Paul may be right.

Caution, everybody reading this thread. There is a bunch of bad information here, along with some true information. I refer everyone seriously interested in getting these configurations to work right to read all the tested and proven data in Andy Lennon's book, "The Basics of RC Model Aircraft Design". (available through Model Airplane News - http://www.rcstore.com/rs/general/li...id=8&catego=BO I always suggest Andy's book, because his numbers work, and this one book can give you a good understanding of the proper configuration for many types of aircraft that all fly well. Your airplanes can look any way you like, but the aerodynamics and balancing considerations cannot be ignored. Air molecules have not changed, along with modern technology, so although new ideas are great, it doesn't mean you can completely ignore or re-write known aerodynamics. ...And, as modelers, we're a little more handicapped, due to the effects of Reynolds numbers.

• It certainly is possible, and typical, with canard aircraft, that the canard will have a higher loading per unit area than the wing. It's simply because the canard is sharing the lift, and for those of us who have built large canard and foreplane-equipped planes, it's a known fact.

• Many modelers have built small parkflyer-size canard aircraft, and claimed that they flew well, violating some known canard configuration data. I haven't seen any that really do. There is some video going around of a nice electric-powered scale canard aircraft in which the builder says he "likes the way it flies", (I won't mention him, because I like his work, regardless) but during the entire flight, the aircraft is oscillating in the normal canard stall/recovery pattern. It's not performing well, and is stalled at least 50 percent of the time. These crazy concepts with high thrust angles and extreme surface incidences are NOT the answer. What you end up with is a draggy, sluggish, airplane that destroys the whole concept of the canard, which was to reduce drag by sharing the lift and enabling a reduction of the main wing area.

• It is a fact that canard aircraft intended to fly with authority (that is, not "flitty", or "scary" ) need to be set up properly, and somewhat more carefully than a conventional layout. That means that Reynolds numbers cannot be ignored, and to work right, the canard needs a chord over approximately 4.5 inches. (Bigger is better) The canard is providing lift, not just balancing the wing with a download. There is plenty of published data on the airfoils you need, (in Andy Lennon's book, in NACA reports, and in the results of flying tests by those of us who have built them) to find what you need. It just takes a little more homework than your typical sport plane. Once set up properly, the are a joy to fly, and often quite fast.

• If you research those canard-equipped models that work well, you'll see that all these things apply. I specifically have experience with the Berkut/Long EZ at 33% scale, as well as a Piaggio "Avanti" at 1/6th scale, and have built non-scale canard aircraft based on Andy Lennon's notes. When rigged properly, a canard aircraft will have a wider CG range, and good elevator response right up to the stall. Dick Rutan does aerobatics in his Long EZ, for example.

• Airfoils matter a lot with these ships. As one example:
I built a 33% scale Berkut-Long EZ ( http://homepage.mac.com/mikejames/rc.../berkut01.html ) As expected, the scale canard, with the scale "slotted flap"-type configuration, was completely ineffective, and the plane would not rotate. A scale-size canard with an enlarged elevator got the plane flying, but it was struggling to maintain level flight at full power. A "Clark Y", with the chord increased 1 inch (to about 5 inches) was substitued for the scale airfoil, with little improvement. Finally, when the canard airfoil was switched to an Eppler 197, the plane transformed from a "dog" to a "beauty". It had good elevator authority even in the deadstick mode. When you're doing canard aircraft, details matter more than a conventional layout.

Short version of the canard story...

At typical model sizes and Reynolds numbers, they don't work too well. So if you want to build one that really flies nice, build them large. And, when you want reliable answers, be sure and check your information against a known source. (i.e., Andy Lennon, NACA, whatever) Any time you have a public forum, you're going to have people who jump in with their opinions, and that's fine... But it doesn't make them right. "Get a second opinion."