Thomas
This is my first email on this open-forum. Since I'm not a current
Europa builder (yet) perhaps I lack credibility on the subject, but on
the other hand having 3,700 fixed-wing hours gives me some credibility.
At any here goes.
Seems to me you are confusing the function of the aileron trim with that
of some rudimentary autopilot/navaid that points your airplane in the
direction you wish to travel. No matter how perfect we build
airplanes, any minor shift in C.G., power change, pitch, airspeed, etc
will result in the aircraft having to aerodynamically balance itself out
again. An airplane that flies out of trim, is an airplane that is
tiresome to fly and just doesn't seem to fly right. Example: A plane
out of yaw trim (rudder) can still be flown with the wings level but
after a period of time you'll find that you are no longer on the
original heading. The plane is in what is called a "flat turn". You'll
find yourself constantly turning the airplane with ailerons to keep the
plane on a constant heading. A plane with an out of trim aileron is
one that that'll give you a tired hand trying to keep the wings level.
The out trim condition can result, as already stated on this forum, by
the addition of a passenger. Pitch trim (elevator) can be affected by
loading cargo fore or aft or simply by changing airspeed.
The navaid-servo device, if I understand correctly, is merely adjusting
the aileron to maintain heading. The airplane is probably still out of
aileron trim and the second you switch off the device, you'll discover
just how out trim you are. I will tell you through my own experience,
one never engages the autopilot until the airplane is trimmed in all 3
axis first. And some aircraft, even with the autopilot on, still adjust
the elevator trim in addition to moving the elevator. The trimming
reduces the amount of autopilot effort to keep the controls neutral. An
airplane out of trim when the autopilot is disengaged can be a handful
to manage until the airplane is trimmed out again. I assume, due to
the Europas lighter weight, the aerodynamic forces the pilot must over
come to manipulate the sticks must also be lighter, but they are still
there nonetheless.
There are other factors that affect trim also, such as P-factor, which
can normally be canceled by rudder trim....which then will cause a
subsequent change in aileron trim and pitch trim. Anytime the airplane
is taken out a aerodynamically balanced condition, such as with wings
level flight and constant speed, there will be a corresponding change in
trim. To ignore trimming would mean increased stick effort for the
pilot. Hope I shed some light on this. (or maybe I just didn't
understand the question)
Attila
113-23@auswaertiges-amt.de wrote:
> but then, why not go for the Navaid-Servo ? It is strong enuff to
> move the entire aileron and it reacts much faster than a spindle-motor
> motor affecting only a small tab.
>
> Don't get me wrong. I understand the fun-factor fully (it gives me
> a childish joy to see the stick being moved by ghostly hands while
> in flight). I am convinced however, that the Navaid serves better
> as the reaction time in wing-level mode is better than human reaction.
>
> Sincerely,
>
> <Thomas, N81EU>
>
> -----Ursprngliche Nachricht-----
> Gesendet am: Donnerstag, 4. Mai 2000 23:43
> An: europa@avnet.co.uk
> Betreff: Tuhoomit maicon sern
>
> The aileron trim tab saga:
> I think the question was: Why have one?
> My reason is to use the datastream from GPS to control the trim
> motor
> to provide a banking signal to keep the aircraft on track to the next
> GPS checkpoint, not especially for trim. Who knows, Maybe both......
> That is, laziness....... and fun.
> Happy landings
> Ferg #A064
>
>
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