Stabs

[Earl Haury]

In the '70's George Albright designed the Utopia (probably the first complete ready to paint pattern offering) which used a flying stab. I flew them for a couple of seasons - the servos / linkages really weren't good enough back then and stab flutter was a concern, even with proper stab pivot placement and stab balance. As obvious from the number of jets flying successfully with flying stabs, that problem is solvable. (Although I've seen several flying stab flutter failures on fun-fli airplanes.)

However, while the neutral feel was fine, low speed effectiveness was poor - requiring large angles of deflection for take-off, landing, and spin entry. (I know - this is counter intuitive.) Of course, this exasperated the linkage / servo strength issues. I retrofitted one of these airplanes with a conventional stab / elevator and it flew the same - except for much better low speed elevator response. Bottom line - the flying stab provided fewer advantages than disadvantages for pattern in the days of light speed 60-size pattern. With today's equipment and slower speeds - maybe?

Earl


----- Original Message ----- 
  From: Bob Richards 
  To: discussion 
  Sent: Tuesday, October 18, 2005 10:45 PM
  Subject: Re: Stabs


  It has been tried before, way back in the 70s as I recall. I think Bob Violet might have sold some hardware to do it. I know he designed a pattern plane that was featured in one of the magazines back then that had a flying stab. I know the glider guys use full flying stabs a lot, but for drag reduction mainly. Not sure why it would not work, but I suspect you would not get the same "feel" as you would with a conventional stab/elevator.

  With a conventional setup, you are able to play with the camber of the horizontal surfaces, which can be used to trim the downlines for hands off.

  Someone correct me if I am wrong, but when wing tubes became prevalent, I believe someone (I think Chip Hyde) experiemented with wings that rotated on the tubes instead of using ailerons.  That did not work well, from what I understand.

  Bob R.



  jeffghughes at comcast.net wrote:
    Now that a lot of 2M planes are going to removeable stabs, it seems a short step to full flying stabs. Is there any advantage to this type of stab? Seems like it almost would be easier set up, you wouldn't need to worry about wing to stab incidence.
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