Finding unknown CG
02-28-2023, 01:26 PM
#1
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Join Date: Feb 2002
Location: Piqua,
OH
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Finding unknown CG
I have a scratch built giant scale Aero master around 65" span forty-two years old.
I'm in the process of resurrecting this bird.
The top wing is forward of the bottom.
can I just block the aircraft up at flight attitude
and put a mark on my workbench at the trailing edge of the straight bottom wing
and the lead edge of the top wing midway out from the center of half the wing
to accommodate for the sweep and put a mark on the bench at that distance and
balance at 30% back of the total distance from the lead edge mark?
I know you're going to tell me to find the MAC of the top wing but is that absolutely necessary.
At seventy-six I'm getting lazy; I'm looking for an easy way out!
Thanks, Bob
I'm in the process of resurrecting this bird.
The top wing is forward of the bottom.
can I just block the aircraft up at flight attitude
and put a mark on my workbench at the trailing edge of the straight bottom wing
and the lead edge of the top wing midway out from the center of half the wing
to accommodate for the sweep and put a mark on the bench at that distance and
balance at 30% back of the total distance from the lead edge mark?
I know you're going to tell me to find the MAC of the top wing but is that absolutely necessary.
At seventy-six I'm getting lazy; I'm looking for an easy way out!
Thanks, Bob
03-20-2023, 02:15 PM
#3
Originally Posted by RapidRobert
I have a scratch built giant scale Aero master around 65" span forty-two years old.
I'm in the process of resurrecting this bird.
The top wing is forward of the bottom.
can I just block the aircraft up at flight attitude
and put a mark on my workbench at the trailing edge of the straight bottom wing
and the lead edge of the top wing midway out from the center of half the wing
to accommodate for the sweep and put a mark on the bench at that distance and
balance at 30% back of the total distance from the lead edge mark?
I know you're going to tell me to find the MAC of the top wing but is that absolutely necessary.
At seventy-six I'm getting lazy; I'm looking for an easy way out!
Thanks, Bob
I'm in the process of resurrecting this bird.
The top wing is forward of the bottom.
can I just block the aircraft up at flight attitude
and put a mark on my workbench at the trailing edge of the straight bottom wing
and the lead edge of the top wing midway out from the center of half the wing
to accommodate for the sweep and put a mark on the bench at that distance and
balance at 30% back of the total distance from the lead edge mark?
I know you're going to tell me to find the MAC of the top wing but is that absolutely necessary.
At seventy-six I'm getting lazy; I'm looking for an easy way out!
Thanks, Bob
Yes..working off your work bench you can use a carpenter's square to figure out what the combined outline [in the overhead view] is of both wings..then take those dimensions to an on line CG calculator.
