[NSRCA-discussion] Air Breaks

[Ed Alt]

The elevator mix I went after was so that at "landing pattern speed" (downwind to base leg), the initial flip of the switch would not cause a noticeable pitch change.  After that point, it doesn't matter a whole lot since it's coming down in a very positive way, so you're soon leaning back on a little up for the rest of the approach.  From what I read in other posts, I might not be using as much spoiler deflection as some others.  I don't have a whole lot of elevator mix, just a few pct.  Similar amounts work on my Temptation and Focus II.

Ed
  ----- Original Message ----- 
  From: brett terry 
  To: NSRCA Mailing List 
  Sent: Saturday, May 13, 2006 9:58 PM
  Subject: Re: [NSRCA-discussion] Air Breaks


  the spoilerons decrease the apparent AOA of the wing, in essence giving the wings "washout" effect.  If I remember correctly, at the same speed there is actually less flow separation with the spoilerons activated, despite the decrease in total lift.  The effective wing loading increases (relative to the amount of lift generated), but the wing is simultaneously resistant to tipstalling and the plane's ability to penetrate increases.  Perhaps the decrease in chordwise flow separation precludes the vortices which create spanwise flow?  I am just speculating at this point. 

  Back when I flew slope soarers some of my lighter planes would not land without spoilerons deflected.  The rotor would just toss them about with devastating results.  With the spoilerons up the plane would punch right through and was much less likely to tipstall. 

  I also had little luck creating an elevator mix.  I haven't tried the spoilerons on a pattern plane for many years now, but I remember some planes pitched up while others pitched down, and the rate and magnitude of pitch change was speed-sensitive.  


  On 5/13/06, Ed Deaver <divesplat at yahoo.com> wrote:
    I use the "spoilers" as we call them a little different than has been mentioned.  

    Use 10-25% up ailerons but I don't mix in any Elevator.  My reasons are simple, don't need it for landing.  As I am flying the downwind leg and activate the spoilers the plane pitches up, and actually have used them for spins on very calm days, but as soon as the plane slows down a bit it flies level.  For me to add the mix in destroys the glide path I like. 

    The spoilers do have a very noticeable effect on cross wind landings suprisingly, eliminating a lot of the choppy effect but I don't understand why.

    Have done this method on 3 different style planes all with the same result. 

    ed


    John Pavlick < jpavlick at idseng.com> wrote:
      Bill, 
      What plane are you trying this on? I have my both my Focii set up with this
      and I like it. I use ailerons up and down elevator. In Futaba land I have
      +30% Flaps (ailerons up) [= ~ 5 degrees] and -20% elevator (down) but you'll 
      need to experiment. On some planes I use very little down elevator in the
      mix, I just do it manually when I land. I found that using the "airbrakes"
      helps me to be able to transition into a nearly flared condition very early 
      on final without worrying about any tip stalling. You basically head
      downwind, chop the power, hit the airbrakes and point the nose down. When
      you get close, start to raise the nose and bleed off speed. You can then 
      drag the plane to the mark with a little power if you need to. Try it at a
      field where you have some room. You may find that you undershoot the first
      few landings until you get used to how the plane comes down with the 
      airbrakes on.

      John Pavlick
      http://www.idseng.com


      > -----Original Message-----
      > From: nsrca-discussion-bounces at lists.nsrca.org
      > [mailto:nsrca-discussion-bounces at lists.nsrca.org ]On Behalf Of
      > Bill Markovitz
      > Sent: Saturday, May 13, 2006 10:00 AM
      > To: nsrca-discussion at lists.nsrca.org 
      > Subject: [NSRCA-discussion] Air Breaks
      >
      >
      > I'm interested in using the air brake function for
      > slower and more controlled landings. Any suggestions
      > for a starting point on the aileron and elevator 
      > throws would be appreciated. Is it better to have the
      > ailerons up and the elevator down or the ailerons down
      > and the elevator up?
      >
      > Thanks, Bill :)
      >
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