How find/estimate Parasitic Area (CDA) in order to calculate V(L/D)max? I am trying to calculate the speed which maximizes lift/drag for an aircraft.  Using Carson's paper, it looks to me like the only unknown variable is "f", the parasitic area, which Carson describes as "a fictitious area which, when multiplied by the free stream dynamic pressure, equals the viscous drag." 
This is where I'm stuck: either I need to find a way to experimentally measure free stream dynamic pressure and viscous drag in order to calculate f, OR I need to find some equation for f based off of measurable qualities of the aircraft.  Everything I've found either brushes this calculation off as too difficult, or appears to devolve into a mess of procedures for gross estimations not really related to the actual problem at hand.  
Am I missing something?  Is there some relatively straight-forward way to calculate this Parasitic Area?  (Referred to as CDA by Stanford instructional materials).  Or do I really need to know the "roughness" and exact shape of every component involved, as the afore-linked Stanford link suggests, in order to have any chance at estimating this variable?
 A: Yes, you need to know the exact dimensions, including surface roughness and gap size, of all components wich are wetted by the airflow. This includes even internal components like cooling ducts and heat exchangers.
What you need next is this book. It covers all aspects of drag, and now you need to do what is called bookkeeping in the industry. List every source of drag, its reference area and the drag coefficient. Now convert all coefficients to the same reference area and add them together. The result will be reasonably close (±5%) to what can be measured in flight.
If you want to measure drag in flight, here is a simple method that works best with gliders: Find two light sources which align along a horizontal line which is above the ground. Fly your tests early in the morning when air is calm. What you now need to do is to calibrate your air data system so your speed indications are correct (or use a good GPS and differentiate the location to get a faithful speed signal). Now fly your aircraft at high speed along the line defined by the two aligned light sources and record how speed decays over time when flying at exactly the same altitude (so any changes in potential energy can be excluded). From the energy loss over time you can calculate the total drag. Subtract lift-related drag and you get the zero-lift drag, which you can convert to a parasitic drag area if you want.
If the deceleration run ends over an airport, you can even re-use the plane after the measurement.
