On Jan 16, 9:52 am, "Paul kgyy" wrote:
Power is a linear function of the amount of air processed through the
engine. The amount of air is a function of the product of manifold
pressure and RPM.

For my Arrow, takeoff numbers 30" 2700 RPM, product 81000, 200 hp.

At 5000 ft, 25", 2400 RPM, product 60000. 60/81 = 74% power, 150 hp.

If I reduce to 2100 RPM, product is 52500. 52.5/81 = 65% power, 130 hp

hmmm my Mooney's POH lists

5000ft / 25" / 2400 RPM = 154 HP / 77% power for a 200hp Lycoming IO -
360-A1A.

and it explicitly states to increase engine speed (RPM) before manifold
pressure and
conversely reduce manifold pressure before RPM. No wife tales in my POH
grin