Use of flaps during heavy crosswinds

[MidlifeFlyer]

Originally Posted by Maurus

Only problem with that is the stronger the x-wind the more of a jerk the passengers will get when landing because of having to kick the rudder in right before touchdown. For purposes of controlling an aircraft, that technique works well.

I'm not sure what you are picturing but slipping all the way down final and jerking the airplane around 1 cm above the runway are not the only two things there.

If you only want to consider those two extremes, it's just as good a bet that passengers, especially those sitting behind the CG, would much prefer the coordinated flight down final and a 2 second jerk to sliding sideways in their seats and having their lunches slide sideways in their bellies (and ultimately out!) for an extended slip on 3-mile final.

Fortunately, we don't have to deal with those extremes and unless you land in a crab even the tightest 1 second "crab and kick" includes a slip (rudder to straighten and aileron to crosswind taxi position to stay on the runway after touchdown). Most pilots tend to find that happy medium of when to transition from the crab to the slip that balances both aircraft control and and passenger comfort.

[minitour]

Originally Posted by MidlifeFlyer

...unless you land in a crab even the tightest 1 second "crab and kick" includes a slip...

Thank you.

-mini

[Maurus]

Originally Posted by MidlifeFlyer

I'm not sure what you are picturing but slipping all the way down final and jerking the airplane around 1 cm above the runway are not the only two things there.

If you only want to consider those two extremes, it's just as good a bet that passengers, especially those sitting behind the CG, would much prefer the coordinated flight down final and a 2 second jerk to sliding sideways in their seats and having their lunches slide sideways in their bellies (and ultimately out!) for an extended slip on 3-mile final.

Fortunately, we don't have to deal with those extremes and unless you land in a crab even the tightest 1 second "crab and kick" includes a slip (rudder to straighten and aileron to crosswind taxi position to stay on the runway after touchdown). Most pilots tend to find that happy medium of when to transition from the crab to the slip that balances both aircraft control and and passenger comfort.

The only way I could visualize 30+ knot x-winds in a 152 with full flaps was with a literal kick in the rudder immediately before touchdown. Otherwise yes, it is a slip, just later rather than earlier.

[tgrayson]

Originally Posted by Maurus

Otherwise yes, it is a slip, just later rather than earlier.

But not a necessarily stabilized one. If the aircraft were capable of a stabilized slip with that sort of crosswind, you wouldn't need to wait to the last second.

[shdw]

Originally Posted by MidlifeFlyer

Most pilots tend to find that happy medium of when to transition from the crab to the slip that balances both aircraft control and and passenger comfort.

Exactly. Maurus, your forgetting momentum during the transition, you don't have to rush it so much, give it a shot. Wheels down around 45-55 knots if you approach at 65-75.

[mshunter]

Originally Posted by shdw

Exactly. Maurus, your forgetting momentum during the transition, you don't have to rush it so much, give it a shot. Wheels down around 45-55 knots if you approach at 65-75.

Isn't that a little fast for a 152? IIRC, POH says approach at 55kts, not land at 55 kts.

[shdw]

Originally Posted by mshunter

Isn't that a little fast for a 152? IIRC, POH says approach at 55kts, not land at 55 kts.

Of course it is, but it also means your under control in those nice gusty winds and won't have to fight it in with a slip. Also should a gust die you have adequate extra speed to keep from stall and allow for an easier go around. I have always been a strong advocate for "fly her to the runway" on a heavy crosswind day. Just my technique though, doesn't mean its perfect or even right but I haven't made any holes yet.

[Bernoulli Fan]

Originally Posted by tgrayson

It's a good place to start, but that doesn't mean that you have to end there. Being satisfied with that answer is simply memorizing procedures without understanding them. That isn't what this thread is about.

Be that as it may, I would like to commend clestudentpilot for going to the POH for answers to start with. Too many of my students would like to view the POH as a slightly unsavory and disorganized collection of incomprehensible characters.

Perhaps in the future clestudentpilot will be one of the rare breed who comes in for a new aircraft checkout already having looked through the POH for V-speeds and other limitations.

[mshunter]

Originally Posted by Bernoulli Fan

Be that as it may, I would like to commend clestudentpilot for going to the POH for answers to start with. Too many of my students would like to view the POH as a slightly unsavory and disorganized collection of incomprehensible characters.

Perhaps in the future clestudentpilot will be one of the rare breed who comes in for a new aircraft checkout already having looked through the POH for V-speeds and other limitations.

[BaronPete]

Originally Posted by shdw

Some aircraft don't have a lot of power, like a 152, so if you get slow on a real gusty day and the student doesn't react with near full power quickly it can become dangerous quick.

I fly a 150..so I'm left with even less power than you Can you elaborate a bit on this point?

I'm still a noob student with a checkride approaching...Soaking up all I can!

[shdw]

Originally Posted by BaronPete

I fly a 150..so I'm left with even less power than you Can you elaborate a bit on this point?

I'm still a noob student with a checkride approaching...Soaking up all I can!

Students tend to be shy about adding power when they get slow, in larger trainers like the 172 where they are 300 pounds under gross there is more than sufficient power. Aircraft like that, even if they are timid will usually still pull through fairly safely. They are also more stable and because they are heavier carry more momentum.

In your smaller 150 which if I remember they have 100 HP right? I know it is 10 less than a 152. Anyways in an aircraft like that you are typically flying near maximum weight with an low powered engine. In a high drag situation, such as full flaps, and running slow, consider around 50 knots slow on a gusty day, if you loose 10 knots to a gust you are now at 40 knots. Your first reaction will be a pull back loosing probably a few more knots and then adding power.

This is a very tough situation for a low powered aircraft to get out of: pitched at a high angle of attack, very slow, with a lot of drag. Full power may be needed to make that save but more importantly GET THE NOSE DOWN and that one step is what most new guys miss. The second those controls feel sloppy let the nose down, that nose will give you airspeed and reduce your AOA away from stall.

So the overall thing to learn is don't get slow. But if you do your first reaction should be to lower the nose followed by a good increase in power. Don't be timid with the power, too much is infinitely better than too little. If you give enough power when you lower the nose you won't even loose altitude, practice this with slow flight at altitude to see what I mean.


Here is how:

Tell your CFI you want to do some slow flight. Go up and get it slowed down and stable at say 40 knots and bring the power back to an approach power which will send you sinking. Let the descent stabilize than stop it by shoving the nose forward and jamming the power in, feel the aircraft seat push up on your butt, that is the sink rate reducing and the controls become more responsive from your airspeed going up. If you don't see it than have your instructor do it and watch the instruments (don't forget to listen and feel it as well, your a VFR guy ). Good luck bud.

[mshunter]

Originally Posted by shdw

Tell your CFI you want to do some slow flight. Go up and get it slowed down and stable at say 40 knots and bring the power back to an approach power which will send you sinking. Let the descent stabilize than stop it by shoving the nose forward and jamming the power in, feel the aircraft seat push up on your butt, that is the sink rate reducing and the controls become more responsive from your airspeed going up. If you don't see it than have your instructor do it and watch the instruments (don't forget to listen and feel it as well, your a VFR guy ). Good luck bud.

Or my personal favorite, "it's like a boat that's not up on plane, and too heavy to float. You have to keep the speed up to keep it from sinking. Let me show you the region of reverse command."

[BaronPete]

Originally Posted by shdw

Students tend to be shy about adding power when they get slow, in larger trainers like the 172 where they are 300 pounds under gross there is more than sufficient power. Aircraft like that, even if they are timid will usually still pull through fairly safely. They are also more stable and because they are heavier carry more momentum.

In your smaller 150 which if I remember they have 100 HP right? I know it is 10 less than a 152. Anyways in an aircraft like that you are typically flying near maximum weight with an low powered engine. In a high drag situation, such as full flaps, and running slow, consider around 50 knots slow on a gusty day, if you loose 10 knots to a gust you are now at 40 knots. Your first reaction will be a pull back loosing probably a few more knots and then adding power.

This is a very tough situation for a low powered aircraft to get out of: pitched at a high angle of attack, very slow, with a lot of drag. Full power may be needed to make that save but more importantly GET THE NOSE DOWN and that one step is what most new guys miss. The second those controls feel sloppy let the nose down, that nose will give you airspeed and reduce your AOA away from stall.

So the overall thing to learn is don't get slow. But if you do your first reaction should be to lower the nose followed by a good increase in power. Don't be timid with the power, too much is infinitely better than too little. If you give enough power when you lower the nose you won't even loose altitude, practice this with slow flight at altitude to see what I mean.


Here is how:

Tell your CFI you want to do some slow flight. Go up and get it slowed down and stable at say 40 knots and bring the power back to an approach power which will send you sinking. Let the descent stabilize than stop it by shoving the nose forward and jamming the power in, feel the aircraft seat push up on your butt, that is the sink rate reducing and the controls become more responsive from your airspeed going up. If you don't see it than have your instructor do it and watch the instruments (don't forget to listen and feel it as well, your a VFR guy ). Good luck bud.

I gotcha, just wanted to make sure I was clear. The 150 is pitifully powered. You are correct in that it has 100HP total, but in reality probably only like 60 usable. I figure 100HP would be with the engine redlining on a "standard" day which we just don't have in Alabama. I would guess that the usable horsies would be somewhere in the area of 60-70ish?

Anyway, when you say losing another 10 kts to a wind gust do you mean that the wind ballooned you nose high, thus draining some airspeed?

[shdw]

Originally Posted by BaronPete

I would guess that the usable horsies would be somewhere in the area of 60-70ish?

Anyway, when you say losing another 10 kts to a wind gust do you mean that the wind ballooned you nose high, thus draining some airspeed?

The HP question isn't my field, maybe one of the mechanics here can give some more information. Lower RPM is certainly less horsepower (work/time), but how much I would have no clue.

For your losing airspeed, I suggest you read into wind sheer a little bit. Gusty conditions imply wind will increase and decrease rapidly, right? So you are flying along at 50 knots with the wind at 20 knots. Now the wind picks up to 30, putting your airspeed at 60, to counter this you slow down back to 50. Now you are at 50 knots with 30 knots of wind and suddenly the wind dies back down to 20 knots, now your airspeed is 40 knots. That was the scenario I was referring too, pitch isn't a factor but instead the sudden loss of windspeed.

[zach bird]

Originally Posted by mshunter

, You want some more Coke?

Edit: P.S. Just make sure that whatever you do, put the damn airplane on the ground w/out bending it.

Could you pass the milk duds please

[BaronPete]

Originally Posted by shdw

The HP question isn't my field, maybe one of the mechanics here can give some more information. Lower RPM is certainly less horsepower (work/time), but how much I would have no clue.

For your losing airspeed, I suggest you read into wind sheer a little bit. Gusty conditions imply wind will increase and decrease rapidly, right? So you are flying along at 50 knots with the wind at 20 knots. Now the wind picks up to 30, putting your airspeed at 60, to counter this you slow down back to 50. Now you are at 50 knots with 30 knots of wind and suddenly the wind dies back down to 20 knots, now your airspeed is 40 knots. That was the scenario I was referring too, pitch isn't a factor but instead the sudden loss of windspeed.

I mean I'm aware (or thought I was) of wind shear and it being the reason behind carrying some extra speed when landing in windy conditions, but it seems almost like we're talking groundspeed here. If I'm flying at 60 knots and get a gust in the face of 20 knots, it doesn't seem to me that the ASI would drop to 40. Isn't the relative wind still producing the same amount of lift, if not more, provided your AoA hasn't changed?

I really hate to think someone needs a crayon box to break this down for me, but I feel it's worth asking.

[shdw]

Originally Posted by BaronPete

I mean I'm aware (or thought I was) of wind shear and it being the reason behind carrying some extra speed when landing in windy conditions, but it seems almost like we're talking groundspeed here. If I'm flying at 60 knots and get a gust in the face of 20 knots, it doesn't seem to me that the ASI would drop to 40. Isn't the relative wind still producing the same amount of lift, if not more, provided your AoA hasn't changed?

I really hate to think someone needs a crayon box to break this down for me, but I feel it's worth asking.

It could also be my method of explanation, so let's try something different. We are not talking ground speed at all, instead it is flight speed through the air as that is all that matters, right? I mean in a 50 knot wind we can be flying at 50 with a ground speed of zero and still not stall.


Let's park the airplane on the ground and face it into the wind. Now let's turn on a big fan that blows air at 20 knots over the wings, this is similar to an aircraft flying at 20 knots (if it could actually do this). Now imagine we turn the fan off, the aircraft is now back at zero, right?

Time to take this and apply it to an aircraft in the air. You are flying forward through the air at 50 knots of airspeed with that fan blowing in your face. Now someone pulls the plug on you, what would happen to your airspeed? Well with the fan off, 20 knots of airflow is no longer being blown into the airplane so the result would be an airplane flying at 30 knots through the air instead of 50.

Let's reverse the scenario to flying at 50 knots with the fan off and then someone turns the fan on. Now you have an additional 20 knots of air flowing over the wing and your airspeed would pick up to 70 knots.

Again ignore ground speed in all of this. What matters is the airflow over the wing and the danger is when a gust dies down, in other words, someone turned your fan off. If you are going slow when the fans shut off you can be left dangerously close to a stalling airspeed.

[BaronPete]

Originally Posted by shdw

It could also be my method of explanation, so let's try something different. We are not talking ground speed at all, instead it is flight speed through the air as that is all that matters, right? I mean in a 50 knot wind we can be flying at 50 with a ground speed of zero and still not stall.


Let's park the airplane on the ground and face it into the wind. Now let's turn on a big fan that blows air at 20 knots over the wings, this is similar to an aircraft flying at 20 knots (if it could actually do this). Now imagine we turn the fan off, the aircraft is now back at zero, right?

Time to take this and apply it to an aircraft in the air. You are flying forward through the air at 50 knots of airspeed with that fan blowing in your face. Now someone pulls the plug on you, what would happen to your airspeed? Well with the fan off, 20 knots of airflow is no longer being blown into the airplane so the result would be an airplane flying at 30 knots through the air instead of 50.

Let's reverse the scenario to flying at 50 knots with the fan off and then someone turns the fan on. Now you have an additional 20 knots of air flowing over the wing and your airspeed would pick up to 70 knots.

Again ignore ground speed in all of this. What matters is the airflow over the wing and the danger is when a gust dies down, in other words, someone turned your fan off. If you are going slow when the fans shut off you can be left dangerously close to a stalling airspeed.

I see what you're saying. I knew it couldn't be groundspeed, just needed a different picture I suppose

[shdw]

Originally Posted by BaronPete

I see what you're saying. I knew it couldn't be groundspeed, just needed a different picture I suppose

That is usually the problem with instruction, we can all learn it, it just needs to be presented a different way for every student. Makes this crap difficult!

[Dazzler]

Originally Posted by shdw

It could also be my method of explanation, so let's try something different. We are not talking ground speed at all, instead it is flight speed through the air as that is all that matters, right? I mean in a 50 knot wind we can be flying at 50 with a ground speed of zero and still not stall.


Let's park the airplane on the ground and face it into the wind. Now let's turn on a big fan that blows air at 20 knots over the wings, this is similar to an aircraft flying at 20 knots (if it could actually do this). Now imagine we turn the fan off, the aircraft is now back at zero, right?

Time to take this and apply it to an aircraft in the air. You are flying forward through the air at 50 knots of airspeed with that fan blowing in your face. Now someone pulls the plug on you, what would happen to your airspeed? Well with the fan off, 20 knots of airflow is no longer being blown into the airplane so the result would be an airplane flying at 30 knots through the air instead of 50.

Let's reverse the scenario to flying at 50 knots with the fan off and then someone turns the fan on. Now you have an additional 20 knots of air flowing over the wing and your airspeed would pick up to 70 knots.

Again ignore ground speed in all of this. What matters is the airflow over the wing and the danger is when a gust dies down, in other words, someone turned your fan off. If you are going slow when the fans shut off you can be left dangerously close to a stalling airspeed.

Nice explanation.

[saria19]

I find that it is better to teach a student to use less flaps in high winds because controlability of the aircraft is better. That is something you want, no matter what stage of your flight career you're in. More importantly, one day when that student is soloing and they run into those sorts of winds, the flight can usually be ended in a safer manner, with less fear on both sides (for both the instructor and student).