Crosswind landing debate • Redux (Go the crabs)

[turboplanner]

41 minutes ago, F10 said:

“TW The aileron on the into wind wing is actually up, not down. If the aileron were down, it would lift the into wind wing.”
Yes…but what I meant is touching down on one wheel in a wing down landing…the aircraft is still flying, most pilots use aileron to lower the other wheel. This roll often causes an out of wind rolling moment with down aileron, at the worst time. Watch the Oshkosh cross wind landings on U Tube….the wing down lads seem to get more out of shape immediately after touch down, to me anyway.

Good point, thend to happen at the lighter end of the scale.

 

The other thing which I don't think has been mentioned is the type of crosswind.

Some pilots will go for years from certain locations without experiencing a major crosswind, let alone what you just described, then with no thought that the next airfield will be any different will encounter gusting sea breezes put the power on and go round. I've seen many people do that, but sometimes their mind lags. If you go over years of RAA Magazine incidents you'll see the result, mostly with the aircraft finishing up sitting on the wing, a main and the nosewheel with relatively minor damage or continue over onto its back. There is never enough discussion about those accidents.

[Flightrite]

I think you guys are over thinking all this, just plant the thing & talk about it in the bar afterwards:-)😉

[turboplanner]

It’s a bit different to Flightsim.

[facthunter]

One thing for sure IF you get it wrong you can write off a small plane easily especially if the nosewheel touches first.. Many Airliners leave the crab on and maintain the centreline. That can put great stress on the undercarriage more so if it's a heavy landing to start with and will usually drop all the masks..

 Discussion can be good but can also confuse, which is not good.

  A couple of comments. In a X wind if you bounce Go around don't muck around with It.   If the idea of landing on one wheel bother's you, train more  IF you are going to go anywhere near the plane's X wind limit you must be comfortable with it.

 Next it you are only inches above the deck, crossed controls cant get you into trouble and when you touch down that's exactly where the controls should be. During the landing roll also you might have full rudder and into wind aileron. and even when you are taxying. Nev

[skippydiesel]

If your "inches above the deck" and you are anxious to get the wheels on, dump/lift flap - works for me.

 

Warning - dont dump flap if you haven't practised this procedure. Dumping flap "reduces lift" at that air speed and will negatively impact on your chances of a successful go round (if required)

Edited October 1, 2021 by skippydiesel

[F10]

10 minutes ago, skippydiesel said:

If your "inches above the deck" and you are anxious to get the wheels on, dump/lift flap - works for me.

 

Warning - dont dump flap if you haven't practised this procedure. Dumping flap "reduces lift" at that air speed and will negatively impact on your chances of a successful go round (if required)

Well, something which has only come up now!…..I would never use anything more than about 10-15 degrees or “Take off” flap, landing in a strong crosswind. Full flap or “Land” flap only increases the crosswind effect on the aircraft and encourages the into wind wing to lift on touchdown, this flap setting will also cause you and your aircraft to work harder on a go around….remember the Golden Rule. Generally:

Around 12 degrees flap, means lots of lift…for a small drag increase

More than 12 odd degrees, means a small lift increase, with a large drag increase.

Choose what’s best for the situation.

Edited October 1, 2021 by F10

[Flightrite]

Took y FlightSim outside today set it up with a strong x-wind blowing across the screen, too easy to land regardless of wind😁

Edited October 1, 2021 by Flightrite

[facthunter]

After you get out of hospital? Talk has it's limits. EVERY consideration of this subject  by a knowledgeable pilot group ends up emphasising GET A GOOD INSTRUCTOR and..... None of this is FULLY one or the other. (crab or slip)The take off embodies some of the same issues. IF you are taking off on a rough strip with a crosswind and you get bounced into the air prematurely.. ask any Auster driver..  whose done a bit of time on them. You allow for X wind before you rotate a jet. Sweep back and dihedral add to X-wind problems.. Nev

[turboplanner]

22 hours ago, F10 said:

“a low wing with its side effect of  boundary layer, high wing, and biplanes where you had to allow for one wing in boundary layer and one not,”

 

Not sure here. “Boundary layer” as I understand it, is the very thin layer of air, on the wing surface. Air molecules right at the wing surface, get dragged along with the wing. They brushed Tulcum powder onto a Mirage F1 wing, flew it to 600 kts, powder was still on the wing. There is a smooth laminar flow at the leading edge area, we then reach the “transition point” where the boundary layer becomes slightly turbulent and finally the separation point near the trailing edge, where reverse flow occurs causing separation.  The energy  characteristics of this boundary layer, and it’s ability to stick to the wing surface, determines the stalling characteristics of an aircraft. Boundary layer breakaway, defines the stall. So, as to bi plane landings, what may refer is the lower wing being more in “ground effect”, a different concept, than the upper wing? I would not have thought this would be noticeable as ground effect can be noticed by a pilot, up to half a wingspan (in theory, 3/4 wingspan) above the runaway surface. Anyone suffering insomnia….well this should have sorted it!😴

Sorry, put you off the trail with the wrong description, should have used the term "ground effect"

[Bruce Tuncks]

Gosh F10, what you say about cross-winds and flap is obviously correct. This is the first time I ever heard about it, so thanks.

Edited October 1, 2021 by Bruce Tuncks

[F10]

39 minutes ago, Bruce Tuncks said:

Gosh F10, what you say about cross-winds and flap is obviously correct. This is the first time I ever heard about it, so thanks.

Cheers! Another interesting discussion I think, are flap types.

Cessna uses Fowler flaps, they travel outwards and down, creating a converging duct between the flap leading edge and wing trailing edge. This duct accelerates airflow over the flap, holding off boundary separation (stall) he flap is like a little aerofoil at the back of the wing. Because they travel outwards they even increase wing area. 747 has “triple slotted” Fowlers, three converging ducts, greater wing area, three “little wings”. Great flap system but complex and heavy, so you won’t see it in GA.

 

Next best, the PC9/Harvard for example used “split flaps”, bottom section of wing trailing edge hinges down. Normally stretch full span of wing, from aileron to aileron (some aircraft STOL can even droop the ailerons) their advantage is your wing top surface area is not reduced with flap down, yet increase bottom surface wing camber, overall lift increase.

 

Plain flaps, Cherokee 140 an example. Simply, the a section of the wing trailing edge hinges down. Work ok, least effective flap type however, but cheap, light weight and easy to build. Thus on a lot of GA aircraft.

Edited October 1, 2021 by F10