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Random Griz Aviation Musings

IKE

IKE

Nerd Whirler
pilot
sevenhelmet said:
The reason for flaps up in the case @ChuckMK23 mentions is to increase weight on wheels, resulting in better braking effectiveness- a common performance landing technique in small aircraft. Often times pilots will also raise flaps on a touch and go, to reduce drag during the subsequent acceleration and climb out. Of note, raising flaps during the ground roll will not have a significant effect on rolling resistance of the wheels.
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Good answer... I was gonna ask why he doesn't just hover and land vertically.
 
Gatordev

Gatordev

Well-Known Member
pilot
Site Admin
Contributor
sevenhelmet said:
The reason for flaps up in the case @ChuckMK23 mentions is to increase weight on wheels, resulting in better braking effectiveness- a common performance landing technique in small aircraft.
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Suspicion confirmed. It still makes me question the effectiveness on my plane. I wonder if it would even be measurable in the real world.

sevenhelmet said:
Often times pilots will also raise flaps on a touch and go, to reduce drag during the subsequent acceleration and climb out.
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Often times? I wonder when you would NOT want to do that (given that "raising the flaps" may also mean "raise flaps to T/O setting")? Why climb out as a giant induced drag air brake when you can climb out with better flow?

I'm asking a mostly tongue-in-cheek rhetorical question. I know what you mean.
 
ChuckMK23

ChuckMK23

FERS and TSP contributor!
pilot
RE Short Field Approach - in the ACS the FAA just wants to see :
Use manufacturer’s recommended procedures for airplane configuration and braking.
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and from the POH:

1675694816745.png

The flap motor in most Cessna products (Caravan included) is a high torque/low speed variety - and it takes a good while for the flaps to fully retract. By that time, the wing has likely stopped flying.
 
sevenhelmet

sevenhelmet

Low calorie attack from the Heartland
pilot
Gatordev said:
Suspicion confirmed. It still makes me question the effectiveness on my plane. I wonder if it would even be measurable in the real world.
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So go out and measure it. I bet you'll see a difference.

Gatordev said:
Often times? I wonder when you would NOT want to do that (given that "raising the flaps" may also mean "raise flaps to T/O setting")? Why climb out as a giant induced drag air brake when you can climb out with better flow?

I'm asking a mostly tongue-in-cheek rhetorical question. I know what you mean.
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I'm with you. Sometimes just getting airborne is the priority, and I will raise the flaps once I clear obstacles. Otherwise yeah, I'm going to put flaps in a TO configuration before adding power. Especially so if power is limited, like in a C-172. Interestingly, in the 172, max gross weight is limited by full-flap climb gradient. There are STCs to limit flap travel to 30 deg (instead of 40), which allows a 100 lb addition to MGW. At least one of the STCs is just a restrictor plate that bolts to the flap switch, so it can't be moved past the 30 degree position. And just like that, you can add more gross weight.

Aviation is weird like that sometimes.
 
Gatordev

Gatordev

Well-Known Member
pilot
Site Admin
Contributor
sevenhelmet said:
So go out and measure it. I bet you'll see a difference.
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I'd have to figure out how to maintain consistency in braking, as well as trying to get the throttle rolled off at the same point in the flare each time. Could be an interesting experiment if the weather was calm, or at least consistent.

Friday's aviation adventure however (weather permitting) will be to go get a main mount changed. I've been flying semi-flacid the last few weeks. I've been told it happens to everyone.
sevenhelmet said:
And just like that, you can add more gross weight.

Aviation is weird like that sometimes.
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The -135 P2+ is like that. Some are 2910 KG, some are 2950 KG. They're the same aircraft, same STCs, same engines, just manufactured at different times. Thankfully ours is a 2950. The spares are 2910 and it can make a difference, especially with a prisoner and guard.
 
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