I could not specifically find a topic on what I am curious about. Like a coin that has 2 sides I am getting 2 different opinions from those that regularly fly a Hershey bar wing 140 and those that flew hundreds of hours. One side says best landing on a calm day is 2 notches of flaps and only use 3rd notch if high or fast. The other side says to use 3 notches all the time. They all agree fly the numbers on approach and on windy days use the best flap setting for the wind conditions. What do experienced 140 pilots use on a calm day; 2 b notches or 3?
‘69 Cherokee 140B: flap use
- Thread starter RonP
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Here’s an exercise you can try that might help you out with determining flap usage...
Try a landing with no flaps, than do another with 1 notch, then 2 notches and then lastly, one with full flaps. You’ll get a good idea how to manage energy during approach and landing, as well as how the flap configuration changes the handling characteristics. Give it a shot, it might help you determine for yourself what’s best.
Country Flier
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Owned a hershey bar wing cherokee many years ago; put 500 hours on it. Always used 3 for landing, none for takeoff. Nearly everyone I ever talked to did something different...1, 2, or 3 (or none) for landing...none for takeoff, 1 for takeoff, 2 for takeoff...sounds like it varies because, well, probably doesn't matter much.
Shepherd
Final Approach
First notch flaps, one turn trim, 85 mph. Second notch flaps, one turn trim, 85 mph, On final: Third notch flaps, two turns trim 85 mph.
You can also slip a hershey bar wing pretty hard. A lot of people don't know that, or won't do it.
You can also slip a hershey bar wing pretty hard. A lot of people don't know that, or won't do it.
Rgbeard
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rgbeard
Flaps? Why? ;-)
The FAA believes you should use full flaps always. Due to the way the early Cherokee flaps work, frankly, I'm tending toward the "as needed to achieve the descent angle you want."
EdFred
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A few hundred hours in Hershey Bar Cherokees and I was always full flaps for landing, regardless of crosswind, and no flaps for take off unless it was short field. And that's how I instruct in them too.
FastEddieB
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General rule-of-thumb: Maximum flaps as consistent with conditions. If something goes wrong at touch down, every extra knot means extra energy to dissipate, one way or the other.
Of course, there are exceptions, as is always the case with rules-of-thumbs.
That's the FAA reasoning. Of course, there's not much of a difference in stall speed on this model between up and down, it's mostly drag.
FastEddieB
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If the full flaps let one land even a few knots more slowly, it can make a difference if things go south. Which we have to remind ourselves could happen on any given landing.
steingar
Taxi to Parking
I can't recall landing my Cherokee with aught but full flaps. In mine you lowered the flaps with a Johnson bar, I think it had detents. Might have left some up with nasty crosswinds.
Gary
En-Route
For landing, full flaps 95% of the time. If there is a really nasty crosswind, might use two notches, but that’s rare. For take-off, no flaps, unless I’m doing a short/soft field.
Yes, they’re all that way.
Shepherd
Final Approach
And if you needed a couple extra degrees of flaps you hauled the Johnson bar all the way up and held it up.
eman1200
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Bro do you even lift
full flippity flaps.
Tantalum
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It's a good little pseudo hand brake.. I used to love doing a monster slip on short final and pulling that thing up with my right hand to the tops!Full flaps here. There is also a quarter flap after the full flap…. Try it too close to the ground and you will drop like a rock - don’t ask me how I know it
PA-28 are awesome. Just one more reason why low wings rock!!
Lots of great replies. Seems the coin landed on the “full flaps” side. However I learned a few things. First my reason for posting it always seems as I flair the airplane sinks faster than I can compensate. Lots of reasons such as too slow, too high, etc. Shepherd mentioned something interesting which is his pattern thru approach is 85 mph. I am on approach at 75 sometimes 65. I think I misread the POH where is states “contact the ground close to stall speed 55 to 65 mph”. Based on what Shepherd wrote and re-reading the POH I am probably on approach too slow already and losing too much energy at round out, removing power and flaring. So I ask, especially Sheperd, do you hold 85 all the way to the runway? When do you pull power; during round out or before flare. I think the answer will be the key to my improvement. Thanks
brcase
En-Route
The answer to your question is much more complex that just what flap setting. Landing is a complex energy management equation and much of the differences in style of landing is due to variations in energy management. Few answers address the 3 major factors.
Your basic tools for energy management are...
Power
Airspeed
Flaps.
Change one and you need to change at least one other one
For example..
If you are going to use maximum flaps you either need to carry more power or more airspeed than with less flaps.
With less flaps you can approach with either less airspeed or less power. This is because you will have more less drag during the round out and flair to stop your descent and set the airplane down nicely.
With less power you will need to carry more Airspeed to have enough energy to flair with.
I like lower energy approaches, meaning less power so I tend to normally land Cherokee’s with one or two notches and a fairly fast approach speed. I also like the fact that with one or two notch’s of flaps on normal approaches I am already configured for a go around.
Referencing the other thread about risk management and the impossible turn. Get a CFI to show you how to practice the 180 power off maneuver. Then you can really start learning how to use the flaps for energy management instead of just a checklist item to let you touch down 3kts slower, if you are landing at stall speed. Many pilots do not touch down anywhere near that slow, especially with full flaps.
Brian
CFIIG/ASEL
Your basic tools for energy management are...
Power
Airspeed
Flaps.
Change one and you need to change at least one other one
For example..
If you are going to use maximum flaps you either need to carry more power or more airspeed than with less flaps.
With less flaps you can approach with either less airspeed or less power. This is because you will have more less drag during the round out and flair to stop your descent and set the airplane down nicely.
With less power you will need to carry more Airspeed to have enough energy to flair with.
I like lower energy approaches, meaning less power so I tend to normally land Cherokee’s with one or two notches and a fairly fast approach speed. I also like the fact that with one or two notch’s of flaps on normal approaches I am already configured for a go around.
Referencing the other thread about risk management and the impossible turn. Get a CFI to show you how to practice the 180 power off maneuver. Then you can really start learning how to use the flaps for energy management instead of just a checklist item to let you touch down 3kts slower, if you are landing at stall speed. Many pilots do not touch down anywhere near that slow, especially with full flaps.
Brian
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Indiana_Pilot
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Full flappy flaps.. all day err day! I have had full control authority through various crosswinds..
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FastEddieB
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Fast Eddie B
Moose runs out in front of the plane?
Runway incursion with unavoidable impact?
Undiscovered crack in a main gear axle decides to let go?
Brakes fail? Flat tire? Swerve into a RWY sign?
Etc, etc.
The odds of any of these things happening on any given landing are admittedly very small. Less so over a flying career. And virtually certain to happen somewhat regularly over the fleet of GA aircraft.
A small change in touch down speed makes a much bigger difference in energy to dissipate. I made a little Excel spreadsheet to calculate the difference for any two speeds:
That’s a typical difference from pilots who are content to land just a “little” fast. Things get rapidly worse for those pilots that just “fly it on” with little or no flaps.
Either could result in the difference between no injury and a minor injury, between a minor injury and a major one, or between a major one and death. All things being equal, the slower the better on landing and full flaps help with that.
dtuuri
Final Approach
Yep, "energy" management equals "airspeed" management. No way to "manage" energy except with airspeed. Lucky that we have an airspeed indicator, because we don't have an energy indicator. I'm for dropping the "energy management" canard altogether. Never liked it and don't know who dreamed it up.
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I think we’re “wired” to see things progress linearly. We compare a 100kt storm with a 50kt storm and intuitively think it must be twice as strong, not four times as strong.
So thinking in terms of “energy” is at least a subtle prod to remind us of the non-linear effects of increasing speed. I don’t see the harm in it.
dtuuri
Final Approach
It may be more intuitive for a trained engineer who's learning to fly, but I'm thinking of a housewife who never had physics and drove a school bus. Airspeed she understood, energy (K.E. = 1/2 m v2) not so much. But she could accept that a crash at a higher speed would hurt a whole lot more than she would normally have thought, so strove to land as slow as possible.
EDIT: With airspeed you have an instant real-time representation of how well you're managing. There's no way to have a visceral indication of energy, as the term "energy management" implies that you should. It's airspeed; manage that and your done with it. IMO.
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EdFred
Taxi to Parking
Potential energy won't kill ya though. Not until it's converted. And the potential energy on touchdown is 0 from a physics standpoint. (yeah yeah, gas in the tanks blah blah blah)
dmspilot
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Energy management is relevant to what happens before touchdown.
EdFred
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Potential energy doesn't matter though, it's pretty much irrelevant when it comes to landing. There's more potential energy at 10ft and 45kts than there is at 1ft and 400kts. I'd much rather be at 10ft and 45kts if I am told that upon touchdown my right main is going to come from together.
dmspilot
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Tell the person who tried to apply the concept of energy management to the wrong context.
Thanks brcase for a very eloquent explanation for what should have been obvious if I thought about it. Evidently I was “oblivious” to what the dynamics were regarding drag and energy use. What you wrote is a keeper in my flying notes along with other lessons learned. Great job! Thanks
dtuuri
Final Approach
Then, you may still be oblivious IMO. You use maximum flaps when you need to use less airspeed. If you use less flaps, you need more airspeed. "Energy management" will get you all confused, don't think about it.
brcase
En-Route
As my post tried to emphasize you did just what most everyone else does when discussing this and over simplified it, totally ignored one of the major factors, Power.
Now admittedly it is easy to start getting confused as it is complex. Many pilots just learn 1 to 3 approach scenarios and ignore other tools they could learn to use. Different airplanes land better is different configurations. The more airplanes you fly the more tools you will likely learn.
If you are going to come in slower with max flaps then you need more power to stop the descent rate for the landing, if not you likely are not really coming in very slow.
It comes down to what are you trying to accomplish with the flaps.
Are you trying for a Steeper approach? Then Max flaps, very slow, and a bit of power at the end will get you in the steepest.
Are to trying for minimum Touchdown speed and ground roll, then Max flaps, very slow, and a bit of power will get you stopped the shortest.
Are you trying use the flaps to control your glide path, then something less the 1/2 flaps for a normal approach is better, do you can add more as needed.
Are you trying to give yourself a nice margin above stall and time to set the airplane down nicely then a faster approach with either a bit less than max flaps or more power will help with that. Add benefits are most planes stall characteristics are better with less flaps and you can already be configured for a go around.
Brian
CFIIIG/ASEL
dtuuri
Final Approach
It's true, I favor the KISS (keep it simple, stupid) system. I note, also, that your avatar shows a sailplane—i.e., no power. I think it has no flaps, either, but probably spoilers. That might explain where you're coming from. Or maybe you are ex-military? They seem to like to make stuff over-complicated.
For any given flap setting there is an airspeed that will allow a power-off flare (not "flair" as somebody in this thread is writing). Nail that and problem solved. Of course, you can come in even slower than that speed if you're willing to "hang it on the prop", as we used to say, which requires power through the flare. I'll let the OP decide how complicated he wants to make controlling his airspeed, but to answer his question, and I'm reaching back some 50 years for this from memory, the Cherokee 140's recommended approach speed is 85 MPH and reduced by 3 MPH for each notch of flaps. It has a stabilator rather than an elevator and just a touch of power left on as the nose is raised will smooth the airflow back there for a more consistently smooth landing. Don't chop the power right before flaring or it'll create turbulence. He should strive for zero thrust or he'll float. Also, he should make sure the control columns are cleaned and lubed before flight, so they slide in and out effortlessly. As for me, I'm in the full-flap camp all the time.
brcase
En-Route
Actually the glider in the photo is exactly the opposite, no spoilers, it used 90-degree flaps to control the glide path instead. My current glider has both flaps and spoilers.
Brian
This is the OP.....more great info with regards to power management. I have been pulling the power all the way off as soon as I round out. Sounds like a really bad thing to to do in the 140. I am always concerned if I don’t then I am going to land long. I come over the numbers at 70mph, 3 notches of flaps, round out, pull power back and start raising the nose while sinking fast. A little more speed on final and wait until flare before pulling power off. Sounds like a big improvement.