Originally Posted by
mrfox
From the text referenced above - locked rotor is not necessarly less drag than windmilling - it depends on the bypass ratio. In straight jets and low bypass fans the losses from the increased flow through the core more than offsets the spillage. The crossover point was mentioned to be around 5:1 bypass - right around where the last gen turbofans live.
Concerning props, it appears there is also a crossover point :
http://www.peter2000.co.uk/aviation/misc/prop.pdf
Last edited by Fly Aiprt; 1st Nov 2019 at 19:37.