Power setting for approach
Posted: Mon Sep 14, 2020 1:52 am
Found it on another forum and sounds like it makes sense. Mind you, a lot of times I just do it by feel.
I fly dozens of aircraft makes and models with one set of numbers 25, 20, 15, 12. These are used for either manifold pressure on constant speed propeller craft or RPM on fixed pitch propeller aircraft. 25" or top of the green for cruise, 20" for entry into the airport traffic area (descent from cruising altitude or level at vectoring altitude, or 45 degree entry into downwind), 15" for approach descent (with initial flaps and gear extended), and 12" for short final with full flaps. If flying an aircraft with fixed pitch prop, ad two zeroes to each number for the appropriate RPM setting.
The resultant airspeeds will match up with the white arc (unless your aircraft has only one flap extension speed), with a suitable speed for stabilized approach, the 3 degree glide path/slope, and not excessive over-the-threshold speed with proper energy remaining for the flare to touch down just above stall speed.
This comes from 9000+ hours in all sorts of GA aircraft. It even works in twins. Give it a try before you comment. In most cases, the numbers work as is. The 15 may need adjusted one number or two up or down, but it is a good starting point.
I fly dozens of aircraft makes and models with one set of numbers 25, 20, 15, 12. These are used for either manifold pressure on constant speed propeller craft or RPM on fixed pitch propeller aircraft. 25" or top of the green for cruise, 20" for entry into the airport traffic area (descent from cruising altitude or level at vectoring altitude, or 45 degree entry into downwind), 15" for approach descent (with initial flaps and gear extended), and 12" for short final with full flaps. If flying an aircraft with fixed pitch prop, ad two zeroes to each number for the appropriate RPM setting.
The resultant airspeeds will match up with the white arc (unless your aircraft has only one flap extension speed), with a suitable speed for stabilized approach, the 3 degree glide path/slope, and not excessive over-the-threshold speed with proper energy remaining for the flare to touch down just above stall speed.
This comes from 9000+ hours in all sorts of GA aircraft. It even works in twins. Give it a try before you comment. In most cases, the numbers work as is. The 15 may need adjusted one number or two up or down, but it is a good starting point.