Excellent point. The question becomes "How much is
some distance?"
This requires a picture!
First example projects out to a point very near the blade path, and is at a significant radius from the hub. Example 2 is located at the same blade
radius, but doesn't project forward as much. Example 3 is near the blade path, but at much less radius and higher, near the spinner.
Steve, your thoughts please. I'll venture that #1 and #2 would result in pretty much the same intake pressure, climb or cruise, thus my previous note saying it doesn't need to be
way out there. However, as you say, if dimension "A" becomes too short, flow following the cowl face will reduce available dynamic pressure. So, returning to Larry's question, is there a rule of thumb for a minimum dimension "A" ?
Agree, Example #3...decent pressure in cruise, although I don't think it will do as well in climb. In cruise, that location exhibits relatively high pressure, but with low forward airspeed, it's too inboard to harvest any significant dynamic pressure found in propeller outflow.
When working with cooling inlets at maximized prop radius, low speed, high power climb coefficients of pressure are much higher than the available freestream dynamic.