HobbyKing.com New Products Flash Sale
Reply
Thread Tools
This thread is privately moderated by z80, who may elect to delete unwanted replies.
Old Dec 26, 2008, 06:55 AM
z80
Registered User
Copenhagen, Denmark
Joined Sep 2006
12 Posts
Discussion
Flying wing CG calculator

I wrote a little CG calculator for flying wings. If you have a HTML 5 browser supporting the canvas object you will get a little image of the wing too.

http://fwcg.3dzone.dk

Bug reports and suggestions are very welcome.
z80 is offline Find More Posts by z80
Reply With Quote
Sign up now
to remove ads between posts
Old Dec 26, 2008, 09:25 AM
Herk
HerkS's Avatar
Virginia USA
Joined Jun 2007
1,652 Posts
z80 ?? Wasn't that an early processor we used back in the CPM days??

Neat calculator. Appears that the area computation is showing a value double what it should be. Also appears that the sweep angle to be specified is the sweep of the wing's quarter chord. If I am correct, you might mention that.
HerkS is online now Find More Posts by HerkS
Reply With Quote
Old Dec 27, 2008, 03:11 AM
z80
Registered User
Copenhagen, Denmark
Joined Sep 2006
12 Posts
Quote:
Originally Posted by HerkS
z80 ?? Wasn't that an early processor we used back in the CPM days??
Yes, that's right. It was also used in the ZX Spectrum computer from 1982. That was my first computer. I spend some time writing a ZX Spectrum emulator for the PC, so that is where that nick is from.

Quote:
Originally Posted by HerkS
Appears that the area computation is showing a value double what it should be.
You're absolutely right -- by mistake i took the span-variable in the script as half the span when in fact it was the full span. So a division by 2 was missing. That is corrected now. Thanks.

Quote:
Originally Posted by HerkS
Also appears that the sweep angle to be specified is the sweep of the wing's quarter chord. If I am correct, you might mention that.
The calculators sweep is defined as the distance the tip is offset from the root and not an angle. That is kind of unclear of course. The different values should be displayed visually somehow, so its clear what they mean. Would be cool if the image showed some help based on what input-field has focus.

Thanks for the feedback :-)
z80 is offline Find More Posts by z80
Reply With Quote
Old Dec 27, 2008, 07:12 PM
resU deretsigeR
PaulVi's Avatar
Dublin Ca
Joined Aug 2004
7,787 Posts
[QUOTE=z80]Yes, that's right. It was also used in the ZX Spectrum computer from 1982. That was my first computer. I spend some time writing a ZX Spectrum emulator for the PC, so that is where that nick is from.

QUOTE]

Nice beginings... My first computer was also a ZX81 Taught my self more on that than on most other after that.. (exept for the c64) The zx81 taught me how to program tight ML code... Poke and save....

OT.

Is there a way to make this work with out having to resort to firefox.. Limmits me from using it at work for sure..
PaulVi is offline Find More Posts by PaulVi
Reply With Quote
Old Dec 28, 2008, 05:56 AM
z80
Registered User
Copenhagen, Denmark
Joined Sep 2006
12 Posts
Quote:
Originally Posted by PaulVi
Nice beginings... My first computer was also a ZX81 Taught my self more on that than on most other after that.. (exept for the c64) The zx81 taught me how to program tight ML code... Poke and save....
Another Sinclair machine :-) I spend a lot of time coding machine code as well. Great fun. A very good way to learn the basics using simple machines like that.

Quote:
Originally Posted by PaulVi
Is there a way to make this work with out having to resort to firefox.. Limmits me from using it at work for sure..
Lack of IE support was a problem for sure. I added IE support now using ExplorerCanvas Let me know if it doesnt work.
z80 is offline Find More Posts by z80
Reply With Quote
Old Dec 28, 2008, 01:57 PM
Envies his own avatar
rockyabq's Avatar
Albuquerque, NM
Joined May 2008
596 Posts
Quote:
Originally Posted by z80
CG calculator
Sweet.
No wonder my Flik flies so poorly.
rockyabq is online now Find More Posts by rockyabq
RCG Plus Member
Old Dec 28, 2008, 02:40 PM
Proud to eat Kraut ;-)
Julez's Avatar
Germany
Joined Dec 2003
5,374 Posts
Nice!

Would it be possible to enter an angle in degrees of the leading edge as an alternative to the Sweep?

Also, a little image describing where to find the required values at a real wing might be helpful for dummies.

Example:

http://www.maltemedia.de/swp/
Julez is offline Find More Posts by Julez
Reply With Quote
Old Dec 28, 2008, 04:17 PM
resU deretsigeR
PaulVi's Avatar
Dublin Ca
Joined Aug 2004
7,787 Posts
Quote:
Originally Posted by z80
Another Sinclair machine :-) I spend a lot of time coding machine code as well. Great fun. A very good way to learn the basics using simple machines like that.



Lack of IE support was a problem for sure. I added IE support now using ExplorerCanvas Let me know if it doesnt work.
That did the trick... Nice work
PaulVi is offline Find More Posts by PaulVi
Reply With Quote
Old Dec 28, 2008, 05:02 PM
z80
Registered User
Copenhagen, Denmark
Joined Sep 2006
12 Posts
Quote:
Originally Posted by Julez
Would it be possible to enter an angle in degrees of the leading edge as an alternative to the Sweep?

Also, a little image describing where to find the required values at a real wing might be helpful for dummies.
Excellent suggestions. I implemented both now

Quote:
Originally Posted by PaulVi
That did the trick... Nice work
Alrighty
z80 is offline Find More Posts by z80
Reply With Quote
Old Dec 28, 2008, 05:26 PM
Proud to eat Kraut ;-)
Julez's Avatar
Germany
Joined Dec 2003
5,374 Posts
Cool!

This looks like my favorite CG calculator now.

But I noticed, that the default 25% MAC value might be a little aft. My practical results seem more like 20%.

How about 3 boxes or something, that can be klicked, and enter predefined values like:

15% - for beginners/ testing new planes
20% - allround
25% - for experts

This might also be helpful for newbies, who have no clue, and affiliate "MAC" with greasy burgers.

Cheers,

julez
Julez is offline Find More Posts by Julez
Reply With Quote
Old Dec 28, 2008, 05:58 PM
z80
Registered User
Copenhagen, Denmark
Joined Sep 2006
12 Posts
Quote:
Originally Posted by Julez
This looks like my favorite CG calculator now.
Cool

Quote:
Originally Posted by Julez
How about 3 boxes or something, that can be klicked, and enter predefined values like:

15% - for beginners/ testing new planes
20% - allround
25% - for experts

This might also be helpful for newbies, who have no clue, and affiliate "MAC" with greasy burgers.
Another fine suggestion... Done
z80 is offline Find More Posts by z80
Reply With Quote
Old Jan 26, 2009, 07:07 AM
Registered User
Pilipinas
Joined Mar 2005
107 Posts
Great idea here Z80, very helpful. Now I can more confidently build flying wing foamies of own design without having to resort to trial and error (mostly error) on maiden. Thank you very much.
bolkow is offline Find More Posts by bolkow
Reply With Quote
Old Jan 27, 2009, 03:40 AM
zoom zoom
gotboostedvr6's Avatar
USA, NJ, Mt Laurel
Joined Oct 2007
3,691 Posts
very helpful thanks
gotboostedvr6 is offline Find More Posts by gotboostedvr6
Reply With Quote
Old Jan 27, 2009, 07:14 AM
Registered User
United States, MI, Parma
Joined Aug 2006
200 Posts
I know this is a wierd request, but I need some help on this one. I have built a forward swept wing and am having trouble calculating where the CG should be. I entered the sweep as a negative number and the calculator did not like that.

If anyone has some ideas on this Thanks in advance.
Rolland Benson is offline Find More Posts by Rolland Benson
Reply With Quote
Old Jan 30, 2009, 08:12 AM
The Hippy
ddoth's Avatar
Perth - Australia
Joined Nov 2008
233 Posts
Not too sure if this would work but put the figures in as if the plane were facing the other way (normal swept wings) and instead of CG being 15% for beginners put in the custom value as 85%.

Point marked and rotate the plane back around, CG will then be 15% as such.

Hopefully making sense.

Goodluck
ddoth is offline Find More Posts by ddoth
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
flying wing cg ?'s mscj Foamies (Kits) 1 Mar 03, 2003 10:53 PM
Flying wing CG with shortened span MSB Foamies (Kits) 2 Jul 28, 2002 08:23 PM
Flying Wing CG Choppa Nutta Power Systems 8 Apr 17, 2002 12:45 PM
Flying Wing CG Paul Susbauer Parkflyers 2 Jan 29, 2002 02:31 PM
Flying wing CG Anders Power Systems 4 Oct 05, 2001 05:39 AM