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Crosswinds!

rongawer

Well Known Member
I was landing yesterday at Byron with turbulent winds coming down off the Altamont mountains at 38 gusting to 44 KT from 200?, making runway 23 the favorable one with a crosswind component of 19-22KT. It was a bumpy landing, but mostly a non-event in the Baron.

However, I'm getting ready for my airworthiness inspection and hoping to be flying soon - which made me consider about crosswinds in the RV12. I've read other posts about it, and obviously the Van's POH that states 12 KT max crosswind and 35 max total wind.

How would you think the RV12 would handle landing in yesterdays winds on RW23?
 
too much

Ron, it is pretty clear to me that yesterdays wind would be no place for an RV12. Luckily, our weather forecasting is so good now days, we can be warned when the wind is coming. In an earlier life, I flew lighter tail draggers in Alaska. When unexpected winds came up, you just had to deal with it. Sometimes landing across the runway, instead of lined up with it. And then, tied down aircraft would "fly" in their ropes. I landed a Baron with its owner once, and the wingtip was just above the surface due to steady wind. It did not worry me but did surprise the owner. He later died in a Duke when an engine failed on takeoff. Proficiency can save the day.... but it is much better to go have coffee instead of fly in many cases.
 
My experience - -

With an RV-12 - work your way up very slowly until you know where you are comfortable. A 10kt 90 degree crosswind can be a real surprise in a very light plane. I have over 1,200 hours in my RV-12. Wind over 25kts sitting on the ramp can be more than you want to be in. The tip up can get away from you, or slam down and break things unless you have your hand on it. Slowly work your way up.
 
And there's that old saying . . .

"I'd rather in on the ground wishing I was in the air, then being in the air wishing I was on the ground" . . . this has always stuck with me:)
 
xw

Crosswind limitations are also about having adequate control authority. It really doesn't matter if the pilot has the ability if the airplane doesn't...
 
Crosswind limitations are also about having adequate control authority. It really doesn't matter if the pilot has the ability if the airplane doesn't...

That's essentially my question - what is the limit of the RV12's control authority?

Normally, most POH's will state a Maximum Demonstrated Crosswind number, that is not a limit, but defined as, for example:
"The demonstrated crosswind velocity is the velocity of the crosswind component for which adequate control of the airplane during takeoff and landing was actually demonstrated during certification tests. The value shown is not limiting." Which is good, because my high-water mark for the Baron has been 56KT with a 30º (that's 28KT XW component) off down at Gen Fox (KWJF), and I commend Beechcraft on the amazing amount of rudder authority provided, which very much allows a competent, proficient pilot to land with confidence, even well above demonstrated crosswind.

BUT, aside from "don't do it", does anyone have advice based on the experience of landing in crosswinds of 15-20KT in the RV12, and if so, what was your impression? If it was difficult, what made it so? What defined your limit? Was it the lack of rudder authority? Was it taxiing?

Van's POH that states "Maximum Direct Crosswind Component is 11KT". So, is that a calculated limit? Is it really a limit? Compare that to a C150 that has a 15KT demonstrated XW and the additional high wing moment arm. Just how bad is the rudder authority of a 12? Or is the POH just being super conservative? It appears to be based on a percentage of stall (discussed in other threads), but I'm curious.

John, I appreciate your comments about sitting on the ramp at 25KT and concern for the canopy - but assuming you have a good handle on the canopy, what is the greatest handling concern?

Fortunately, I am based at a great airport for crosswind practice, with multiple runways and varying winds throughout the year. So I will work up to it, but I'm very interested in the high wind experiences of others. The lingering question in my mind is whether I need to keep my Baron for these days, or can I work a plan for the daily commute that includes the 12.

Or do I just go ahead and get going on my RV10 now and put the 12 up for sale...
 
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More comments - -

The RV-12 is light enough, that just about the time you think you are going to touch down, a slight puff of wind will have you back up - and quickly. I have developed the habit of taking the flaps off the second at least one wheel touches down. I have been describing to those interested, that landing the 12 is like having to be a "rabbit on the stick" for the last few seconds.

As far as the canopy. It will blow shut with a serious gust of say 25kts. You just want to close it a soon as possible if gusting winds ( whether getting in or out ). Also, with the castering nose wheel, if you get out with a serious wind, the plane will move on its own. Have chocks ready. Don't park too close to another plane. I am just saying, work your way up to where you feel comfortable.
 
The RV-12 is light enough, that just about the time you think you are going to touch down, a slight puff of wind will have you back up - and quickly. I have developed the habit of taking the flaps off the second at least one wheel touches down. I have been describing to those interested, that landing the 12 is like having to be a "rabbit on the stick" for the last few seconds.

As far as the canopy. It will blow shut with a serious gust of say 25kts. You just want to close it a soon as possible if gusting winds ( whether getting in or out ). Also, with the castering nose wheel, if you get out with a serious wind, the plane will move on its own. Have chocks ready. Don't park too close to another plane. I am just saying, work your way up to where you feel comfortable.

I flew an RV-12 for a while - can't agree more with this and other comments. I got caught on one long cross country flight with higher than forecast, gusty winds (around 14-19kts) at 45 degrees to runway. The airplane was fully controllable with no loss of control authority but it was a lot of work. The airplane is so light and sensitive to gusts and up/down drafts that it requires full and undivided attention - not unsafe just very different from a heavier/higher wing loading type airframe. I flew a Bonanza for a while and it cut through crosswinds and gusts "like butter" compared to the RV-12.
 
Exceed the POH limits and you become a test pilot as I tell my students. As Dirty Harry would say, ?Do you feel lucky??
 
Even more comments - -

Try to get a ride with a very experienced RV-12 pilot. It flies much better with two in it, but you will get the idea if it is gusty and more than 15kts.
 
From my experience I feel the RV-12 can handle a 15 knot X-wind if the Pilot is really proficient with X-winds. The problem comes as the aircraft decelerates after landing and rudder losses effectness causing the nose to weather vain. The brakes are not effective enough to keep the nose from turning into the x-wind.
I like to land on the runway center line but this isn?t a good idea in X-wind. I land on the down wind side of the runway and try to get it stopped before running off the up wind side. A couple of times I had to get the tow bar out to get it off the runway.
In strong X-winds I find it impossible to taxi due to weather vaining.
I?ve flown another RV-12 and it?s the same. It just doesn?t have enough brake power to keep it from tuning into the wind.
The aircraft handles great in the air and landings but lacks brake power for directional control on the ground.
If anyone knows of larger brakes for the RV-12 I?d appreciate the information.
 
From my experience I feel the RV-12 can handle a 15 knot X-wind if the Pilot is really proficient with X-winds. The problem comes as the aircraft decelerates after landing and rudder losses effectness causing the nose to weather vain. The brakes are not effective enough to keep the nose from turning into the x-wind.
I like to land on the runway center line but this isn?t a good idea in X-wind. I land on the down wind side of the runway and try to get it stopped before running off the up wind side. A couple of times I had to get the tow bar out to get it off the runway.
In strong X-winds I find it impossible to taxi due to weather vaining.
I?ve flown another RV-12 and it?s the same. It just doesn?t have enough brake power to keep it from tuning into the wind.
The aircraft handles great in the air and landings but lacks brake power for directional control on the ground.
If anyone knows of larger brakes for the RV-12 I?d appreciate the information.

This is good feedback and the type of information I was looking for - thanks.
 
The only time I?ve experienced weak brakes was right after replacing brake pads before the conditioning runs. Have you checked for any possible contamination in the brake pads like brake fluid?
 
I?ve checked my brakes many times and they are clean and they can stop the aircraft satisfactorily. The only problem is holding the aircraft straight in a 10knot X-wind component.
I?ve also flown another RV-12 several times and it?s the same.
It maybe that be that I fly stronger winds than most RV-12 operators. The RV-12 is a popular fun aircraft here at our airport but the others seem only to fly in perfect weather and clam winds.
Regardless I can land this aircraft in a much greater X-wind than it can be taxied in.
 
I?ve checked my brakes many times and they are clean and they can stop the aircraft satisfactorily. The only problem is holding the aircraft straight in a 10knot X-wind component.
I?ve also flown another RV-12 several times and it?s the same.
It maybe that be that I fly stronger winds than most RV-12 operators. The RV-12 is a popular fun aircraft here at our airport but the others seem only to fly in perfect weather and clam winds.
Regardless I can land this aircraft in a much greater X-wind than it can be taxied in.

I have spent entire afternoons doing RV-12 demo flights at OSH with a direct left 90 degree cross wind of about 15 Kts (wind sock standing straight out).

The only challenge was during the take off roll (combined yaw to the left from take-off power torque, and the yaw induced by the cross wind).
Lifting the nose as soon as possible greatly increased the rudder effectiveness and allowed for steering without dragging a brake. I didn't have any problem doing long slow taxi's on the parallel taxiway.

An nose wheel with the steering friction not adjusted correctly will have an influence in weather vaning tendency during taxi.
 
An nose wheel with the steering friction not adjusted correctly will have an influence in weather vaning tendency during taxi.

Can you expand on this a bit? I recently bought an RV-12 and immediately installed the upgraded nose fork and adjusted the friction per the installation instructions. It turns fairly easily during taxi (both on purpose and when weather vaning), which I prefer as it makes it easy to correct small mistakes and I don't end up chasing the turns and over-correcting. I'm also still fairly inexperienced though.

On the other hand, the RV-12 I transitioned in seemed to have fairly high friction. Once it started turning it was pretty hard to fix and you had to be really on top of things to prevent it happening in the first place. Especially during landing.

Which is correct?
 
Can you expand on this a bit? I recently bought an RV-12 and immediately installed the upgraded nose fork and adjusted the friction per the installation instructions. It turns fairly easily during taxi (both on purpose and when weather vaning), which I prefer as it makes it easy to correct small mistakes and I don't end up chasing the turns and over-correcting. I'm also still fairly inexperienced though.

On the other hand, the RV-12 I transitioned in seemed to have fairly high friction. Once it started turning it was pretty hard to fix and you had to be really on top of things to prevent it happening in the first place. Especially during landing.

Which is correct?
Trust me, the breakout force adjustment in the manual is correct. Having the friction too high makes it VERY difficult to steer in any wind conditions (including calm). I let mine get too stiff due to some old grease and contamination, and it was no fun at all on the ground. Once adjusted properly it got a lot easier to taxi and my takeoff runs were back to normal.
 
Can you expand on this a bit? I recently bought an RV-12 and immediately installed the upgraded nose fork and adjusted the friction per the installation instructions. It turns fairly easily during taxi (both on purpose and when weather vaning), which I prefer as it makes it easy to correct small mistakes and I don't end up chasing the turns and over-correcting. I'm also still fairly inexperienced though.

On the other hand, the RV-12 I transitioned in seemed to have fairly high friction. Once it started turning it was pretty hard to fix and you had to be really on top of things to prevent it happening in the first place. Especially during landing.

Which is correct?

The correct value is what is specified in the manual (18 lbs I think).

Too high, or too low both cause there own (but different) issues.
 
.......max Wind

.....the Van's POH that states 12 KT max crosswind and 35 max total wind.

I understand Cross Wind, Demonstrated Cross Wind, etc.....

What is maximum total wind? Does that mean ' max surface wind conditions' ...therefore, it better be tied down and secured or in the hanger?....OR?
 
.....the Van's POH that states 12 KT max crosswind and 35 max total wind.

I understand Cross Wind, Demonstrated Cross Wind, etc.....

What is maximum total wind? Does that mean ' max surface wind conditions' ...therefore, it better be tied down and secured or in the hanger?....OR?

I take that to mean the maximum wind in any direction. I took off this morning with a 17KT direct XW from the right, gusting to 20KT without issue. Based on that, I'd say 20KT XW is quite doable.

I just passed my first 100 hours in the RV12, but I'm going to limit my operation to 35KT maximum wind from any direction until I get another 100 hours or so. My opinion is that landing and taking off in XW is very controllable with plenty of authority (great rudder), but steering after landing and taxiing are a bigger challenge, IMHO.
 
Maximum Direct Crosswind Component

I appreciate all the comments in this thread and in another one that I started. I still have one question.

Does any know, and maybe someone from Van's can chime in here, did Van's intend the "Maximum Direct Crosswind Component" to be a limitation? As has been discussed, all other POH's that I have read have "Maximum Demonstrated Crosswind Component", and that is not a limitation. Van's left our the word demonstrated.

So I presume that Van's considers this a limitation. But I am still wondering why. Is it the light weight? Light wing loading? Is it mandated by the Light Sport regulations or certification requirements?

It does not matter for flying. I am going to fly conservatively but I would just like to know the reason.

Thanks.

John
 
I take that to mean the maximum wind in any direction. I took off this morning with a 17KT direct XW from the right, gusting to 20KT without issue. Based on that, I'd say 20KT XW is quite doable.

Just keep in mind that a left cross wind is the direction with the most influence on controlability during a take-off or go around because it turns the airplane to the left along with engine torque and p factor.

I right crosswind is helping to counter the torque.
 
Just keep in mind that a left cross wind is the direction with the most influence on controlability during a take-off or go around because it turns the airplane to the left along with engine torque and p factor.

I right crosswind is helping to counter the torque.
..............................................................
Hey Scott!

Are we close with our interpretations of POH.. 'Max Total Wind'?

The word 'Total' is an interesting description...Doug in IL
 
..............................................................
Hey Scott!

Are we close with our interpretations of POH.. 'Max Total Wind'?

The word 'Total' is an interesting description...Doug in IL

Think of it as max in any condition.... steady state or gust.
Examples -

If the steady state wind is 35 with no gust value, and the calculated cross wind component is 11 Kts or less, you are good.

If the steady state is 25 with gusts no higher than 35, and the calculated cross wind component is during a 35 Kt gust is 11 Kts or less, you are good.
 
If you get out your wiz wheel and calculate the actual cross wind component for a condition where the wind is 15 Kts directing perpendicular to the runway, because of fwd movement aligned with the runway heading, the crosswind component wont actually be 15 Kts. It is 9 Kts
That is why you have seen me post here that I have made landings in conditions where the wind was at 15 Kts, perpendicular to the runway.

To reach the published maximum of 11 Kts, the perpendicular steady state wind would have to be 18 Kts.

This might be a dumb question but I'm struggling to see this. If the steady state wind is blowing 10 knots directly perpendicular to the runway and the plane is moving at 10 kts down the runway, the relative airflow over the plane will be about 14 kts at 45 degrees to the direction of movement. However the crosswind component that the plane sees will still be 10 kts. Am I missing something? What is the speed of the fwd movement in the two examples above?
 
This might be a dumb question but I'm struggling to see this. If the steady state wind is blowing 10 knots directly perpendicular to the runway and the plane is moving at 10 kts down the runway, the relative airflow over the plane will be about 14 kts at 45 degrees to the direction of movement. However the crosswind component that the plane sees will still be 10 kts. Am I missing something? What is the speed of the fwd movement in the two examples above?

Aircraft speed doesn't matter.

Look at any calculator (even an old E6B) there is no input for aircraft velocity.

BTW I corrected the calculated crosswind component in my other post..... I had fat fingered the wrong runway heading in the calculator.
 
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Aircraft speed doesn't matter.

Look at any calculator (even an old E6B) there is no input for aircraft velocity.

BTW I corrected the calculated crosswind component in my other post..... I had fat fingered the wrong runway heading in the calculator.

OK. I still don't get it. Back to the drawing board. :confused:
So what was your runway heading in the above examples?
 
Just keep in mind that a left cross wind is the direction with the most influence on controlability during a take-off or go around because it turns the airplane to the left along with engine torque and p factor.

I right crosswind is helping to counter the torque.

That’s interesting, because my airplane always wants to go left when I power up and I have to use right rudder to compensate. It would seem a right crosswind would be harder to control.

Also, you stated earlier that a perpendicular wind of 24 knots would result in an 11KT crosswind, but perpendicular means 90º, which would result in a 24KT XW, so you may have meant something else. A 24KT wind 30º off of the runway heading with result in an 11KT crosswind.
 
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Actually it?s sine. Sin(90 deg)=1.

Man, Scott, they sure swept in and picked the flesh off your sun bleached bones on this one!😜
 
Flying 360 with a wind of 270 at 15 kts is a 15 kt crosswind
Flying 360 with a wind of 027 at 15 kts is a 7 kt crosswind

Flying 360 with a wind of 270 at 24 kts is a 24 kt crosswind
Flying 360 with a wind of 027 at 24 kts is a 11 kt crosswind

My faith in Pythagoras has been restored !! :D
 
What?s the likelihood we?ll see more wind capable RV SLSA?s?

Sorry if this is borderline thread creep, but bigger is better for some winds....in an old geezer’s remaining flying life what about SLSA’s in RV10, 14, 9, and 7 formats? Perhaps new rules in this next bout will support more crosswind and bump bustin capable SLSA’s. I’d pick a 9 with a 160 Or the 915is.......Just dreaming about my next Christmas present....;)
 
That’s interesting, because my airplane always wants to go left when I power up and I have to use right rudder to compensate. It would seem a right crosswind would be more limiting.

A "left" crosswind causes the airplane to "weathervane" to the left requiring more right rudder. You are already using right rudder to compensate for "P" factor, so you will run out of right rudder sooner with a left crosswind.
 
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A "left" crosswind causes the airplane to "weathervane" to the left requiring more right rudder. You are already using right rudder to compensate for "P" factor, so you will run out of right rudder faster with a left crosswind.

Well, while that is factual, the comment Scott made was that “controllability” is harder from the left, and I just personally think it’s easier to control; possibly because I’m already modulating with my right rudder.

The take-away for anyone reading this is that you will run out of “rudder authority” (that maximum limit of control) sooner with a wind from the left, but a 17G20 from the right is doable in an RV12 and it has good rudder authority for this situation, but any steady wind up to 15KT is very “controllable” from either direction - in my experience. Now, after landing and trying to taxi...that’s a different story.

I’m sure I’ll have the opportunity and will definitely check out heavier XW from the left during this winter.
 
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Well, while that is factual, the comment Scott made was that ?controllability? is harder from the left, and I just personally think it?s easier to control; possibly because I?m already modulating with my right rudder.

By controlability I meant you will run out of rudder during take-off with a left crosswind, sooner than with a right cross wind.
 
That website;
https://www.ivao.aero/db/xw/default.asp?rwy=36&dir=270&wst=15&gst=
asks for ?runway number? (two digit) and ?wind direction? (three digit, not two digit) the difference is 27 vs 270

Flying 360 with a wind of 270 at 15 kts is a 15 kt crosswind
Flying 360 with a wind of 027 at 15 kts is a 7 kt crosswind

Flying 360 with a wind of 270 at 24 kts is a 24 kt crosswind
Flying 360 with a wind of 027 at 24 kts is a 11 kt crosswind

You would think I would have learned by now.... not to try and post something in two minutes at the end of my lunch :rolleyes: (real busy.... in the middle of a complete panel makeover on one of the demo airplanes, but ignore that because I cant talk about it :rolleyes:)

I have deleted the (totally messed up) examples from my other post.
 
Actually, it’s really easy to approximate a crosswind in your head without resorting to whizz wheels, tables or sines.

Sine 60 is 0.87. Therefore we can approximate that a wind 60 degrees or more off the runway heading is the full crosswind component. We know that Sine 30 is 0.5 ie half the wind component as crosswind. This gives us the “watch code”.

10 degrees off - 1/6th component
15 - 1/4
20 - 1/3
30 - 1/2
40 - 2/3
45 - 3/4
60 - All

In other words, just use the percentage of your 60 minute watch face.

The purists might argue it’s not totally accurate but then aviation is not a precise art. In any case, it is unlikely that the wind you actually experience is the same as the one reported. So it’s close enough and easy to work out in your head. Well, it is for me who was brought up before calculators and digital watches ;)
 
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Crosswind math made easy

Here's an easier way for me...since calculating crosswind components is an estimation due to variable wind velocity and direction anyway.

We really only need to calculate the crosswind components at 30, 45 and 60. Anything in between we can "round up." And surely we don't have to calculate crosswind components for a headwind and a direct crosswind!

For headwind 30 degrees off the nose, multiply by 0.5.
For...............45 degrees, multiply by 0.7.
For ..............60 degrees, multiply by 0.9.

When doing crosswind components, we really only have to remember those three numbers, 0.5, 0.7 and 0.9.

For the curious, you'll recognize the factors as the Sine of 30 degrees, the Sine of 45 degrees, and Sine of 60 degrees.

And for the real mathematicians, the factors are found by calculating the Square Root of 1 divided by 2, the Square Root of 2 divided by 2, and the Square Root of 3 divided by 2...which are 0.5, 0.707, and 0.866, respectively!

So don't worry about the trigonometry, just use your common sense and remember 0.5, 0.7 and 0.9.

P.S. To complete the math, for a direct headwind the Square Root of 0 divided by 2 is 0.0, and for a direct crosswind, the Square Root of 4 divided by 2 is 1.0.
 
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Wind

For airports with weather reporting, Foreflight runway page gives headwind, crosswine, tailwind component for each runway.
 
Here's an easier way for me...since calculating crosswind components is an estimation due to variable wind velocity and direction anyway.

We really only need to calculate the crosswind components at 30, 45 and 60. Anything in between we can "round up." And surely we don't have to calculate crosswind components for a headwind and a direct crosswind!

For headwind 30 degrees off the nose, multiply by 0.5.
For...............45 degrees, multiply by 0.7.
For ..............60 degrees, multiply by 0.9.

When doing crosswind components, we really only have to remember those three numbers, 0.5, 0.7 and 0.9.

For the curious, you'll recognize the factors as the Sine of 30 degrees, the Sine of 45 degrees, and Sine of 60 degrees.

And for the real mathematicians, the factors are found by calculating the Square Root of 1 divided by 2, the Square Root of 2 divided by 2, and the Square Root of 3 divided by 2...which are 0.5, 0.707, and 0.866, respectively!

So don't worry about the trigonometry, just use your common sense and remember 0.5, 0.7 and 0.9.

P.S. To complete the math, for a direct headwind the Square Root of 0 divided by 2 is 0.0, and for a direct crosswind, the Square Root of 4 divided by 2 is 1.0.

We had a guest engineer speaker in my high school trig class (when dinosaurs roamed the Earth :rolleyes:) who claimed the Boeing 707?s number came from the sine (or cosine) of 45 degrees. Anyone know whether this is true? The speaker was evidently very nervous and had imbibed a shot or three of Dutch courage.
 
Trig

ALL headwinds and crosswinds can be calculated using sin and cos.

That being said, determining the design limits on the aircraft can have many variables. Some top examples would be the absolute control authority of the ailerons and rudder at the design reference speed, i.e., at a given speed, the control surfaces can only generate a certain amount of force and thus moment. When the forces/moments required to overcome the crosswind are greater than the forces/moments generated by the control surfaces, a maximum limit is defined.

Other factors can be less obvious, such as bank angle limits due to underwing engines and maximum side loading forces on the landing gear...

When the engineers say that there is a maximum design limit for something, it is generally not arbitrary; there is usually a pretty good reason for it...
 
When you break cloud at 700' in 3000m vis with rain and a 30kt crosswind and see the runway out the FO's windshield, you are earning your corn that day...

Or....

You lock onto the localiser at 12 miles and the crosswind is 73kts - again, the runway isn't in front, you know it is gunna be interesting.

Only in phase 1 with our RV12 so will limit myself to 10 knots across I think :D
 
We had a guest engineer speaker in my high school trig class (when dinosaurs roamed the Earth :rolleyes:) who claimed the Boeing 707?s number came from the sine (or cosine) of 45 degrees. Anyone know whether this is true? The speaker was evidently very nervous and had imbibed a shot or three of Dutch courage.

FWIW
Back while getting my degree, heard the same thing. In control system design.. .707 is the optimal damping factor to maximize control performance vs, stability.
 
I like the thumbrule of adding half the wind and all the gust to approach speed. If you can?t hold the centerline transitioning from crab to slip it?s time to think about landing somewhere else.
 
x wind

Very good advice , if you cant hold the rwy center line the last few feet, GO AROUND! Personally I never let my ego make my GO decision.
 
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