Trim

[Bill Glaze]

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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