I see several questions on the NACA ducts found on airliners Example 1, Example 2, Example 3 and I was wondering how much drag is normally generated by these inlets? As they take in air, I imagine there must also be some momentum losses.
I found this source, which gives a nice overview of the distribution of inlet drag for varying locations, but it's hard to judge the total amount from it.
Is the inlet drag a significant portion of the total drag? What percentage of the total drag is it?