BFoote

Ok. MANY misconceptions of Canard being put forth here:

1) CG, NP, MAC for canard is calculated the same as for a tail dragger or a tricycle gear
Draw the diagram with the lift components and moment in the correct orientation and viola exact same simple equation. Get those signs right. How "touchy" your Canard will be the exact same as on a normal plane.

2) A high pitch moment airfoil is just fine on a canard.
There is 0 need to obtain a "zero" pitch airfoil section. Stating one needs this, doesn't understand point number 1).

3) Vhtc(Vertical tail coefficient) needs to be SUBSTANTIALLY increased over that of a rear empenage design. Rotaryphile posted this up above. This is especially true of dutch roll as posted above. Increase by 50% over a normal Vtc! otherwise you will be rolling your plane right... into.. the .... dirt. Been there, Done that. Ain't no fun. +++75% wouldn't be wrong either! 25% is TOO DANGED LOW. 50% minimum increase from scaled planes guys. If you can SWEEP your wings backwards to increase your Vtc; do so. Draw the diagram. You will quickly see why. A Yaw on a normal plane will have the entire fuselage length as a lever arm and likewise will have MUCH longer time in which to react, visual clues especially to ground based controlers, before a complete flat spin is initiated. On the canard, the visual clues just are not there. Add in most canard designs have very "thin" fuselages already further decreasing side area requisite to counter yaw. On a straight wing with NO sweep, you have 0, nada, zilch, lever arm until your plane is ALREADY IN a spin!

4) Canard aircraft suck at aerobatics unless you go for a completely Unstable setup. Even then they are hampered by the lack of rudder yaw control making them near useless as aerobatic planes. WOO HOO they can roll and loop.

5) A) Main reason no commercial aircraft will ever be built using canard configuration is that at cruise, the horizontal tail already has next to 0 lift on it. Its called wing sweep along with super critical airfoils that at cruise essentially when the whole planeform is added up, creates 0 moment and low drag. Modern commercial aircraft are essentially flying wings already except with a long tube and these additional blobs used for low speed maneuvers. Those blobs are already LOCKED out of the controls at high speed along with all aileron function. Small changes are created by changing the flap over the engine. Slightly larger changes are done via said flaps and tiny portions of the vertical horizontal stab down near the APU. We even were considering using steerable thrust on said APU on the 787, but the cost benefit was just not there when one already had to have partially moveable vertical stabilizer(rudder). It did provide a cruise boost though, though VERY small.
B) See 3 above for landing purposes = horrific drag penalties at high speed with the need for more area, though this could be done by wing tips that "bend up" for landing.
C) Sideslip landings with a canard airplane because of 3) above are VERY hard as the arm length requires far harder throws on the vertical stabilizers = need to be much stronger and likewise the gear needs to be beefier to throw the stabilizer around faster to compensate for the short lever arm to counter act yaw. This equals WEIGHT.
D) You see canard on delta wings(Eurofighter, Boeing Sonic Cruiser). The reasons should be readily apparent to most as delta wing configurations televons pretty much suck for longitudinal control
E) Vertical fins on wings put even higher stress on the wing adding Huge additional weight penalties.

There is one and only one requisite to a stable canard aircraft differentiating itself from others. Canard must STALL first. If main wing stalls before canard your plane falls out of the sky or at best does a loop before you can assume control again. As pointed out above, one can do this by using a thicker camber airfoil for main wing or by picking a different airfoil. You cannot do this via incidence ALONE. I will now discuss why.

Camber increases thickness of airfoil and will generate a lower angle and higher Cl at which it will stall(generally). THE CANARD airfoil therefore MUST be a thicker airfoil generally if you are staying in the same family, but there is one MAJOR caveat especially in RC problems. Reynolds number vastly changes in normal flight(high speed stall conditions) compared to landing. So staying in the same family is for all practical purposes impossible other than the fact that all RC airplanes are so overpowered in the end it doesn't really matter. So, in short, when the wing is at max, the canard is stalled and therefore you CANNOT STALL THE MAIN WING.

For instance you can place slats/flaps on canard as well, but the rotation angle for slats essentially means you cannot use them as the prop just shaved itself a couple inches shorter. Half extended slats on main wing combined with dual flaps on canard and main wing will work. Full slats on main could work as well along with half slats on canard if one wanted to do a real STOL version of a canard. It can be done. If you want to see pictures of such a plane let me know, I can go digging in my files. Video is VHS, so sorry, no can do. Plane easily took off in half the length when flapped and likewise SLOWED down on landing. Get ready for some interesting linkages on your canard though or placing the servo in the small canard.

Ok, why you cannot use incidence alone to prevent main wing stalling before canard. Under static conditions with a piece of paper and a pencil this would take care of the problem, but when doing a yo-yo this incidence difference can vanish. Think Landing here guys where high speed change in input is done. Can blow right past max lift stall angle on canard and go completely into separated flow lift/stall that will still achieve enough lift to increase AoA and stall the main wing. If one has two ways in which said canard stall first, then you are ahead of the game. It is certainly not a deal breaker. For near all RC airplanes, one can simply just add incidence to the canard and it will fly beautifully. You wouldn't see my butt flying in such a plane, but for RC purposes it is fine.