Help! Need help with CG of a scratch-built canard

[Dereeki]

I had some extra foamboard laying around, plus some electronics from a FT millenium flerken that I had crashed awhile ago, so I decided to try my hand at designing and building a plane out of these parts. I ended up with a canard design that used 3 servos for all the control surfaces (one for each aileron and one for the full flying canards up front) I am not quite done with the build, as I need to cut out and glue on a vertical stabilizer, and a prop guard on the bottom. I am aiming to us a 1300 mAh 3s battery to power this plane, and as this is the first plane I have designed myself, I have no idea how to calculate the center of gravity. Is there an equation or website I could use for this? or just trial and error?

 

[Mr NCT]

I had some extra foamboard laying around, plus some electronics from a FT millenium flerken that I had crashed awhile ago, so I decided to try my hand at designing and building a plane out of these parts. I ended up with a canard design that used 3 servos for all the control surfaces (one for each aileron and one for the full flying canards up front) I am not quite done with the build, as I need to cut out and glue on a vertical stabilizer, and a prop guard on the bottom. I am aiming to us a 1300 mAh 3s battery to power this plane, and as this is the first plane I have designed myself, I have no idea how to calculate the center of gravity. Is there an equation or website I could use for this? or just trial and error?

View attachment 245291 View attachment 245292

Here's an easy calculator that I used for a LongEZ. Get out your tape or ruler and enter the numbers.

Canard Center of Gravity Calculator

Canard Center of Gravity Calculator. Helps you locate your Canard's Center of Gravity (CG).

rcplanes.online

 

[Dereeki]

Thanks! but what is the 'canard root LE' that it says you can measure from to get the CG?

 

[Mr NCT]

That's the furthest forward point on the canard. Not sure how this will translate for a full flying canard but should get you close.

 

[Dereeki]

Okay

 

[Shurik-1960]

You forgot to glue 2 keels on the sides of the fuselage and your duck will fly steadily. I take a piece of plasticine (by weight of the battery) and attach it with 2 rubber bands to the fuselage of the model. Throwing in the planning, I find the perfect place for the battery and CG.