aviast
Well-Known Member
This morning I read a story which included this image:
This is Airbus' E-Fan and I immediately started wondering why they had decided to use shrouded propellers.
I vaguely remember from previous reading that using a shroud increases the efficiency of the propeller by preventing flow of air around the tip, but it also creates drag (hopefully less than the increase in thrust!) and requires supporting structure (looking at the photo I think the stators will also have an adverse impact on efficiency, both in terms of the drag they generate and the disruption to airflow going through the propellers). I can see how a shroud might absorb propeller noise, so it might be considered if low noise is an important requirement.
Obviously most engineers have concluded that shrouds do not provide enough benefit to be worthwhile. I can only think of a couple of examples where shrouded propellers have been used: The Edgley Optica and the RFB Fantrainer.
Have I accurately captured the reasons for and against?
Why has Airbus used a shroud on the E-Fan?
This is Airbus' E-Fan and I immediately started wondering why they had decided to use shrouded propellers.
I vaguely remember from previous reading that using a shroud increases the efficiency of the propeller by preventing flow of air around the tip, but it also creates drag (hopefully less than the increase in thrust!) and requires supporting structure (looking at the photo I think the stators will also have an adverse impact on efficiency, both in terms of the drag they generate and the disruption to airflow going through the propellers). I can see how a shroud might absorb propeller noise, so it might be considered if low noise is an important requirement.
Obviously most engineers have concluded that shrouds do not provide enough benefit to be worthwhile. I can only think of a couple of examples where shrouded propellers have been used: The Edgley Optica and the RFB Fantrainer.
Have I accurately captured the reasons for and against?
Why has Airbus used a shroud on the E-Fan?
