Another descent option: regardless of cruise altitude (from 2500-10,000 feet) where I indicate 135-145 mph (higher is faster due to thinner air, reduced drag, etc.; True Airspeed is generally Indicated + 2% per thousand feet of altitude), I descend to 1000' above the airport at a constant 500 feet per minute, and let the airspeed increase. This generally makes the airspeed indicator point to 170-175 mph and groundspeed can be 200 or more. I take the free acceleration to make up for fighting it to reach altitude at slower speed. You can generate a good free body diagram with this, just convert everything to feet per minute first.
Then I level off, slow down from drag (give it 2-3 miles to do so), reduce throttle to slow down to 120 mph or less so I can begin to configure for landing. I generally fly around the airport at 90 mph, descending around 3° and reaching the runway at 70 mph, slowing to stall speed (mid-50s depending on flap position) before touching.
Considerations affecting descent: I start based on time, as 500 fpm is 2 minutes per thousand feet. If field elevation is 567' and I'm flying at 7500, I need to lose 6000' in 12 minutes, plus a couple of minutes to decelerate, so I start down when I am 14 minutes out. Do I start on time, or late? How well do I hold constant 500 fpm? What are the winds at cruise altitude,and how do they change as I descend? Near the surface, winds are generally slower and often shift counterclockwise due to the no-slip condition and Coriolis force from earth's rotation. Call it 15-20 seconds to initiate descent and stabilize rate, and the same to level off and begin slowing.
For a good visualization of winds changing with altitude, check this:
https://www.windyty.com/?975h,29.361,-85.485,6
Don't forget that flight path and wind are both vectors, and apwhen level and slow I need to align my flight path parallel to the runway. Wind is rarely in line with the runway. Landing is made into the wind as much as possible.
Then there are things like other planes I may need to avoid during descent; if I am IFR, then ATC may clear me to descend to 6000', where I level off then may be cleared to descend to 4000' or even 3000', and I must level off again and wait to be cleared down to my desired 1600'. Sometimes I will be cleared for further descent before reaching the first clearance and do not level off; I like this!
Hope your project goes well!
For my fellow pilots, your airplane is experiencing acceleration all day; so are you. Gravity is not a constant force, it's an acceleration, 32.2 ft/second squared. Drop a shoe off your bed, then throw the other up near the ceiling. With. I acceleration, their descents would be at the same speed and they would hit the floor with the same force. Does it happen that way? That's how I accelerate making a power on descent, gravity gives it to me free. If I don't pay attention, gravity will pull me right past Vne, all still for free.
