Thread: Question 72" corsair .. @12 lbs
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Old Jan 27, 2013, 01:07 PM
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United States, FL, Orlando
Joined Feb 2008
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72" corsair .. @12 lbs

I'm not sure of the brand the plane is but the Wingspan is 72" and weighs about 12lbs. I measured the wing root chord and the wing tip chord plus the swept distance. I actually entered all the data into a CG calculator that was part of another thread a while back.

I can get a lot of different estimates by slight changes in the Static Margin % and the type of stabilizer efficiency. These are the specs that I entered.

Wing root: 14"
Tip chord: 10"
swept distance: 1"
1/2 wing span: 35.75"

Stabilizer root: 8
Stabilizer tip chord: 4.5
Stab sweep distance: 2.5
Stab half span: 13
Distance between both LE: 35
Stab efficiency: Std

Static margin: 7% .... because seems to be @ 1/2 way pt between 5% & 15%?

This gives me the following calculations:

MAC: 12.11
CG: 4.97

Does that seem right? Does anyone have a similar plane that could verify these calculations? I have talked to a few others way back in the past and they were saying 25% of the MAC .... That would be about 3.1" ( It does not sound like a winner here)? .... but depending on where you measure CG from, ... it may actually be a viable measurement. Keep in mind that the wing is swept so that measurement changes as you move from root chord to tip chord. Where is the correct location to establish the CG, ... At the "d" measurement: from the root chord to MAC .... which is 16.88" from the center of the Fuse ... out towards the wing tip, .... or right next to the fuselodge, ... or in the center of the wing right under the fuselodge itself?

I know thwere are a lot of different ways to get this and I appreciate your input.
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