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Old August 29th 13, 09:43 PM posted to rec.aviation.soaring
Craig Funston[_2_]
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Posts: 115
Default Weight and Balance - a micro-rant

On Thursday, August 29, 2013 11:38:23 AM UTC-7, Eric Greenwell wrote:[color=blue]
Brad Alston wrote, On 8/28/2013 9:36 PM:

'Uncle Fuzzy[_2_ Wrote:


;844103']On Wednesday, August 28, 2013 2:30:05 AM UTC-7, Uncle Fuzzy


wrote:-




No, different 'previous owners. The measurements that they 'inked'


into the log books were accurate - with both wheels on the hangar


floor. Unfortunately, that's not what the POH calls for. Both manuals


specify 'level' and the Janus, (if I remember) actually gives a


distance. from the floor to the tailwheel. (which, conveniently


corresponds to the height of the box the scale comes in.




Is he difference significant? I doubt it. But I'm kinda' OCD about


specifications (also why I won't use RG-58 for L band (yet another


rant.


LOL-[/blue]




What?...you mean we should read AND understand the POH!? Hmmmm...when


you are throwing your person into the air and trusting in laws of


physics and someone else's engineering, I would think accuracy counts!


But then again, that's just me thinkin' again!




The difference in the two measurements is small (1% or so) and therefore

irrelevant. The critical measurement that will be strongly affected by

measuring in the wrong attitude is the distance of the main wheel axle

from a datum point; in the case of my ASH 26 E, that datum point is the

leading edge of the wing at the root. A 1" error in this measurement

means a 1" error in the location of the CG - a substantial error on wing

chord of only 33".



--

Eric Greenwell - Washington State, USA (change ".netto" to ".us" to

email me)

- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm

http://tinyurl.com/yb3xywl


The weight distribution between the main wheel and the tail wheel/skid changes with the aircraft attitude because the vertical CG is above the tire contact patch. Like the others have said. Follow the manual.

Craig