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4-Place - last knotch of flaps?

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  • 4-Place - last knotch of flaps?

    I was reading Bill's post on this past year with the Patrol. Noticed his "wheaties" comment and thought I would finally ask this question.

    I am in the rigging stage. As hard as I tried and the time I spent on getting the forward flap pulleys just right, I missed the right one by just a hair. There is just a slight interference with the rear spar support as the flap goes into the last position. Just enough to make a slight noise. Options include a little metal removal which I have seen done. Another option is not going all the way to 50 deg flaps. Visually this setting is pretty "impressive"!! I could easily remake the aluminum guide and stop around 47 deg. I don't know that I can ever be skilled enough pilot to notice the difference.

    So my question to the flying 4-place Bearhawks, "Is using the last notch of flaps a regular and needed occurence for short field performance?". I see it as a "wheaties" issue too as time passes!


    Last edited by John Bickham; 03-15-2018, 10:35 AM.
    Thanks too much,
    John Bickham

    Los Lunas, NM Mid Valley Airpark E98
    BH Plans #1117
    Avipro wings/Scratch
    http://www.mykitlog.com/users/index....er&project=882

  • #2
    I don't have much time in BH's yet to say anything about the last notch. I flew Gash's plane and we never went past the third notch... and even with that, I'm glad I ate my wheaties that morning!

    That said, I had interference issues with my build as well. However, I was able to eliminate the clearance problems by shimming the pulleys with washers and by going to a slightly larger pulleys.
    Bobby Stokes
    4-Place Kit Builder
    Queen Creek, AZ
    http://azbearhawk.com

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    • #3
      I used full flaps frequently but only because I wanted to be proficient for those times when I was playing in the dirt. On the other hand, every Cessna pilot I've flown with used full flaps every landing except in heavy cross winds. I don't see why the BH would be any different.
      Scratch Built 4-place Bearhawk. Continental IO-360, 88" C203 McCauley prop.

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      • #4
        If you place a washer behind the spar hinge bracket, can you space it out enough such that there is no interference? Or am I visualizing it in the wrong place?
        Christopher Owens
        Bearhawk 4-Place Scratch Built, Plans 991
        Bearhawk Patrol Scratch Built, Plans P313
        Germantown, Wisconsin, USA

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        • #5
          delete........
          Last edited by bearhawk2015; 05-24-2019, 04:48 PM.

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          • #6
            Full flaps every time, unless a strong cross wind. Do what you have to to use those nice big full flaps.

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            • #7
              Hi John!! 4 place or Patrol, wouldn't matter to me. Those big flaps are a wonderful thing. I wasn't able to get the 4th notch out, so I felt the need to change something. My issue wasn't a component interference. I just flat couldn't pull hard enough. My grip was impaired by my interior fitment. I made a longer handle, to allow more leverage and use all the flaps, except when winds dictate otherwise. The Patrol is solid as a rock at slow speeds. I don't pull any flap over 75 mph. 4 th notch below 65 mph.
              Flaps (IMHO) are kinda like money. If you get used to it, you don't want to be without it. You can't have too much.
              On that note, PM me if any of you want to send your excess cash.......

              Bill

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              • Chewie
                Chewie commented
                Editing a comment
                The Gubmint beat you to it Bill, sorry!

            • #8
              Full flaps every time unless crosswind is too strong.
              Remember the air loads mean you don't get 52 degrees in the air, only on the ground. More like 45 degrees in the air. Interference may be a non-issue in reality, provided it won't damage the rear spar end.

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              • #9
                Hi Swpilot3. My 4 Place turns 8 next month! I never could pull in the last notch of flaps until one day the prop departed while flying along.

                After we circled a field a couple times then turned short final, i extended full flaps with aboslutely NO problem! Turns out they can be extended very easily just do it with aircraft slowed down. I’ve flown with full flaps 180hp O360 & the drag held IAS to about 55 MPH.

                Fakecub

                Ps. We always takeoff with one notch, An Alaskan pilot said they always do that so we’ve made it a practice.

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                • #10
                  Appreciate the input and suggestions. Hit me with the "stupid stick" on the washer spacing!! Anyway, plan going forward is to eliminate the interference so full flaps are available as Bob designed.
                  Thanks too much,
                  John Bickham

                  Los Lunas, NM Mid Valley Airpark E98
                  BH Plans #1117
                  Avipro wings/Scratch
                  http://www.mykitlog.com/users/index....er&project=882

                  Comment


                  • #11
                    I'm so glad that folks around here aren't really wierd about hijacking subject threads, 'cause I'm gonna try to hijack John's thread. Sorry John. BTW John, it's crawfish season!! 😮
                    Fakecub brought up a subject that deserves some banter. 'Fake' takes off with 1 notch of flap. I fly a Patrol and it's been a while since I've logged PIC in a 4 place, so allow me some slack. I use 3 (of 4) notches for takeoff. The difference from no flap to 3 notches is huge! I'd bet 3 notches gets me off in 40% less ground roll. 4 notches may be a bit quicker off the ground, but it just feels sluggish in the air. 3 notches is about perfect, for me. I've tried "popping" flap on a short takeoff roll, but it lifts off so quickly, I don't feel any advantage. I pull 3 and push the loud lever..
                    What say you guys? No flap takeoff? Flaps? How much flaps?

                    Bill

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                    • #12
                      Originally posted by Bdflies View Post
                      I'm so glad that folks around here aren't really wierd about hijacking subject threads, 'cause I'm gonna try to hijack John's thread. Sorry John. BTW John, it's crawfish season!! 😮
                      Fakecub brought up a subject that deserves some banter. 'Fake' takes off with 1 notch of flap. I fly a Patrol and it's been a while since I've logged PIC in a 4 place, so allow me some slack. I use 3 (of 4) notches for takeoff. The difference from no flap to 3 notches is huge! I'd bet 3 notches gets me off in 40% less ground roll. 4 notches may be a bit quicker off the ground, but it just feels sluggish in the air. 3 notches is about perfect, for me. I've tried "popping" flap on a short takeoff roll, but it lifts off so quickly, I don't feel any advantage. I pull 3 and push the loud lever..
                      What say you guys? No flap takeoff? Flaps? How much flaps?

                      Bill
                      Definitely pop the flaps for a STOL contest or demonstration. It does make a small difference but your timing has to be perfect. You need to be able to feel the right time in the seat of your pants, which comes with currency, and be well practised. Pulling too early only makes things worse. Bumping the tailwheel is a sure sign of pulling too early.

                      In terms of technique - lifting the tail under power helps, obviously the plane should be approximately level to the ground as you accelerate, when you feel the wings *just* starting to develop lift, you rotate aggressively and pull flaps just after you start rotating. You should not feel the tailwheel touch the ground, and the plane should not lift off the ground before you finish pulling full flap - otherwise you are early or late respectively. The plane should complain and stagger off the ground, while you hold the Johnson bar and elevator back. You can also roll the ailerons as you pull back, in order to pull one wing up using the aileron like a flaperon, thus reducing drag on that wheel allowing more acceleration. The Bearhawk should linger there for a second, while you keep holding everything steady; before accelerating gradually away from the ground. Once you feel the upward acceleration you can safely bleed the flaps off. This complex technique does make a small difference in a contest situation. My best takeoff in the 4 place is 29m or 89ft, with vapour in the tanks and nothing else on board. I would be interested to know whether the lighter 4 place machines do better, as I am relatively heavy with fuel injection.

                      In a real life backcountry flying situation, I like to set and forget. I set two notches for T/O and climb out.
                      If things get hairy, I wouldn't hesitate to pull full flap.

                      Try dumping full flaps just as you're rounding out on a landing. Dump them aggressively. The plane should flop sharply onto the runway and stick like glue. Great technique for crosswinds or gusty days. If you can dump full flapsand the plane only sinks a little, then you may be flying much too fast when rounding out.

                      One place where popping the flap is a complete waste of time, is in long thick / wet grass, or other crops. In that case, you need to get clear of the grass before the plane will accelerate. Set and forget in that case, let the plane fly clear.
                      IMG_20180317_135030_001_COVER.jpg
                      Last edited by Battson; 03-19-2018, 09:58 PM.

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                      • Chewie
                        Chewie commented
                        Editing a comment
                        Another casually-epic pic...

                      • Chris In Milwaukee
                        Chris In Milwaukee commented
                        Editing a comment
                        Inspiration :-)

                    • #13
                      Big airplanes do something with a similar effect. The huge fowler flaps and slats move way to slow to "dump", but the speed brakes and flight spoilers pop up together with WOW, killing the lift and increasing brake effectiveness. You "arm" the spoilers for TO and Landing. On TO they pop up automatically during a rejected takeoff, under a certain set of circumstances. On landing, they pop with WOW.

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                      • #14
                        delete...............
                        Last edited by bearhawk2015; 05-24-2019, 04:47 PM.

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                        • #15
                          Goodmorning, Judt rembered what old pilots said, “match flaps to maximum down deflection of ailerons for maximum lift.”
                          Today is one of those rare days I get to hang out at hanger with my old dog & work on condition inspection for my 8 year old.😊

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                          • Bdflies
                            Bdflies commented
                            Editing a comment
                            Sounds like a great day to me!!
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