If a propeller had aerodynamic improvements to create trailing edge vortices, would it help to keep the air from being forced outward by centrifical force?
On a fixed airfoil the centrifical force of the air causes the downwash behind the airfoil. on a spinning airfoil, the outward centrifical force is much greater than the downwash and it "throws" the air outward away from the propeller. If that propeller created vortices, would the centrifical force of the rotation of the air be strong enough to counter the outward centrifical force? if not completely, do you think it could help efficiency at all?
2006-07-13 06:54:39 · 2 answers · asked by Doggzilla 6 in Science & Mathematics ➔ Physics
Yes, I know that putting a shroud on a prop makes it better, its called a ducted fan.
What about in tractor aircraft with the prop on the front? You cant make it into a ducted fan if its in your line of sight!
2006-07-13 08:28:37 · update #1
My instinct says that in general you don't want to deliberately form additional vortices since they are lost energy. That's why winglets were added to some airplane wings, to prevent energy loss to wing vortices (ref.)
2006-07-23 08:27:52 · answer #1 · answered by kirchwey 7 · 0⤊ 0⤋
Two dimensional airfoils the most efficient more lift for a given drag. So a shroud around the propeller will help. And they do use it . In older jet engine they didn't have a fan in front of it. Only a compressor. But now almost all the jet engines have a shrouded fan in the front. They do reduce the noise and as well produce thrust more efficient than open propeller.
2006-07-13 07:23:14 · answer #2 · answered by Dr M 5 · 0⤊ 0⤋