Full Flaps or No Flaps in heavy winds

[Tram]

Originally Posted by fbrewer

Bret, thanks for your reason.

Anyone else have reasons why they might choose NO Flap and 3pt vs Wheelie?

Or Wheelie vs 3pt.

This applies to winds over 15 knots, variable and gusting to 25.

I'm with Paul. I prefer the speed for directional control.

[912ry]

Originally Posted by Ironflight

When I have really strong crosswinds, I generally leave the flaps up becasue I am goign to keep some speed up to maintain better control, and once I am on teh ground, I want as little lift as I can get - to keep the airplane from trying to lift back off. The flaps will lower stall speed, and I actually want a HIGHER stall speed to facilitate killing the wing?s lift.

I also use a wheel landing with significant crosswinds becasue I want more speed for better directional control until I have planted the airplane. Then with no flaps, it is less likely to balloon back off the ground if I take a sudden gust, because of the higher stall speed. Less lift, less likelihood of lifting back off.

BTW - I don?t really consider it ?windy? until the wind is sustained over 20 - for 15 knots within 45 degrees of the runway, I would probably still be using flaps.

Usual disclaimers apply - this works for me, YMMV, and I don?t give flight instruction over th internet!

Paul

Same here. Except when I'm practicing my landings, then I mix it up as much as conditions allow. More fun that way.

[Ed_Wischmeyer]

A couple of thoughts...
* In directional control on landing, there are really three speed regimes to consider: above stall speed; below stall speed but still generating considerable lift; and slow enough that almost all weight is on the wheels. Nobody talks about the second one, but RVs can be vulnerable in that regime. In my RV-4, with full flaps, I was on the ground at about 40 mph with a crosswind, full flaps, and a gust of wind pushed me sideways a few feet;
* It's not just approach speed, it's also deceleration capability. In my RV-9A, fixed pitch prop, landing with full flaps, if I fly constant airspeed to the flare, the time in the flare increases a lot with extra airspeed. This means that if I add speed for the crosswind, I'll spend more time in the flare bleeding off speed and be susceptible to gusts there;
* The reason for extra speed on final in crosswinds is not necessarily for rudder authority. Consider sideslip angle, the difference between where the airplane is pointed laterally and where it is actually going, sort of like a lateral version of angle of attack. To counter a crosswind while still being tracking the runway, the airplane needs a sideways airspeed component. That component is the product of true airspeed and the sin of the sideslip angle (if the airplane is aligned with the runway). Everything I've read (not that all those sources were completely correct) inferred that maximum sideslip angle was constant with airspeed. So more crosswind, more speed is needed at the same sideslip angle;
* I've heard from a reliable source that in the RV-8, full flaps with the tail down can give rudder blanking from obstructed airflow. Dunno;
* In my RV-9A, with the castering nosewheel friction set correctly (I believe), the directional stability on rollout is better than a tailwheel airplane but not as good as a tricycle gear with a steerable nosewheel. I'd not observed that in any of the other planes I'd flown with castering nosewheels.

In flying, there are many styles of flying, each with advantages and disadvantages, but seldom are there obvious distinctions between right and wrong. Paul Dye gave the best advice -- don't get flight instruction over the internet.

[N941WR]

Which airplane are you asking about?

The -9, with its Ronco airfoil and long wing, needs as much drag as you can give it. All of my landings, regardless of the wind strength and direction are made with full flaps. The only variation is two ore three point. I was taught two point for windy conditions, so that's what I do.

[Robb]

Full flaps all the time for me

[Ender]

Ed-

The term you are looking for is Beta (vs Alpha for AOA). You are sorta on the right track. As Beta increases, the stall speed of the wing also increases (because you are adding more and more drag and moving it out of perpendicular to the relative wind). So increased airspeed allows you to keep the wing lifting. The ground track portion of it is maintained by the amount of roll you have in. In a cross wind you are limited by a) the amount of roll you can put in to counter the crosswind and b) the stall speed of your wing due to the increased beta.

[Ed_Wischmeyer]

Originally Posted by Ender

Ed-

The term you are looking for is Beta (vs Alpha for AOA). You are sorta on the right track. As Beta increases, the stall speed of the wing also increases (because you are adding more and more drag and moving it out of perpendicular to the relative wind). So increased airspeed allows you to keep the wing lifting. The ground track portion of it is maintained by the amount of roll you have in. In a cross wind you are limited by a) the amount of roll you can put in to counter the crosswind and b) the stall speed of your wing due to the increased beta.

Thanks, I know about beta, phi, phi to beta ratio and such... I was just writing for the less-technical audience, based on some of the previous comments. Agreed on the increased stall speed (I'd not thought about that, actually) but if you've increased your approach speed by flying faster, that's a non-issue. And the amount of roll you can put it in is not per se the limiting factor for ground track, IMHO -- the limiting factor is how much rudder you can put in to keep the plane from turning as you increase the bank angle. The planes in which I've tried this ran out of rudder first. Yes, a small point.

Now back to root-locus, Kalman-Bucy, and all those other barely remembered concepts from my youth. Nah, back to bucking rivets, that's more fun.

[Veetail88]

Full flaps all the time. I wheel land almost exclusively except when I have a passenger and landing in grass. No matter the wind, as soon as the wheels touch I dump the flaps (easy flip of the thumb on the stick) no matter the conditions. Kills the lift right away.

I'll go in a 15 knot direct crosswind but that's my self imposed limit..... except for that time I came home at night with at least 20 knot 90 degree gusts....yeah, that was interesting.

[Ender]

Ed- Ah! roger. That's a good point, my brain was stuck on something with engines under the wing, I didn't think about how much rudder I put in on just a "normal" crosswind, your right, I'm much closer to running out of rudder than roll.