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Dan,
A most sincere thanks for putting this all together, and for posting for all to see/use. My IV-P performs similarly
in these configurations… just a bit better when “normally” loaded at about 3100#; very close to the same at my max gross weight (set/tested at 3600# by me). I would encourage all Lancair owners to try this for yourself, and to practice it until you can do
it comfortably…every time. Take an instructor with you to start if you’re the least bit uncomfortable, but this should be a “standard maneuver” in every Lancair owner’s bag of tricks IMHO.
Bob
LMLers,
During flight testing of my 320 several years ago, I collected glide ratio data for 3 different configurations as you can see below in the copy of the spreadsheet where I keep this data.
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Config
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Flaps
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Gear
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Prop
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Decent Rate
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KIAS
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Glide Ratio
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Cruise/low drag
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up
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up
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low RPM
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600
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103
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17.3
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Approach/low drag
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10 deg
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down
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low RPM
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1300
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92
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7.1
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Approach/high drag
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10 deg
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down
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high RPM
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1900
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92
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4.9
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NOTES:
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Test aircraft is Lancair 320 MKII, N320DK, owned and flown by Dan Olsen on 8/10/04
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Engine is Lycoming IO-320-D1B, stock, 160hp
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Prop is Hartzell HC-F2YL-8468-14D
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Engine power set to idle (not completely shut off)
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Empty weight
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1142
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Pilot
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195
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Fuel (36gal)
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216
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Baggage
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20
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Gross Weight
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1573
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Test altitude was 7500' - 9500'
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Aircraft was flown with Jim Frantz's AOA Pro at the best glide AOA and KIAS was then noted
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It is quite alarming to see the incredible difference between a clean, max glide config and a normal approach to landing config. Glide ratio goes from 17:1 down to 5:1. I remember speaking with Orin Riddel at the Lancair factory years
ago and him describing that if you were on downwind, abeam the numbers, and your engine quit and you left it in the high-drag congif, you will not make the runway. First reaction should be to immediately retract the gear, low RPM on the prop and get the flaps
up.
I practice this scenario regularly and I can always make the runway with the main issue typically being that I land long and have to turn up the RPM to add drag on short final:
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Fly normal downwind
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Chop the throttle to dead idle on downwind
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Low RPM (coarse pitch)
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Gear and flaps up
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Pitch for best L/D on the AOA
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Fly the pattern (tighter than normal)
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On short final when runway is assured, drop the gear and 10deg flaps
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Add flaps and increase RPM, as necessary, to avoid landing dangerously long
I encourage all Lancair drivers to get some experience with your plane in the various drag scenarios with the engine at idle, especially the dramatic difference that flat vs. coarse pitch on your prop makes. There is nothing like feeling
it for real to teach you some of the “muscle memory” needed to react in a pinch.
Upon departing OSH a few weeks ago, I wanted to fly across Lake Michigan to visit my daughter. Going around is very long and going over is very scary
J So, I was able to take the knowledge from actual glide testing of my 320 to create the following table to show how high above the water I need to be in order to glide to the shore in the case of engine failure at
the middle of the lake. The area of the lake I went across was about 60nm across, so 30nm from center to shore.
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Lancair 320
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N320DK
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Glide Ratio
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17
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15
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12
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10
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8
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7
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5
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Distance to Glide (nm)
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50
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17,871
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20,253
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25,317
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30,380
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37,975
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43,400
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60,760
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45
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16,084
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18,228
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22,785
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27,342
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34,178
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39,060
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54,684
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40
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14,296
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16,203
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20,253
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24,304
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30,380
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34,720
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48,608
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35
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12,509
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14,177
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17,722
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21,266
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26,583
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30,380
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42,532
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30
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10,722
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12,152
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15,190
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18,228
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22,785
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26,040
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36,456
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25
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8,935
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10,127
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12,658
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15,190
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18,988
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21,700
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30,380
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20
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7,148
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8,101
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10,127
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12,152
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15,190
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17,360
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24,304
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15
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5,361
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6,076
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7,595
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9,114
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11,393
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13,020
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18,228
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10
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3,574
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4,051
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5,063
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6,076
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7,595
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8,680
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12,152
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5
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1,787
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2,025
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2,532
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3,038
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3,798
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4,340
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6,076
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1
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357
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405
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506
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608
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760
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868
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1,215
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Clean
Low RPM
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Landing
Low RPM
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Landing
High RPM
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My table shows about 12,500’ above the water (approx. 13,500’ MSL) would get me to the shore (to be conservative I used a 15:1 glide ratio even though my testing showed 17:1 because the engine was still producing minimal power during the
test). So, with approved floatation gear donned, we charged across at 15,500’, giving us a good 5nm of buffer to account for extra weight and other fudge factors.
I hope this data is helpful to some of you and encouraging to others to go do this testing and practice engine-out procedures in your Lancair.
Regards,
Dan Olsen
N320DK – 750 hrs
IV-P in gestation
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