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In a message dated 11/12/2002 8:20:44 AM Central Standard Time, harrelson@erols.com writes:
Our 320 doesn't like to slow down in the pattern. Seems that you have 3
choices in methods to slow down; 1. Bring the MP down to around 13"- 15"
several miles from the pattern while at pattern altitude and reduce speed
very slowly, 2. Pull the power back lower, maybe to idle (last choice) or 3.
Enter the pattern a little low and climb to pattern altitude at 13"- 15" MP
or so. Any other techniques?
Bill,
In a recent experiment, I found that by pulling power, re-trimming to stay at the same altitude and slowing to steady (5 minutes) speed X required 1 inch less MP and about 80 less rpm than the power required to get up to speed X (from a slower speed) and stay there for 5 minutes. This supports your second technique, although it is not visually pretty to others in the pattern. It seems that reducing the laminar flow performance is at least as hard as getting it to attach in the first place. I say that because OPT's (Old Pilot's Tales) have talked about "getting on the step" quickly by climbing to a altitude higher than cruise, set the known cruise power and diving to the cruise altitude and speed - that way, you only have to trim once to the known cruise speed. The OPT additional claim that you will cruise faster is false although the airspeed needle might show a higher speed from friction holding it on the side of the speed from which you approached it.
I use a slightly different technique. The pattern target altitude is 200 feet higher than you would fly it in a 172. The slow down is started at a reasonable distance from the airport and at the target altitude by pulling the power to about 18 inches (IO 320) and when the speed reaches 160 kts with the nose starting to rise, 1/2 take off flaps is added - this drops 15 kts and allows the nose to come down, at 140 kts, flaps go to the takeoff position and power may be reduced to about 15 inches - this should result in about 120 kts (ready to lower the gear). Once the gear is out, the speed drops to about 100 knots - flaps and power as needed.
Caveat: I have the heavy duty (5/16?) flap push rods.
Scott Krueger
N92EX
1. I put the gear out almost every time I land.
2. You can go down or slow down but you can't do both!
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