Increasing power required with altitude.. what's a good plain english explanation?

In article ,
"Danny Deger" wrote:

"Danny Deger" wrote in message
...

P.S. I have a Master's in Aerospace and have worked in the industry for many
years. I will admit most of my schooling and experience was with jets and
rockets -- not pistons and props. But I do recall the equations and
techniques to calculate engine horsepower required for various flight modes
of a prop plane was VERY complex. I am CERTAIN equating thrust horsepower
(thrust times velocity) to brake horse power (torque time RPM) is wrong.
Anyone have an aircraft performance chart to look at the IAS for 75% power
at sea level and at altitude?? I am not going to say it will be exact, but
I think it will be close.

Danny Deger

Danny,

Go back to "Airplane Performance Stability and Control," by Perkins &
Hage, John Wilet & Sons, NY, London (1949).