TAS increases when Weight decreases
In the Cessna 172S POH, a note to the cruise performance tables says that you may add 1kt per 150LBS below MTOW.
There's no such note in the 182RG POH.
So I was wondering if I could derive that information from the performance tables.
For different RPM/Manifold settings, and altitudes, the table gives the %Power and the TAS.
I could try to write the equations of Lift, Drag, and Power. From the tables I think I could get a sort of Cx as a function of Cz, and then at the end get my answer.
As I don't want to reinvent the wheel, I would like to know:
Is there a simple rule of thumb everybody knows but me?
Do my ideas to solve the problem make any sense at all?
As anyone any link to a well documented solution?
Thank you all for your answers