Copter not reaching speed in Auto Mode

Hi guys.

When doing a survey pattern in auto mode and say at 15 mph, I am always seeing the copter about 1 mph less in speed during the mission and on each line in the grid pattern. The survey pattern is 3-4 acres so it is a straight line for a while. GPS is good and healthy the whole flight. What might cause this?

Thank you.

I fly mapping at a MAX 8 mphs… Its not a fixed wing. Slower flight, = higher resolution, or better gsd.

I am not doing camera stuff…it is a granular and liquid spray drone. Thank you.

Not saying I can help much, but we’d definitely need to see a .bin log file. Upload one to dropbox or google drive (or similar) and share the link to it.

Ok, will do tomorrow. Thank you, Shawn.