Multirotor motor/prop selection - practical testing and review

The perceived wisdom is that larger blades turning slowly can produce the same amount of lift but use a lot less power. How true is this? In this video I fly the same model using the 7x4.5 inch props on 1800 KV motors and then fly the same model again using 10x4.5 inch props on 935Kv motors and review the results.
This is not a video to show the impact of changing the prop size on a single model of motor - data sheets exist for this purpose - it compares to two options that should produce almost identical levels of thrust. I hope that this video will help answer:
- Do I go for a smaller prop spinner faster or a larger prop rotating more slowly?
- What difference in power consumption does it actually make?
Every motor has a recommended prop for the size of battery you use (2S,3S etc.). Both of the setups here use the recommended prop for the 3S LIPO battery used.
I used an ImmersionRC EzOSD to record the telemetry data and provide a set of data for comparison. The answers speak for themselves.
This isn't scientific as the flights were on different days and the air temp was different but the battery charge, model setup and conditions were the same for both flights. The only difference was the slight change in weather and the heavier model using the larger blades. Even accounting for variances in the data the difference is too big to ignore.
I hope this proves useful to those of you looking to choose a motor and prop setup and need help to understand the potential impact of your choice.
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Happy flying!