According to the Cessna pilot handbooks of operation for the common 152, 172 variety, the normally aspirated avaition engines seem to lose roughly about 1% of horsepower per 1,000 feet of increase in altitude. >Colin & Bev Rainey +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Colin, 1% sounds low to me. You will lose 1 inch of manifold pressure with each 1000 feet altitude. At 10,000 feet you're down to 20 inches MP or ( I'm guessing) less than 65% power, not the 90% Cessna says you would have. Would you check that number again. I know that tired old C182 isn't capable of 90% power at 10,000 feet when I'm hauling jumpers. By the time I've reached 5000 to 6000 feet I have the throttle all the way in to hold 24 inches MP and 2400 rpm. By 10,000 it's down to 20 inchs MP at 2400 rpm. While altitude does affect airframe performance the greatest, most noticable effect of altitude is on the engine. Larry Flesner
