floaty landings

Henning said:
??? Try to make sense and not confuse other students...
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I thought the context made it clear my comment was about your unclear comment.

With respect to your and other poster's earlier advice about the 1.3 factor - that factor appears to derive from FAA airplane certification requirements. How they determined it is unclear to me; none of my textbooks on aerodynamics appear to have anything on it (not surprisingly.) The closest I can find is a text that refers back to FAR Part 25!

Also - to avoid confusion I would say that is essential to make clear in future advice that the values in the "1.3 time Vs or Vso" should be in KCAS. Then convert back to KIAS using the (ahem) conversion table in the POH.
 
Jim Logajan said:
Also - to avoid confusion I would say that is essential to make clear in future advice that the values in the "1.3 time Vs or Vso" should be in KCAS. Then convert back to KIAS using the (ahem) conversion table in the POH.
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Why?

You have plenty of reserve energy at 1.3.

Besides, you shouldn't be using the ASI much anyway -- it's a reference speed, but should be a "feel" you have (controls a bit sloppy, not a smuch lift, airplane slower, etc).
 
azure said:
Actually by the book, 1.3*Vso adjusted for your weight comes in at about 53 KCAS.
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That makes the stall speed 40 KCAS. That seems low; perhaps you multiplied 1.3 by the KIAS rather than the KCAS?

The procedure should be: find stall speed in KCAS for the desired landing configuration, multiply by 1.3, then convert to KIAS using the KCAS to KIAS conversion table for the airplane in the POH to determine what is a reasonable target number, give or take.
 
Jim Logajan said:
The procedure should be: find stall speed in KCAS for the desired landing configuration, multiply by 1.3, then convert to KIAS using the KCAS to KIAS conversion table for the airplane in the POH to determine what is a reasonable target number, give or take.
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I'd rather take the bird up a bit, do some slow flight, feel for the stall, get that feeling in hand, and then go land a few times.
 
dmccormack said:
Why?

You have plenty of reserve energy at 1.3.

Besides, you shouldn't be using the ASI much anyway -- it's a reference speed, but should be a "feel" you have (controls a bit sloppy, not a smuch lift, airplane slower, etc).
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Are we talking about different things? Earlier some were advising 1.3 Vs or Vso for the target speed on final, but neglecting to clarify whether the stall number to multiply 1.3 by is in KIAS or KCAS. It makes a BIG deal at the low speeds.

Now here I think you and Henning appear to be discussing speeds in the flare and roundout - in which case of course you shouldn't be looking at the airspeed indicator.

I tried to make clear I was just a student too so my advice had no experience behind it.

Now I'm going to say that regardless of the extensive experience you and Henning have, it does no good if you do not communicate it with consistency, clarity and as unambiguously as possible. I appreciate good advice and informed opinion freely offered, but if someone like me points out that perhaps you have provided advice that contains ambiguity or may be incorrect, please don't think it is intended to insult or demean. (If I do manage that, it is due to momentary irritation on my part.)
 
Jim Logajan said:
That makes the stall speed 40 KCAS. That seems low; perhaps you multiplied 1.3 by the KIAS rather than the KCAS?

The procedure should be: find stall speed in KCAS for the desired landing configuration, multiply by 1.3, then convert to KIAS using the KCAS to KIAS conversion table for the airplane in the POH to determine what is a reasonable target number, give or take.
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Yep, that's a good way to get the number. Now you can also go up and fly at the verge of stall, just in the buffet, trim it up good, get a feel for what the controls feel like when you are there, now go ahead and speed up a bit until the stall horn is chirping on and off and fly around at that speed trimmed out for a while and get a feel of what the controls feel like. Now add 5 knots to that, trim it out and fly around for a while and get a feel for that. (all the while note how much you are adjusting the trim as well as the sound of the airplane) That is the feel you are setting for as you settle in from your turn base to final. Now go practice some approaches. As you settle in and trim up for for that elevator feel watch the runway and your perspective lines and adjust your power to stabilize them while maintaining that feel. As you start to come closer to the bottom, say around 50', pull out some power and start rolling that trim in and slowing down until the horn starts chirping and adjust your power for steady state to your landing spot. As you lose sight of the threshold under the nose, tap in that last nudge of trim and as the threshold passes abeam of you take out the last of the throttle and just hold your attitude as the stall horn gets louder and the plane settles in. You'll have done a perfect landing without once having looked inside the cockpit.
 
Hey Henning - what was that 360 degree turn on downwind in your video? or was it that? couldn't quite tell but that's what it looked like...

pretty area too

And, what cameras are ya'll using for those vids?
 
Henning said:
Yep, that's a good way to get the number. Now you can also go up and fly at the verge of stall, just in the buffet, trim it up good, get a feel for what the controls feel like when you are there, now go ahead and speed up a bit until the stall horn is chirping on and off and fly around at that speed trimmed out for a while and get a feel of what the controls feel like. Now add 5 knots to that, trim it out and fly around for a while and get a feel for that. (all the while note how much you are adjusting the trim as well as the sound of the airplane) That is the feel you are setting for as you settle in from your turn base to final. Now go practice some approaches. As you settle in and trim up for for that elevator feel watch the runway and your perspective lines and adjust your power to stabilize them while maintaining that feel. As you start to come closer to the bottom, say around 50', pull out some power and start rolling that trim in and slowing down until the horn starts chirping and adjust your power for steady state to your landing spot. As you lose sight of the threshold under the nose, tap in that last nudge of trim and as the threshold passes abeam of you take out the last of the throttle and just hold your attitude as the stall horn gets louder and the plane settles in. You'll have done a perfect landing without once having looked inside the cockpit.
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Thank you - that's clear procedural advice I can actually use and will try next chance I get.
 
Jim Logajan said:
That makes the stall speed 40 KCAS. That seems low; perhaps you multiplied 1.3 by the KIAS rather than the KCAS?
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Actually, I was using the OP's figure of 43 kts for Vso and adjusting it for weight. I assume he got it from the POH, and that it was in KCAS not KIAS. I don't know what I did with my old 172 POH so I don't have anything official to check this against. I was mainly trying to point out (1) that even at max gross, the approach speed of 1.3*Vso that FAA guidance suggests is much slower than the OP was flying his approaches at, and (2) adjusting for weight makes it even slower.

However, since I do recall that 1.3*Vso at max gross in a 172 is about 57 kts, and 1.3*43 comes out to about 56, I don't think these numbers are that far off.

The procedure should be: find stall speed in KCAS for the desired landing configuration, multiply by 1.3, then convert to KIAS using the KCAS to KIAS conversion table for the airplane in the POH to determine what is a reasonable target number, give or take.
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To get the guidance final approach airspeed, I agree. But also, realise that a number of other variables come into play (weight being the easiest to quantify). In the end I agree with everyone who says you just gotta take the airplane up and get a feel for the controls. If I followed the numbers, I'd be flying my Cardinal at ~60 kts on final. But for reasons I've yet to figure out, at anything under about 65 KIAS I start to sink like a rock and the controls get to feeling quite mushy, so I usually aim for 65-70 kts.
 
Jeanie said:
Hey Henning - what was that 360 degree turn on downwind in your video? or was it that? couldn't quite tell but that's what it looked like...

pretty area too

And, what cameras are ya'll using for those vids?
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Tower requested a 360 for spacing. Nic was using a little Olympus Tough Shot camera on video mode.
 
GeorgeC said:
The 172N POH says 55-65 kias flaps down approach speed; I don't understand the discrepancy between this figure and 1.3 Vso. Incidentally, Vso is 33 on my checklist, but is 41 in my POH.
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Cessna's recommended speeds were extra conservative since they didn't want people getting too slow and stalling the plane. Which is rather humorous, because the 172 is such a docile aircraft in a stall.

When you're going into a long runway, it usually doesn't matter, other than you're embarassed that you didn't land in the first third. At a 6,000 ft runway, you can land 2/3 of the way down in a 172 and still stop well before the end.

The problem is when you're going into a short runway, where you don't have that extra margin, and need to come in slow or else you'll go off the end.
 
Henning said:
As you start to come closer to the bottom, say around 50', pull out some power and start rolling that trim in and slowing down until the horn starts chirping and adjust your power for steady state to your landing spot. As you lose sight of the threshold under the nose, tap in that last nudge of trim and as the threshold passes abeam of you take out the last of the throttle and just hold your attitude as the stall horn gets louder and the plane settles in.
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The only time full up trim results in speed slow enough for the stall horn to sound is heavy with near max aft CG and some additional back pressure on the yoke (I don't have all the various Certification requirements handy, But I'm guessing it didn't change between CAR and CFR)

Interesting summary of the physics of trim: http://www.grc.nasa.gov/WWW/k-12/airplane/trim.html
 
nosehair said:
Here's a technique from the old days:

Go up and actually stall the airplane in power-off landing configuration(Vso), note the actual airspeed reading at the moment of stall on that day at at that weight, multiply the number by 1.3, and try a few approaches at the actual airspeed your airplane indicates best.
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My airspeed indicator hits the bottom peg and stays there before the plane stalls. What do you suggest for that?
 
azure said:
As lots of others have said, 65 kts in a 172 is too fast on short final unless you've got a whale of a gust factor.
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I'll say it about the 182, too. Far too many people coming over the fence too fast in 182s all the time, thinking they're a "bigger heavier" airplane, when actually the bigger wing at certain loadings means a lighter wing loading than the typical 172 loading.

Our Robertson STOL equipped 182 has an even slower than usual landing speed... the Robertson addendum to the POH calls for 65 MPH (56 knots) on final, and touchdown main wheels first at 54 MPH indicated (46 knots). That took some getting used to.

But "normal" 182's aren't that much higher than that, by the book. 55 knots over the fence is fine unless you're dealing with gusts, but you'll see people pucker up and freak out in the other seat when you do it.

People often teach the 85 (knots!) downwind, 75 base, 65 final in 182s, and I've watched folks float the club 182s around here well past the 1000' marker when they were shooting for the numbers or earlier... it also sets them up for a hell of a Pilot-induced-oscillation porpoise effect, if they're not smooth while waiting for all that excess energy to bleed off.

People seem to build in "fudge factors" and forget to get the real performance numbers and avoid carrying tons of extra energy when it's not necessary for stable, fully-controlled flight. Get the flaps out there and realize they're far more effective at creating drag than lift when fully-deployed (especially if you're flying an older Cessna with 40 degrees of barn door available)...

Another good practice thing... go out and get a nice high altitude, and then set up as if you were landing on a "runway" 1000' below you. Find the power setting that gives you the rate of descent you want, with no flaps, flaps 10, flaps 20, flaps 30, flaps 40. Write it down.

Now smoothly throttle back to idle and "flare" after this mock "approach" to arrest your descent at your target "landing" altitude. Feel how quickly the aircraft loses speed/momentum. Watch the airspeed indicator but also feel it... how fast does your aircraft really lose speed. Keep pulling and keep slowing trying to maintain that target altitude. When does the stall horn come on? Do you hear the differences in the sounds of the airflow over the wing? If you have the type of stall horn that gets more "aggressive" as the stall progresses, do you hear that? When do you bust through your target altitude (touch-down), did you fall rapidly through it?

By the way, you're now practicing a power-off approach type stall. Recover normally. And remember that ground-effect will have a tendency to "cushion" whatever you just saw in a real approach to a landing in the last few feet of the flare/touchdown portion.

Do it a few times. See what the control movements are and how fast to not blow through the "landing" altitude. Get smooth at it. There's no real ("big scary") runway really coming up to meet your tires. Try it slightly more aggressively the 2nd or 3rd time. The only bad habit you don't want to build here is in looking at the altimeter too much, so remind yourself that you'll be looking outside and not at the instruments during a real landing... but give yourself a safe way to go up and look... see what they're doing at altitude.

Next, if possible... be a passenger when you can and watch someone else land the airplane, paying close attention to the nose attitude for "good" landings, remembering the distance up the cowl or window of the runway and other marks you can accurately reproduce yourself later. Gawk at the airspeed indicator while they're doing it if you like, it's their landing -- you get to look at whatever information you'd like to see/learn about while they're doing the landing. It's an eye opener to see just how low the airspeed indicator really goes with both calibration errors (it'll read lower than you're really flying at nose-high angles) and how much speed you actually have to scrub off in and after the flare in most Cessnas. (I can't speak for other trainers, I'm a Cessna geek.)

Just some thoughts/ideas for you. Go give 'em a try.
 
Downwind speed is actually irrelevant as you can burn off the energy relatively easily by pulling a couple of steep turns to final or a quick slip on base. It's from 200' AGL on down where it pays to be stable, and if you know your plane, as long as you hit you position and energy mak by the time you go into the flare, it's all good.
 
Thanks for all of the advice. For now, I think I'm going to learn to walk before I learn to run and avoid crosswind/gusty days until I can land decently under friendlier conditions. Once I'm soloing, I like the idea of mock landings in the practice area to concentrate on the feels and sounds at various airspeeds.
 
denverpilot said:
the Robertson addendum to the POH calls for 65 MPH (56 knots) on final, and touchdown main wheels first at 54 MPH indicated (46 knots). That took some getting used to.
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Interestnig. Those nosewheel things must be harder to land than I thougt. I had no idea that you actually looked at the ASI after you crossed the fence. I honestly have absolutly no idea what speed I touch down (or come off the ground) at.

I guess every airplane is different.
 
Capt. Geoffrey Thorpe said:
I had no idea that you actually looked at the ASI after you crossed the fence. I honestly have absolutly no idea what speed I touch down (or come off the ground) at.

I guess every airplane is different.
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I reference the ASI in a new-to-me airplane to make sure my "feel" of the airplane is calibrated. I shouldn't, but do from habit.

When I was getting checked out in the Chief I looked a few times and that was worth the glance -- 35 MPH??!?!!
 
Henning said:
Downwind speed is actually irrelevant as you can burn off the energy relatively easily by pulling a couple of steep turns to final or a quick slip on base. It's from 200' AGL on down where it pays to be stable, and if you know your plane, as long as you hit you position and energy mak by the time you go into the flare, it's all good.
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While this may be true for a highly experienced pilot like Henning, less experienced pilots generally do a lot better if they "hit their marks" all the way around the pattern from the abeam position on down. As experience builds, you'll find you can be farther off later in the approach and still make the speed/altitude/configuration you need as you approach the flare, but early on, being on the numbers all the way through the pattern makes the whole thing work better.
 
During my initial 172 lessons, my instructor told me:

Abeam, add first notch of flaps and target 75 knots.
Base, second notch of flaps and target 70 knots.
Final, full flaps and target 65 knots.

These targets were simply in place to make sure that I stayed well away from stall speed throughout my approach, but it also caused relatively bad landings because I had to fly wide patterns and hold the plane off for so long.

Right now, I simply target 5 knots less for each position and still fly a wide pattern.

My next goal is to remove another 5 knots (65 60 55) to tighten my approach up.

The excess speed that was "instructed" to me made for some pretty interesting/floaty landings. However, it also added a lot to my comfort level because I knew we weren't near the edge.
 
sanforce said:
During my initial 172 lessons, my instructor told me:

Abeam, add first notch of flaps and target 75 knots.
Base, second notch of flaps and target 70 knots.
Final, full flaps and target 65 knots.

These targets were simply in place to make sure that I stayed well away from stall speed throughout my approach, but it also caused relatively bad landings because I had to fly wide patterns and hold the plane off for so long.

Right now, I simply target 5 knots less for each position and still fly a wide pattern.

My next goal is to remove another 5 knots (65 60 55) to tighten my approach up.

The excess speed that was "instructed" to me made for some pretty interesting/floaty landings. However, it also added a lot to my comfort level because I knew we weren't near the edge.
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Same for me. Try this:

abeam, pull the power, hold the nose to maintain altitude and when you reach Vfe drop all the flaps you got and start your turn.

You'll make the threshold easily and you won't be more than an eighth of a mile from it.
 
My SOP has been:
* at 1000' AGL (TPA), establish 85 kias and 10° flaps abeam the numbers
* turn base at 800' AGL or when the runway is 45° between the wing and fuselage, establish 75 kias base and 20° flaps
* turn final at 500' AGL, establish 65 kias and 30° flaps

My timing on turning downwind to base to final is decent. My glideslope is decent, even without the VASIs. I'm getting better at not flying 747 patterns and being less hesitant to pull the throttle on short final. I'm still, however, having a hard time juggling trim/flare/crabbing and not sideloading the gear.

My last flight or two have been in a 180hp 172 with a STOL kit.
 
George,

That's pretty standard and will work well in that airplane.

As you progress, you can add new methods, such as slow to 70, apply full flaps, and do a wide 180 to short final.

What makes flying so much fun is the variety!!

:thumbsup:
 
George:

I am assuming that you are flying a conversion 172 (you did mention a 172N in an earlier post, I believe). My first plane was a standard 172N-160, the current bird is a 172N-180 conversion, and there are differences in how she handles the airspeed configurations due to: the increased weight of the 180 vs the 160 out front and the torque of the 180 compared to the 160..it tends to be a bit nose heavy and learning the feel of that difference tended to make me want to use a bit more airspeed at first because she drops out alot more rapidly once the power is gone.

Most interesting have been dealing with approaches stabilized for 90kts on the glide slope to MDA-DH and bleeding off the energy quickly enough to plant the thing down in a normal fashion...

In any case, trim is your friend!!!

The 180 does make, at least to me, a difference. YMMV
 
GeorgeC said:
having a hard time juggling trim/flare/crabbing and not sideloading the gear.
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Just as you start the flare, whilst juggling the trim/flare/crab, add a little power, enough to 'stretch out' the flare, continue to add the power stretching out the flare into a long 'powered float' down the runway, while you practice this 'juggling' that you have to do to get the crab out and the slip in as you flare and float and feel for the runway. Don't let the wheel(s) touch until you have gained the control to not allow crabbing which is the cause of sideloading.

matter of fact, if you are having trouble transitioning from crab to slip during the flare, practice slipping all the way down final. Power off.
 
nosehair said:
matter of fact, if you are having trouble transitioning from crab to slip during the flare, practice slipping all the way down final. Power off.
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If there is nobody onboard with me, this is definitely my preferred method because it lets me know if the crosswind is too much for me way ahead of time since I don't rely that heavily on ASOS/ATIS/AWOS
 
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