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JSeward
13th Apr 2013, 08:42
Hi guys,

The POH for several Cessna's I fly say to gently fly the plane onto the runway but instructors say to stall it on to the runway. It seems to me that a smoother landing could be achieved by flying in at the correct speeds, flaring and gently lowering it on to the runway without having to float above it for ages until it stalls.

Also a Cirrus I went in the other day must be flown gently on to the runway in this way otherwise there will be a tail strike.

How do you do it?

Heston
13th Apr 2013, 08:55
I'd try to do everything the way my instructor suggests. You are, after all, paying him or her large sums of money to teach you how to fly: why doubt what they are telling and showing you?

(In the instance you ask about, your instructor is right by the way. The aim is to touch down with the main wheels first at the lowest practical airspeed. This protects the nosewheel, which is easily damaged, and gives a shorter ground roll. These things may not seem important if you are flying from a huge tarmac runway in ideal weather, but that won't always be the case. You need to learn to do it well right from the start.
The aim is not to land as gently as possible! Its to land as safely as possible. They are not always the same thing.)

AdamFrisch
13th Apr 2013, 10:24
Most airplanes land smoother with a little power kept in to be reduced by roundout. My old twin can simply not be landed fully stalled smoothly - you have to keep a little power in for greasers. That said, a fully stalled landing has benefits as it's easier on the brakes, uses less rwy etc. Do whatever he says, but if you want to impress your first female/male date, keep a trickle of power in.;)

IFMU
13th Apr 2013, 10:51
I try to stall it 1mm above the runway or less. Then it is smooth. I am in a different camp than Adam though, I prefer power off, unless I have screwed up, or wild sink requires a burst of power to sort things out. Those landings are generally not smooth though, just survivable!
If you are floating down the runway, power will make that worse.
Bryan

Gertrude the Wombat
13th Apr 2013, 11:04
without having to float above it for ages
Usually caused by having the approach speed too high, and best avoided by not having the approach speed too high.

bravobravo74
13th Apr 2013, 11:05
A so-called full stall landing is one whereby the aircraft is held off within a foot of the ground for as long as elevator authority will allow, before settling onto the runway at a low forward speed with the stall warner blaring. Ground effect delays an actual stall in this condition.

Use of this technique is probably the practical ideal for simple single-engine training aircraft. The landing performance charts for these aircraft usually stipulate 'power off' and the normal operations section usually advocates touching down at the slowest possible speed. Both of these conditions allude to the aircraft having been designed to perform 'full stall' landings.

Aircraft with high wing loadings typically need to be flown onto the runway as they tend to drop like a stone when power is removed.

mikehallam
13th Apr 2013, 11:13
Obviously each pilot has a favourite technique, hopefully aligned to the 'plane he has, but as ever in life, no one Rule fits all !

I fly a fixed wing 'Cub look alike' Microlight, in my case a Rans S4 - delightful little creature with delicate ways and excellent characteristics. BUT if you dare come in without power she'll fall out of the air far too high. (Unless you master the high speed powerless dive onto the deck).

With similar microlight a/c you do have to fly in with power, till like the man above says, a few mm above the ground. Even alternatively waiting a moment longer & doing a wheeler gives a very short and controlled landing.

[BTW. The Rans S6 approach/landing technique is quite different].

mike hallam.

tecman
13th Apr 2013, 11:52
Some wise words above. Just watch out that "fly it on gently" does not become an excuse for slack technique, with approach speeds too high. I see that with many pilots and I wouldn't mind betting it's something your instructor is trying to avoid. There's also quite a lot of incorrect folklore out there. For example, when I started flying a Comanche single, lots of people advised intermediate flap settings, faster than required approach speeds, and so on. But done correctly, it's beautiful aircraft to land in the classical slow, full flap mode - and does wonderfully on many of the short strips we have here in Oz. You do need what my instructor used to call a "chuckle" of power in the flare sometimes, but it rewards you with a great touchdown. Given the traps many people fall into, I'd be with your instructor in saying to learn to land your C172 etc in full stall mode, barring any really extreme conditions. (And, even there, watch out for the folklore. 10kt of crosswind is not excuse enough to start arbitrary increases in approach speeds, less than recommended flap settings, and so on). Excess approach speed is a really bad habit; too many people are complacent about it in both GA and recreational aviation (your "microlight" and similar community). Good luck!

pudoc
13th Apr 2013, 12:04
During my CPL I was told that I need to keep some power on for touchdown and avoid the stall warner.

Prop swinger
13th Apr 2013, 12:29
How do you do it?I keep the aircraft off the ground until it's at the correct landing attitude.

In a nosewheel aircraft that means that the aircraft will touch down on the mainwheels only. It won't actually be stalled at touchdown, although many of us think of it as a stalled landing. If you hold off until you reach the landing attitude, & then maintain that attitude, then as drag slows the aircraft down, the wings create less lift & the aircraft will descend. If the wheels were less than 1m off the ground, it will be a reasonable touchdown.

If you had the right airspeed as you crossed the threshold, the hold off will last about 2 seconds. That's just enough airspeed on approach to give you a margin above the stall but not so much that you float for ages down the runway.

Trying to fly the aircraft onto the ground conjures up images of nosewheel first touchdowns & wheelbarrowing down the runway. If you really, really try to stall before touchdown then you could indeed have a tailstrike, particularly in a low wing aircraft.

Good landings are the result of the right airspeed on approach & the right attitude before touching down.

maehhh
13th Apr 2013, 12:45
Full stall landing is a in my opinion the best and easiest way to teach how to land an SEP. And it certainly has the benefits of bringing the aircraft down as slow as possible.

Now with some more experience and in some more fancy aircraft I prefer flying the thing onto the runway. You can still do that with power idle actually all you need to do is adjust is the flare.

Steve6443
13th Apr 2013, 13:05
I try to stall it 1mm above the runway or less. Then it is smooth. I am in a different camp than Adam though, I prefer power off, unless I have screwed up, or wild sink requires a burst of power to sort things out. Those landings are generally not smooth though, just survivable!
If you are floating down the runway, power will make that worse.
Bryan

1mm above the runway? How the heck do you judge that without a radio altimeter ;-)

But seriously, my instructor said he wanted to hear the stall warner sounding on landing - it was nothing to do with the speed but more to do with the attitude of the plane, on nose wheel planes hearing the stall warning means the nose is high enough to ensure the main gear touches down first and I've stuck to that - if I don't hear the stall warner, something wasn't quite right with the landing....

However, that doesn't mean I want to hear the stall warner whilst still descending, just whilst flaring..... :=

taxistaxing
13th Apr 2013, 16:06
How do you do it?


In the 172s I fly I follow the POH approach speeds, fully retard the power as I cross the numbers and then just fly the aircraft onto the runway. I couldn't tell you exactly what speed I touch down at as I'm 'eyes out' judging the flare, but I occasionally hear the stall warner go off just before touchdown. As mentioned above ground effect delays the stall and published stall speeds are 'clean air' (i.e. out of ground effect).

During my PPL the instructors seemed to teach very high approach speeds. Fine on the 1500m runway at the field I learned at, but would be dangerous at some of the short strips I have visited as a PPL.


I'd try to do everything the way my instructor suggests. You are, after all, paying him or her large sums of money to teach you how to fly: why doubt what they are telling and showing you?



Agreed up to a point. I imagine the higher speeds taught during the PPL are to add a safety margin for students, I don't really see why its necessary to add 5-10 knots over and above the POH speeds once you're qualified and proficient at landing. Surely the most important thing is getting the aircraft down and stopped safely in the distance available. 172s balloon like nobody's business if you come in too fast which could be lethal at a 600m grass strip.

mad_jock
13th Apr 2013, 16:17
I imagine the higher speeds taught during the PPL are to add a safety margin for students, I don't really see why its necessary to add 5-10 knots over and above the POH speeds once you're qualified and proficient at landing.

Its more to do with instructors not being taught properly themselves and pretending to be flying an airliner.

there is no reason to add anything onto the POH speeds.

piperboy84
13th Apr 2013, 16:22
As a rank amateur I think good landings are for the most part a result of a disciplined approach speed, I do my utmost to stay to the approach speeds in the POH, my particular plane does not list the approach speeds so I use the following calculations to determine what speed I should fly

Weight Stall Speed
Stall @ Gross with power in landing config from POH 2400LBS = 47 MPH
Usual landing Weight with 2 person and half tanks = 2000LBS = 42 MPH*
Stall Speed adjusted for Weight X 1.3 for final = 55 MPH
Stall Speed Adjusted for Weight X 1.25 for over the fence=53 MPH

*Weight difference = 400LBS divided by 1 MPH per 80LBS = 5MPH

Now this may be all academic due to the airspeed indicator not being worth a **** on final but its the only speed reference i have other than feel and sound. The second thing i do is keep a scan from the cowling out to the end of the strip and use peripheral vision for the edges of the runway for depth perception.

When I make an arse of it, it is usually due to a feeling of familiarity especially at my home field were I tend to get a little loose on the speeds and not do the runway end scan which normally results in either dumping it in or gliding for what I deem as to far before the plane is done flying. Also as i fly a taildragger i tend to keep a little power on for longer thru the flare to maintain a little rudder authority, which I probably would not do in a trike

IFMU
13th Apr 2013, 16:47
Steve,
No radio altimeter, I just trust the Force!

Gertrude the Wombat has it right. Too fast is no good. I have just recently been re-introduced to the 152 & 172 and the stall horn does honk on my landings.

On my commercial I was taught to land power off. Also on my private.

Bryan

piperboy84
13th Apr 2013, 17:06
there is no reason to add anything onto the POH speeds.

But there may be a reason to lower speeds listed in the POH due to those numbers being based on gross weight, The aircraft manufacturer has no way of knowing if the plane is loaded with 10 gallons and a svelte chap like myself or it has full tanks and a couple of Aberdeenshire farmers daughters in the back

alexbrett
13th Apr 2013, 19:33
I guess the other thing to point out here (it'll be obvious to some, but not all) is the stall warner going off does not necessarily mean you've actually stalled, as by design it starts before the point at which a stall will occur - as such your instructor wanting the stall warner to go off does not necessarily mean they actually want you to stall it onto the runway, just that they want you to be very close to that point...

mary meagher
13th Apr 2013, 21:15
Nail the approach speed, and, while looking well ahead, do a gradual change of attitude into the roundout, at about 6 inches above the ground..... the roundout or flare is often too hastily done.

A few years back I was flying a Piper TriPacer into Annapolis, Maryland USA, home of the United States Naval Academy. The Piper Tripacer is not a speedy aircraft, along the motorway, the cars were overtaking us without difficulty. What upset me most was that an impatient Naval Academy aircraft cut in front of our stately final approach. (there was no ATC, traffic was self-regulating at the small local airfield.)

We had the last laugh, however. The Navy pilot did a carrier style landing in front of us, and his undercarriage gave way.

India Four Two
14th Apr 2013, 03:18
but I occasionally hear the stall warner go off just before touchdown
I'm firmly in the "land as slowly as possible" camp, but I learnt by experience, that is a good idea to brief your passengers about the stall warner to avoid scaring them.

172s balloon like nobody's business if you come in too fast
I once had to do a full-throttle, flaps-up ILS in a 172, to assist ATC in traffic sequencing (in VMC). It took a VERY long time to slow down and I had a tendency to try to flare too soon and consequently balloon. Luckily, it was a 12,500' runway. ;)

007helicopter
14th Apr 2013, 06:04
Stall Warner equals ready to land buzzer

Jonzarno
14th Apr 2013, 06:42
Also a Cirrus I went in the other day must be flown gently on to the runway in this way otherwise there will be a tail strike.

If you land a Cirrus in the correct configuration (100% flaps) you are very unlikely to have a tail strike.

The big problem is people landing them to fast when they either float for ages or bounce. If the pilot then slams the throttle open to go around, the torque from the engine (especially on an SR22) can cause you to lose directional control. There have been several accidents caused by this.

Recommended best practice when landing with full flaps and no significant crosswind (for an SR22) is 80 KTS on final, 75 - 77 over the fence and hold it off and wait for the stall horn (59) on landing.

Pilot.Lyons
14th Apr 2013, 06:45
I dont do any equations i just "fly the plane" you can feel it...... Never had a problem yet!

However, I was taught not below 65kts in a Cessna 152 but my examiner told me to do a shortfield at 50kts and that worked fine too

I was always taught to "just fly the plane" and i know what he meant and it works

piperboy84
14th Apr 2013, 07:43
I dont do any equations i just "fly the plane" you can feel it...... Never had a problem yet!

However, I was taught not below 65kts in a Cessna 152 but my examiner told me to do a shortfield at 50kts and that worked fine too

Its been many, many years since I read a POH for 152 but 65kts seems high to me, granted that is based purely on my calculation method that may be wrong but allow me to explain my logic and I would be interested to see if someone could pick it apart, and if so it would change the way i figure my landing speeds on my plane, so here goes.

If your short field speed is 50KTS which which would represent a multiple of 1.25 of stall ( more experienced pilots use 1.2 but i am not there yet) would mean a stall of 40KTS, so a normal landing should be flown at no more than 1.3 of stall which is 52k. I would assume that anything north of that speed and especially 65kts which is a significant addition would be unnecessary and may in fact provide a greater chance of a long a float or ballooning in less experienced flyers.

Edit: I just thought i would add the reason i do those calcs is not because i am a mathematics genius ( far from it) it is because if and when i fly planes where the POH does not list approach speeds (like my POH does not), but always lists a stall and gross weight I can figure out a guide for my speeds prior to take off and without feeling its a trial and error thing especially if its the first time i have flown the plane

Pilot.Lyons
14th Apr 2013, 09:00
Thats probably what people are talking about when they say schools add to the figures (probably to reduce problems/risks on final)

Maybe the 50kts has had some added to it too then... I don't know. All i do is fly it, feel it and i have never had a problem yet.

I did have a ballooning/floating problem whilst learning so that would confirm what you just said

Crash one
14th Apr 2013, 16:07
Some years ago we were taught 70/65knots in the 152 on 700ish metre tarmac, I believe, for safety? This practice was trodden on by the CFI after a while but several students had learned to fly using this method for some time. It is still quite amusing entertainment to watch the wheelbarrowing antics, though it does lead me to worry about flying the 172, am I going to bounce all the way down the runway or are 172s really that bad?
Also during gliding years ago it seemed to be +5 for the wind shear +another 5 for the wife & kids & you ended up heading for the far end at an alarming rate & had to stuff the nose skid into the ground before reaching the workshops.

Chuck Ellsworth
14th Apr 2013, 17:12
I seldom post here anymore because having retired from aviation I now have a different life style.

However sometimes these discussions make me wonder how aviation never seems to evolve in an upward trend......especially when it comes to how to hand fly an airplane.

Logic tells me flight training should have evolved upward, reading these forums tells me it is evolving downward when it comes to flight training generally speaking.

The cause is not difficult to determine though, because you can not evolve upward using flight instructors who have not only been taught improperly generally they have never worked in commercial aviation.

As to the following comment.....



Aircraft with high wing loadings typically need to be flown onto the runway as they tend to drop like a stone when power is removed.

For decades the Americans flew the space shuttle with zero landing incidents or accidents, the space shuttle had a high wing loading and a high rate of descent on approach and the landings were hand flown with no incidents.

sevenstrokeroll
14th Apr 2013, 18:17
someone already has. Dear Original Poster...go out and BUY, yes BUY a book called: Stick and Rudder by Wolfgang Langweische.

He discusses fully the types of landing...the most amazing is the ''stall down' landing, starting your flare prior to the airport fence.

It is all about energy management...you would like to touchdown with no energy...but you must have some for unexpected things in flying.

Read the book...memorize the book...teach the techniques to others. The only thing is the author uses a term for elevators that has fallen out of favor, the term is : flippers....you see he doesn't want you to think that elevators elevate...read it and enjoy it.

Heston
14th Apr 2013, 19:04
Yes - Stick and Rudder is the best "how to" guide there is. Written in the 1940s when rather a lot of young men were being taught to fly, it still reads well and offers great insight. When you read it you find yourself saying "yes, of course, it MUST be like that, why didn't anyone else explain things that way?" Thats when you know you really understand something.

I rather like "flippers".

Also his emphasis on Angle of Attack and always knowing what it is, is really good. He calls it the "relative wind", which is another better name. If you don't understand AoA (the relative wind), you don't understand how an aircraft flies or how to control it well.

Edited to add: Chuck E has assumed that everyone reading this will know that the space shuttle had no power at all during approach and landing - a big heavy glider with a high wing loading...

Chuck Ellsworth
14th Apr 2013, 19:31
The space shuttle was an awesome machine, I had the privilege of flying with one of the space shuttle pilots for two years.

I never tired of his stories of flying it.

The initial approach speed for re-entry was over 17,000 mph and the final approach speed at gear extension was 270 mph with touch down at 215 mph.

The rate of descent during the final approach was close to 10,000 feet per minute.

The latter part of the approach and landing was generally hand flown.

So from that we can be certain that landing without power is actually normal procedure in some cases. :ok:

bfisk
14th Apr 2013, 19:42
Some of the stuff I've read here now scares me quite a bit to be honest, but I see where it's coming from. I did my initial training on 152s and 172s, later twins, later instruction, the turboprop, and now jets.

Perhaps the most important thing I've picked up from this progression, it's the following: do what it says in the book.

There is a very good reason why the aircraft manufacturer has given you the required procedures, speeds, charts and described the techniques for operating the airplane. They built it, they know how it works, and their test pilots found out what it will and won't do. It does what it says on the tin, it really is that easy.

Now this does of course not exempt you from using airmanship, knowledge and sound judgment to fly the aircraft according to the conditions and your own skill level. Obviously, smaler aircraft do not have the same comprehensive manuals larger aircraft have. However, the manufacturer's procedures should be your starting point, not some made-up procedures that your 300-hour GA instructor told you, because that's what his instructor told him, and that's what his instructor told him before that. (I myself have been that instructor, because I did not know any better at the time.)

As you gain experience in a type, you will learn what the results of procedural deviation will be. As an example, you will learn that it is certainly possible to land a C172 with an approach speed of (let's say) 80 knots, but you will also learn that the landing attitude, the timing and feel for the flare, and the landing distance will be very different. My point is that this should not be your starting point - start by doing it the way Cessna (or whoever designed the plane) wants you to do it, then go from there. Not the other way around.

Chuck Ellsworth
14th Apr 2013, 20:08
The following is one of the best pieces of advice on this thread.....

All instructors should follow it.


However, the manufacturer's procedures should be your starting point, not some made-up procedures that your 300-hour GA instructor told you, because that's what his instructor told him, and that's what his instructor told him before that.

Lightning Mate
16th Apr 2013, 08:21
.....and that sums it up very nicely!

Heston
16th Apr 2013, 08:51
Indeed it does.

I've flow aircraft where the book says use an approach speed of 45-50knots depending on the likelihood of wind gradient. Instructors then tell students to approach at 55knots. Someone tells an early hours pilot that adding "5knots for the wife and kids" is a good idea and you end up with an approach flown at 60knots when it should have been 45knots! And they are surprised by how far it floats, or they get caught out by a big ballooned landing...

Stick and Rudder has a whole chapter about why it is important to fly at the right speed for the particular phase of flight and condition of the aircraft.

Pace
16th Apr 2013, 09:22
I will just add one small point which is not relevant to student pilots learning to land but it is a misconception that stall speed and landing are part of the same!
It does for the shortest landing with full flap but remember land with partial or even clean and those speeds will increase!
Taking clean speeds they could be fixed at 1.3 times the stall speed in clean configuration but you could make that 1.5 times the stall speed or more!
The biggest restriction for high speed landings is the distance between. Main and nose gear!
Long coupled the nose will be well clear even at high speed.
Short coupled and a much larger chance of doing an all point landing !
It takes skill and fine movements too land fast but it can be done

Pace

Shaggy Sheep Driver
16th Apr 2013, 09:36
Another reccomendation for 'Stick & Rudder'. Never mind the dated pictures, it's the best book on how to fly you can buy.

I agree with Chuck that it's dissappointing that things in flight training don't seem to be getting any better. I think this might be beciase some (by no means all) instructors are low-houred and of narrow experience, focussed on an airline job. When I did my PPL in the '70s many were ex-services guys of vast experience who did it becuase they enjoyed it.

And of course the almost universal training fleet of nose-wheel aeroplanes might be a factor. Now I was taught to fly on the C150, but almost immediately converted on to my beloved Chipmunk with not too much difficulty, so my basic training in landing the C150 must have been reasonably OK. The problem is that one can get away with some awful landing techniques in a nosewheel aeroplane that a tailwheel one will simply not tolerate. And standing alongside the runway at any GA field watching the non-held-off and far too fast landings typical there, one can see this for onself any day of the week.

Perhaps everyone interested in developing a good landing technique should get a tailwheel conversion? Or read and digest Stick & Rudder!

Lightning Mate
16th Apr 2013, 09:36
Chuck it on hard for an accurate touchdown point that's what I say.

http://i636.photobucket.com/albums/uu82/Lightning_29/untitled-5_zps44ee14cd.png

Shaggy Sheep Driver
16th Apr 2013, 09:41
Chuck it on hard for an accurate touchdown point that's what I say.

http://i636.photobucket.com/albums/u...ps44ee14cd.png

At least he's got the stick back with the nose high!

Heston
16th Apr 2013, 09:45
Awesome pic of an awesome aeroplane LM. But the tyres didn't last long did they?

Lightning Mate
16th Apr 2013, 09:51
The tyres did not last long indeed.

Bear in mind that a gentle "kiss the runway" landing wears out tyres faster due to the longer spin-up (hence slip) time, and that generally applies to all aeroplanes.

The worst was with large amounts of crosswind. The Lightning did not have nosewheel steering and there was a pronounced weathercock effect when the 'chute deployed.

Differential braking under such conditions meant a wheel change every landing.

Tyre pressures were 300psi btw.

john_tullamarine
16th Apr 2013, 11:15
A few thoughts ..

(a) final approach and approaching the flare should be conducted at a speed providing adequate margin above the stall. Generally this is accepted to be 1.3Vs in smooth conditions and a little faster if conditions are bumpy.

It is reasonable to view 1.3 as a short field factor.

Less and, generally, you are outside the certification envelope for a light aircraft. Too far less and you expose your aeroplane and occupants to an unintended stall with unpleasant and potentially expensive and/or tragic results.

If you have plenty of runway and it floats your boat nicely then, by all means, hold a low flare until the aircraft falls the last few inches to the runway. However, as a general rule, don't confuse yourself by thinking that gives you the shortest landing distance - ground roll may be short but - the overall distance will be up. Better deceleration is achieved using brakes on the ground rather than waffling through the air .. assuming that your steed has such devices.

Coming over the fence at breakneck speeds achieves little other than making for a difficult manipulative exercise and a much extended actual landing distance. The reasonable aim is to achieve/approximate the expected landing distance for the aeroplane.

Maintaining a higher speed during the circuit and initial final may provide advantages for circuit flow. However, one should consider reducing speed to something appropriate for final approach when on mid final.

(b) if you are intent on doing some arithmetic, remember to do the sums in CAS rather than IAS as the PEC back near/at stall can provide for a moderate difference between the two.

Well into the stall and all bets are off .. we all have had fun in the small single engine Cessnas stalling with the ASI indicating something approaching zero .. pretty meaningless but still fun, I guess .. however, whatever the ASI may be indicating .. it certainly doesn't mean that you are at zero speed.

If figuring for weight, run the speed sums at the square root of the weight ratio .. for a small difference a linear approximation will be fine but the error picks up as the weight difference increases.

(c) With some high wing machines one may need to be careful with flap selection in strongish crosswinds lest the fuselage airflow create problems at the tail.

piperboy84
16th Apr 2013, 11:44
Pace

Taking clean speeds they could be fixed at 1.3 times the stall speed in clean configuration but you could make that 1.5 times the stall speed or more!

Just wanted to clarify how I do my calcs in case someone misreads and runs into trouble trying it. For approach speeds that are not stated in the POH, whether in the clean or landing config I always use the 1.3 multiple but my starting number(s) for each config are taken from the bottom of the airspeed indicator green or white ranges then deducting 1MPH for each 80lbs I am under gross then apply the 1.3 to a standard and 1.25 for a short field landing.

The only time I stray north from those numbers is when there is a xwind pushing up against my personal limits (which are under the POH published demonstrated number) and decide that instead of a no flaps clean approach I will go to a negative 7 degrees flap setting which is unique to my aircraft (a taildragger) and recommended by the manufacturer in xwinds, however I do not know what the exact stall is in that config as its not in the POH or AI markings so I stay a bit faster than what the clean stall calc would be which I think is good practice in the xwind anyway.

Disclosure: the writer as stated before is a rank amateur and none of the above should be paid heed to and taken as gospel and is purely for conversational purposes only, the above practice is my personal methods based on trying different things with the plane and always remember opinions are like assholes, everybody has one. Bottom line, listen only to your instructor

mad_jock
16th Apr 2013, 12:03
Piper don't do it by airspeed.

Fill you aircraft up to the MLW.

Put a bit of string on the airframe/window.

Then go up to 1000 feet and desend in landing config at the POH speed.

Take note of angle of said bit of string.

This is then you angle of approach. Then go to your min weight you can manage again at the same alt. Then configure and pitch to the same angle. See what the speed is. The POH is the max speed and the last one is the min speed. Then make up a table for the weights between the two.

The stall is the critical angle of attack. The approach is something which is an angle of attack less than this by a safe margin. The speed is just the thing we can see in the cockpit all you are doing by changing the speed with weight is getting the angle off attack correct

Lightning Mate
16th Apr 2013, 12:07
Put a bit of string on the airframe/window.

That should be interesting on an SEP with the prop turning.

mad_jock
16th Apr 2013, 12:26
It works and he flys a tail dragger he can stick it out on the strut or on his pitot tube or further out.

bravobravo74
16th Apr 2013, 16:00
For decades the Americans flew the space shuttle with zero landing incidents or accidents, the space shuttle had a high wing loading and a high rate of descent on approach and the landings were hand flown with no incidents.

They did indeed however descending at 10,000 fpm in a light single isn't an ideal precursor to performing a full-stall landing (the original subject of this thread).

Chuck, I imagine that you were trying to contradict my post so why would you refer to an example that validates it?

Heston
16th Apr 2013, 16:43
bb74 the bit of your post that is simply wrong was the reference to high wing loading aircraft dropping like a stone when power is removed - it just ain't so.

bravobravo74
16th Apr 2013, 17:35
bb74 the bit of your post that is simply wrong was the reference to high wing loading aircraft dropping like a stone when power is removed - it just ain't so.

Admittedly, on its own that inference is incorrect as you say. I omitted the condition of airspeed.

What I believe to be the case is that if you're flying at a speed where there is a lot of induced drag and you close the throttles, especially when the propellers are of the constant-speed variety, then you're going to go down quickly.

Piper.Classique
16th Apr 2013, 20:31
Just wanted to clarify how I do my calcs in case someone misreads and runs into trouble trying it. For approach speeds that are not stated in the POH, whether in the clean or landing config I always use the 1.3 multiple but my starting number(s) for each config are taken from the bottom of the airspeed indicator green or white ranges then deducting 1MPH for each 80lbs I am under gross then apply the 1.3 to a standard and 1.25 for a short field landing.
Sounds a bit complicated. How about flight manual speed on final, round out and then hold off until the aeroplane doesn't want to fly any more. Failing a flight manual, 1.3x stall speed for the configuration.

DavidHoul52
17th Apr 2013, 12:47
In my experience of Cessna 152 and 172 the POH is correct. My instructor told me never to land with a stall, and have never done so.

Some points:

On any checkout flight every instructor will tell you something different and that what any other instructor told you is likely to kill you. This is not true - every instructor is qualified to instruct, they just have different opinions, that's all. There's more than one way to fly a Cessna, despite what you read in PPRune :)

Do what your instructor says but read the POH cover to cover. Most instructors don't get you to do that.

It's not necessary to suddenly kill the power when you round out. Doing it gradually leads to a better landing IMO and is kinder on the engine. Leaving a bit of power on when landing and taking the power off completely after touchdown also works nicely.

phiggsbroadband
18th Apr 2013, 00:10
Hi, there is a PPL training exercise (10A Slow Flight), where your instructor may require you to 'Fly Beyond The Stall' using high power and a very high nose attitude.

This is flight beyond the peak of the Coefficient of Lift curve, on the negative portion of the curve. Where if you pull back on the column, the plane stalls further and descends, and if you push forward you get more lift and the plane climbs.

I think that any landing in this configuration would result in a tail strike, as the pitch attitude is over 20 degrees.

sevenstrokeroll
18th Apr 2013, 00:56
we sure talk different...ever hear of flying behind the power curve?

I know in the USA we have to teach many types of landing...including short field, short field over an obstacle, soft field and combinations of each. full stall landings are taught too and ''normal'' landings.

landing ''with power on past touchdown'' can be useful if you are landing on a soft field (grass, mud etc)...but please think like a carpenter with different grades of sand paper.

each landing (each grade of sandpaper) has its place and it takes an artist to know which one to use.

sevenstrokeroll
18th Apr 2013, 01:09
in some trainers it is quite easy, with engine off, near the tie down spot, to have the student sit in the plane and the instructor push down (at the right spot) to push the tail down and the nose up to allow the student to ''see'' the landing attitude without the noise or time criticality.

Piper.Classique
18th Apr 2013, 06:21
Thank you for a couple of useful additions to the discussion, Sevenstrokeroll.

I would also point out that in a tailwheel aircraft the landng attitude is easy to see on the ground. Just put it back down like that.........

Another thing. If the aircraft is properly trimmed, by which I mean no load required to hold the attitude required (Did I need to say that? Sadly, yes)
You can feel the lift decreasing in the hold-off, the aircraft wanting to sink to the ground.

Here in France we teach different sorts of landing, too. Soft field comes naturally in the winter, as our 800 metre long 90 metre wide grass gets soggy. We have to use our imagination for the obstacle clearance but the ditch and road at the end is provided by the council. We go elsewhere for tarmac, runways of normal proportions, and slopes.

We have runway lights, no centreline lighting, no papis. If anyone would like to experience landing in a black hole they are welcome to visit.

sevenstrokeroll
18th Apr 2013, 11:00
piper...isn't it funny about trim? once you master trim, the flying is so much easier.

I would also say to take a brick or two and place it under the nose wheel to show the landing attitude.

just like food has become so refined as to be less nutritious, flying has become so automated as to be less organic

phiggsbroadband
18th Apr 2013, 11:52
Hi 7/R, I think the two terms are different...
Flying on the back-side of the power curve occurs below Max L/D speed (below Vy.) Whereas Beyond the Stall is at Vs or less.

This chap is most likely just beyond Vs , by using power, to 'prop-hang' the last few yards onto the grass. (and it looks as if his tail-wheel will land first.)

http://ukga.com/images/content/preview/image30090.jpg

Pace
18th Apr 2013, 12:08
I am going to add a couple of points for thought? Firstly why do you want to judge a 10 foot point for the flare?
Could that be 20 feet? 10 feet ? 5 feet ? or even 2 feet ?

Landing at just above the stall has little to do with landing an aircraft other than meeting the published stopping distance as I have stated before it is quite possible to land an aircraft which stalls at 60 kts at 120kts if you have the skills.

At 1.3 times the stall gives you a buffer to change AOA and hence loose speed without stalling before contacting the runway but it is a misunderstanding to connect these speeds with actually landing which could be at any speed.

I had a friend who had a control problem in a Citation who landed at Edinburgh at 200 kts when his VREF should have been 105 kts !!!
Way above even the tyre limits but he stopped safely.

Pace

mad_jock
18th Apr 2013, 12:39
If that was 5-6 years ago I saw the crew afterwards.

The FO was white as a sheet and the Captain looked in need of quite a few stiff drinks.

Pace
18th Apr 2013, 12:48
Captain flew for 24/7 next to me at Kudos at Southend ; )
Not surprised they were as white as sheets as the radar traces showed their landing speeds at 200 kts ( yikes)
Yes around 5 years ago

But just used it as an example to remove a misconception regarding stall and landing an aircraft
Or for that matter a flair point :E

Pace

riverrock83
18th Apr 2013, 15:14
And to confirm the "fly by the book" and the "every aircraft is different" comments:
The SA Bulldog's short field landing technique involves keeping the power on all the way to touch down, on the back side of the drag curve. 55kn is my memory. You need the power to maintain that speed, and have enough energy to flare, although despite getting into the landing attitude with power still on, flare will be minimal. Power comes off and flaps come up as soon as you touch the ground...

The technique requires practice and it isn't the normal landing pattern...

Piper.Classique
18th Apr 2013, 17:56
just like food has become so refined as to be less nutritious, flying has become so automated as to be less organic

Fraid so. If I'm not getting in anyone else's way, then I will always do a glide approach in the cub, with or without a sideslip, according to my mood at the time. Once had a controller comment that I was high on final, over the radio. I reckoned that was my business, but made a point of touching down at the very start of the runway, no sideslip required. Of course I then had to taxi the best part of a mile to the exit......

What really worries me about many pilots of light aircraft is that they try to fly as if they are in a heavy. I am trying to ban the phrase "rotate speed" at our club. So many people fly so little that every other flight is a currency check, and have no feel for the aircraft. (trimmed or not, usually the latter) Trouble is feel comes with experience and currency and so we rely on the numbers instead.

But I have the luxury of my own aircraft and no pressure to conform, or to fly in conditions that are unsuitable for the aircraft or incompatible with flying for fun.

Chuck Ellsworth
18th Apr 2013, 18:20
So many people fly so little that every other flight is a currency check, and have no feel for the aircraft. (trimmed or not, usually the latter) Trouble is feel comes with experience and currency and so we rely on the numbers instead.

Exactly:

It is the dumming down of flight training to the point that when the numbers are not there they crash. ( Such as airspeed indicator failure. )

Pace
18th Apr 2013, 20:25
Chuck

It is the dumming down of flight training to the point that when the numbers are not there they crash. ( Such as airspeed indicator failure. )

That is a good training regime to cover up the the AI and get a pilot to fly a circuit by power setting and feel.
Also to land clean and with full flap at different speeds as well as steep and flat approaches.
A PA28 can be landed at 60 kts as well as 100 kts albeit your stopping distance will be far longer.
You can flare at 20 feet 10 feet or 2 feet :ok:

Pace

piperboy84
18th Apr 2013, 20:29
Power comes off and flaps come up as soon as you touch the ground...

I'm a bit hesitant to lean down and drop the flaps right after landing, in case I veer too far of centerline or put myself closer to a groundloop, I considered buying one of those flap handle extensions
EZ Flap (http://www.ezflaphandle.com/)

Has anyone tried one?

Pace
18th Apr 2013, 21:12
Power comes off and flaps come up as soon as you touch the ground..

PiperBoy

There is an argument that you touch nothing till clear of the runway!
With the Citations I fly touchdown on landing with full flaps makes the aircraft quite tail light and twitchy.

I tend to raise the flap to takeoff setting after touchdown which gets a disapproving look from my co :E

I feel its much smoother and more precise under braking with takeoff and app setting so what the heck :ok:

Pace

JSeward
21st Apr 2013, 20:43
Is anyone here a Cirrus pilot? If so when landing do you gradually pull back until the stops/stall like a Cessna or does this bring risk of a tailstrike?

ArcticChiller
21st Apr 2013, 21:53
Cirrus SR20 - Full stall landings FPV Part 1 - CirrusWorld (http://www.cirrusworld.com/cirrus-sr20-full-stall-landings-fpv-part-1-video_a936ca548.html)

Seems to be working in a Cirrus. :)

mary meagher
21st Apr 2013, 22:20
Couple of thoughts: nobody has mentioned crosswinds....

Interesting to think of the Space Shuttle as a stubby winged glider...

And if the engine quits on your aircraft, having chosen the best place to put it, endeavour to touch down as slowly as possible, on the top of the crop/trees/warehouse or parking lot.

Famous landing happened in a gliding club up North of the border.....the girlfriend in the front, the son of the owner as PIC; running a bit short of height on the down-wind, decided to elevate the turbo and fire up the engine.

Which declined to run. They landed in the club car park, on top of several cars, one of which contained an elderly couple enjoying a snack while watching the gliding. They were shocked and surprised, the girlfriend was not impressed, and the pilot suffered bruising when his father was informed.....

flyingtool
25th Apr 2013, 08:23
I fly my 172 low on approach, no flap, power off 70 knots back to 65 it's then about 15 feet I hold it level, letting airspeed wash off and when I feel it start to sink I slowly pull back. Smooth every time. If however I use flap il keep the tiniest amount of power on as if I don't I find with my Cessna (L model) and 40 degree of flap it just falls out of the sky. Good if you're high on approach though. Take full flap and nose it down. I've had it nose down 10 degrees and full flap and lost airspeed!!