One of the hot button issues in the Tiny Whoop community has always been: What’s better, two or four blades? To make the question more complex, RakonHeli has recently complicated the issue with a three-bladed prop for the Whoop. It’s a question that’s got militant supporters on all sides, and until recently there wasn’t really much in the way of empirical evidence.
Two vs. Four in a Nutshell
The two-blade proponents often argue that less mass on the propeller means that the motors have to work less. This is true. They also point out that a two-blade propeller is more efficient than a four blade propeller.
The four blade camp will point out that less blades does not automatically mean the same amount of thrust. The issue is that two blades at the same RPM theoretically does provide the same amount of thrust, assuming the blades are longer than the four blades.
There are various other arguments and counter arguments. Responsiveness, punch, etc. all come into play. But there has yet tests done (that I’ve been able to find) that allows for consistent, controlled testing of the Whoop with different counts of blade propellers, all of which have the same size.
Don Price and the Whoop Dyno
Don Price took up this challenge on Facebook, and built himself the rig you see above. In his test, he set things up as follows:
“Whoop specs are as follows….
BeeCore Flight controller on Clean Flight with factory settings
19,000kv Insane Motors
220mAh 50C BangCool batteries with updated power connectors
Blade Inductrix factory camera with a trimmed down housing
Each flight was conducted with a freshly charged battery. Ample time was given for the motors and FC to cool between flights. Each battery was tested before flight and all batteries had a starting voltage of 4.17 volts. Flight times are from lift off to the lack of ability to generate lift. Flights where hover only flights, no maneuvers.”
2 Bladed prop (4 blade prop with 2 blades removed)
Take Off Weight: 29.04 grams
Lift Generated: 9.04 grams
Total Lift: 38.08 grams
Flight Time: 2:38
3 Bladed prop
Take Off Weight: 29.10 grams
Lift Generated: 11.00 grams
Total Lift: 40.10 grams
Flight Time: 2:40 flight time
4 Bladed prop
Take Off Weight: 29.30 grams
Lift Generated: 13.00
Total Lift: 42.3 grams
Flight Time: 2:45
This is a great and solid start, showing us we can get a lot of performance from four blade propellers.
Much like the rest of drone racing though, this test is still somewhat new. The test itself doesn’t account for maneuverability, and one could argue that when you’re having to throttle motor up or down to account for angle or yaw changes, we could either different response times or better battery usage in these cases. Many pilots, myself included, do notice a dramatic improvement in the way the Whoop handles with fewer propellers. It’s why despite the number I prefer my three blade propellers.
What we lack for that hypothesis right now is a good, consistent test that helps reduce variables and is repeatable.
There are still a lot of Whoop class pilots that love their blade count of choice, and I think ultimately the answer still remains the same: Try them out, see what you like and what works best for you.