We need to take a look at the relationship between power required and thrust required.
With an increase in weight there must be an increase in power required and a corresponding increase in velocity.
The configuration concepts are pretty much the same as the jet performance section with the exception that instead of dealing with thrust required or really the drag curve it must be converted into power required.
The basic idea that the parasite drag increases and causes the power required curve to open up at the top.
In analyzing the power required curve as altitude is increased remember that the TAS goes up and as a result the power required must increase.
The L/Dmax tangent point stays the same for each curve its just that the velocity needs to be increased.
Developed by Richard Whitcomb
Max specific range is the same at altitude as sea level
PR to overcome induced drag varies inversely with V
For max range at high altitude the same EAS is flown resulting in a higher TAS
It takes more power to hold the same EAS at altitude because of less density
Best angle of climb Vx is a function of excess thrust
Best rate of climb Vy is a function of excess power
Best range IAS is higher for a higher gross weight
Best range IAS is the same at any altitude for a given weight
Best glide ratio is the same regardless of weight
Best glide ratio is found at L/Dmax
Best rate of climb Vy is at (PA-PR) max
Best angle of climb Vx is at or near stall
The increase in PR curve for a weigh increase is greater at low speeds because of the increase in induced drag