Right, got it now.
The drag, and thrust required curves are the same, but the power required curve is not. (see above diagram.) The power required curve also represents the fuel flow required, and as the min. fuel flow is the best endurance speed,(100kt TAS) then it has to be lower than min. drag speed (130kt TAS).
Where a line drawn from the origin of the graph makes a tangent to the power/fuel required curve is the best range speed. as can be seen, this corresponds with the min. drag speed.
MJ
