How long will my battery last at wide-open-throttle? Will the battery warning kick in before I start losing altitude? How much weight can the Iris hold? What happens if my transmitter dies during flight? Which props work the best?
These are questions I wanted to be able to answer without risking a crash, so I went to Lowes and built this quadcopter dyno with my son. It allows us to test and measure performance and behavior as a complete system without doing test flights.
The three eye-bolts hold a fishing scale with a backlit LCD display loosely in place (you can see the faint aqua glow through the hole in the dark blue bucket). The two cables connected to the top of the scale connect to a harness I built for the Iris. The two orange fiberglass poles squeeze the hourglass shape of the Iris body keeping it steady during flight. You just slowly take off in STB mode and perform your tests once you've established the desired amount of throttle. Measurements can be taken through a ground station and reading the scale inside the bucket.
The weight of everything the Iris is lifting is about 115 grams (harness, scale, etc), so you need to add that to whatever number appears on the scale's display, which can be read through the hole in the side of the bucket.
Some interesting findings so far (adjusted for the "tare" of the setup):
- The battery that comes with the Iris only lasts about a minute at wide open throttle. (MP reported current draw at 25-27 amps)
- The Iris can pull about 900 grams for a brief period of time at wide open throttle.
- Drawing 16 amps the Iris can hold 145 - 195 grams for several minutes.