When do you NOT use flaps landing?

[C. Brenden]

Leaving the flaps down after landing is not a 'signal' to ATC.

[sailvi767]

It once was a signal in the part 121 world but has been discontinued for years.

[zilik]

Originally Posted by rightrudder

During calm conditions, I can't see a reason not to use full flaps (short of no-flap landing practice). Less kinetic energy on touchdown, less chance of nose wheel shimmy (for us -A guys), easier on brakes, tires, etc.

Flaps have ZERO influence on nose wheel shimmy. Touchdown speed when you let the nose wheel down does.

I land full flaps 98.736% of the time in my 6A. The only time I land flapless is in very gusting conditions.

My landings are full flaps, Zero throttle unless conditions warrant otherwise.

[zilik]

Originally Posted by sblack

Why? Still don't see the purpose of doing that.

My experience only. The hardest landings I have to make are when the wind is straight down the runway and gusting 30+. I hate that. Two things flaps do. 1. increase lift. 2 increase drag. The gusts comes, I balloon. The gust drops, I drop. With zero flaps this is affect is lessoned some.

Strong crosswind. Again the gusting 30+ 80 degree crosswind. A zero flapper for sure. If I used flaps the fact that the flaps are hanging down gives more area for the crosswind to grab, hence harder to compensate for. The gusts in this instance do not increase/decrease lift. An easier landing than straight down the runway gusts.

I really like challenging crosswinds. I loath challenging straight down the runway winds.

My $0.02

[rv699jb]

Using extremes makes it easier to see sometimes. Imagine an airplane that lands at two hundred, versus one that lands at twenty. We have a twenty mile per hour crosswind. The two hundred m.p.h. plane goes forward 200 units for every 20 sideways, while the twenty m.p.h. plane goes 20 forward and twenty sideways. So, the angle the plane crabs while flying to maintain a track over the runway is different. The twenty m.p.h. plane is in a 45 degree crab. The 200 m.p.h. plane less than ten degree crab. To land, we transition from a crab to a slip by using rudder to push the nose to align with the direction of runway, so the tires are parallel with the direction we need to be going to land. The 200 airplane needs very little rudder imput to accomplish this. It is almost like the crosswind is non existent. The twenty m.p.h. plane takes a huge amount of rudder, and may not even have enough rudder imput to swing the nose that far! If we could have a way to just change the 20 m.p.h. airplane into a 200 m.p.h. airplane when we need that for landings. So, the point of this is two fold. One, the faster we can land, the less crab angle we have to overcome. If we are close to a speed where we are using full rudder and we get gusts on top of it, we might not have enough control to land. So, a no flap landing raises the stall speed slightly to allow us to touch down faster with less crab angle to remove with rudder! This is the control our airplane has to make it closer to the 200 m.p.h. plane. Secondly, the faster we go, the more force a deflected control has for a given imput. If we can land faster (stall at higher speed), the rudder won't need as much deflection to align the nose to the direction of travel necessary to land as it would at a slower speed. We have more control reserve, so to speak, at higher landing speeds! The rudder works on a lever arm back from the center of gravity of the plane. If you can make the plane land faster, less rudder imput is necessary for the force required to align the airplanes with the runway, and less change of angle is required too. If you move the center of gravity forward, your rudder has more authority too, because you lengthen the lever arm (another discussion)! Now, one last thing: remember, lift causes drag. After touchdown, the airplane still wants to weathervane towards the wind. Let's say we have a right crosswind. The plane wants to turn right. As we slow, the rudder runs out of enough force to keep the plane aligned with the runway. The plane is still light on the tires, so brakes don't work well either. If only we could have some way to pull backwards on the left wing till we get a little slower and the tires have enough friction to grip! We do, but most pilots quit flying after touchdown. Roll the ailerons full stop towards the wind after touching down. In this situation, the left aileron is down, causing lift and also drag. More drag on the left wing is free help to keep us aligned with the direction we want to go and not the way the cross wind wants us to weathervane and go! It is like giving the full left rudder we are holding just a little boost! Just some thoughts I hadn't seen up to this point..

jimmyB
RV-6

[HAMFLYER]

I always use minimum flaps in high cross wind conditions.

[Dugaru]

Originally Posted by jpowell13

I thought of one case where adding flaps can be a problem. When practicing coupled approaches my autopilot pitch servo gets overloaded due to out of trim condition when I add flaps. For that reason I may land without flaps after flying a coupled approach. John

No need to worry. I've been told by several people here that the failure of an autopilot would never be a safety concern.

[kstone]

Interesting discussion. I've had my (bought) -7A less than a year, but my experience is that flaps on my plane add very little lift, mainly just drag. When going from no flaps to full flaps, the plane does not required any trimming, which tells me there's little additional lift. I always use full flaps landing except in strong, gusty crosswinds, because the drag from the flaps combined with the flat CS prop are like putting on speed brakes during the flare and floating is negligible, even at the fairly high approach speeds I use.

[David-aviator]

Originally Posted by kstone

Interesting discussion. I've had my (bought) -7A less than a year, but my experience is that flaps on my plane add very little lift, mainly just drag. When going from no flaps to full flaps, the plane does not required any trimming, which tells me there's little additional lift. I always use full flaps landing except in strong, gusty crosswinds, because the drag from the flaps combined with the flat CS prop are like putting on speed brakes during the flare and floating is negligible, even at the fairly high approach speeds I use.

Try 10 degrees of flaps for take off.
It does provide earlier lift not there at zero flaps.

[lr172]

A question for the experts. I fly my 6A from a field where most strong winds are 80-90* crosswinds from the South. There are a bunch of buildings and trees on the south side of the field that are about 100 yards away and for the whole length of the runway. I get a lot of unpleasant gusting, rotors, etc. When the winds are gusting >20-25, I get violent sinks of 5' or so while flaring. Due to this, I have dropped my SOP from 40 -> 30* of flaps.

I am wondering, will reducing flaps further help me to better manage these situations? It is a 4000' runway, so I have plenty of room to work with.

Thanks,

Larry