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Landing issue

Old 12th Aug 2011, 10:58
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try to keep the aeroplane in the air as long as possible - try to stop it from landing
Even on a short runway?
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Old 12th Aug 2011, 12:01
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There is no way any landing can be achieved without a flare.
Though a flare is generally a good thing in a tricycle aircraft, otherwise, I do not agree with this statement. As previously mentioned, some operations in some types are purposefully "fly it to the surface" or no flare landings. Think of aircraft carrier arrivals (though I concede this is an extreme, and not relevent within the spirit of this thread). I am not familiar with Pace's operations, but agree that he probably has valid points.

I was doing the initial test flying of a modified Cessna Caravan, with a towed survey "bird" hanging under the aft belly. Full flap, three point, or nearly so landings were preferred, so as to not strike the tail of the bird. I spent a half hour doing circuits in another Caravan to perfect this technique. With satisfaction that I could land nose low, I went out in the test aircraft. My objective was to touch all three wheels at the same time, at the lowest possible airspeed. If I felt the mains touch at the same time I felt the nosewheel touch through the pedals, I was happy. I was very careful to have back pressure applied at all times (and ready to apply more), so as to prevent wheelbarrowing. The Caravan did it perfectly happily.

Notice one main not on yet...




This is not a "normal" operation, though it is what you might want to do in any tricycle, if you had a flat main tire.

There are number of other aircraft types, where a flare should be minimised, though these are not tricycle wheelplanes.

Even on a short runway?
Well, probably. If you have a short landing to do, the major factor in how little runway you'll use, will be the speed and height above the fence, as you cross the end of the runway. Fast/high, will get you a longer landing roll much more easily than the way you contact the ground. Aerodynamic braking at landing speeds will generally be more effective than wheel brakes for slowing down right after touchdown, so it's going to be more effective right before touchdown too, for as long as you can hold it off. If you're really working at a short landing, you'll be nose high, carrying power, and removing it at touchdown, so everything will happen at once.

The nose held high will get you the best braking, when you need it. The use of the brakes just after you touchdown in a GA aircraft is pointless. With the wing carrying some of the weight of the aircraft, you're just going to slide the tires, and wreck them. (The 172 I've been test flying in the last few days has obviously been a victim of this, and I'm having a main tire replaced later today, as it's more of a polygon, than round).

The landings I did as pictured above were definately not intended to be short, and did not involve the use of any brakes 'till just before the turnoff. Similarly, the technique for landing that plane is stated to not be suited to short or rough runways.

The main theme of holding it off for as long as you can, is the very best for a newer pilot in a tricycle aircraft, but is certainly not the only way to land. Indeed, it will be dangerous in other types and types of landings. This is why there is type training. Holding off a Lake Amphibian as long as you can, during a calm water landing, will at least give you a very rough landing, or worse, a less safe one.
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Old 12th Aug 2011, 12:28
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Be aware that there are varying techniques for different conditions and aircraft

I always found getting the correct speed over the keys for the weight of the aircraft the key. I f you have the right speed and the stabilised approach, the aircraft will pretty much land itself. As you get 6 ft or so above the ground treat it as an excercise in level flight, look down the runway, relax, and as throttle is closed, it will sink slowly. As it sinks, ease back on the controls progressively more. Thats the hold off.
Forget about the stall warning. I generally try to let it land before the stall warning, and you will be greatful for this on a summers day with a full load, when you can get a rude shock,especially if you lose your headwind 15 feet off the ground.
Hold the nose off if you can, and with flaps 30 plus, you be amazed how quickly the drag from the flaps plus nose up slows things down. However the typical short field landind is to get all three wheels down and brake firmly, with
elevators up .

Last edited by Mimpe; 12th Aug 2011 at 12:40.
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Old 12th Aug 2011, 13:45
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I am not familiar with Pace's operations, but agree that he probably has valid points.
Pilot Dar

I am purely pointing out two misconceptions in the thread! The first that a Greaser has anything to do with holding off and being near the stall but everything to do with the rate of descent at touchdown (the nearer 0 at touchdown the better the greaser! whether that is at 50 kts or 150 kts, whether that is near the stall or 30 kts above it makes no difference to a Greaser.
The other misconception is that to land you have to be at the point that the aircraft stops flying.
Again totally untrue infact in certain situations holding off near the stall is a very hazardous exercise.
An aircraft can land near the stall at the slowest speed possible for the shortest landing distance to stop or an aircraft can land way above the stall even at cruise speed clean.
In certain situations you will need to have 1.3 x the stall speed plus half the gust factor or more.
Maybe pilots of PA28s should try high speed landing clean on suitable runways as touch and goes just to see that landing is not connected other than for minimum stop distance to the stall.
Higher speeds take more skill as with higher speed comes more elevator authority for less control movement so elevator movements will be smaller but a skill worth practising.

Pace
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Old 12th Aug 2011, 15:26
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Even on a short runway?
Oh yes! Especially on a short runway! The object is to dissipate the energy in the air, so that on touch down the aeroplane has minimum speed and will roll to a stop in the minimum length possible. This does not preclude touching down at your aiming point, just in from the downwind end of the runway.

But use your short runway sensibly - don't float along for ages because you approached far too fast; get the approach speed right first! The last thing one should do (and this is far from uncommon) is to approach far too fast, force it onto the ground (yer 3-point trike landing), then stand on the brakes! If you land your trike on all 3 at once, you have put it down at far too high an airspeed. The nosewheel isn't designed to absorb much of that sort of mistreatment, and it indicates a poor basic landing skill level.

Some have questioned the fully-held-off technique for x-winds and for non-GA types. I distinctly posted that the technique is for light SEPs (where my 32 years of experience lies) and perhaps not for strong x-winds (though in the right aeroplane with sensitive and powerful controls right down the stall, that's OK as well). I perhaps should have added gusty days as well.

3-pointing a taildragger guarantees it touches down at or close to the minimum speed possible (if it's going any faster, the mains will touch first). There are occasions (very gusty days for instance, or in strong winds even if down the runway, which cause turbulence) when one might want to touch down at a higher speed. That's what wheeler landings are for.

Again, the above might not be relevant for heavy metal, carriers (deffo not appropriate for carrier ops!), water landings etc. Just for light GA.

Last edited by Shaggy Sheep Driver; 12th Aug 2011 at 15:44.
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Old 12th Aug 2011, 15:59
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Right, I think it's time to define flare. If, by flare, one means an angle of attack different than the approach, i.e. some backpressure has been applied to elevators to arrest either descent or change attitude, then I still claim it's impossible to land without a flare. If a flare is defined as the above but only in the immediate connection with the touchdown, then maybe not. Logic says that there is no way a landing can be made without using back pressure at some point during the approach, or else you'd be driving it on the field like a car.

This has become very a**l...
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Old 12th Aug 2011, 16:07
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There was no flare in the Phantom-you maintained same attitude from the threshold to touchdown.

We certainly never flared the Airbus if landing on a limited performance runway-once you flare you use up tarmac!

In certain situations you will need to have 1.3 x the stall speed plus half the gust factor or more.
Not for the landing-only at the threshold and its actually 1.2 on some types

then I still claim it's impossible to land without a flare. If a flare is defined as the above but only in the immediate connection with the touchdown, then maybe not. Logic says that there is no way a landing can be made without using back pressure at some point during the approach, or else you'd be driving it on the field like a car.
You are wrong there-a swept back wng aircraft with leading edge slats will be in the landing attitude at the threshold usually-you just wait for ground effect and close the thrust levers-with a flare you risk a tail strike. Also minimal flare if any on some long bodied jets for same reason

Last edited by Pull what; 12th Aug 2011 at 16:42.
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Old 12th Aug 2011, 16:13
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Some massively helpful and informative post lads thanks. I went again yesterday for my lessons and tried some of what was said. Of the 10 or more landing I done I only had one bump and that was due to me not leaning into the wind enough on a sudden cross wind.Also what I found out was I'm not looking at the end of the runway, Now this is something that has happened recently as I used to always do it, I'm more looking half way down which is unusual for me. I also had one where I came down nearly on the nose wheel, Granted I sorted that quickly and managed a lovely landing, I didn't even hear the touchdown I also tried the floating along and although I preferred this on a flap-less landing I didn't enjoy it so much with a full flap landing. The fear of hitting the runway is starting to leave me more and more as I fly. The best advise I can take from this is to learn step by step as I go. Some very good advise and I thank you all for it, Someone asked if I wore glasses and the answer is I don't.
Thanks again lads. I'm sure I'll have many more questions as I go along
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Old 12th Aug 2011, 16:30
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The nose held high will get you the best braking, when you need it. The use of the brakes just after you touchdown in a GA aircraft is pointless.
Dont forget to mention that the hedge will stop you too!
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Old 12th Aug 2011, 17:14
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Adam

Right, I think it's time to define flare.
A Flare is not small elevator changes you make down the approach but something much larger as the word depicts.

In the actual process of landing a flare in my books is continuing back pressure ie a large movement on the column with the effect of destroying lift so that the aircraft gets to a point where sink occurs.

I would not consider a wrist jerk on landing as a flare

Pace
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Old 12th Aug 2011, 21:54
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In the actual process of landing a flare in my books is continuing back pressure ie a large movement on the column with the effect of destroying lift so that the aircraft gets to a point where sink occurs.
Destroying lift so that the a/c gets to a point where sink occurs.
Not so, in fact a very bad explanation which I would interpret as stalling the aircraft above the ground. You are not destroying lift(thats done on the ground by decleration or devices such as air brakes or spoilers) you are in fact reducing the amount of lift to below that required to maintain level flight, thats what produces the descent which you call sink.

Flare is an adjustment of the A of A to reduce the rate of descent before touchdown-its secondary effect is to put the aircraft in the landing attitude. The amount of elevator or stabiliser movement needed to achieve this adjustment has many different variables even on the same aircraft-speed,weight, density, C of G, thermal activity, sink/wind, turbulence and of course the height that you choose to round out has a bearing on this too.
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Old 12th Aug 2011, 23:55
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Jason....just practice a lot, and when your instructor lets you, do lots of crosswind practice. I used to love an hour or more of circuit after circuit..its such great practice, and if you progress through the commercial types, you may never have so much landing practice again!
I trained at an aerodrome almost famous for its crosswinds, and it stands me in good stead.

I even heard about a guy who used to routinely calculate the cross wind component from his crab angle and airspeed in early final, as a habbit!
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Old 13th Aug 2011, 07:31
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Not so, in fact a very bad explanation which I would interpret as stalling the aircraft above the ground. You are not destroying lift(thats done on the ground by decleration or devices such as air brakes or spoilers) you are in fact reducing the amount of lift to below that required to maintain level flight, thats what produces the descent which you call sink.
I dont see what is wrong with the use of the word destroying! Had I used the word destroyed lift then yes the aircraft would be in a stalled state.
I also question the assumption that lift can only be destroyed on the ground.
Take one accident where a student attempted to flare at 30 feet agl? The aircraft fully stalled and dropped a wing into the tarmac injuring the student.
I would say his lift had been destroyed in the air.
So I am quite happy with the word destroying when directed at ever increasing angle of attack.

Pace
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Old 13th Aug 2011, 08:03
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Well, if we are going to be picky here, I don't think you can destroy (literally speaking) the entire lift, even if you maintain the aircraft in fully stalled condition. Once you reach maximum lift coefficient, still increasing the angle of attack will reduce the lift (by reducing the lift coefficient) and we know this as stalled wing. But I wouldn't use the word destroy, more spoil/reduce, since the lift actually exists way past the stalling angle of attack - it is just too small to create an equilibrium with lift and therefore the aircraft will be descending.

Less on the grammar, more on the topic now. I think it is very important, I could say even vital to understand the theory behind flying the aircraft, be it aerodynamics, construction, systems, instruments, performance, etc. But as you all know it, one can have 5 PhDs in aerodynamics, yet only practice, more practice and finally - much more practice will allow him to fly the aircraft consistently well (including landings). I agree that we can give the OP some pointers on how to make his landings better, but they can only go that far, the rest will have to be practiced in the real aicraft in different conditions in order for the skill to develop, and then practiced regulary so that newly attained skill doesn't fade away.

All in all, I think people are complicating landing techniques. If you aren't limited by runway length (e.g. C172 on a 1500+ m runway), hold off the aircraft as long as you can, grease the landing and then hold the nose gear off the ground for as long as you have sufficient elevator authority - the engine and nose wheel assembly will be very grateful. But please, don't complicate landings at short airfield: fly the approach with the speed in the manual, power off at 50ft, flare the aircraft just enough to touch down with main wheels only, slightly reduce back pressure on the stick/column for the nose wheel to touchdown and then simultaneously apply brakes as required and slowly pull the stick to its back stop (warning: doing this too fast could raise the nose significantly with some aircraft with very good elevator authority at low speeds, mostly T-tails) to ensure maximum braking efficiency. Nobody cares if you make a bit harder landing on a short runway and stop before the end, but I think nobody will be particulary happy if you grease the landing and end up in trees at the end of the runway.
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Old 13th Aug 2011, 08:42
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For an effective short field arrival, do it shallow and slow and nose-high with power, on the back of the drag curve, then chop the power over the threshold. But don't land anywhere you can't take off from!

And of course if it's a short off-airfield strip ensure beforehand there are no obstructions you don't know about on the approach (trees, power lines etc) as forward viz will not be good with the above technique.

Another problem with landing too fast is the aeroplane still has enough speed to fly. Any bumps (grass strips have loads) will have you airbourn again. Do it fully held off, and once it's down it's down!
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Old 13th Aug 2011, 10:35
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The aircraft fully stalled and dropped a wing into the tarmac injuring the student.
No the aircraft didnt fully stall- one wing stalled -its more than likely that the upgoing wing was unstalled and above the critical angle of attack.

You need to look at a CL curve graph-lift is still produced below the critical angle of attack
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Old 13th Aug 2011, 12:43
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I don't think my arse would fit in one.

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Old 13th Aug 2011, 14:23
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The music doesn't really match the imagery does it!

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Old 13th Aug 2011, 15:08
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I don't know what music would go with a collection of tent poles, a kiddies bath with some shopping trolley wheels attached, a lawnmower engine and some tarpauline being persuaded to fly in close formation.

I wasn't joking when I said I don't think my arse would fit in it.
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Old 13th Aug 2011, 18:32
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I strongly resemble that remark Mad Jock!

I've had many very enjoyable flying hours under a collection of tent poles and a lawnmower engine, and would recommend it to anybody.

As for setting it to music, this wonderful bit of history does it quite well.

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