Great article and some very interesting points on these new props, especially the 6 inchers.
As an aerospace engineer I would like to correct you on some of the terminology used.
First there is no such thing as "air cavitaion". Cavitation is a phenomena in liquids where the pressure drop on an airfoil for example is sufficient to cause a local boiling of the water and as a result a gas bubble. It can't happen in gases. What you are talking about is called flow separation - where a pressure rise on the upper surface of the blade is enough that the airflow can no longer follow the shape of the blade and separation occurs. When the separation is sufficiently large it results in loss of thrust - this is referred to as a stall.
I called it a stall before in another venue and was corrected that it wasn't technically a stall. I think you're probably right though, as that was my initial understanding. I need to ask my buddy who is a specialist in fluid dynamics at Jacobs. Maybe I'll do a write-up on the topic after I get some background from him.
GV27:
Dec 01, 2017 at 05:15 PM
Great article and some very interesting points on these new props, especially the 6 inchers.
As an aerospace engineer I would like to correct you on some of the terminology used.
First there is no such thing as "air cavitaion". Cavitation is a phenomena in liquids where the pressure drop on an airfoil for example is sufficient to cause a local boiling of the water and as a result a gas bubble. It can't happen in gases. What you are talking about is called flow separation - where a pressure rise on the upper surface of the blade is enough that the airflow can no longer follow the shape of the blade and separation occurs. When the separation is sufficiently large it results in loss of thrust - this is referred to as a stall.
quadmcfly:
Dec 18, 2017 at 09:16 AM
I called it a stall before in another venue and was corrected that it wasn't technically a stall. I think you're probably right though, as that was my initial understanding. I need to ask my buddy who is a specialist in fluid dynamics at Jacobs. Maybe I'll do a write-up on the topic after I get some background from him.