Best way to descent with max speed

Hey,
For all i know Ardupilot in Auto mode, calculates to get exactly to certain point in certain height.
I got an issue that when i want to decent with the fastest ground speed using WPNAV_SPEED, the copter descent in slow ground speed (half of WPNAV_SPEED) and slow decent rate (WPNAV_SPEED_DN)

To put in nutshell, what is the best way to decent using WPNAV_SPEED_DN (fasest decent rate) and WPNAV_SPEED (fastest ground speed).

Thanks for your attention. I’m looking forward to your reply.

Hi @Spring_blades

So I suspect the issue you are running into is that you are simply against one of the other limits, my best guess would be a position controller limit. Can you post a log and param file so I can see what is limiting you.

Also, are you using Copter 3.6? Is there a particular reason for this? Why not go to Copter 4.0.

Matt

Hi,

Are you talking about vertical flight? In that case only the descent or climb speed are used.
If you are talking about a slanted flight, then it should depend on the angle. I made a calculation once for flight time estimation:
speed(m/s) = √((hspeed × cos⁡(α))^2+(vspeed ×sin⁡(α))^2 )

hspeed is the ground speed
vspeed is the climb or descent speed

I’m not sure it helps you and even not sure it is correct :slight_smile:

@IAMMATT and @cedg thank you very much for you comments.

@cedg equation helped me a lot!