Here is some info about a small canard glider that I designed and built. The model flys ok but I don't consider it a complete success. The good news is that it can fly fast and handle well in windy conditions. The bad news is the elevator control is unpredictable in low speed flight and the glide ratio is worse that I hoped for. I can take this model to the slope when the conditions are light but I would only really fly it for the novelty value.
My impressions based on my experience with this model:
1) For small canard models it can be difficult to get enough elevator authority when relying on canard elevator alone. I think it is important to choose the airfoils and aspect ratios carefully to avoid this type of problem.
2) It was probably a bad idea to use an airfoil with 10.5% thickness for the canard wing. Applying the canard elevator worked like an air-brake. The lift to drag ratio would have been very poor due to the low reynolds numbers for the canard wing.
3) I think that gliders using the canard layout tend to peform better at the upper end of the speed range. This makes them better suited to slope soaring than thermal soaring.
Specs:
Main wing - Span = 112cm (44"), Area = 1745cm^2 (270.5sq"), Airfoil = AG36
Canard - Span = 48cm (18.9"), Area = 406cm^2 (63.0sq"), Airfoil = S7055
Weight = 0.27kg (9.5oz)
Build details:
Introduction (2007-11-23)
Forward wing design issues (2007-11-27)
Wing Construction I (2007-12-17)
Wing Construction II (2007-12-22)
Dihedral and tail fin calculations (2008-01-09)
Forward wing construction (2008-02-05)
Fuselage plan (2008-02-15)
Canard HLG completed (2008-03-02)
Canard HLG flight testing (2008-03-03)