Originally Posted by
Otto123
would you bank sharply (knowing you will lose altitude, but gain airspeed that you can then use to gain altitude again up until hitting best glide speed), or would you bank shallow and make a slow turn at glide speed?
At 6,000 feet this isn't much of an issue IMO. However, there is one technique that does give you the best 180 degree turn performance. In this case performance means maximum rate of turn with minimum loss of altitude.
Minimum altitude loss would be the bottom of the power required curve, or minimum sink. A speed that occurs approximately 5 knots below best glide (reminder: both change with weight). Since we know the speed we want to fly, we can reverse engineer the bank angle that will give us a stall speed that occurs within a comfortable safety margin of this speed.
For example: Take a 172 with best glide of 65 and a stall speed of 44 clean. Assume minimum sink to be 60 knots.
For maximum performance we'd find the bank angle that stalls us at 60 knots and fly at stall. However, this doesn't seem safe. So let's look for a stall speed of 55:
@57 degrees bank the stall speed is 59.6 knots.
@50 degrees of bank the stall speed is 54.9 knots.
The later technique, using a 5 knot fudge factor, makes flying to maximum performance simpler as well. Since most stall horns trigger at ~5 knots ahead of stall you can simply fly 50 degrees of bank with the stall horn barely audible and be at max performance +5 knot for safety.
Formulas used:
Load Factor (G) = 1 / Cosine (Bank Angle)
Accelerated Stall Speed (Banked) = Level Flight Stall Speed * Sqrt (Load Factor)