How can you have min fuel flow at a speed below min drag?
Derfred, drag and thrust are forces acting on the aircraft. A force does not say anything about what happens over
time. Fuel flow is measure in unit of mass
pr.
time unit. It's a rate.
For that reason the lowest fuel flow does not occur at the min drag/thrust. It occurs at the lowest
power required.
Power = force x (distance/
time) = force x speed =
Drag x TAS.
At min drag speed (Max Range), your True Airspeed is higher than at min power required (Max Endurance). Hence:
Lower TAS x higher drag < Higher TAS x lower drag
You are fighting a higher force, but you are doing it at a slower rate. Rate of fuel flow is therefore lower. You are not getting very far (lower speed = lower distance covered over time), great for holding, but not so great for cruise.
Hope this helps refreshing what is basic (European) ATPL knowledge. It has nothing to do with TSFC - that only modifies the curves a bit, but the basic physics remain the foundation.
I give again the link I gave before, which show the basic curves for power and thrust required. And yes basic physics applies to all aircrafts, no matter if they have propellers, jet engines, straight or swept wings, obviously the real curves may not be so nice and linear because we do not live in a perfect world, anyway:
Maximum Endurance, Maximum Range, and Optimum Cruise Speeds