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Thread: PSTOL flaps Landing technique

  1. #1

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    PSTOL flaps Landing technique

    With my old flaps… I’d come in at are strip about 60ish…. Now with the pstol been coming a little slower…. I could get WAY slower.. seems like I need to relearn flying/Landing with the pstol… nose is diffidently a little more nose down… and it seems with just a little bit of power it will keep on flying.

  2. #2
    RaisedByWolves's Avatar
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    Burn some fuel and do some landings. See what works best


    Sent from my iPhone using Tapatalk

  3. #3
    Crash, Jr.'s Avatar
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    60 is already way too fast with a stock PA-18. That should be 55 tops and closer to 45. With the PSTOL flaps that speed will be about 5mph slower.

    More time in the plane is needed. Work on getting the plane slower.

  4. #4
    BC12D-4-85's Avatar
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    Do those flaps affect the accuracy of the indicated airspeed differently than stock flaps?

    Gary

  5. #5
    stewartb's Avatar
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    Try coming in steeper. Take advantage of that new attitude.
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  6. #6

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    What happens if you lose your engine at 45-50 no out…. I’m not landing on a runway my approach is steep….over obstacles..shops.house .bales.fence….with a big dip n middle of the pasture ….. and if the cows there you’ll need to dodge them…..then need to touchdown before the dip or you’ll end up on your nose…..We’ve been landing there for over 50 years…. Not a strip for the novice
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    Sounds like you should trade the cub for a helicopter I bet there’s several hundred threads on here that talk about disregarding the ASI. This makes several hundred and one. Fly the attitude not the airspeed. Power to arrest sink which if you’re flying a Pstol flapped cub right you get a lot of when slow…….losing an engine? Guess that’s the deal you have to make with the devil.
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  8. #8

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    You need to describe everything that is happening when you fly final or we will be trying to figure this out over the next two weeks. It sounds like you come in fast over the obstacles then dive to the landing area is this correct? How high are you above the trees/house/whatever before you dive to the runway at 60 MPH? How long are you floating before you touchdown? What is your normal touchdown speed? Do you normally land power on or power off?
    DENNY
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  9. #9

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    Agree. There is an optimum speed for minimum glide angle - get slower than that and your angle increases. The advantage to going slower is if it quits you might be able to increase your speed and regain the optimum descent angle.

    This is dramatic close to stall. I know nothing about Pstol, but a J3 glide angle can be 45 degrees if you get slow enough - almost as good as a slip.

    Disadvantage is that you have no energy left for a flare. In a Helio you just "hold what you got" but a Cub might need a burst of power.
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  10. #10
    Crash, Jr.'s Avatar
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    Quote Originally Posted by 3689A View Post
    What happens if you lose your engine at 45-50 no out…. I’m not landing on a runway my approach is steep….over obstacles..shops.house .bales.fence….with a big dip n middle of the pasture ….. and if the cows there you’ll need to dodge them…..then need to touchdown before the dip or you’ll end up on your nose…..We’ve been landing there for over 50 years…. Not a strip for the novice
    An engine out and coming up short is a risk regardless of how fast or slow you're going. Whether fast or slow you're only going to travel a certain distance and if that distance is one foot further than it needs to be you simply won't make it. You can be going 100mph but if you're low and a mile from the runway you'll end up in the trees.

    You've installed flaps specifically designed to add drag and decrease landing speed but you're approaching very close to max flap extension speed. You simply need to slow the plane down if you want to take advantage of the flaps.
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  11. #11
    frequent_flyer's Avatar
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    I'm having a hard time understanding the problem. Every airplane, for any flap setting, can be set up for an idle power approach to the desired landing spot. Power may be needed in the flare to make a nice landing but loss of power anywhere in that idle approach should still get you close to the intended landing point.

    I hate dragged in landings and, if I had more effective flaps, I'd simply be flying a steeper approach. What am I missing?
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  12. #12
    stewartb's Avatar
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    You can fly a steep approach more slowly and still have a safety margin. All you need to do is lower the nose if you get a little too slow. Pstol flaps are a great tool for that technique. Beware of modulating power like you used to. You’ll want to limit the added power by half or so to achieve the same results. And then you need to learn to trust ground effect, because there'll be more of it.

  13. #13
    RaisedByWolves's Avatar
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    I don’t pull full flaps until 60. Airspeed stops working at 45. Land slower than that.


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  14. #14
    BC12D-4-85's Avatar
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    My way....keep the runway just in sight over the top of the cowl call the way down until stopped

    Gary

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    Steve Pierce's Avatar
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    Quote Originally Posted by 3689A View Post
    What happens if you lose your engine at 45-50 no out…. I’m not landing on a runway my approach is steep….over obstacles..shops.house .bales.fence….with a big dip n middle of the pasture ….. and if the cows there you’ll need to dodge them…..then need to touchdown before the dip or you’ll end up on your nose…..We’ve been landing there for over 50 years…. Not a strip for the novice
    Sounds like you have plenty of experience, you just need to fly them and figure them out.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  16. #16

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    You are me 6 months ago

    Two things that helped me - slow flight and figuring out that the AOA is very much changed from the barn door style flaps. Once you understand that, set up your landing descent at that AOA you have burned into your mind with idle or low power and trim. The rest is easy.
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  17. #17
    Formandfunction's Avatar
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    Was your first flight not stall practice? I would assume installation instructions would call that out as the last step to completion. In reality figuring out your planes new performance parameters shouldn't even be a discussion. If you're concerned with engine outs and coming up short your decent is not steep enough. Personally I would practice stalls and engine out landings till I could nail my spot with nothing more than a slip. In a real engine out a slip is your only tool for alt.Personally I think that should be required on the check ride to get a license. Not trying to be rude but not knowing your plane is scary.

  18. #18

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    Click image for larger version. 

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    Landing technique
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  19. #19
    stewartb's Avatar
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    What is stall practice? How often does a guy need to practice in order to be proficient? How about to get really good at it?

  20. #20

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    I have a stall series for the Super Cub. Turns out even experienced instructors need "brush-up." You would think that, given that they have to teach stalls, they would be good at it.

    what I have the most trouble with is turning stalls - most want to recover long before the wing even starts to shudder (which, I suppose, is what the federales want).

    Slow flight is the eye-opener. Most pilots think slow flight is Vx. They are shocked to find that a Cub can be stalled and yet maintain altitude.

    We also do full flap full power stalls, which, if done properly, are not scary and quite educational.
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  21. #21
    BC12D-4-85's Avatar
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    Does the Cub with P-STOL flaps stall at the same AOA as with regular ones? Half and full flaps deployed. No slats or slots. I seem them landing what appears more nose down vs stock but never flew one.

    Gary

  22. #22
    Gordon Misch's Avatar
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    The chord line changes with flaps and/or slats deployed, hence merely deploying changes AOA.
    Gordon

    N4328M KTDO
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  23. #23
    BC12D-4-85's Avatar
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    Ok, thanks Gordon. What I'm wondering is if the P-STOL flaps change the AOA of the stall at the same flap setting when compared to the factory flaps?

    Gary

  24. #24
    skywagon8a's Avatar
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    Has anyone used a test boom like this with the PSTOL flaps? The flaps on this Cub are of the original Piper design, only are 110" long. No leading edge devices of any kind. Stall angle of attack is 20 -21 degrees.

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    N1PA

  25. #25
    frequent_flyer's Avatar
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    Quote Originally Posted by Gordon Misch View Post
    The chord line changes with flaps and/or slats deployed, hence merely deploying changes AOA.
    I think you are referring to the concept that AOA is the angle between relative wind and the mean chord of the wing and that mean chord changes with wing configuration. That's a nice theoretical concept but does it actually work that way in practice?

    Put a long boom on the wing and use a string to show undisturbed airflow. Neither the string nor the boom scale knows the wing configuration.

    Garmin AOA probe measures pitot pressure and pressure at a port lower on the nose of the probe. Difference in pressures is an indication of the local airflow and hence AOA. Garmin systems display AOA for all flap settings whether they know flap setting or not.

    MD-11 air data computer receives a raw angle of attack signal from the fuselage mounted alpha vanes. I see nothing in the air data computer block schematic that indicates this angle is compensated for wing configuration.

    This Boeing reference defines AOA as the difference between pitch angle and flight path angle. Neither requires knowledge of the wing configuration:
    https://www.boeing.com/commercial/ae.../whatisaoa.pdf

    I suppose all any of this means is know what you want to measure, indicate, or discuss and define it so everyone uses the same definition.

  26. #26
    BC12D-4-85's Avatar
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    I assume that if the P-STOL flaps extend down more than stock at one or both extended flap settings, then their effect on the new mean chord line is also different. If the chord line changes in the P-STOL flapped wing section, then the AOA at stall (pitch angle vs flight path above), of that section only, may be lower. The P-STOL flaps create more lift and drag, and from Airframes Alaska "With PSTOL flaps deployed, lower airspeed does not equal a higher angle of attack. Pilots fly at a flatter deck angle without increasing their airspeed." The flaps create more lift a a lower wing section AOA.

    Here's one answer to my question: Do the P-STOL flaps change the AOA of the stall of that wing section at the same flap setting when compared to the factory flaps?"
    http://n91cz.com/AOA/AoA_Article_Web.pdf

    Note the effect of the propeller on wing critical angle and stall speed. Prop blast helps STOL.

    Gary
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    Steve Pierce's Avatar
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    You can read and try and comprehend all of this but I would go fly the airplane and get the feel of it.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  28. #28

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    Took a CFI up yesterday in a 160 Cub. We had to go to 5000’ before he was comfortable, and after a reasonably good straight ahead stall and recovery he refused to even induce a break in any condition except flaps up straight ahead. And no demo stalls.

    He knows I routinely fly upside down, and he has done stalls with me previously. He used to trust me.

    old age is a bitch.
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  29. #29
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    Quote Originally Posted by bob turner View Post
    Took a CFI up yesterday in a 160 Cub. We had to go to 5000’ before he was comfortable, and after a reasonably good straight ahead stall and recovery he refused to even induce a break in any condition except flaps up straight ahead. And no demo stalls.

    He knows I routinely fly upside down, and he has done stalls with me previously. He used to trust me.

    old age is a bitch.
    Not sure if you were lamenting your old age or the age of the timid CFI you flew with.

    I'm well past 70 and very early in phase 1 with my new FX-3 I did all I could to provoke it into surprising me. I do not understand anyone who would fly an aircraft without exploring its potential to bite.
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  30. #30
    skywagon8a's Avatar
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    Quote Originally Posted by bob turner View Post
    Took a CFI up yesterday in a 160 Cub. We had to go to 5000’ before he was comfortable, and after a reasonably good straight ahead stall and recovery he refused to even induce a break in any condition except flaps up straight ahead. And no demo stalls.

    He knows I routinely fly upside down, and he has done stalls with me previously. He used to trust me.

    old age is a bitch.
    If that CFI was not comfortable performing as you have described, it is time he turned in his ticket to teach as he has become part of the lowering of quality airmen standards.
    N1PA

  31. #31
    stewartb's Avatar
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    Anyone else notice that the original post made comments most of us with PStol flaps have made. He never asked for advice.
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  32. #32

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    Quote Originally Posted by bob turner View Post
    Took a CFI up yesterday in a 160 Cub. We had to go to 5000’ before he was comfortable, and after a reasonably good straight ahead stall and recovery he refused to even induce a break in any condition except flaps up straight ahead. And no demo stalls.

    He knows I routinely fly upside down, and he has done stalls with me previously. He used to trust me.

    old age is a bitch.
    that CFI would not do well in UPSET training... LOL...time for him to quit---age is not always an issue--I`m 89 and still "play" seriously with CUB and RV-8---you get old when you stop flying---Capt Cub------PS--how did he pass the check ride???


    "You cannot teach experience, you must acquire it."
    Captain Cub

  33. #33

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    A flight review is not a check ride. And my stall sequence is now completely outside FAA requirements. I cannot force a student to go beyond FAA requirements - it has to be voluntary.

    I do not mind demonstrating or watching an FAA recommended stall sequence, but I want to see if pilots can fly on the ragged edge without stalling, and then I want them to force the aircraft to stop flying, followed by a minimum altitude loss recovery. Not everybody sees the value in this.

    I no longer recommend folks for checkrides. First, I do not know 4000 factoids about anything, much less aviation. A six hour oral is officially longer than any oral I ever took, including those in a university environment.

    And second, most designees are unable to specify what they want during a checkride (can you show me a 60 mph approach with power on?). Had a J3 student flunk because the examiner couldn't say that sentence. I don't understand that philosophy.

  34. #34
    skywagon8a's Avatar
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    Quote Originally Posted by bob turner View Post
    ... but I want to see if pilots can fly on the ragged edge without stalling, and then I want them to force the aircraft to stop flying, followed by a minimum altitude loss recovery. Not everybody sees the value in this.
    That sounds like slow flight to me. Don't they do that anymore?

    Isn't that what they are doing during those STOL contests such as at Valdez? That fellow a few years ago in Talkeetna couldn't do slow flight.
    N1PA
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  35. #35
    frequent_flyer's Avatar
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    Quote Originally Posted by skywagon8a View Post
    That sounds like slow flight to me. Don't they do that anymore?
    https://www.faa.gov/training_testing...s_change_1.pdf

    See - VII. Slow Flight and Stalls
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  36. #36
    skywagon8a's Avatar
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    Quote Originally Posted by frequent_flyer View Post
    Establish and maintain an airspeed at which any further increase in angle of attack,increase in load factor, or reduction in power, would result in a stall warning (e.g., airplanebuffet, stall horn, etc.)
    Accomplish coordinated straight-and-level flight, turns, climbs, and descents with theairplane configured as specified by the evaluator without a stall warning (e.g., airplanebuffet, stall horn, etc.).
    N1PA

  37. #37

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    Yep. I see less value in that than I do in notifying airmissions.
    The stall warning horn in my Decathlon was set to go on a full 8 mph before onset of buffet. Obnoxious on approach.

  38. #38
    BC12D-4-85's Avatar
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    Nice to know what the FAA thinks about flying

    Gary

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