balances with motors straight or tilted to either side – So the mass of the motors does not influence (in a serious way) the way the bicopter transitions from hover to forward/backwards flight.

Attachments:

1. 

   Bicopter-001-2.jpg
   

[Terje]

Don’t know if it is relevant anymore, but you won’t see the servos moving in the motors tab. Only motor 1 and motor 2 have motor resource assignments.

To move the servos, you will need to go to the servos tab (enable expert mode in Betaflight). Here the mapping is:

Servo 1 = Servo 4
Servo 2 = Servo 5

Hope that helps.

[Terje]

@David, anytime 🙂

Hope to build a bicopter from existing parts in the coming weeks 🙂

[Terje]

Well the tail would in forward flight give the bicopter a self righting tendency, but in reverse it would amplify the angle of attack? Also the direction of the prop rotation would in the current configuration (towards the fuselage in forward flight) cause corrections to not amplify the yaw when correctiong for tilt – something we with the reversing of the props on the minitri, used to our advantage in improved cornering. When reversing, corrections in motor rotation to counter tilt, would amplify yaw?

[Terje]

No, it is for 19mm cameras. Pull the f3d file into Fusion360 and adjust for your needs 🙂

[Terje]

Thanks for testing @Kevin_Erik! Were you using the “old” metal gear servos, or the steel version?

[Terje]

Thanks for testing. I’ve updated the design to be used with the 2208 and 2217 motors (same mount). New back holder with more clearance for the babytri, new back holder with indicator indent on the Mini and V4.

[Author]

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