Wild guess: at the same rotational speed, with the same pitch, eight blades move more air than four do. The big diameter of the props also means the prop move more air. More air = more lift from the wings.
The tips of very long blades move at supersonic speeds; the characteristic noise of helicopters and small planes is the series of sonic booms caused by the props. With a design that moves a lot of air, the blades don't have to spin as fast, which would make the plane quieter, if the engines can put out enough torque.
If this motivation for this design isn't to make the plane quieter, it might be to get away with two engines, rather than four. Note the folding wings for transport in the hangar deck of an aircraft carrier.
Nappy's no engineer, but has hung around hardware geeks and flyboys enough to have a feel for how they think. Nappy would love if if someone who knows what they're talking about would comment on the pic and give us the real dope.
Wild guess: at the same rotational speed, with the same pitch, eight blades move more air than four do. The big diameter of the props also means the prop move more air. More air = more lift from the wings.
The tips of very long blades move at supersonic speeds; the characteristic noise of helicopters and small planes is the series of sonic booms caused by the props. With a design that moves a lot of air, the blades don't have to spin as fast, which would make the plane quieter, if the engines can put out enough torque.
If this motivation for this design isn't to make the plane quieter, it might be to get away with two engines, rather than four. Note the folding wings for transport in the hangar deck of an aircraft carrier.
Nappy's no engineer, but has hung around hardware geeks and flyboys enough to have a feel for how they think. Nappy would love if if someone who knows what they're talking about would comment on the pic and give us the real dope.
I'd guess that the lower-speed, lower vibration explanation has something to do with. Maybe a heavy-weather issue too?