Introduction
Painless360's latest in-depth review tackles the AtomRC Penguin, a uniquely-designed fixed wing drone that promises versatility for FPV use. Read on for a full rundown of his thorough testing and final verdict.
TL:DR - The Good and Bad
The Good:
- Twin motors provide tons of thrust for aggressive climbs and easy hand launches
- Wide speed range from 10 mph up to over 70 mph
- Efficient cruise at lower throttle settings allows long flight times
- Durable foam construction has held up well so far
- Capable of basic aerobatic maneuvers like loops and rolls
- Very quiet thanks to 6-inch props
- Protected nose section fits FPV gear nicely
- Large internal capacity for big batteries up to 4200mAh
The Bad:
- Flight controller mounted far back from CG point
- Pre-set throws are much too high
- Does not excel at very high speeds over 90mph
- Airframe remains bulky when broken down for transport
- Nose durability uncertain long-term
- Shovels grass and dirt into nose openings during landings
Straightforward Build with Room for Improvement
Construction of the Penguin took just a couple hours, with no major issues. Painless360 opted for ExpressLRS over SBUS to avoid telemetry problems with the flight controller. Upgrading the firmware to iNav 6.1 enabled key fixes like improved AHRS. He also tuned settings like AHRS type and arming to better suit the plane.
While the spacious airframe easily fits large batteries or HD FPV gear, its rear-mounted flight controller could be positioned further forward. This would enhance balance by placing it nearer the CG and also allow more room in the back for components. Painless360 found the extreme pre-set throws made the plane too twitchy.
Impressive Speed Range with Twin Electric Power
The Penguin's twin motors generate substantial static thrust for rocket-like climbs and effortless hand launching. At just 1/3 throttle, it cruises efficiently at 30mph and 3.5A draw. This makes slower, longer flights possible. At 50% throttle, it zips along at 46mph and 8A. Top speeds exceed 70mph at full throttle.
Despite its odd shape, the Penguin tracks well and feels stable in the air. With lowered throws, the roll and pitch response feels crisp but not too sensitive. It can easily perform aerobatic loops and rolls thanks to the ample thrust and control authority. The 6-inch props keep noise pleasantly low.
Durable Airframe with Some Minor Shortcomings
Though the foam construction has proven durable so far, more flight time will reveal how well the nose holds up. The Penguin excels at most tasks but won't break any speed records. Transport and storage is mediocre since the airframe remains bulky when broken down.
On the plus side, the wings can be removed without disconnecting servo links. FPV equipment fits nicely within the protected nose section. Landings are gentle thanks to its glide capabilities and low stall speed. The ample interior space allows large batteries up to 4200mAh for long flight times.
Verdict: A Versatile FPV Performer
Despite a few small areas for improvement, the AtomRC Penguin shines as a versatile all-purpose FPV plane. With excellent efficiency, a wide speed envelope and aerobatic abilities, it makes a great platform for casual and aggressive flying alike. For these reasons, Painless360 gives it his official seal of approval.
AtomRC Penguin Inav Diff
Here is the Diff file provided by Painless360 that he used on his build, please only use this with the exact same version of Inav, otherwise use this as a guide to get your settings optimally configured.
# version
# INAV/ATOMRCF405NAVI 6.1.1 Jun 13 2023 / 10:02:51 (42ced253)
# GCC-10.2.1 20201103 (release)
# WARNING - USE WITH CAUTION, NO MODES OR OSD LAYOUT IN THIS FILE
# ALSO - BE AWARE THAT AUTOLAUNCH IS ON ALL THE TIME AND THE PROPS ARE SET TO SPIN ON THROTTLE UP
# Mixer: motor mixer
mmix reset
mmix 0 1.000 0.000 0.000 0.000
mmix 1 1.000 0.000 0.000 0.000
# Mixer: servo mixer
smix reset
smix 0 1 0 80 0 -1
smix 1 2 0 80 0 -1
smix 2 3 1 80 0 -1
# Outputs [servo]
servo 1 1000 2000 1539 -100
servo 2 1000 2000 1479 -100
servo 3 1000 2000 1426 100
servo 4 1000 2000 1500 -100
servo 6 1000 2000 1500 -100
# safehome
# features
feature MOTOR_STOP
feature GPS
feature PWM_OUTPUT_ENABLE
feature FW_LAUNCH
feature FW_AUTOTRIM
# beeper
# blackbox
blackbox -NAV_ACC
blackbox NAV_POS
blackbox NAV_PID
blackbox MAG
blackbox ACC
blackbox ATTI
blackbox RC_DATA
blackbox RC_COMMAND
blackbox MOTORS
blackbox -GYRO_RAW
blackbox -PEAKS_R
blackbox -PEAKS_P
blackbox -PEAKS_Y
# Receiver: Channel map
map AETR
# Ports
serial 0 0 115200 115200 0 115200
serial 3 2 115200 115200 0 115200
serial 4 33554432 115200 115200 0 115200
# LEDs
# LED color
# LED mode_color
# Modes [aux]
# Adjustments [adjrange]
# Receiver rxrange
# temp_sensor
# Mission Control Waypoints [wp]
#wp 0 invalid
# OSD [osd_layout]
# Programming: logic
# Programming: global variables
# Programming: PID controllers
# master
set gyro_main_lpf_hz = 25
set dynamic_gyro_notch_q = 250
set dynamic_gyro_notch_min_hz = 30
set gyro_zero_y = -2
set ins_gravity_cmss = 997.973
set acc_hardware = BMI270
set acczero_x = -15
set acczero_y = 8
set acczero_z = -11
set accgain_x = 4098
set accgain_y = 4086
set accgain_z = 4100
set align_mag = CW270FLIP
set mag_hardware = NONE
set baro_hardware = SPL06
set motor_pwm_protocol = DSHOT600
set failsafe_procedure = RTH
set align_board_yaw = 1800
set platform_type = AIRPLANE
set has_flaps = ON
set model_preview_type = 14
set servo_pwm_rate = 100
set small_angle = 180
set ahrs_inertia_comp_method = ADAPTIVE
set applied_defaults = 3
set gps_sbas_mode = AUTO
set gps_ublox_use_galileo = ON
set airmode_type = STICK_CENTER_ONCE
set nav_extra_arming_safety = ON
set nav_wp_radius = 5000
set nav_wp_max_safe_distance = 500
set nav_rth_allow_landing = NEVER
set nav_rth_altitude = 7000
set nav_fw_control_smoothness = 2
set nav_fw_launch_velocity = 150
set nav_fw_launch_accel = 1500
set nav_fw_launch_max_angle = 180
set nav_fw_launch_motor_delay = 100
set nav_fw_launch_timeout = 10000
set nav_fw_launch_max_altitude = 5000
set nav_fw_launch_climb_angle = 25
set osd_video_system = AVATAR
set osd_units = IMPERIAL
set osd_time_alarm = 20
set osd_alt_alarm = 110
set osd_home_position_arm_screen = OFF
set osd_switch_indicators_align_left = OFF
# profile
profile 1
set fw_p_pitch = 15
set fw_i_pitch = 5
set fw_d_pitch = 5
set fw_ff_pitch = 80
set fw_p_roll = 15
set fw_i_roll = 3
set fw_d_roll = 7
set fw_p_yaw = 50
set fw_i_yaw = 0
set fw_d_yaw = 20
set fw_ff_yaw = 255
set max_angle_inclination_rll = 450
set dterm_lpf_hz = 10
set fw_turn_assist_pitch_gain = 0.400
set nav_fw_pos_z_p = 25
set nav_fw_pos_z_d = 8
set nav_fw_pos_xy_p = 55
set d_boost_min = 1.000
set d_boost_max = 1.000
set rc_expo = 30
set rc_yaw_expo = 30
set roll_rate = 18
set pitch_rate = 9
set yaw_rate = 3
# profile
profile 2
set fw_p_pitch = 15
set fw_i_pitch = 5
set fw_d_pitch = 5
set fw_ff_pitch = 96
set fw_p_roll = 15
set fw_i_roll = 3
set fw_d_roll = 7
set fw_ff_roll = 40
set fw_p_yaw = 50
set fw_i_yaw = 0
set fw_d_yaw = 20
set fw_ff_yaw = 255
set max_angle_inclination_rll = 600
set max_angle_inclination_pit = 600
set dterm_lpf_hz = 10
set fw_turn_assist_pitch_gain = 0.400
set nav_fw_pos_z_p = 25
set nav_fw_pos_z_d = 8
set nav_fw_pos_xy_p = 55
set d_boost_min = 1.000
set d_boost_max = 1.000
set fw_level_pitch_trim = 2.000
set rc_expo = 30
set rc_yaw_expo = 30
set roll_rate = 31
set pitch_rate = 13
set yaw_rate = 3
# profile
profile 3
set fw_p_pitch = 15
set fw_i_pitch = 5
set fw_d_pitch = 5
set fw_ff_pitch = 80
set fw_p_roll = 15
set fw_i_roll = 3
set fw_d_roll = 7
set fw_p_yaw = 50
set fw_i_yaw = 0
set fw_d_yaw = 20
set fw_ff_yaw = 255
set max_angle_inclination_rll = 450
set dterm_lpf_hz = 10
set fw_turn_assist_pitch_gain = 0.400
set nav_fw_pos_z_p = 25
set nav_fw_pos_z_d = 8
set nav_fw_pos_xy_p = 55
set d_boost_min = 1.000
set d_boost_max = 1.000
set rc_expo = 30
set rc_yaw_expo = 30
set roll_rate = 18
set pitch_rate = 9
set yaw_rate = 3
# battery_profile
battery_profile 1
# battery_profile
battery_profile 2
# battery_profile
battery_profile 3
