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Biplane COG Calculator

How to find it.

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Tim Mackey18/07/2009 23:23:56
20920 forum posts
304 photos
15 articles
Courtesy of Eric Bray our resident wing expert, heres how to calculate the correct balance point of your biplane.
As the sweep on the top wing, and the straight bottom wing more or less cancel out for chordal area, just follow the multiply described procedure -
Find the root chord of the top wing, and mark one third back.
Find the tip chord of the top wing, and mark one third back - on both sides.
Put a straight-edge across the two one third marks on the tips, and mark where it crosses the ROOT chord.
Then divide the space between the two marks into thirds, and assume the start position is going to be near the first third back mark.
so if it works, you have a mark on the root chord rather like
and end up with
To complicate matters, do the same for the bottom wing, and then see how the two - one third - marks match up, and if there is a significant distance, take one third of THAT distance! 

Edited By Timbo - Moderator on 18/07/2009 23:24:24

Nobby15919/07/2009 02:20:12
330 forum posts
44 photos
I understood that, thanks Timbo/Eric please make it a sticky
Eric Bray20/07/2009 11:55:16
6600 forum posts
2 photos
resident wing expert
Who? Me?
Tim Mackey20/07/2009 15:29:17
20920 forum posts
304 photos
15 articles
Dont be bashful Mr Bray
robin andy05/03/2012 11:48:27
9 forum posts

Beutifle information and suggestion for people suggested by you guys.

Thanks all for same, actually i am in newbie in this fourum. could anybody help me?

Biggles' Elder Brother - Moderator13/05/2012 20:02:37
15748 forum posts
1460 photos

Hi RA - help with what exactly - CoG for bipes?

Well the above is one approach. Also for a discussion on it see last month's copy of the mag. Finally there are a few threads on here dealing with this - try the search box at the top of the thread.


Chuck Plains21/01/2014 18:41:58
1096 forum posts
244 photos

Wasn't this covered in the Magazine last year? Still, useful to have something as a sticky on the forum though. thumbs up

cymaz22/01/2014 11:56:30
9194 forum posts
1186 photos

I found this very useful. Easy to use and it works it out for you, in theory onlycool

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