Primarily for general aviation discussion, but other aviation topics are also welcome.
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By Flyin'Dutch'
FLYER Club Member  FLYER Club Member
#1899916
Ibra wrote:0.2×VS0 actually :wink:

Not tempted with 0.3×VS in Maule but with low stall speed 13mph seems huge for me... ideally a well handled ground loop shoudl result in smaller ground runs, I only need LDA/(2×3.14159): not bad for performance landings on STOL machines :D

https://www.govinfo.gov/app/details/CFR ... 33/summary


Sorry for the inaccuracy, stall speed of Maule is something like 39 mph IIRC!

Anyway if you are going to limit yourself, after having built up the requisite experience, and recency, to 13 mph in the Maule, then you are going to miss out on a lot of great flying days.

It was my experience that it was very much possible to manage decent crosswinds with the Maule, and that is with my very average flying skills.
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#1899947
I can never get the idea of flying a known wing down angle in a low wing tricycle. I’m always like, crab, crab, crab, time to close the throttle, rudder to straighten, centre line going left, ailerons left, centre line going right, ailerons right. Who knows how much aileron that is?
How can you even judge it when you have the transition from power to glide and ground effect. You just rudder the wheels in line with the runway and steer back to the centreline with the control column if you lose it. That inevitably puts you in the correct wing down angle and produces an into wind wheel touchdown. We are talking about the last couple of seconds of the flight, who can possibly be cognisant of the angle of the wing at that point?
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#1899952
@TLRippon you're right of course, but unfortunately quite a few PPL students get taught to consciously transition from crab to wing down much earlier than that. I can only assume that's the way the airlines do it (I must watch some of those videos that get posted every time it's a bit windy).
Incidentally those of us who started in gliders use your method - it IS possible to ground a wingtip if doing wing down with a big wingspan.
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By Flyin'Dutch'
FLYER Club Member  FLYER Club Member
#1899953
lobstaboy wrote:Incidentally those of us who started in gliders use your method - it IS possible to ground a wingtip if doing wing down with a big wingspan.


Indeed, and sitting so close to the ground it soon becomes second nature to align the glider with the direction of travel, not to would be and feel very wrong.

Ground looping with a large span glider is very easily done and is not just bad for the glider - your beer drinking account will be abused by friends too to help you obliterate the shame! :D
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By VRB_20kt
FLYER Club Member  FLYER Club Member
#1899959
lobstaboy wrote:@TLRippon you're right of course, but unfortunately quite a few PPL students get taught to consciously transition from crab to wing down much earlier than that. I can only assume that's the way the airlines do it


It appears that modern aircraft are designed to land with uncorrected drift. Just hit the runway and the undercarriage will handle it. The forces must be substantial.

(Hopefully someone better qualified can confirm the limits)
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By BoeingBoy
#1899984
Oh God! Crosswind Landings...... Don't get me started..!! :twisted: :twisted:

When I first commenced commercial flying it was expected that an attempt to correct for drift using whatever method the pilot preferred or manufacturer stated would be made in an attempt to land with the aircraft nose pointing down, and tracking the centreline. If that meant full control deflection then so be it. It was not unknown for FO's to get a severe dressing down, or even reversion training in the sim if they couldn't achieve a good result. I even knew of one or two who solicited a clip around the ear from their trainer which in today's world would be regarded as assault.

Nowadays the litigation experts have reasoned that if the manufacturer certifies the aircraft to land with crab at its full published crosswind limit, then there is risk exposure to the airline if the pilot makes a mess of the landing and causes an accident. This is the reason you see endless YouTube videos of 'Hero Airline Pilots' making the biggest hash of crosswinds in a way that leaves even the most inexperienced PPL scratching their heads. The official teaching now is not to fully correct the drift but to simply 'make an effort' and let the manufacturer take the strain. This at best results in a Captain who's never been taught to 'control' an aircraft allowing it to crash sideways into the runway and accept what happens next as fate. It's not the fault of the crews. They are all competent and capable. It's the fault of the system that exists between manufacturer, training schools and airlines. The crews are badly let down, and Captain's in particular are left exposed as they are still expected to carry the can if they end up damaging the aircraft. If you disagree with me go and watch the videos and concentrate on the rudder. In most it never moves at any time. As for ailerons they might as well have disconnected them.

However, the original poster asked if there was a bank angle on a PA28 that precluded using the wing down method. Firstly there is only one method to counter a crosswind and (if done properly) we all use the same one. A perfect crosswind landing is achieved by applying rudder to align the nose with the runway and with enough aileron to counter the secondary effects of yaw. The difference is simply when we choose to apply the necessary corrections. When using the 'crab and kick' method (better known as the 'kick and miss') crabbing is used to maintain the centreline until the pilot thinks the aircraft is about to settle and applies enough rudder to straighten the aircraft. At the same time opposite into wind aileron is applied to counter the roll and hopefully the aircraft touches down moments later. Except it doesn't on most occasions, because we all carry a little more speed on windy days and more often than not the aircraft floats. Now the (kick and miss) leaves the aircraft drifting sideways, so into wind bank is applied to counter and wait for the touchdown. Hence we have achieved the 'wing down' method by default. A lot of pilots shrug off any errors resulting in lateral drift or untidy touchdowns as being part of the day. That's not acceptable and to the person who regarded 2mtrs of drift as normal. I'm glad you don't fly my aircraft!

If the the whole process is started as you approach the threshold (or earlier if desired) the landing becomes a calm and collected exercise in creating a controlled state that can be varied and altered to suit the prevailing conditions. Slowly applying the rudder and aileron to achieve the necessary slip/skid into wind allows a new 'neutral' condition of crossed controls to be created from which a perfectly normal landing can be made. In most aircraft the crosswind limit can be handled with the wings level throughout. It's only when coping with gusts or corrections that putting the wing down becomes essential.

The biggest issue is that most people are not practised nor mentally prepared to use full control defection on their aircraft. Few if any airline pilots have had the opportunity and most GA pilots have not flown in conditions that dictate it. Yet it's essential that you are mentally prepared to maintain control of the aircraft at all costs despite what the environment is trying to do to you.

I used the wing down method on most high wing aircraft and the crab method in low wings for most of my early career. However when converting to the 757 I was encouraged to use the wing down at all times and with practise (and full controls if needs be) began to achieve some very good results. Moving back to the low pod 737's even allowed for a considerable degree of bank before reaching the limit (which was the trailing edge flap actually, not the engines as most people think).

On my PA28 I've found that the book figure of 18kts is easily controlled by applying the correction as the threshold is approached and then maintained throughout a perfectly normal wings level landing. Yes, the wing goes down and the rudder increases to correct for gusts or sheer but in essence the bank is never limiting. However it's not unknown to reach the control stops to achieve a perfect touch down.
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#1899997
@lobsatboy

unfortunately quite a few PPL students get taught to consciously transition from crab to wing down much earlier than that. I can only assume that's the way the airlines do it


Interestingly, that’s the way many commercial airliners’ autopilots fly autolands. Though to be fair the crosswind limit for auto land is generally a fair bit lower than the hero flown attempts!

However, on large four engined aircraft people get very nervous of touching down with more than the absolute minimum amount of bank. In these circumstances the outboard engine pod will and has hit the ground.

Another point of interest is that when you kick the rudder to straighten up, the aircraft pivots around a point very close to it’s C of G. On larger types, that can be a long way behind the flight deck. So it’s very important the flight deck tracks down the approach quite a long way into the upwind side of the runway, so when you do kick off the drift, hey presto, the dunlops are astride the centreline, rather than on the runway edge markers!

Personally, like Boeing Boy, I hate to see the crab angles some airlines seem to touch down with. It may be both possible, and even ‘demonstrated’ but it’s just not necessary!

https://www.flightglobal.com/safety/atlas-747-400f-sustains-pod-strike-on-three-engines-in-shanghai/139673.article
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#1899998
lobstaboy wrote:@TLRippon you're right of course, but unfortunately quite a few PPL students get taught to consciously transition from crab to wing down much earlier than that. I can only assume that's the way the airlines do it (I must watch some of those videos that get posted every time it's a bit windy).
Incidentally those of us who started in gliders use your method - it IS possible to ground a wingtip if doing wing down with a big wingspan.

That is exactly how the airlines do it, and in fact what a Boeing Autoland does. The main thing with a large aircraft in a high crosswind is to get the main wheels equidistant on the centreline. This may mean offsetting the Flight Deck up wind until around 200 feet when the aircraft is straightened up and bank introduced to hold the aircraft on the centreline. The 747 would scrape the inboard pod at 4 degrees of bank so care is needed!!
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#1900016
lobstaboy wrote:OK, so that is how the big boys do it. I guessed right.
But that doesn't mean you have to be taught to do it like that in a PA28. Same argument as 3deg approach paths and PAPIs and all that.
Students should be taught to fly the aeroplane they're in.


Lobstaboy

Early ‘wing down’ may be the way that some airlines do it, but it’s never been my preferred method, and I’ve never felt pressured into doing it that way. As for being “taught to fly the aeroplane they’re in” is concerned, the big jets are still just aeroplanes. They all obey Newton’s universal laws of power and attitude.

Over the years I’ve come to realise there’s a million different ways to fly these contraptions, but as long as you achieve the desired result, few if any, of those techniques are entirely wrong, and few are entirely right. It often just comes down to personal preference, and long may that continue.

Unless of course we are having the track up/north up debate in which case there’s clearly and obviously only one possible correct answer! :lol:
#1900019
VRB_20kt wrote:....It appears that modern aircraft are designed to land with uncorrected drift. Just hit the runway and the undercarriage will handle it. The forces must be substantial. ...
(heavily snipped by me)

Do you mean by "modern" those with a nosewheel? If so, you may be largely correct; the ground reaction forces against the aircraft centre of gravity tend to stabilise a crosswind landing (although I have seen nosewheel-equipped aircraft groundloop).

I don't wish to fight the nose/tailwheel battle by any means, but it is of no coincidence that there are no longer any mass-produced airliners with tailwheels any more.

Four of my favourite aircraft have nosewheels; North American B-25, Douglas DC-6, Lockheed Constellation and Cessna 150.
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