Doc Holliday
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Yes, all of them. Brought about by 3 crashes of a high sink rate by landing flaps 40.
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40deg flaps
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Yes, all of them. Brought about by 3 crashes of a high sink rate by landing flaps 40.
Flaps change the camber of the wing, When you deflect the flaps you're tilting the chord line of the wing, so its effective AOA is greater for a given deck angle.
luvflyin
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Yeah, got that. By deck angle I meant relative to the ground.
Larry Vrooman
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I wrote "is not something people miss" rather than "was not something people missed" very intentionally.
I was around when the C152 was introduced and I remember very well the hue and cry that went up over the C152 only having 30 degrees of flap. Now however, you won't find that item anywhere near the top of the list of items that are discussed when considering the relative merits of the C150 versus the C152.
Personally, if I have to fly a C150, I prefer the old johnson bar flapped C150s. The manual flaps give you a lot more flexibility in terms of applying and removing them than electric flaps.
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I hear you on the use of flaps in general. Full flap landings seem to be the norm in most light single engine aircraft with ample rudder, even with 6000' of runway and gusty crosswinds, and I just don't see the need or agree with all landings being full flap landings.
Stewartb
Final Approach
There's a LOT more to it that stall speed. I haven't used less than full flaps to land my Cessna in 20 years. No exaggeration. Full flaps allows a pilot to fly a steeper final in a useful attitude with easy speed control. And contrary to what you guys think? Given adequate power 40* flaps is a very useful takeoff tool in some conditions.
Lots of pilots are freaked out by the "steep" descent of a 172 power off with full flaps.
kgruber
Final Approach
Cessna recommends less flap in crosswinds for good aerodynamic reasons. Full flaps give more turning moment than zero flaps because the downwind flap is in the lee of the fuselage.
This is EASILY demoed in a floatplane, where turning into the wind on the water is faster with flap than without.
This is EASILY demoed in a floatplane, where turning into the wind on the water is faster with flap than without.
denverpilot
Tied Down
It’s a valid aerodynamic point, but I just looked through three Cessna POHs from the pre-restart/pre-lawyer days and can’t find that instruction. Perhaps I checked too quickly but I don’t see it. It’s certainly not a checklist item.
If the airplane is done flying and all weight is on the mains, comparing water turns to tire friction is a pretty small force. We could do the math but tires overcome it on thousands of crosswind and just plain bad landings every day.
But people landing twenty knots fast with the flaps down, tend to notice the lack of weight on the mains and therefore friction to alleviate their bad rudder use and resulting side loads, by the screeching sound coming from said tires.
The “but it’s only two MPH slower” crowd always ignores that the chart is in CAS, too. Let’s see it in groundspeed.
And then let’s remember that force squares with any collision by speed.
Therefore the answer to the original question posed is...
Pro: You can approach steeper and land slower.
Con: You have to learn how to properly land slower. The crossover from your car will bite you in the ass here. You need more control movement as you slow. Often all the way to the stops. Your car taught you not to do that. You’ll have to overcome it and move them fast and full sometimes. Exactly what you’re not supposed to do in cruise.
And if you’re out of control authority or just horribly behind and slow about it, you risk a loss of control accident that’s usually more about the pilot than the capability of the aircraft.In other words, the aerodynamics is true but it’s likely not as important as getting your hands and feet moving. If you’re hearing those tires slide and landed close to stall with appropriate braking and control inputs, you probably have a 30 knot cross. Or more. The airplane can do the tested 17 or so for most of them, without so much as a yawn, aerodynamically.
It’s usually the pilot who can’t.
FastEddieB
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Fast Eddie B
That would be my take as well. I went through the 150 to 152 transition teaching at Burnside Ott in the 1970's, and I thought getting rid of that last 10º was "dumbing down" the plane.
My mantra is "Maximum flaps as consistent with conditions". So, normally full.
Lots of pilots are freaked out by the "steep" descent of a 172 power off with full flaps.
Nothing a few landings in a biplane or an ultralight won't cure...
Tantalum
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San_Diego_Pilot
Someone here had mentioned that the reason is the turbulent airflow wears out some bearing in the rudder assembly? No idea if that's true or not
If you are talking 172, in my experience the 160 hp versions really are barely able to climb (if at all) at 40 deg flaps. Heck, even maintaining level slow flight needs a lot of juice. The 180 hp versions I'm not sure, the ones I have flown though only go to 30 deg. Pro's.. more drag so you can be more steep and touch down a little slower
In my experience planes tend to land better when you don't have all the flaps in, runway length permitting of course
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Pilawt
1967 Cessna 150G:
1966 Cessna 172G:
1978 Cessna 172N:
1985 Cessna 172P:
2010 Cessna 172S:
In Cessna - Wings for the World: The Single-Engine Development Story, former Cessna Manager of Flight Test and Aerodynamics William Thompson wrote in his chapter on the development of the Model 172, "[...] wing-low drift correction in crosswind landings is normally performed with a minimum flap setting (for better rudder control) [...]" [emphasis in original]
In ground effect, The drag of 40 degrees allows for some really slow touchdowns and at that speed, there just isn't much rudder authority left unless you use power to keep the nose straight. That isn't a great idea, though because you are already behind the power curve and the only way to recover is with a definite pitch down (forward yoke, downward elevator- if you have it!).
I always taught students to land at the slowest possible speed for conditions. That usually meant full flaps, unless there was a decent crosswind. In my STOL modified 150, the only way to maintain directional control with full flaps at 28 knots (that's a guess because the airspeed read near zero) was to use lots of power and get deep behind the power curve. That technique is not for the faint of heart, but resulted in sub 100 foot landings...
One of my favorite demonstrations for pre-solo students was to show them how LOWERING the nose during a go-around would make the aircraft climb with 40 degrees of flaps and full power! Then they could slowly retract the flaps to achieve a normal climb...
The 152 was a disappointment since they sacrificed an increase in gross weight for better full-flap climb performance.
Cessna flaps are one of the best things to experience in GA. Right up there with Grumman canopies!
I always taught students to land at the slowest possible speed for conditions. That usually meant full flaps, unless there was a decent crosswind. In my STOL modified 150, the only way to maintain directional control with full flaps at 28 knots (that's a guess because the airspeed read near zero) was to use lots of power and get deep behind the power curve. That technique is not for the faint of heart, but resulted in sub 100 foot landings...
One of my favorite demonstrations for pre-solo students was to show them how LOWERING the nose during a go-around would make the aircraft climb with 40 degrees of flaps and full power! Then they could slowly retract the flaps to achieve a normal climb...
The 152 was a disappointment since they sacrificed an increase in gross weight for better full-flap climb performance.
Cessna flaps are one of the best things to experience in GA. Right up there with Grumman canopies!
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In the book cited above, Bill Thompson's chapter on the Model 150 is interesting. It is certainly authoritative, as he was on the design team, and was the test pilot on the Model 150's maiden flight. He wrote:
For most airplanes I agree with “full flaps all the time.” I landed my Cheetah with full flaps all the time, as with my Bonanza — except the two times when the flap motor quit. IMHO the C-150 and C-172, lightweight, relatively underpowered airplanes with oversized flaps, are exceptions.
I’ve flown both extensively since the 1960’s, have owned both, and my experience is that their handling and control response in the flare is better at flaps 20-30 than at flaps 40.
I would routinely land my C-150F with flaps 20, gently on the mains with stall horn blaring, and hold the nose off until elevator power dissipated (longer than is possible at flaps 40) and the nose gear touched at a speed barely above a fast walk, and make the first turnoff with no braking or added power at all. I’d submit that’s easier on the undercarriage (especially the relatively fragile nose gear). Less wear on the flap motor and flap tracks, too.
It depends on the airport, too. If the first turnoff is 600 feet down the runway, full flaps may help. If like at my airport it’s 1500 feet away, a full flap landing might slow things down, require the use of power to ‘expedite’ to the turnoff, and increase pilot workload.
At flaps 40 a Cessna 150 or 172 is not a healthy bird. In event of a balked landing drag is so great it ain’t gonna climb worth beans until flaps are milked up to 20. (If you gotta go around at flaps 40 what do you do if the flap motor quits?) On approach with flaps 20 the potential pilot workload is decreased and safety margin increased.
FAA pamphlet P 8740-48 (”On Landings, Part I”):
As mentioned in the previous post, as to the C-150 and C-172 (among others) the manufacturer does suggest otherwise for crosswind landings, and further says that normal landings may be made "with any flap setting." So I am compliant with the published FAA guideline if I land a C-150 with 20 degrees of flap down. Would the same be said of a pilot who prangs a 150 in a strong crosswind with full flap on a mile-long runway?
I agree with the general principle that consistency is a good thing. In a perfectly consistent world we would always fly at the same weights, at the same temperatures, with the same winds, etc., etc. Some day a student may fly a high-performance airplane that requires partial flap for takeoff. Does that mean he must use partial flap for every takeoff in his trainer (within the allowable range), for consistency’s sake?
That said, please don’t interpret my comments as disdain for the use of full flaps, and I certainly don’t agree with training for only flaps 20 landings. The pilot should be proficient in all of the configurations as recommended by the manufacturer, so that he/she is familiar with all of the options available to complete a safe flight with minimal physical or emotional trauma to machine and occupants. Full flap? Partial flap? No flap? Sideslip? Forward slip? No slip? Oversquare or undersquare with a controllable prop? Wheel landing or full-stall in a taildragger? If it’s recommended or permitted by the book (as it is in the case of the airplanes we’re discussing), be familiar with it, know its advantages and disadvantages, and use your judgment to fly the way that is best for you under the circumstances.
All this said ... I have deferred the STC that would give my 180 hp C-172N an additional 250 pounds of useful load, because I don't want to limit the flaps to 30°. I like having 40° as an option.
With the popular 100 HP Continental O-200-A engine as a starting point, it became obvious that the extra weight and drag of a nosegear would make this a low-performance airplane. Thus the attainment of the FAA's minimum climb requirement (10Vs ft/min) would be a challenge. [...] Our experience with tricycle gears on other airplanes, indicated that most low-time pilots use about 10-mph excess speed in the approach glide, and then they would float many hundreds of feet before touching down. Thus the C-150 would need lots of drag with big flaps. Fortunately, these large slotted flaps had been developed for a projected C-140B that never reached production. The C-140B's elliptically-shaped horizontal tail was inadequate for handling the large pitching moments caused by the 40°flap setting, and, therefore, the project had been canceled before C-140A production was terminated. Understandably, my preliminary design report was not very enthusiastic for the projected low-performance C-150 with enlarged tail surfaces and more powerful flaps. It seemed that the performance should have exceeded the predecessor model C-140's performance to gain customer acceptance. However, the tricycle gear was to be the real selling point.
For most airplanes I agree with “full flaps all the time.” I landed my Cheetah with full flaps all the time, as with my Bonanza — except the two times when the flap motor quit. IMHO the C-150 and C-172, lightweight, relatively underpowered airplanes with oversized flaps, are exceptions.
I’ve flown both extensively since the 1960’s, have owned both, and my experience is that their handling and control response in the flare is better at flaps 20-30 than at flaps 40.
I would routinely land my C-150F with flaps 20, gently on the mains with stall horn blaring, and hold the nose off until elevator power dissipated (longer than is possible at flaps 40) and the nose gear touched at a speed barely above a fast walk, and make the first turnoff with no braking or added power at all. I’d submit that’s easier on the undercarriage (especially the relatively fragile nose gear). Less wear on the flap motor and flap tracks, too.
It depends on the airport, too. If the first turnoff is 600 feet down the runway, full flaps may help. If like at my airport it’s 1500 feet away, a full flap landing might slow things down, require the use of power to ‘expedite’ to the turnoff, and increase pilot workload.
At flaps 40 a Cessna 150 or 172 is not a healthy bird. In event of a balked landing drag is so great it ain’t gonna climb worth beans until flaps are milked up to 20. (If you gotta go around at flaps 40 what do you do if the flap motor quits?) On approach with flaps 20 the potential pilot workload is decreased and safety margin increased.
FAA pamphlet P 8740-48 (”On Landings, Part I”):
“One final point: full flaps should be used for all normal landings unless the manufacturer suggests otherwise.” [emphasis added]
As mentioned in the previous post, as to the C-150 and C-172 (among others) the manufacturer does suggest otherwise for crosswind landings, and further says that normal landings may be made "with any flap setting." So I am compliant with the published FAA guideline if I land a C-150 with 20 degrees of flap down. Would the same be said of a pilot who prangs a 150 in a strong crosswind with full flap on a mile-long runway?
I agree with the general principle that consistency is a good thing. In a perfectly consistent world we would always fly at the same weights, at the same temperatures, with the same winds, etc., etc. Some day a student may fly a high-performance airplane that requires partial flap for takeoff. Does that mean he must use partial flap for every takeoff in his trainer (within the allowable range), for consistency’s sake?
That said, please don’t interpret my comments as disdain for the use of full flaps, and I certainly don’t agree with training for only flaps 20 landings. The pilot should be proficient in all of the configurations as recommended by the manufacturer, so that he/she is familiar with all of the options available to complete a safe flight with minimal physical or emotional trauma to machine and occupants. Full flap? Partial flap? No flap? Sideslip? Forward slip? No slip? Oversquare or undersquare with a controllable prop? Wheel landing or full-stall in a taildragger? If it’s recommended or permitted by the book (as it is in the case of the airplanes we’re discussing), be familiar with it, know its advantages and disadvantages, and use your judgment to fly the way that is best for you under the circumstances.
All this said ... I have deferred the STC that would give my 180 hp C-172N an additional 250 pounds of useful load, because I don't want to limit the flaps to 30°. I like having 40° as an option.
Along with the hand held microphone, ash tray, and ADF.
Doc Holliday
En-Route
Boeing did the same thing (B727). Then the bolt was placed to limit to 30.
My point.All of which were used a lot when the airplane was built.
FastEddieB
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All of which were used a lot when the airplane was built.
I think there’s an implication that limiting flaps to 30° in the 152 was due to declining pilot skills over the years, leading to accidents.
“Idiot-proofing” as it were.
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Pilawt
The C-150 manual says, "Normal landings are made power-off with any flap setting."
Thompson again:
"The new C-152 featured a 28-volt electrical system, an oil cooler, a new fixed-pitch propeller, and a 30° maximum flap setting (instead of 40°). This reduced flap setting decision was related to a power effect on flying qualities."
He noted that the heavier Lycoming engine moved the 152's CG forward half an inch compared to the 150. Also, the 152's gross weight was 70 pounds more than the 150.
Clip4
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-1 knot is lower
Source for 1KT difference between 30 and 40?
The 150 becomes a manhole cover with 40*, ie it is coming straight down. Thing will stop in 200 ft if you have any wind but in the event of a go around, those big barn doors have to come up RIGHT NOW. Might take flying level to get enough smash to actually start climbing. So, go practice landings with all flap settings but realize 40* takes some careful flying in certain situations.
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Pilawt
See Post #39 in this thread.
On the C-150 it's actually 1 mph (0.87 knot) difference in stall speed between 20 degrees and 40 degrees of flap. You'll have to look awful hard to see what it is between 30 and 40 degrees.
Yes, exactly- 20 to 40, not 30 to 40. And since 20 degrees is not quite at max lift deflection, I’m not convinced there’s any stall speed difference between 30 and 40.
Stewartb
Final Approach
My Cub flaps drop to 70*. There have been a lot of times I wished my 180 had more than 40. Didn't Birddogs have 50*? Same wing.
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Pilawt
60 degrees, but they needed external hinges to do it.
denverpilot
Tied Down
Haha cool thanks.
Have to note that it looks like nobody will ever learn how to land with flaps ever again, following Cessna’s advice at my home airport.
And they’ll suck even worse at using the rudder than most already do.
What Cessna requests there isn’t even possible to pass a private checkride, so that’s an incredibly stupid sentence.
Probably why I missed it. Hahaha.
Grum.Man
En-Route
I wonder why the H model with a 1600lb gross has a lower stall speed than my C with 1500lb gross? Mine is listed at 54 flaps up, 53 flaps 10, and 50 flaps 40
ktup-flyer
En-Route
Different wing, probably. The 182 changed wings at some point.
Stewartb
Final Approach
The Camberlift leading edge didn't work on the 150 and was never added. The only important change after the C model was the addition of the rear window. Gross weight and stall speeds appear to be paper numbers.
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Pilawt
Another change was balanced elevators and rudder on the 150D, along with increased gross weight from 1500 to 1600 lb.
To say the cuffed leading edge "didn't work" on the 150 was putting it mildly. Thompson again:
"A prototype was so fitted, and all flying qualities and performance checks proceeded routinely. Then came spins. Right out of the box, a 2-turn spin took 13 turns to recover! Variations on the full-span camber-lift airfoil, such as an outboard-droop-only and increased wing twist, were tested, and unacceptable spin behavior was noted."
The only other strutted high-wing piston-engine single in the Cessna line that did not get the cambered leading edge was the C-207, and that was only because the volume of sales didn't justify the flight test and certification expense.
Dan Thomas
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When I learned to fly we used that handheld mike and the ADF. Headets were rare and expensive. VORs in my part of the world were rare and a long way apart. Broadcast stations were handy and far more powerful than any NDB. GPS was science fiction.
Dan Thomas
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Idiot-proofing is mostly a waste of time. The world just comes up with better idiots. The money would be better spent on better training. It's too easy to get a PPL.
Dan Thomas
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That 150 nosegear is stronger than a 172's. It's attached to the stout steel-tube engine mount. The 172's gear attach is via relatively small brackets on the firewall, supported by a light aluminum tunnel structre behind the firewall. Easy to wreck.
denverpilot
Tied Down
I helped test this in 1991 and 1992. Can confirm. Takes a solid beating without damage. LOL.
Matthew
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It's been a while since I flew a 150, but I remember that flaps 40 gave me a very good view of the approach end of the rwy...at the top of the windscreen.
Short runway, tall trees owned by the government a few hundred feet from the end of the runway. The other end of the runway abutted a railroad ROW with the rails 20 feet above the runway, and telegraph wires 30 feet above the runway.
All the local flying schools forbid students flying into College Park, KCGS, due to the number of accidents related to the obstructions.
Our standard approach from the tree end was 40 degrees of flaps, 10 MPH over stall, and just above idle, so the engine would respond quickly if you needed it. Cross 10 feet over the trees, engine to idle, drop the nose, and head for the numbers. Make a progressive flare, reaching level at a couple of feet about 200 feet down the runway, and slowly set it down, full stall, and hold the nose up for max air braking (We had Bendix brakes). When the nose came down, lightly brake, and turn off midfield. We did not come close to running off the end of the runway landing.
No flap approach, 7 MPH faster, flare a quarter of the way down the runway, settle in half way down, lower drag without flaps, so set the nose down, brake gently, and turn off at the end of the runway. Those tiny Bendix pucks wore out about once a month, so the no flaps landings accelerated replacement.
The difference in margin of runway length was immense, club rules were strong on preferring full flaps. Ground instruction also included the sequence of 40 to 20 flaps as soon as a go around started (Johnson bar), as soon as full throttle was applied and carb heat was off. Safe speed, 20 to 10, best angle of climb speed, and 10 to 0. Spare time in the sequence, the trim wheel spinning to take yoke forces off, to make flying easy, and assure no pitch up problems. With that carefully trained prior to actual flight, we had no problems.
About 20 guys learned to fly in our 150 with out any damage from trees or excursions from the runway, so the technique worked. All first solo's were at CGS, as the student would have to be proficient in getting home after solo practice. During the same time, the trees ate a 172 and a Beechcraft, and the railroad ate a Mooney flown by an ATP Airline pilot.
One of the advantages of 40, or 30 degrees of flaps, if the engine quits, just raise to 20, then 10, and the reduced drag greatly extends the distance/ height of your approach, and then when the runway is made, the flaps can be used again to reduce speed to get down near the beginning of the runway, making the whole runway available. This is particularly true with an engine failure, and fine tuning touchdown into a pasture close to the fence, at minimum speed.
All the local flying schools forbid students flying into College Park, KCGS, due to the number of accidents related to the obstructions.
Our standard approach from the tree end was 40 degrees of flaps, 10 MPH over stall, and just above idle, so the engine would respond quickly if you needed it. Cross 10 feet over the trees, engine to idle, drop the nose, and head for the numbers. Make a progressive flare, reaching level at a couple of feet about 200 feet down the runway, and slowly set it down, full stall, and hold the nose up for max air braking (We had Bendix brakes). When the nose came down, lightly brake, and turn off midfield. We did not come close to running off the end of the runway landing.
No flap approach, 7 MPH faster, flare a quarter of the way down the runway, settle in half way down, lower drag without flaps, so set the nose down, brake gently, and turn off at the end of the runway. Those tiny Bendix pucks wore out about once a month, so the no flaps landings accelerated replacement.
The difference in margin of runway length was immense, club rules were strong on preferring full flaps. Ground instruction also included the sequence of 40 to 20 flaps as soon as a go around started (Johnson bar), as soon as full throttle was applied and carb heat was off. Safe speed, 20 to 10, best angle of climb speed, and 10 to 0. Spare time in the sequence, the trim wheel spinning to take yoke forces off, to make flying easy, and assure no pitch up problems. With that carefully trained prior to actual flight, we had no problems.
About 20 guys learned to fly in our 150 with out any damage from trees or excursions from the runway, so the technique worked. All first solo's were at CGS, as the student would have to be proficient in getting home after solo practice. During the same time, the trees ate a 172 and a Beechcraft, and the railroad ate a Mooney flown by an ATP Airline pilot.
One of the advantages of 40, or 30 degrees of flaps, if the engine quits, just raise to 20, then 10, and the reduced drag greatly extends the distance/ height of your approach, and then when the runway is made, the flaps can be used again to reduce speed to get down near the beginning of the runway, making the whole runway available. This is particularly true with an engine failure, and fine tuning touchdown into a pasture close to the fence, at minimum speed.