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canard CG

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Old 02-17-2003, 04:49 PM
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stall
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Default canard CG

I'm wanting to design/build a canard fun fly plane. Does anyone know of a good web site or have info on how to balance a canard aircraft? All of the canard planes I have seen are like the EZ plane.

Any help would be appreciated.

Thanks
Jack
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Old 02-17-2003, 05:36 PM
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Default canard CG

here to do cg.
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Old 02-18-2003, 05:08 PM
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Default canards

Adrian,
That graphic method works well for conventional airplanes but doesnt take into account the physics of a canard. If it is used to calculate the CG for a canard odds are the airplane will be tail heavy.

Jack & Adrain,
If you like you can send me a PM and I can e-mail a mag article to you that covers basic canards pretty well. Warning - Some algebra
may be involved for the calculations.
Just a note; I have faith in the info because I built a small glider to test the math

Cheers.
James
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Old 02-18-2003, 05:16 PM
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Default canard CG

I used a program out of a magazine one time that showed cg and size of canard required. We used it to design a glider but I have no clue as to where the program went. It was in basic and was a lot of code to type. I had it working well, but that was long ago. I think we got it out of RCM a in the mid 80s. Might be the one James is talking about.
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Old 02-18-2003, 06:21 PM
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Default canard CG

There is some discussion going on over in the Aerodynamics forum about canard CG calculation. I posted a link to Ron Van Putte's formulas in a M.A. article that worked for me in a canard design I did some time ago. Read this thread: http://www.rcuniverse.com/showthread...369&forumid=19

HTH )
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Old 02-18-2003, 07:52 PM
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Thanks HTH.
Thats the one. I have a copy of that file on my other puter at home. Couldnt remember the author.

Didnt use the calcs for the fin area cause I was going off a scale subject. So no comment on those numbers.

Cheers.
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Old 02-18-2003, 08:40 PM
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Default canard CG

Quote:
Originally posted by mdlav8r
Thanks HTH.
Oops, I finally remembered to use some of that cool new-age internet abbreviation stuff (HTH = Hope This Helps) and now I got me a brand-new name.

Regards,
Milton Dickey
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Old 02-19-2003, 04:51 AM
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Default Canard CG

If anyone is interested I got a copy of an Excell spreadsheet a couple of years ago which will calculate the CG of canards, bi-planes, monoplanes, swept and tapered wings. It will also do the design calculations. you just plug in the span, chord etc. If anyone would like to have a copy let me know.

Will Varnado
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Old 02-19-2003, 01:16 PM
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Default oops :p

Milton (HTH) Dickey

Prime example of what happens when your brain misfires while in a hurry.

Cheers.
James
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Old 02-21-2003, 02:52 PM
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Default wvarn1957, I would love a copy of that program

Hey there WVARN,

I would love a copy of that Excell spreadsheet. I have gotten hooked on building scratch built foamies in electric and small sail planes. That would help a lot on future projets.

I'll be adding my new v-tail sail plane to the gallery as soon as I am done with it. (very soon!) Wing design had too much drag but is at 13OZ! Flies, but will be better after a different wing is on it. Looks like it will stay up forever untill forward speed drops off due to drag and then down it comes with a fast sink rate like there are spoiler up.

Back to the drawing board.

mshjhg@attbi.com

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Old 02-22-2003, 03:38 AM
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Scott

I tried to send you the spreadsheet using the address in your post, but it came back. E-mail me with your correct address and I'll try again

Will
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Old 07-25-2003, 09:40 AM
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Hi WVARN - I would like a copy of that speadsheet too. A friend called me last evening to say that he is building a canard and asked if I know how to calculate the CG. His version will have swept wings and tip fins!
Regards to all
Gordon
from way down here in Wellington, NZ
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Old 07-25-2003, 09:43 AM
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Well it would probably be easier if I included my yahoo email flywellnz@yahoo.co.nz
Cheers
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Old 07-25-2003, 11:31 AM
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The link to download the excel sheet is available on this thread i think..

http://www.rcuniverse.com/showthread...474&forumid=19]
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Old 07-25-2003, 12:33 PM
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Default Canard CG

Hi everybody,

I have some recent experience with a large canard airplane, and found that, regardless of the formula you use, the fact is that it really depends on the lifting potential of the canard.

In the case of the plane I worked on, I found that what "should have" worked didn't... By increasing the span of the canard, switching airfoils, (to an Eppler 197) and increasng the proportion of elevator to canard. (elevator was about 30% of the canard chord) everything worked great. (Andy Lennon's book, "The Basics of RC Model Aircraft Design", available through Model Airplane News, helps a lot.) I found that if the canard chord drops below about 5 inches, you may as well use sheet balsa, as opposed to an airfoil. (Reynolds effect, especially at lower airspeed)

One bit of good news...
Since canard aircraft generally have a wider safe CG range than conventional aircraft, you might find that simply moving the CG a bit aft will help a lot.

When they're right, they're fun!
Happy flying!
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Old 07-25-2003, 04:18 PM
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Default canard CG

Here is the article by Ron Van Putte, June1980, Model Aviation on canard CG and vertical fin sizing

http://www.angelfire.com/scifi2/wiza...es/Canards.zip

It covers the major equations that were used in my spread sheet referenced in the thread above.

Alan
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Old 07-29-2003, 04:04 PM
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KenLitko
 
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Hi Guys,

I currently have a Ducted Fan Canard jet in the early-to-mid design phase. I have a spreadsheet that I put together for calculating static stability. It's in pretty rough shape right now, but I could polish it up and make it available on my website.

Just let me know who's interested.

Ken - www.litkoaero.com
R/C Laser Cutting and Design
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Old 08-02-2003, 12:39 PM
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Default canard CG

CG calculations :

The most efficient way is to build a reduced version of your canard as a glider and hand launch it from a litlle hill, facing the wind.
Is is relevant to check the grass is high enough underneath, otherwise, finding the right Cg may be a very lengthy process...
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