Basic Turboprop vs turbofan Q
Am thinking myself in circles here and might be beating my head against a brick wall. So if anyone can set me straight I'd appreciate it.
I'm finding it hard to understand why turbofans are able to operate at vastly higher speeds and alts than a turboprop. The majority of an turbofans thrust comes from the fan component. And I understand that this is partly due to the fact that the fan is ducted, therefore the fan experiences airflow at a lower mach compared to free stream velocity. Now if this is the case then why don't turboprops simply slap a cowling around the prop component allowing the Ac to operate at higher speeds? I'm sure there is a ridiculously simple explanation to this but I'm blind to it at present.