Stable canard glider?

I read that canard gliders are largely unstable. I was wondering if this was true bec. G. Harry Stine seems to accept them as a way to make a Boost glider. I was wanting to build a canard glider-can i build a stable canard?

Thanks,
Julian

Take a look at the Edmonds Aerospace canard gliders. They're great.


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Julian said:

I read that canard gliders are largely unstable. I was wondering if this was true bec. G. Harry Stine seems to accept them as a way to make a Boost glider. I was wanting to build a canard glider-can i build a stable canard?

Thanks,
Julian

Click to expand...

Are they talking about launch conditions or glide conditions? Sometimes a canard can be challenging to get stable under launch---that whole fins in the front thing--in glide mode a canard is one of the most stable designs available. Trimming them out tends to be easy too. In a true canard the two airfoils tend to have different cross sections or at least different AOA , allowing the front wing to stall before the rear wing. Instead of stalling out and dropping a wing or losing control, they tend to mush through a stall---sorta porpoise--. We can mimic this and refine it at our scale for a nice controlled flight. On canard RBG's, the canard usually has a control surface at the rear for vertical trim. This needs to lay flat at launch and kick down upon motor cut off or kick out. Test glide your model several times to determine how far you have to deflect this surface--just get it stable--you'll re-adjust after the first launch and you look at the flight profile. On my timberwolf I took a bit different approach. I used a full flying canard . It took some trimming to get it right and the glide tests were from the third story of my building--fortunately I was close to begin with and no damage was done except for a broken ventral. It flys like a brick ---compare to the old Estes Bomarc--but it's heavy and has a small wing---- --A lighter purpose built canard will fly as well as a standard design-- so fear not my lad . Go and build it !!

Julian said:

I read that canard gliders are largely unstable. I was wondering if this was true bec. G. Harry Stine seems to accept them as a way to make a Boost glider. I was wanting to build a canard glider-can i build a stable canard?

Thanks,
Julian

Click to expand...

Canards can be as stable or unstable as you like to make them. Perhaps you can share the context of the information about their instability.

Most Edmonds canards rely on drastic shift in CG when they spit the motor, but some don't (Ecee). All fly very well.

Ari.

Absolutely, they can be stable. Mi friend Braz had a fleet of what he called "BORG"s - Big Old Rocket Gliders - big foamboard delta wing gliders with canards. The angle of attack was changed on motor eject, causing the transition from boost to glide.