Got a 172n flap usage question

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fudge80

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fudge80
Hey everyone, my first post on the forum but I am actually an aviation junkie nowdays so I thought I would register on here.

I got my private license back in Augustand bought 172n Skyhawk the same day. I did all of my training pretest(other than a short half hour test fly in the 172 I ended up buying) and check ride in my instructors 152.

The question I have is about flap usage. When in the 152 it had 10, 20, 30 degree and 10 degrees was for takeoffs only pretty much and would make you "float" on landings according to my instructor.

The 172 has "stops" for 10, 20 and 40. The owner of the plane(he has owned it for 25+ years) told me that he used 10 and 40 for landings and landings, and 20 degrees for takeoffs.

I spent a few hours in the 172 with my instructor but didn't do a but 10 or so landings with him with .

I have about 6 hours in it so far and maybe 25-30 landings. I generally have been just landing no flaps, 30(without a notch), or 40. I trust my instructor greatly as he has done nothing but fly his whole life but I would just like some input from the public abroad.

Any responses appreciated!:yes:
 
What exactly is your question?
 
I love 40* flaps in a Cessna. I often wish somebody'd STC a Birddog's 50* flap setting for my 180. That would rock!
 
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I trained in a 172M, I think. Downwind, 70 knots, 10°; base, 70 knots, 20°; final, 65 knots, flaps as required to land where I wanted to on the 3000' runway.

My Mooney does not have stops, or even a lever, for flaps, just a two way toggle switch. The flaps move down as long as I hold the switch down, or move up as long as I hold the switch up. Enjoy being able to quickly move the lever and let go while the flaps move on their own.

Won't swear to takeoff usage, maybe for short field? What does your POH / Owners Manual say?
 
If you are asking about what setting to use. I only used 40 degrees in the 150 if I was high and I knew pulling power to idle wouldn't cut it, or if I no kidding needed to do a short field landing for real. Usually ended up coming in with a lot of unnecessary power. Normal ops I used no more than 30.

Here's a good article on flaps

http://flighttraining.aopa.org/magazine/2012/September/feature-flaps.html
 
No flaps for TO unless soft field or short field then use 10. 40 for landing.
 
Gucci Pilot said:
What exactly is your question?
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Yep, I see now I clearly did not ask the question, haha.

My understanding is this:

10 degrees is for takeoffs.
20, 30, 40 degrees is for landings.

Is that correct?


I wouldn't even bother to ask other than the conflicting training I have had from my instructor and the things I was told by the person who sold me the plane.
 
Hank S said:
I trained in a 172M, I think. Downwind, 70 knots, 10°; base, 70 knots, 20°; final, 65 knots, flaps as required to land where I wanted to on the 3000' runway.

My Mooney does not have stops, or even a lever, for flaps, just a two way toggle switch. The flaps move down as long as I hold the switch down, or move up as long as I hold the switch up. Enjoy being able to quickly move the lever and let go while the flaps move on their own.

Won't swear to takeoff usage, maybe for short field? What does your POH / Owners Manual say?
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POH, says "flaps as required" generally for landings. Has 10 degrees listed for the specialty takeoffs such as short field and soft field.

Like I was saying I think my instructor was correct, just got conflicting reports.
 
I should add my instructor has flown everything under the sun and is currently flying ER patients out of the state in one of two Cessna Citations while the guy I bought the plane from is in his sixties and sold me a 1978 plane he has owned since 1984 with 1700ttaf hours on it.
 
It's been a while since I flew one, but 0 flaps for normal T/O, full flaps for landing, I'm a fan of landing as slow as possible, with a occasional 0 flap landing for practice.

Short/Soft was 10 or 20, forget which but it matched max deflection of the ailerons if memory serves.
 
For takeoff, 20 is too much in a 172N -- adds a lot of drag. If you look in the 172N POH, it recommends zero flaps for both normal and short-field takeoffs;10 flaps are recommended only for soft-field takeoffs. FWIW, the later 172P POH recommends 10 flaps for short-field as well as soft-field, but there's no aerodynamic difference between the N and P, and when I asked Cessna, they said they had no explanation for the difference. However, I tend to do what the book says unless there a good reason to do otherwise, so I'll do 10 flaps for short-field in a P, but zero flaps in an N.

For landings, while the book just says "as recommended" for normal landings, and that normal landings "can" be made with any flap setting The POH also specifically recommends full flaps for short-field landings. Further, the airplane as enough lateral and directional control to make landings with full flaps in crosswinds of twice the demonstrated maximum crosswind component, so there's no need to reduce flaps for a higher approach speed in crosswinds. Further, my experience is that most pilots do best that which they do most often, and those who vary the parameters on every landing tend not to make good landings routinely. All things considered, my feeling is that if you want to be good at landings, you should use one setting all the time unless you have a really good reason to do otherwise (the occasional no-flap landing to practice for electrical power loss excepted). Which setting? Well, full flaps maximizes drag to reduce float (and thus landing distance) as well as allowing the lowest landing speed, minimizing wear on the tires and brakes. So, I land 172's with full flaps, period, using 1.3 Vs0 for the actual landing weight (typically about 55-60 knots IAS depending on load). I use 10 on downwind, 20 on base, and full flaps on final. Also, trying to set 30 flaps with your system is not likely to give you a consistent flap position, which is why I recommend sticking with the detented positions of 10, 20, and 40.

BTW, a 152 won't float significantly on landing with flaps extended unless you're landing too fast, but that's not an issue for you now.
 
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I was taught, and went on to teach, the mantra:

"Maximum flaps as consistent with conditions."

The goal is to touch down with the least possible energy, since excess energy can cause so many problems. And that lowest energy state will be achieved with full flaps.

This discussion comes up periodically. I learned full flaps (40°) in a C150 from the very beginning. Anything else was the exception. Law of Primacy, 40 years later I still think that way.

Pilots who learn with partial flaps at first "because its easier" may carry that mental image ahead with them and revert to partial flap landings as their norm*.

Finally, see what the POH says. Cirrus wants full flaps on every landing, and says so in a "CAUTION" in the POH. The only exception are flaps that fail to deploy and training for such a failure.


*Or even no flaps. Anecdote: Bonanza coming into Copperhill, runway about 3,000' long. Fast, flat approach. No flaps. Touches down fast and flat and uses virtually ALL of the runway to get stopped.

After he taxied in, I asked about why no flaps? Answer, "Don't much care for them", or words to that effect.

In any case, that's hardly an isolated case, and I wonder about how these guys were taught, and if they were taught correctly I wonder when and why they got lazy and began to disregard their training.
 
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Student Pilot here. I am been flying a 172n for training I have only 3 solo's under my belt but a lot of landing in the last 2 weeks. I ask this very question he said whatever you feel comfortable with. So I did landing in each configuration with head wind, I actually have more grease landings with 10-20 degree flaps keep in mind ground effect and the likely of a balloon right before flare is higher if you pull back to quick as it floats longer but lands nice. Yesterday in crosswind 9k direct my restriction is 10kt I used only 20 degree flaps I wanted more control easier to stay ahead of the plane. Since I am a very low student 18 hours I have a hard time with full flaps it does sink very fast and I bounced a few landings and also the control inputs are not as responsive. I am working on landing in every configuration but right now full flaps are giving me all I can handle. I hope that helps
 
I have a lot of time in the 40 degree flapped 172N.

10 degrees will decrease the ground roll on a short field but will not get you to the 50' obstacle faster as climb is affected. The flaps on that thing do not move quickly enough that I'd consider moving them during takeoff (if you have one of the manual flapped 170 or 172's, you can use the trick of starting the roll with them retracted, extending them to break ground and then retracting them once you have climb airspeed).

Nice thing about that plane is that you can put the first 10 degrees of flaps out at 110 Kts (where the subsequent settings require 85 or less).
 
I did most of my training in a 172N and the way I was taught was that you used no flaps for normal takeoff, 10 degrees for short & soft field takeoffs. For landing (uncontrolled field so always flew a standard pattern) we did 10 on downwind, 20 on base, and at least 30 on final.

The school I was at had 172's with only 30 degrees of flaps available in addition to the ones with 40 degrees, and while I had a favorite aircraft there were times I would fly one of the others due to availability. My CFI's suggestion was to be comfortable landing with 30 degrees since I was always guaranteed to have that available for a normal landing and only use 40 if I felt it was needed on final.

The only exception were short field landings where I was taught to use all available flaps.
 
Fredbob711 said:
I did most of my training in a 172N and the way I was taught was that you used no flaps for normal takeoff, 10 degrees for short & soft field takeoffs. For landing (uncontrolled field so always flew a standard pattern) we did 10 on downwind, 20 on base, and at least 30 on final.

The school I was at had 172's with only 30 degrees of flaps available in addition to the ones with 40 degrees, and while I had a favorite aircraft there were times I would fly one of the others due to availability. My CFI's suggestion was to be comfortable landing with 30 degrees since I was always guaranteed to have that available for a normal landing and only use 40 if I felt it was needed on final.
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Note that many 172N's have been STC modified with a flap limiter which limits flap extension to 30 degrees, but gives an extra 100 lb of max gross weight -- and that's all extra useful load since there's no empty weight change. If you're flying both types, it makes sense to use 30 all the time (except for short fields), since you do best what you do most often.
 
If your really familiar with what your flying, experience, it should be second nature to you what settings to use, under varied conditions.
 
Fredbob711 said:
I did most of my training in a 172N and the way I was taught was that you used no flaps for normal takeoff, 10 degrees for short & soft field takeoffs. For landing (uncontrolled field so always flew a standard pattern) we did 10 on downwind, 20 on base, and at least 30 on final.

The school I was at had 172's with only 30 degrees of flaps available in addition to the ones with 40 degrees, and while I had a favorite aircraft there were times I would fly one of the others due to availability. My CFI's suggestion was to be comfortable landing with 30 degrees since I was always guaranteed to have that available for a normal landing and only use 40 if I felt it was needed on final.

The only exception were short field landings where I was taught to use all available flaps.
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Wouldn't landing slower be better in most conditions?
 
Ron Levy said:
FWIW, the later 172P POH recommends 10 flaps for short-field as well as soft-field, but there's no aerodynamic difference between the N and P, and when I asked Cessna, they said they had no explanation for the difference.
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But there was a gross weight difference, by 100 pounds. Maybe at the time their flight tests showed it would unstick more readily with a notch of flap out? Just speculatin'.

flyingron said:
Nice thing about that plane is that you can put the first 10 degrees of flaps out at 110 Kts (where the subsequent settings require 85 or less).
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Not true for all 172Ns. The 110-knot "approach flap" limit was added with the 1979 model year (s/n 17271035 and up). '77 and '78 172Ns, like mine, still carry the 85 knot limit for the whole range.

As far as I know, it was simply a paper change, no mechanical change to the system. The flap limiting/gross weight STC (SA2196CE) also permits the "approach flap" speed limit change for 172M and 172N aircraft.
 
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Ron Levy said:
Note that many 172N's have been STC modified with a flap limiter which limits flap extension to 30 degrees, but gives an extra 100 lb of max gross weight -- and that's all extra useful load since there's no empty weight change. If you're flying both types, it makes sense to use 30 all the time (except for short fields), since you do best what you do most often.
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Most of my 172 time is in a 172N with the 180 hp Penn Yan conversion. As part of that, flap travel is limited to 30 degrees. Several years ago I was being checked out in a 172N with 40 degrees available and had trouble getting consistent landings. I limited myself to 30 degrees and all went fine. It's a matter of what your are used to and it does make a difference. Oh, and the 180 hp with the flap limit gives you a 250 pound bump in max gross, the vast majority of which translates directly to extra useful load. That 172N, with long range tanks, can carry 755 pounds in the cabin with full tanks.
 
Ghery said:
Most of my 172 time is in a 172N with the 180 hp Penn Yan conversion. As part of that, flap travel is limited to 30 degrees. [snip] Oh, and the 180 hp with the flap limit gives you a 250 pound bump in max gross, the vast majority of which translates directly to extra useful load.
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For the Air Plains conversion, the engine change and the flap limit/gross weight change are two separate STCs. I purchased both, but never installed the flap limiter. So my 172N is 180 hp, 2300-lb MGW and has 40° of flap. Nice short-field airplane, though it doesn't carry as much load.
 
James331 said:
Wouldn't landing slower be better in most conditions?
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I'd probably chalk it up to personal preference. Landing slower is always better in the event of a crash/forced landing. I doubt that the touchdown speeds between 30 and 40 degrees of flaps is significant enough to get markedly different wear patterns out of a set of tires. If one likes, or is comfortable with, the drag/steep decent angle that throwing 40-degrees of flaps produces, go for it. If 20 or 30 degrees is sufficient for what they are doing, it's fine too. You should be able to land consistently in every configuration, but what configuration you use on a regular basis is entirely up to personal preference as long as it falls within the limitations given in the POH.
 
James331 said:
Wouldn't landing slower be better in most conditions?
Click to expand...

I really only used 40° of flaps if I was either too high or too fast on final after getting speed and attitude settled with 30°. If I didn't have the last 10° I would have either slipped or called a go-around to try again, and had to on a couple occasions when I was in different aircraft.
 
SoonerAviator said:
............. You should be able to land consistently in every configuration, but what configuration you use on a regular basis is entirely up to personal preference as long as it falls within the limitations given in the POH.
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I think that's true. I fly a '53 Cessna 170B with manual flaps notches at 10*, 20*, 30* & 40*, usually I deploy 10 for normal t/o, 20 for short/soft field t/o, 30 for normal landing and 20 for strong gusty x-wind landing. Very seldom do I deploy 40*, only time would be perhaps landing on a short runway with a high obstacle close to the threshold.
 
Shy of glassy water, I always use full flaps in the 185, and that thing has barn doors on it, even droop ailerons. The slower the better IMO
 
Hmm. I haven't landed with less than full flaps for as long as I can remember. I don't reckon I'll start anytime soon, either. Take-off flaps is a factor of gross weight and horsepower. Any guy interested in performance should add some extra take-off flaps when light to see how it works. :wink2:

When I had my Hawk XP there was a placard to avoid 40* flaps on floats. I was a newbie. I obeyed. During my float checkride, after the expected exercises my float DPE looked at me and said I was a pilot (I passed)... "Now let me show you how to fly this thing." It was 40* flap landings, step turns around corners to take-offs, J turn take-offs... That was a seriously fun ride. I'm not sure I've ever done a less than full flap landing since then, come to think of it.
 
I don't get it... Flaps, no flaps, comforable with this and that... There is something to be said for repetition, i guess, but that seems a little robotic to me. I rarely use flaps at all on runways over 4000' and still (usually) make the first turnoff. I Never use flaps for takeoff unless short or soft field and then only 10. 10 is the sweetspot for lift vs drag in the hawk and the 150/152. Don't get hung up on how much when and where... fly the airplane and set it up for the best results under the current condtions. IMHO!
 
James331 said:
Shy of glassy water, I always use full flaps in the 185, and that thing has barn doors on it, even droop ailerons. The slower the better IMO
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Is that the Robertson STOL Kit? Friend of mine just bought a late model 180 with the Robertson Kit, he was showing it to me one day and I noticed the ailerons were actually negative a little (like UP from normal) with the flaps at zero, 10 degrees of flap brought the ailerons back to the normal position, 20 degrees and 30 degrees of flap had the ailerons following the flaps down and a 40 degrees of flap the ailerons actually went back UP to where they were for the 20 degree flap setting.
 
Why not full flaps for glassies? Set the rate od descent with full flaps and a little power, it's the slowest way to go, and being glassy the wind isn't a factor.
 
Stewartb said:
Why not full flaps for glassies? Set the rate od descent with full flaps and a little power, it's the slowest way to go, and being glassy the wind isn't a factor.
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Less flap gives more nose up at water contact. Safer....better.
 
Stewartb said:
…………….. Set the rate of descent with full flaps and a little power, ………….
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Concerning Cessna "paralift" flaps, unless a really steep short final approach is required why deploy full 40 degrees of flaps if it requires adding power to make the runway :confused:
 
peerlesscowboy said:
Is that the Robertson STOL Kit? Friend of mine just bought a late model 180 with the Robertson Kit, he was showing it to me one day and I noticed the ailerons were actually negative a little (like UP from normal) with the flaps at zero, 10 degrees of flap brought the ailerons back to the normal position, 20 degrees and 30 degrees of flap had the ailerons following the flaps down and a 40 degrees of flap the ailerons actually went back UP to where they were for the 20 degree flap setting.
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Yep Robertson :)


Stewartb said:
Why not full flaps for glassies? Set the rate od descent with full flaps and a little power, it's the slowest way to go, and being glassy the wind isn't a factor.
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It's a L/D thing, aside from my float supplement saying to not use full, it also feels more stable and requires me to not have to overcome all that drag to get that nice shallow decent profile.
 
Concerning Cessna "paralift" flaps, unless a really steep short final approach is required why deploy full 40 degrees of flaps if it requires adding power to make the runway
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We were talking about glassy water float landings. That's all about rate of descent and aircraft attitude. You aren't just gliding in unless you want to take a swim.
 
kgruber said:
Less flap gives more nose up at water contact. Safer....better.
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Not sure about your floats or plane, but I find touching down as slow as possible quite safe, my 185 is still somewhat new to me, that said I've never felt I touched down with my nose too low at full flaps.
 
So you come in with less than full flaps and drooping ailerons rather than just using full flaps? I don't get it.
 
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