Mavic Air 2 four-bladed props?

HassoBoxhead · Jan 5, 2021

Interesting:

Cymruflyer · Jan 6, 2021

In the world of aviation, the more blades you have the smoother the operation but the less efficient the prop is. You may not know this.

k9kids · Jan 7, 2021

icecoldgin · Jan 7, 2021

So far it is all drawing and a dog and pony show.

The proof of the dumpling is in the eating. Or in this case, the flying (and hard data) ?

Piper J3 · Jan 7, 2021

More blades = more drag. I have Blade Inductrix Micro Quad that comes with four-bladed props. I cut off two blades and flight times increase with no loss in performance.

See....

Thmoore · Jan 7, 2021

Cymruflyer said:
In the world of aviation, the more blades you have the smoother the operation but the less efficient the prop is. You may not know this.

I did not know that! Thank you!

Cymruflyer · Jan 7, 2021

Thmoore said:
I did not know that! Thank you!

Yes, for a prop the most efficient type would be a single or one blade prop. In fact this type of prop was once made for airplanes, but very limited because people did not like the way they looked. They had a big counter weight to offset things on the opposite side of the prop. It is the most efficient because it always travels through clean air. However, there is an offset pull of that blade on the prop shaft, so it is not ideal from a mechanical point of view, due to stress on the shaft from an offset pull of the blade through the air.

Now a 2 blade prop equals out this offset pull, so it works well and and as long as the aircraft is moving through the air quickly enough each blade of a two blade prop travels through clean air. As you increase the number of blades you then have to change the pitch on the blades because you can't have the same course pitch on each blade as you increase their number on a hub. The other thing to take into consideration is the fact that each following blade, when you have many blades on a hub, may be travelling into dirty air thrown up by the blade in front of it.

This is especially true when the aircraft is flying more slowly through the air. In fact it can be so slow with a course blade that the following blade cavitates in the air left by the blade in front of it. You may well have heard that slapping sort of sound if you have ever been to an airshow and heard some of the T-6 type trainer aircraft flying around. It makes that very loud sort of air slapping sound a times as it flies around the sky. Then is smooths out a bit and sometimes begins to make that noise again. That sound you are hearing are the prop blades cavitating in the air because the aircraft is not flying fast enough through the air and /or the blades are two course for the speed of the flight and number of blades on the prop. If this aircraft was flying at full speed, then you would not be hearing that noise because each blade would be getting clean air to bite into.

The most efficient way for a prop to work would be to have a variable pitch control on the aircraft. That way you can pitch the blades down as you start to move forward through the air, especially with many blades on a hub, and as your speed increases you begin to pitch the blades up, so they take a bigger bite out of the air. Having too much pitch on a blade before it starts to move fast through the air also puts extra strain on the engine, trying to turn that prop at the slow air speed point of the flight.