C172L flap switch
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C172L flap switch
Anyone has experience with C172L series flap switch? Was flying it the other day, doing some touch & go.
To extend the flaps, the flap switch has to be held down until you see the flaps physically move to the desired position, then the switch is to be released.
The problem comes when you are at flaps 40, doing a touch & go. At touchdown, you have to retract the flaps & apply full power. But I found that I had to hold the flap switch for up to almost 8 seconds for the flaps to retract from 40 to up, all this while with the aircraft rolling on the runway. Until the flaps are fully up, then only do I have a free hand to move the throttle to max power.
If the flaps switch stays in the up position that would be much better, I can flip the switch to up (& the switch stays there) while immediately after that apply full power.
Is the flap switch supposed to spring load back to center after being released from UP & DOWN position, or is there something wrong with the C172L I'm flying?
BTW, anyone knows what kind of switch this is called?
Cheers!
To extend the flaps, the flap switch has to be held down until you see the flaps physically move to the desired position, then the switch is to be released.
The problem comes when you are at flaps 40, doing a touch & go. At touchdown, you have to retract the flaps & apply full power. But I found that I had to hold the flap switch for up to almost 8 seconds for the flaps to retract from 40 to up, all this while with the aircraft rolling on the runway. Until the flaps are fully up, then only do I have a free hand to move the throttle to max power.
If the flaps switch stays in the up position that would be much better, I can flip the switch to up (& the switch stays there) while immediately after that apply full power.
Is the flap switch supposed to spring load back to center after being released from UP & DOWN position, or is there something wrong with the C172L I'm flying?
BTW, anyone knows what kind of switch this is called?
Cheers!
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Nothing wrong with it, it's how that type works. We have K, M and N models at our place and all three have different flap switches. The K is like yours, you have to hold it in position, the M has to be held down to lower but has an 'up' position which will retract them automatically and the N is the gated switch. I prefer the spring loaded type as you can select exactly how much flap you want, if you count when you're holding it then you don't even have to look at the flap gauge, at the time when you're lowering flap you need eyeballs out of the cockpit looking for the nut job who is going to cut you up. I know that counting to five gives me 20 degrees of flap for instance using the 'one thousand and one' counting method.
There's still a gap between selecting up and having the flaps retract even on the gated type, they don't retract immediately, also you don't have to retract them fully, if you're in a real hurry to get off the ground retracting them to 10-15 degrees will give you extra lift without too much extra drag.
You could also (obviously depending on length of the runway that you're using) not use 40 degrees of flap. I usually land with 20 degrees selected, anything more than that is just drag flap.
Do bear in mind I'm a novice and no doubt someone will be along to say that I'm going to die if I use those methods.....and if you're still a student don't do any of what I've said unless you run it by your instructor. In fact, just do what he says.
As for what it's called I don't know. Spring loaded flap switch?
There's still a gap between selecting up and having the flaps retract even on the gated type, they don't retract immediately, also you don't have to retract them fully, if you're in a real hurry to get off the ground retracting them to 10-15 degrees will give you extra lift without too much extra drag.
You could also (obviously depending on length of the runway that you're using) not use 40 degrees of flap. I usually land with 20 degrees selected, anything more than that is just drag flap.
Do bear in mind I'm a novice and no doubt someone will be along to say that I'm going to die if I use those methods.....and if you're still a student don't do any of what I've said unless you run it by your instructor. In fact, just do what he says.
As for what it's called I don't know. Spring loaded flap switch?
Last edited by thing; 29th Aug 2011 at 08:36.
If the flaps switch stays in the up position that would be much better,...
Standard procedure here for all three aircraft is 10°, respectively 15° flaps for take-off from such a runway, so having the flaps retract fully during a touch & go could be somewhat embarrassing.
I have to admit that with that runway length and when I'm alone, I much prefer full-stop landings instead, when practising take-off's and landings. T&G's are much too stressful...
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Some Cessna flap switches of that series and era were required by service bulletin to be changed from the "hold it to go down, but it will hold itself to go back up" type to the "hold it both ways" type. This was a corrective action for flap motor limit switch failures, where the pilot would have no idea that the flap motor limit switch had failed, and the motor continued to run (or attempt to) after the flaps were fully retracted. This often resulted in something expensive being burned out, and the flaps not being available for landing.
Thus, the flaps of the affected Cessnas will only move if you're holding the switch. This made the preselect systems popular by comparison, though they had some limit switch issues of their own.
The speed with which the flaps move (or time required to get them from one extreme to the other) is governed by several several factors. The motor "coasting" to a stop after power removed is one. The faster that the flaps were moving, the further they'd coast (uncommanded position, and hard on the mechanizm, when they reach a limit). More importantly, there is a controllability requirement with sudden and total flap motion. For those Cessnas with manual flaps, it is possible to move the flaps from 40 to zero instantly, and at a slow speed in flight, this can create a sudden (and non compliant) drop if the pilot is unwary. The slower cycle time for the electric flaps assures that controllability is maintianed with any pilot controlled use of the flaps.
I suggest that you are looking for 10 degrees, rather than zero, for most takeoffs, in accordance with what the flight manual says. Though not approved in the flight manual, if you become airborne again with flap settings a little greater than 10, the world will not end. I do commend your using 40 flap for landing when ever you can, that will give you better landings, and save people money and risk. My experience, as recently as yesterday, is that with appropriate skill, lesser flap settings are not requried for safe crosswind landings. I agree that the flight manual says otherwise, though flap settings are not limited for crosswinds.
If the "pilot workload" is too great for reconfiguring the aircraft during a touch and go (particularly with runway length a factor), perhaps touch and goes in those circumstances are unwise, paticularly solo. Though capable, the aircraft was not designed to be pilot friendly for touch and goes. It was desinged to be landed and stopped, then flap position changed. There is a requirement for full flaps go around, but in that situation, full power would have been applied first, then with the throttle locked at fully open, you have a free hand for the flaps (don't raise them all at once). Re trim as required.
Go around is another reason that the "held in the up position" switch was not liked, as, with a very slow go around, the pilot could switch to "flaps up" and forget to interrupt the retraction. In one motion, from 40 to zero, the aircraft could easily settle, and the unwary pilot, already overloaded, would not be able to climb away. This is why the manual flap Cessnas (all 180, 185's, and all very old 100 series) are still safe, as if the flaps are in motion, your hand is on the flap lever, and you can reselect instantly if you need to prevent settling.
The manual flaps are very well liked in the 180/185 floatplanes, where "modulation" of the flaps on takeoff is employed by some pilots. Also great for instantly killing lift after touchdown.
The switch is a "Momentary Contact, double pole, double throw" type.
Thus, the flaps of the affected Cessnas will only move if you're holding the switch. This made the preselect systems popular by comparison, though they had some limit switch issues of their own.
The speed with which the flaps move (or time required to get them from one extreme to the other) is governed by several several factors. The motor "coasting" to a stop after power removed is one. The faster that the flaps were moving, the further they'd coast (uncommanded position, and hard on the mechanizm, when they reach a limit). More importantly, there is a controllability requirement with sudden and total flap motion. For those Cessnas with manual flaps, it is possible to move the flaps from 40 to zero instantly, and at a slow speed in flight, this can create a sudden (and non compliant) drop if the pilot is unwary. The slower cycle time for the electric flaps assures that controllability is maintianed with any pilot controlled use of the flaps.
I suggest that you are looking for 10 degrees, rather than zero, for most takeoffs, in accordance with what the flight manual says. Though not approved in the flight manual, if you become airborne again with flap settings a little greater than 10, the world will not end. I do commend your using 40 flap for landing when ever you can, that will give you better landings, and save people money and risk. My experience, as recently as yesterday, is that with appropriate skill, lesser flap settings are not requried for safe crosswind landings. I agree that the flight manual says otherwise, though flap settings are not limited for crosswinds.
If the "pilot workload" is too great for reconfiguring the aircraft during a touch and go (particularly with runway length a factor), perhaps touch and goes in those circumstances are unwise, paticularly solo. Though capable, the aircraft was not designed to be pilot friendly for touch and goes. It was desinged to be landed and stopped, then flap position changed. There is a requirement for full flaps go around, but in that situation, full power would have been applied first, then with the throttle locked at fully open, you have a free hand for the flaps (don't raise them all at once). Re trim as required.
Go around is another reason that the "held in the up position" switch was not liked, as, with a very slow go around, the pilot could switch to "flaps up" and forget to interrupt the retraction. In one motion, from 40 to zero, the aircraft could easily settle, and the unwary pilot, already overloaded, would not be able to climb away. This is why the manual flap Cessnas (all 180, 185's, and all very old 100 series) are still safe, as if the flaps are in motion, your hand is on the flap lever, and you can reselect instantly if you need to prevent settling.
The manual flaps are very well liked in the 180/185 floatplanes, where "modulation" of the flaps on takeoff is employed by some pilots. Also great for instantly killing lift after touchdown.
The switch is a "Momentary Contact, double pole, double throw" type.
This reminds me of the following story, from another airfield I used to fly from - but don't try this at home:
A fellow pilot was returning to land with two passengers on board in the club C172P. He touched down with flaps fully extended, and for unknown reasons suddenly veered almost perpendicularly off the runway, into the safety zone. In front of him was a narrow river, a row of trees and a highway (in that order). Instead of letting the aircraft come to a standstill in what remained of the safety zone, he panicked and applied full throttle. Our trusty C172 staggered into the air, flew through a gap in the trees (but nonetheless hit some), crossed the highway at an "altitude" which would have resulted in collision has a bus or lorry crossed the aircraft's path and continued clawing for altitude. Eventually, climbing at an AoA which does not form part of the POH, sufficient altitude was gained to return and make a successful landing.
The flaps remained fully extended for the entire "circuit".
The aircraft required a new propeller, a new engine, new engine cowlings, new wheel pants, a new wing strut and major structural surgery to one of the wings.
I've been a big fan of C172's ever since.
A fellow pilot was returning to land with two passengers on board in the club C172P. He touched down with flaps fully extended, and for unknown reasons suddenly veered almost perpendicularly off the runway, into the safety zone. In front of him was a narrow river, a row of trees and a highway (in that order). Instead of letting the aircraft come to a standstill in what remained of the safety zone, he panicked and applied full throttle. Our trusty C172 staggered into the air, flew through a gap in the trees (but nonetheless hit some), crossed the highway at an "altitude" which would have resulted in collision has a bus or lorry crossed the aircraft's path and continued clawing for altitude. Eventually, climbing at an AoA which does not form part of the POH, sufficient altitude was gained to return and make a successful landing.
The flaps remained fully extended for the entire "circuit".
The aircraft required a new propeller, a new engine, new engine cowlings, new wheel pants, a new wing strut and major structural surgery to one of the wings.
I've been a big fan of C172's ever since.
Originally Posted by EDMJ
The aircraft required a new propeller, a new engine, new engine cowlings, new wheel pants, a new wing strut and major structural surgery to one of the wings.
I've flown 172s with all the types of flap switches mentioned and the "spring loaded flap switch" is my least favourite.
I don't think I've done a full-flap overshoot since my original checkout and I don't remember what we did. It was £10 an hour dual, so you can imagine why I might have forgotten!
To answer shumway76's question, if I was confronted with that situation either on the ground or in the air, I would apply full power first and then hold the flap switch up for five seconds, while at the same time, remembering to push with my left hand to maintain a proper attitude. Then re-trim.
This of course assumes that the throttle friction is behaving properly. I know students are taught to keep their hands on the throttle during takeoff, but if there is another more important control to operate, then switch to that.
In my glider towing days, I would routinely move my hand after full-power was set and hold a fuselage tube immediately adjacent to the tow release. A much more important control under the circumstances and I've never had a throttle roll-back in nearly 1000 tows in Scouts, Citabrias and 182s.
I agree with PilotDAR's comments about full-flaps. Always use them where possible and "with appropriate skill" even in strong crosswinds.
I don't think I've done a full-flap overshoot since my original checkout and I don't remember what we did. It was £10 an hour dual, so you can imagine why I might have forgotten!
To answer shumway76's question, if I was confronted with that situation either on the ground or in the air, I would apply full power first and then hold the flap switch up for five seconds, while at the same time, remembering to push with my left hand to maintain a proper attitude. Then re-trim.
This of course assumes that the throttle friction is behaving properly. I know students are taught to keep their hands on the throttle during takeoff, but if there is another more important control to operate, then switch to that.
In my glider towing days, I would routinely move my hand after full-power was set and hold a fuselage tube immediately adjacent to the tow release. A much more important control under the circumstances and I've never had a throttle roll-back in nearly 1000 tows in Scouts, Citabrias and 182s.
I agree with PilotDAR's comments about full-flaps. Always use them where possible and "with appropriate skill" even in strong crosswinds.
Avoid imitations
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Many years ago (aged 17), I was sent off to do some practice circuits various including short field landings, in a C150.
The flap switch had to be held down from centre to lower flaps and from DOWN it was spring loaded back to centre. If it was moved from centre to the UP position would hold it there, so the flaps would fully retract.
On short finals, at low IAS I selected FULL flap, checked they were fully down (what a strange place for the indicator, well out of eyeline for short finals) then let go of the switch.
Unknown to me, the switch was worn out. Rather than the switch just going back to centre after letting it go from DOWN, the springloading overcame the centre detent and went straight to the UP position again.
I got a very strange sinking feeling.... I thought I had full flap but in fact the aircraft was becoming increasingly flapless.
Thankfully, I didn't bend it but it took a while to regain my composure. I taxied in totally confused about what had happened until I saw the flap switch was UP.
The flap switch had to be held down from centre to lower flaps and from DOWN it was spring loaded back to centre. If it was moved from centre to the UP position would hold it there, so the flaps would fully retract.
On short finals, at low IAS I selected FULL flap, checked they were fully down (what a strange place for the indicator, well out of eyeline for short finals) then let go of the switch.
Unknown to me, the switch was worn out. Rather than the switch just going back to centre after letting it go from DOWN, the springloading overcame the centre detent and went straight to the UP position again.
I got a very strange sinking feeling.... I thought I had full flap but in fact the aircraft was becoming increasingly flapless.
Thankfully, I didn't bend it but it took a while to regain my composure. I taxied in totally confused about what had happened until I saw the flap switch was UP.
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why not go in clean using this as an opportunity to practice flap failure
Though 40 flap climbouts are not approved for the 172, they can be safely accomplished, if the departure space is available. This capability is required by the certification requirement for "balked landing", which in the case of the 172, assures a rate of climb at gross weight, with 40 flaps, of at least 200 feet per minute (at sea level, standard atmosphere). I'm not advocating this be done, as there are a lot of certification requirements which should not be done in general flying, but they have been demonstrated at certification, to assure that margin of safety.
For some reason, some pilots seem reluctant to regularly use 40 flaps in a Cessna. I wonder why.....
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In general:
- during touch & go, you would retract flaps then apply full power.
- in a practice dirty stall, you would apply full power then retract flaps in stages.
Are the steps above correct?
But in the case of having to hold the flap switch up, in a touch & go it would mean better to apply full power, then only hold the flap switch up...?
- during touch & go, you would retract flaps then apply full power.
- in a practice dirty stall, you would apply full power then retract flaps in stages.
Are the steps above correct?
But in the case of having to hold the flap switch up, in a touch & go it would mean better to apply full power, then only hold the flap switch up...?
Moderator
In general:
- during touch & go, you would retract flaps then apply full power
- during touch & go, you would retract flaps then apply full power
Any flight manual, and all good airmanship, will direct that that the pilot "fly the plane first". This means, in order of importance: Maintain pitch control, maintain directional control, and maintain flying speed. After that, everything else is secondary. Anything which could interfere with the primary objectives must be relegated to lesser importance - this includes fiddling with the flaps. I have certainly experienced other pilots insisting that flaps not be retracted until 400 feet up after takeoff, so why would pilots be willing to reposition them on the roll, if there is the least risk of distraction?
The maintain pitch control means that whether you have power or not, prevent a pitch attitude which will result in an undesired stall. That is always most important. Directional control, go toward the point you intend (runway centerline, in this case). Maintain flying speed can be associated with the use of power (assuming that you are managing pitch well already). If you need to fly, and climb, manage the power to accomplish this. I agree that flaps play a role in flying speed and pitch, but it is secondary, knowing that the aircraft has demonstrated an adequate climb with full flaps extended. If anything else you do at the controls could interfere with the prime objectives, don't do it! To me, a configuration change on the roll, as happens in a touch and go, increases the risk of a loss of directional control, so must not be done, if directional control cannot be safely maintained. If this means that you come airborne with full flaps while aborting a landing (you could be on the runway already when deciding to abort), so be it.
If you have decided that a full stop landing is no longer what you want to do, you've decided to abort/overshoot/go around. This can be done after touchdown, as maybe something enters the runway ahead of you. If that happens, you're not going to roll toward whatever it is, while looking for the flap switch, before adding power, you're just going to open the throttle and go, getting the flaps as best you can as you do. The aircraft has demonstrated that it can do this without requiring unusual pilot skill
Touch and goes require at the very minimum, a mindset change on the roll, though more likely, a configuration change as well. I would expect huge philosophical resistance to touch and goes in retractable aircraft, where flaps are being retracted on the roll. So, flap equipped fixed gear planes probably deserve similar caution, just from the distraction and loss of directional control risk perspective.
Touch and goes become a pilot workload issue. If they can be accomplished safely, they are a time saver, but there is a fine line, where they are no longer safe, and the skill lies in making that determination - sometimes very quickly. This determination has to allow for a bit of unexpected after the decision is made - like a misbehaving flap switch.
I recall doing solo touch and goes in a C 180 float plane decades ago. After landing with 40 flap, I retracted them to 20 while on the step. Though precise directional control and runway dimensions were not a concern, sudden pitch changes while on the step a not good. The flaps jammed, and would not retract to less than 20. Rather that diagnose this while planing across the water with the full power I had already applied, I took off. The flaps could not be repositioned at all, so I flew home and landed with 20. It turned out that the flaps had jammed because of a broken flap track - that could have been very much worse! In hind sight, staying on the water would have had some merit in this case, though out in the hinterland is not the ideal place to shut down and look for repairs!
If you're going to do touch and goes, you have to assure that you have the excess pilot capacity to deal with things like flaps, and the extra runway space to assure it can be safely done.
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flaps...
Have to disagree here. Flaps are there to be used, sure, but they should be used in an appropriate way. Doing every landing with full flaps is not appropriate, in the case of the 40deg models downright dangerous. While I know you can climb away with 40 flaps (tried it myself years ago with an instructor), this is most certainly not something you want to do on a regular basis. There is no need for it, other than going into a very short strip. Also consider that the performance a brand-new a/c with a company test pilot at the controls could achieve 30, 40 years ago is probably a lot better than what you can achieve in it today.
IMO you should always consider the circumstances – if you are landing on a 7000 ft rwy with jet traffic behind, you most definitely don’t want to hover around at full flaps and 40kts. Going into a short dirt strip, OTOH you would of course fly full flap. Also be aware that on some models rudder authority decreases significantly if operating with full flap.
In any case, you should always read the POH for YOUR airplane, as the approved (and tested) procedures may well differ from pilot lore and internet wisdom. An example – for the type I mostly fly, Cessna 172RG, the POH procedure for short field t/o is zero flaps, not 10deg, as many people seem to believe.
If you really want to know what your a/c can and cannot do in various configurations then read the POH, go out and find a nice long rwy and practice the various techniques, alone or with an instructor.
IMO you should always consider the circumstances – if you are landing on a 7000 ft rwy with jet traffic behind, you most definitely don’t want to hover around at full flaps and 40kts. Going into a short dirt strip, OTOH you would of course fly full flap. Also be aware that on some models rudder authority decreases significantly if operating with full flap.
In any case, you should always read the POH for YOUR airplane, as the approved (and tested) procedures may well differ from pilot lore and internet wisdom. An example – for the type I mostly fly, Cessna 172RG, the POH procedure for short field t/o is zero flaps, not 10deg, as many people seem to believe.
If you really want to know what your a/c can and cannot do in various configurations then read the POH, go out and find a nice long rwy and practice the various techniques, alone or with an instructor.
Moderator
The choice of flaps for 100 series Cessnas will forever remain a personal preference, and be correct as long as the flight is safe, and the Flight Manual procedures are adhered to. Agreeing to disagree is fine, but for every pilot who tells me that they use different flaps settings for different conditions, I will tell I land every aircraft I fly, with full landing flaps for every landing, and the greatest permitted flap setting for takeoff.
My objective is to achieve the slowest speeds practical, which will result in safety, and the least wear and tear on the plane. Yes, with a 7000 foot runway, and a jet behind me, I will fly up to the intended touchdown point, then deploy full flaps for the same slow landing. It works out just the same.
If doing every landing with full flaps is considered dangerous by some, I would examine the skill of the pilot involved. The oft used reference to the "test pilot in the brand new plane" getting better results, is a myth. The procedures are the same now, as they were 40 years ago, for obtaining performance data, and super skill is not tolerated during flight tests for certification. If the aircraft will not achieve the performance in the approved flight manual at any age, it probably has a defect, and should be repaired.
For certified aircraft, you can depend upon the rudder to be as effective as you need it to be, with any flap position. This relates to crosswind landing capability. Certified aircraft are required to demonstrate crosswind landings as follows:
Directional stability and control.
(a) There may be no uncontrollable ground or water looping tendency in 90 degree cross winds, up to a wind velocity of 0.2 VS0, at any speed at which the airplane may be expected to be operated on the ground or water.
(b) A landplane must be satisfactorily controllable, without exceptional piloting skill or alertness, in power-off landings at normal landing speed, without using brakes or engine power to maintain a straight path.
(c) The airplane must have adequate directional control during taxiing.
This is something I often have to test for, and you'd be amazed just how much control is available.
I agree that the 172RG Flight Manual does specify zero flap for takeoff, so that is what the pilot should do. I find it unusual though, as all of the 182 Flight Manuals I have specify up to 20 flap for takeoff, and the wing and power loading of both aircraft are quite similar, with I believe the same airfoil.
Fly what the Flight Manual says, but consider the wear and tear on the aircraft too...
My objective is to achieve the slowest speeds practical, which will result in safety, and the least wear and tear on the plane. Yes, with a 7000 foot runway, and a jet behind me, I will fly up to the intended touchdown point, then deploy full flaps for the same slow landing. It works out just the same.
If doing every landing with full flaps is considered dangerous by some, I would examine the skill of the pilot involved. The oft used reference to the "test pilot in the brand new plane" getting better results, is a myth. The procedures are the same now, as they were 40 years ago, for obtaining performance data, and super skill is not tolerated during flight tests for certification. If the aircraft will not achieve the performance in the approved flight manual at any age, it probably has a defect, and should be repaired.
For certified aircraft, you can depend upon the rudder to be as effective as you need it to be, with any flap position. This relates to crosswind landing capability. Certified aircraft are required to demonstrate crosswind landings as follows:
Directional stability and control.
(a) There may be no uncontrollable ground or water looping tendency in 90 degree cross winds, up to a wind velocity of 0.2 VS0, at any speed at which the airplane may be expected to be operated on the ground or water.
(b) A landplane must be satisfactorily controllable, without exceptional piloting skill or alertness, in power-off landings at normal landing speed, without using brakes or engine power to maintain a straight path.
(c) The airplane must have adequate directional control during taxiing.
This is something I often have to test for, and you'd be amazed just how much control is available.
I agree that the 172RG Flight Manual does specify zero flap for takeoff, so that is what the pilot should do. I find it unusual though, as all of the 182 Flight Manuals I have specify up to 20 flap for takeoff, and the wing and power loading of both aircraft are quite similar, with I believe the same airfoil.
Fly what the Flight Manual says, but consider the wear and tear on the aircraft too...
The 172M I fly has a flap switch that you need to hold up to raise flap but you don't need to hold it down to lower it (i.e. you just flick it to the down position and it will lower all the flap if you leave it alone). I was wondering if this is unique to that 172?
I unwittingly flicked it slightly on downwind during my checks once and wondered why we had started to balloon before I realized it had lowered 20 degrees of flap and was going for the last 10 before I stopped it.
I unwittingly flicked it slightly on downwind during my checks once and wondered why we had started to balloon before I realized it had lowered 20 degrees of flap and was going for the last 10 before I stopped it.
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Well, I don't believe in the 'one size fits all' philosophy, but we can agree to disagree. My 'dangerous' comment was, if you read my post, aimed at the 40deg variants.
Agree re the 182, though. Don't have a POH to hand right now, but also recall flaps for t/o (that's the fixed-gear version).
Agree re the 182, though. Don't have a POH to hand right now, but also recall flaps for t/o (that's the fixed-gear version).
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40 degree flap isn't dangerous either - I'd very much agree with PilotDAR on that basis. Anecdotally I have been lead to believe the reason that the 40 setting went away was the full flap climb out requirement. Limiting the flap to 30 allowed a higher useful load whilst still being able to climb out at 'full' flap. Possibly urban legend, but in any case, I'd take a '40' model over the 30 any day.
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I've been renewing my homework on the 40 to 30 flap change in the 172's. Quoting from William Thompson's magnificent book "Cessna, Wings for the World", Page 41, with respect to 172's:
"With the advent of the large slotted flaps in the C-170, C-180, and C-172 we encountered a nose down pitch in forward slips with the flaps deflected. In some cases it was severe enough to lift the pilot against his seat belt, if he was slow in checking the motion. ........... Although not stated in the owner's manuals, we privately encouraged instructors to explore these effects at high altitude and to pass the information to their students. .....
When the larger dorsal fin was adopted in the 1972 C-172L, this sideslip phenomenon was eliminated, but the cautionary placard retained. In the higher powered C-172P and C-R172 the placard was applicable to mild pitch "pupming" motion resulting from flap outboard end vortex impingment on the horizontal tail at some combinations of sideslip angle, power and airspeed. "
It is noteworthy that some modifications on Cessnas, particularly float installations, result in more restrictive maximum flap use, as pitch effectivness or balked landing climb can be inadequate with 40 flap. I have only ever seen this limits by placard, as opposed to actually rerigging the flap limit switches.
I prefer the 40 flap available in 100 series Cessnas, and use it at all times for landing (which is why I prefer the 150 to the 152).
For my interest, and my being most effective in drafting Flight Manual Supplements, I would be pleased to hear the reasons why some pilots choose to use lesser flap settings for landing. What factors influence the choice of flap setting? Is this generally a result of personal experience, or training carried over?
Some of the modifications I test and approve are better taken off, and landed in more flat attitudes, and I am interested to understand why a pilot might not wish to use full flaps for all landings, so I can consider this in my normal procedures information.
"With the advent of the large slotted flaps in the C-170, C-180, and C-172 we encountered a nose down pitch in forward slips with the flaps deflected. In some cases it was severe enough to lift the pilot against his seat belt, if he was slow in checking the motion. ........... Although not stated in the owner's manuals, we privately encouraged instructors to explore these effects at high altitude and to pass the information to their students. .....
When the larger dorsal fin was adopted in the 1972 C-172L, this sideslip phenomenon was eliminated, but the cautionary placard retained. In the higher powered C-172P and C-R172 the placard was applicable to mild pitch "pupming" motion resulting from flap outboard end vortex impingment on the horizontal tail at some combinations of sideslip angle, power and airspeed. "
It is noteworthy that some modifications on Cessnas, particularly float installations, result in more restrictive maximum flap use, as pitch effectivness or balked landing climb can be inadequate with 40 flap. I have only ever seen this limits by placard, as opposed to actually rerigging the flap limit switches.
I prefer the 40 flap available in 100 series Cessnas, and use it at all times for landing (which is why I prefer the 150 to the 152).
For my interest, and my being most effective in drafting Flight Manual Supplements, I would be pleased to hear the reasons why some pilots choose to use lesser flap settings for landing. What factors influence the choice of flap setting? Is this generally a result of personal experience, or training carried over?
Some of the modifications I test and approve are better taken off, and landed in more flat attitudes, and I am interested to understand why a pilot might not wish to use full flaps for all landings, so I can consider this in my normal procedures information.