Today's Message Index:
----------------------
1. 01:08 PM - Datum Line (BobbyPaulk@comcast.net)
2. 01:58 PM - Re: Datum Line (Jay Bannister)
3. 02:03 PM - Re: Datum Line (Larry McFarland)
4. 07:05 PM - Re: Datum Line (Mark Hubelbank)
Message 1
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Guys,
Can anyone verify what station on the wings to drop a plumb line to get the proper
Datum line.
My information says it is the fourth nose rib or the one just outside the fuel
tank ( 15 gal. ).
I now hear that we should add 20mm outboard of this rib.
I am helping a friend get his ready to weigh and would like to know. I used the
fourth rib and have not had any problems.
Is there a place on the Zenith website that would show the latest info?
The distance from my right wheel to the datum is 26.016" The left is about 5/16"
less. Is this close to what most are getting?
Thank you for your help
Bobby ( age 75 )
Zodiac 601 XL "B"
Jabiru 3300 S/N 1141
Sensenich 64" x 51" Prop
Bing Carb 260 Main & 285 Needle Jet
Status - Flying 181 hrs.
Do Not Archive
Message 2
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Bobby,
There is no "proper datum line." The datum can be anywhere you want it. M
ost find it convenient to locate it at the leading edge of the wing. I cho
se to locate my datum line at the leading edge of the wing, adjacent to the
fuselage, taking the forward sweep of the wing out of the picture. I supp
ose locating it further out on the wing could make it easier to draw on the
floor.
Both my main gear wheels were the same distance from the datum.
Jay
-----Original Message-----
From: BobbyPaulk <BobbyPaulk@comcast.net>
Sent: Fri, Jun 28, 2013 3:10 pm
Subject: Zenith601-List: Datum Line
Guys,
Can anyone verify what station on the wings to drop a plumb line to get the
proper Datum line.
My information says it is the fourth nose rib or the one just outside the f
uel tank ( 15 gal. ).
I now hear that we should add 20mm outboard of this rib.
I am helping a friend get his ready to weigh and would like to know. I used
the fourth rib and have not had any problems.
Is there a place on the Zenith website that would show the latest info?
The distance from my right wheel to the datum is 26.016" The left is about
5/16" less. Is this close to what most are getting?
Thank you for your help
Bobby ( age 75 )
Zodiac 601 XL "B"
Jabiru 3300 S/N 1141
Sensenich 64" x 51" Prop
Bing Carb 260 Main & 285 Needle Jet
Status - Flying 181 hrs.
Do Not Archive
Message 3
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HI Bobby,
You can use any point you wish for a Datum line, so long as
you=99re consistent with it.
The sum of the moments divided by total weight will locate a CG for any
object.
Zenith would have you loading the CG limits to the design they
established though.
Larry McFarland (age 73)
From: owner-zenith601-list-server@matronics.com
[mailto:owner-zenith601-list-server@matronics.com] On Behalf Of
BobbyPaulk@comcast.net
Sent: Friday, June 28, 2013 3:08 PM
Subject: Zenith601-List: Datum Line
Guys,
Can anyone verify what station on the wings to drop a plumb line to get
the proper Datum line.
My information says it is the fourth nose rib or the one just outside
the fuel tank ( 15 gal. ).
I now hear that we should add 20mm outboard of this rib.
I am helping a friend get his ready to weigh and would like to know. I
used the fourth rib and have not had any problems.
Is there a place on the Zenith website that would show the latest info?
The distance from my right wheel to the datum is 26.016" The left is
about 5/16" less. Is this close to what most are getting?
Thank you for your help
Bobby ( age 75 )
Zodiac 601 XL "B"
Jabiru 3300 S/N 1141
Sensenich 64" x 51" Prop
Bing Carb 260 Main & 285 Needle Jet
Status - Flying 181 hrs.
Do Not Archive
Message 4
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Bobby,
As pointed out, to use Zenith's recommended CG limits (which you
really should) you do have to start with their datum point. I believe
the good news is that the CH601 leading edge is basically perpendicular
to the centerline (at least the CH601XL is) so the exact spot is not too
critical, I can't see that +/- 20 mm along the leading edge makes any
measurable difference.
On 06/28/2013 5:03 PM, Larry McFarland wrote:
>
> HI Bobby,
>
> You can use any point you wish for a Datum line, so long as youre
> consistent with it.
>
> The sum of the moments divided by total weight will locate a CG for
> any object.
>
> Zenith would have you loading the CG limits to the design they
> established though.
>
> Larry McFarland (age 73)
>
> *From:*owner-zenith601-list-server@matronics.com
> [mailto:owner-zenith601-list-server@matronics.com] *On Behalf Of
> *BobbyPaulk@comcast.net
> *Sent:* Friday, June 28, 2013 3:08 PM
> *To:* zenith601-list@matronics.com
> *Subject:* Zenith601-List: Datum Line
>
> Guys,
> Can anyone verify what station on the wings to drop a plumb line to
> get the proper Datum line.
> My information says it is the fourth nose rib or the one just outside
> the fuel tank ( 15 gal. ).
> I now hear that we should add 20mm outboard of this rib.
> I am helping a friend get his ready to weigh and would like to know. I
> used the fourth rib and have not had any problems.
> Is there a place on the Zenith website that would show the latest info?
> The distance from my right wheel to the datum is 26.016" The left is
> about 5/16" less. Is this close to what most are getting?
>
> Thank you for your help
>
>
> Bobby ( age 75 )
> Zodiac 601 XL "B"
> Jabiru 3300 S/N 1141
> Sensenich 64" x 51" Prop
> Bing Carb 260 Main & 285 Needle Jet
> Status - Flying 181 hrs.
>
> Do Not Archive
>
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--
Mark Hubelbank
NorthEast Monitoring
2 Clock Tower Place
Suite 555
Maynard, MA, 01754 - USA
mhubel@nemon.com
978-443-3955
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