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Just Propwash or PID Adjustments?

French

Construire Voler S'écraser Répéter
#1
I've noticed that my Nighthawk Pro 280 ARF has significant oscillations when I try to descend straight down. I'm guessing that this is just a propwash issue, but wanted to make sure that I couldn't adjust my PIDs to clean up the issue.

PIDs for my main profile:
set pid_controller = LUX
set p_pitch = 40
set i_pitch = 30
set d_pitch = 23
set p_roll = 40
set i_roll = 30
set d_roll = 23
set p_yaw = 85
set i_yaw = 45
set d_yaw = 0
set p_pitchf = 1.500
set i_pitchf = 0.260
set d_pitchf = 0.029
set p_rollf = 1.500
set i_rollf = 0.260
set d_rollf = 0.029
set p_yawf = 8.000
set i_yawf = 0.000
set d_yawf = 0.020
set level_horizon = 5.000
set level_angle = 5.000
set sensitivity_horizon = 75
set p_alt = 50
set i_alt = 0
set d_alt = 0
set p_level = 20
set i_level = 10
set d_level = 100

set rc_rate = 90
set rc_expo = 65
set rc_yaw_expo = 0
set thr_mid = 50
set thr_expo = 0
set roll_rate = 14
set pitch_rate = 14
set yaw_rate = 10
set tpa_rate = 0
set tpa_breakpoint = 1500
 

Craftydan

Hostage Taker of Quads
Staff member
Moderator
Mentor
#2
Does it wobble it in a gentle climb or hover?

No? Then you've called it right -- you're fighting self-generated turbulence.

Yes? Then you've got some tuning to do.

There's still a chance you can tighten your PIDs further to improve their resistance to turbulence of any kind, but comparing raw numbers won't help much unless someone happens to be flying almost exactly the same setup (including battery weight and props). Who knows? Someone may have the same ARF and be proud of their numbers, but unfortunately that's as far as I can lend a hand.
 

French

Construire Voler S'écraser Répéter
#3
Thanks, Dan. It climbs and hovers fine, bot gentle and aggressive ;) PIDs are daunting for a new guy since there's so much trail and error. To be honest, I pulled these values from someone else (2dogRC). I'm generally happy with them. I found the rates were not that snappy, so I created a second profile with higher rates.

Now my Aux1 switch is horizon mode (safety), low rate mode, and high rate mode.
 

Snarls

Gravity Tester
Mentor
#4
Try increasing you I gain on pitch and roll. It should help, but not completely negate the effects of prop wash. Also, when descending try to descend at an angle rather than straight down. That will keep you out of the prop wash for a nice clean descent.