OK I have to get more specific. I only know the Legacy but I assume the 320/360 and IV are the same. The short answer is that when you properly balance the ailerons, they'll return to level. When you balance the elevator and rudder, they'll have no preferred orientation.
The ideal is to have a hinged surface like the elevators and rudder with counterbalance weight *ahead* of the hinge point, which when properly balanced will have no preferred orientation. That completely decouples angular inertia from hinge motion. That is, when the stabilizer twists or buffets up and down (or sidewise, on the vertical), the hinged surface does not rotate in response. In this geometry, a "nose-heavy" surface is just as risky as a "tail-heavy" surface.
In the Legacy ailerons, the hinge point is at the upper surface of the wing, rather than than halfway between the upper and lower surfaces.** For this reason, the counterweight has to be *below* the hingeline. Since the aileron is normally in a level position and the hinge motion of interest is up and down (not fore and aft), Lancair says to balance it in the level position. So, as long as the ailerons are level, you get the same result as with the elevator or rudder -- the aileron won't rotate in response to up/down wing motion. A rotated aileron is slightly out of balance with respect to up/down hinge motion, and I guess that means that we're slightly more susceptible to aileron flutter or buzzing when in a turn than when flying straight and level.
**Now I'm curious why -- since it forces a departure from the balancing method of the elevator and rudder. As I recall, Mooney ailerons are hinged just like the elevator, and they have a counterweight ahead of the aileron just like the elevator, except that it swings *within the wing* which severely limits aileron travel in a Mooney. I think Cheetahs and Tigers are similar, which may be no coincidence since Roy Lopresti cleaned up both designs.
On Feb 21, 2012, at 10:30 AM, Jim Nordin wrote: Hummmm … correct me if I’m wrong. Balance of control surfaces is attained when the component (aileron or elevator for example) hung at the center of rotation and given a perturbation (trailing edge pushed down) minimally returns to the level condition or better a small nose down condition. Any other condition (leading edge high above level, trailing edge below level) warrants adding weight to make the nose (leading edge) to settle below level. Nose heavy is the point here. Any other condition may result in flutter. Jim
From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Charles Brown
Sent: Tuesday, February 21, 2012 8:02 AM
To: lml@lancaironline.net
Subject: [LML] Re: 360 rudder balance They should stay in any position where you let them go. They should not return to level. If they are out of balance, they will have some preferred orientation (as you say, will move up or down). MS Aero/Astro Engineering On Feb 20, 2012, at 6:51 AM, Bill Bradburry wrote:
I have a question about balancing the flight surfaces. If they are in balance, should they return to level from where ever you move them to, or should they just stay where you put them. I assume that if they are out of balance they will either move up or down from level depending on whether you need to add or remove weight. Bill B
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