Canard Slotted Flapevators?!

[LaGaffe]

IIRC the Rutan VariViggen has flaps on the canard (with the hingeline below the canard) and Lennon uses slotted flap "flapevators" (sp?) on at least one of his canards. But all slotted flaps I could find in Lennon's book are pure flaps, so how do you set up slotted flaps to work as "flapevators" (or pure eleveators)? And would it have any noticable effect compared to plain elevators/flaps on a small-ish model (parkflyer or slightly larger)? Probably a Really Stupid Question™, but …

Cheers

[Andrew McGregor]

Just mix some flap into the elevators.

Depending on the airframe it might do very little, make it completely unflyable, or help a lot in slowing down for landing.

Some aircraft slow down better with spoilers rather than flaps too, so don't forget that option.

[LaGaffe]

It's the mechanical side of things that I'm curious about: every slotted (and fake fowler) flap (with an offset hingeline) I can remember moves down but not up (unlike a plain flap). So what is done? X degrees is neutral/level, less is (for a canard) down, and more is up? This is a stupid question™. What I'm interested in is the use of a slotted flap as a flapevator/elevator on a canard, not as a high lift device on the main wing.

[Andrew McGregor]

Oh, I see... well, you could have two pivots, I suppose, one for the flap extension offset below the surface, and one (that would move with the flap extension) for the elevator. That wouldn't be precisely a mix, but rather a control surface mounted on the flaps. It might be a tad entertaining to figure out the linkage to drive that.

[LaGaffe]

Something like that has crossed my mind, but there must be a simpler solution (and as far as I remember, and it's my memory that is the problem, it is not the way it works on the full scale VariViggen). I guess I should try to find the plans for Lennon's canard.

[Patrick K]

You could just have the entire canard move for elevator control and use the flaps at lower speeds, and/or just mix the flaps to deflect only when pulling back on the stick. Oh, btw, the control surfaces on canards are normally called flaps instead of elevators, just to make things more confusing. :)

~Patrick