KC10 FATboy

Photon, I agree 100%. To ad further data to suggest that a forward slip landing and landing on one gear is ok, I have a TriJet Newsletter from McDonnell Douglas which discusses crosswind landigs. If has numerous diagrams and force polygons (for the physics geeks). Ultimately, they recommend the forward slip landing method for crosswind landings.

250 or point 65

What I was trying to say, only worded much better.

PearlPilot

thanks everyone for a great discussion! I learned a lot more than what I expected from a question that had to do with a technical term. I understand that mechanical inputs such as memorizing aileron into the wind, opposite rudder to keep nose aligned would never enable student pilots like me to grasp basic stick and rudder skills. Again, a great discussion.

ryan1234

So basically let me get this straight.... (since my explanations are not true):

You say that your are still a ways to go from stall speed (critical AoA) when landing on one wheel. Please explain "significant lift" with one wheel on the ground... what are we talking here 50kias? 45kias? (in a 172 let's say) or a touch and go (at whatever would be slowest speed to stay in contact with the ground, considering the ground effect). Basically you are saying you touch down a ways from your stall speed?

I may have rode the short bus to work here... but just curious why would you want to be all cross-controlled during a gusty day? That doesn't seem like positive aircraft control.


What I usually do is a little of both but mostly crab during approach and just a really slight bit of opposite rudder and roll back to centerline ... works pretty good.

ryan1234

The DC-10/trijet series was designed to be landed like that. Other companies tried different ways (i.e. Boeing) and preferred the crab til the end... some of which was because of where everything was located (wing tips, engines, etc)... I think the 73 has a max of 7 degrees wing down during landing (word on the street) before brushing either engine. This whole conversation we are having (along with some other factors) was what caused Boeing to look into castoring mains (B-52).

You all have valid points about the landing style I understand.... just playing the devil's advocate as well as some questions I've had about pragmatic instruction.

NoyGonnaDoIt

Are you thinking that somehow an intentional silp in which the pilot makes constant, moment-by-moment adjustments for changing wind conditions from a selected point before touchdown all the way to touchdown involves less positive control of the airplane than coordinated flight?

"Positive aircraft control" means getting the aircraft to do what you want. If there is, for example a 12G20 KT crosswind component and the goal is to touch down with the airplanes path and longitudinal axis both aligned with the runway, cross-controls (aka "doing what is necessary to produce the goal") at the point of touchdown is the way to produce "positive aircraft control" to meet that goal.

Or are you thinking that a slip to landing is something that is all or nothing? This might not apply to you but an awful lot of arguments about "crab and kick" vs "slip" are based on that misconception.

In order to perform a crosswind landing slip properly, you do not need to begin the slip 30 miles from the runway. That's obviously an exaggeration, but it's to make the point that you do not need to begin it 1/2 mile from touchdown or even 100' from touchdown. Or even 10. Plenty of pilots do just fine making the decision to begin the crosswind slip in the flare just a second or so (or less) from touchdown.

Now there's "positive aircraft control!"

Photon

What I really meant was that you made something very simple, very advanced by going in depth into what happens when an airplane stalls, which was not really relevant to the discussion.
Seemed more like a way to try and hide something that was wrong with a lot of technical explanations to try and throw people off? I might be wrong on that one though, just what it seemed like.

I would say, when I land in rather "severe" crosswinds (talking >10 crosswind component in a 172), I would imagine my speed at touchdown would be around 50 or so. If you want to stall the aircraft into a touchdown then the amount of correction you would have to put in would be rather significant, and holding centerline at this reduced speed would also be harder. You also land with less than full flaps, say 20 degree flaps, as to get your airplane more stable in the wind. If you try to stall a landing, at full flaps, with a at-the-limit crosswind, I can't imagine that would be easy to control at all.

It's not like I slip the airplane on a 600-feet final. The way I teach is the "crab transition to sideslip" method if you'd like. Crabbing down final, until at a position to flare, where I transition to a sideslip and land. We're talking approach speed of 65 (+50% of gust factor if applicable), and touchdown would not be much less than 50, so we're talking still ca 10kts IAS from Vso.
Remember also, that when stalled, the airplane still develops a "significant" amount of lift, just not enough to keep the airplane flying level.

I guess this goes as the crab and kick method. Even though all sorts of pilots will argue to the end of time which one is better between the three:
- Crab and kick
- Sideslip
- Crab and sideslip

Personally I still prefer the last one. You land with a minimum of sideloading on the tires and landing gear, and everything runs in the same direction they were supposed to go.
With the crab and kick I feel that, you have to be really good to pull it off, because if you wait to long, especially in a smaller airplane, that momentum you were carrying, will not hold long in a 15kts crosswind component type of wind, and sideloading will in that instance be imminent. Touchind down with the downwind wheel is also a problem? Making the airplane, especially a highwinged Cessna, susceptible to be blown over?
With the sideslip all the way down final, I don't feel comfortable beeing cross-controlled at 600 feet, so that's why I prefer to transition to it when I actually need it (right before touchdown)

ryan1234

Are we still talking about one wheel touch and goes or just general landing methods?If you all read my previous posts you'll see that it mostly pertains to that. I don't have any firm data to back up one gear loads... Just exploring all the critical dynamics of it

Photon

I don't see the major difference. In a one-wheel touch and go you just add some power to be able to take off again , in a sideslip touchdown you just let that power subside and let the other wheels settle onto the ground. I don't see where there is a difference in landing gear loads

Cubdriver

Mr. Trome- we discussed this on another thread some months ago. You may wish to consult:

Eights On Pylons thread