Some of the deeper modifications center on details inside the airframe. The flaps are reflexed, air holes are plugged, lighter components are used, and the center of gravity is moved aft. This makes for a faster and more efficient racer, but the flying qualities change so much that some pilots don’t like it very much. In many cases, these racing Mustangs take forward stick when making pylon turns!
Do I understand correctly that you took the exhaust heat into account as well? (Since that's the majority of the engine heat)What I did to arrive at this was take an engine I had the heat balance on and do an analysis just like the cooling system was a ram jet.
I've never fully understood the need for it. First of all, in our region (up to 250 mph or so), boundary layers are thin and thus, momentum loss is pretty small. Also, like you said, you're re-energizing that same boundary layer again. Thirdly, having a "lip" to not ingest the boundary layer has a lot of extra area, producing drag as well.Another sacred cow is that you must have a boundary layer diversion scheme.
It, the boundary layer gutter, was required on later models of the P-51 because at about 400 mph the fuselage BL buffeted the oil cooler and created a rumble that caused metal fatigue in the aft fuselage of the "A" model.I've never fully understood the need for it. First of all, in our region (up to 250 mph or so), boundary layers are thin and thus, momentum loss is pretty small.
I agree, the comparison with a ramjet is essentially invalid as we are working with far lower expansion rates and temperatures.I would be carefull with the ramjet comparison. As far as I'm concerned, my domain is limited to subsonic, incompressible (M<0.3) airflow. Thus, the cooling duct should be a divergent to compress air, not a convergent as a ramjet. I might be stating the obvious but I felt the need for it. I can't use the EngineSim applet on this computer, how do you set the compression ratio of the ramjet ?
There is a compromise to be made : if you choose to slower the radiator air flow, the drag will be decreased but pressure hence temperature will increase compared to a faster flow speed (talking about identical mass flow obvisouly). So as stand-off, the delta T between radiator and flow is decreased thus cooling potential is decreased, which means less thrust.