Trim

Brian Young b4598070 at yahoo.com
Mon Feb 16 13:19:07 AKST 2004


What do they do put this on the opposite side of the
surface as the control horn?

--- Bill Glaze <billglaze at triad.rr.com> wrote:
> To prevent this very thing, and to forestall any
> flutter, I have heard 
> of some folks who actually pre-load the surfaces
> with a rubber band, and 
> then are able to completely neutralize the surface,
> while preventing 
> flutter.  Kind of like a snubber, which is used with
> great success in 
> the Boeing 727 and 757/67, with which I have some
> experience.  Although 
> Boeing does not use a rubber band, (not even a very
> large, strong one) 
> to my knowledge! :-D
> 
> Bill Glaze
> 
> george kennie wrote:
> 
> > I agree!
> >
> > "Karl G. Mueller" wrote:
> >
> >> Georgie, One thing you don't want is a
> "completely neutral" set up. 
> >> Itwill be very hard on the servo gears,
> especially when it is 
> >> tooneutral in pitch.My last years Star had an
> almost neutral set up 
> >> in pitchand it started stripping the gears in the
> elevator servos.It 
> >> took me a little while to arrive at this
> conclusion since therewasn't 
> >> too much left of the plane when this happened the
> secondtime. My 
> >> suspicions were confirmed after talking to some 
> >> "AerodynamicsExperts". Every moveable surface
> wants to hunt for a 
> >> neutral positionand if there is no opposite force
> ( Trim ) to stop it 
> >> from doing thisyou will get a certain amount of
> oscillation ( flutter 
> >> ). Having a minuteamount of trim offset puts a
> slight force from the 
> >> airflow over it in onedirection and will put a
> stop to any 
> >> oscillation. "Completely Neutral"is not the ideal
> condition. Karl G. 
> >> Mueller
> >> kgamueller at rogers.com
> <mailto:kgamueller at rogers.com>
> >>
> >>     ----- Original Message -----
> >>     From: george kennie <mailto:geobet at gis.net>
> >>     To: discussion at nsrca.org
> <mailto:discussion at nsrca.org>
> >>     Sent: Friday, February 13, 2004 12:50 PM
> >>     Subject: Re: Trim
> >>      "Completely Neutral" is the most complex
> descriptive condition
> >>     that one can conceptualize. There are so many
> variables, that
> >>     there is only one specific set that will
> approximate the required
> >>     parameters to achieve the "voila"
> condition.Change one thing and
> >>     you no longer have "completely neutral".
> >>     Not trying to be corrective here, just
> stating that in my
> >>     experience completely neutral is more than
> elusive, but somewhat
> >>     attainable under certain conditions.
> >>     What I'm currently searching for is the
> correct force arrangement
> >>     that will give me a neutral airplane at the
> C.G. that I like to
> >>     fly at. I would like to fly an airplane that
> adapts to me not the
> >>     other way around. Elusive? Yeah! But
> attainable? At this point, I
> >>     think maybe!
> >>     Georgie
> >>      
> >>      
> >>
> >>     Patternrules at aol.com wrote:
> >>
> >>>      In a message dated 2/12/2004 11:26:21 AM US
> Eastern Standard
> >>>     Time, natpenton at centurytel.net writes:
> >>>
> >>>         For an airplane that goes to the canopy
> in knife-edge most
> >>>         trim charts say , after adjusting cg ,
> to increase the wing
> >>>         incidence . My " theory " says to
> decrease the wing
> >>>         incidence. What is your
> theory/experience ?
> >>>
> >>>      What does the plane do in the down lines,
> if they are good you
> >>>     could just mix in a little down elevator
> with rudder, for the
> >>>     knife edge.  Nat, I would have thought that
> a guy that designed
> >>>     the Voo Doo Express that was completely
> neutral, would have all
> >>>     the answers LOL.  Steve Maxwell
> >>
> 


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