Linear output - was Notes to Self 3

[Dean Pappas]

We don't adjust for "linear" throw:
Some of adjust for a linear "feel", which has to be put in quotes 'cause nobody can define it, and because there are wild differences of opinion. 
Others simply dial enough EXPO in to get manageable sensitivities arounsd neutral with the maximum throw that was found necessary to perform some maneuver.
That usually means like the plane feels like it has a break-point in the stick response, which has always driven me, personally, nuts.
 
The breakout force needed to budge the stick out of neutral is an important part of the deal.
Jon's Dad always asserted that three ounces of breakout force were the "correct" amount. When in doubt, listen to the Guru.
Lots of flyers dial EXPO in to solve the problem of too soft sticks, which allow them to unconsciously put undesired inputs in.
The soft neutral reduces a problem caused by something else ... like too darned much caffeine!
Some peoples' feel is by stick pressure, others by movement.
You'll never come up with a one-size-fits-all deal, though Don Lowe's breakout force spec is a pretty good one.
 
Later,
Dean Pappas 
Sr. Design Engineer 
Kodeos Communications 
111 Corporate Blvd. 
South Plainfield, N.J. 07080 
(908) 222-7817 phone 
(908) 222-2392 fax 
d.pappas at kodeos.com 
-----Original Message-----
From: discussion-request at nsrca.org [mailto:discussion-request at nsrca.org]On Behalf Of Atwood, Mark
Sent: Thursday, February 10, 2005 1:04 PM
To: NSRCA Discussion List (E-mail)
Subject: Linear output - was Notes to Self 3


Ok...I have a question for the Aeronautical engineers in the group...   All of this discussion has been centered around an assumed desire to get a linear relationship between our stick movement, and that of the control surface.  Clearly the effect of moving a control surface on the aircraft is proportional to the amount of movement...but is it linear??  I have to beleive it's not...   Just don't know the mechanics behind it...
 
Assuming it's not...(And I'm betting for some portion of the throw is close enough to be considered linear and then at higher deflections it becomes either more or less efficient) is there really a purpose to trying to exact the linear nature of the stick/control surface linkage...or it is an exercise in retentiveness :)
 
I also know that our spring tension on the sticks in not linear...especially around center...so it seems unlikely that what "Feels" linear isn't anyway.
 
To me it's akin to comparing two high end stereo systems both of which have specifications well beyond the range of human hearing....
 
-Mark
 
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