Mission 3
Payload Problems
More weight, a shifted centre of gravity, and a swinging load.
Difficulty
Briefing
A survey team needs a sensor package delivered to the pad 25 m north. Check the numbers before you lift it: will it be within the published maximum takeoff weight, how much harder will the rotors work, and how much spare thrust is left?
Objectives
- Stay within the published maximum takeoff weight
- Deliver to the pad 25 m north and land inside the circle
- Touch down gently (under 1 m/s)
Physics in play
Weight and required thrustCentre of gravity and differential thrustThrust-to-weight margin
Hampton’s .02 cents
thrust goes up with the square of RPM, so carrying 10% more weight costs only about 5% more RPM — but about 15% more power. The battery notices before the motors do.
Instructor insight
It would behoove you to check the margin to maximum takeoff weight before you check anything else. If it doesn’t fit on paper, it doesn’t fly.