V-Tail .... uh ..... V-Nose Canard?

[Dave Hederich]

The question is, if a V-tail can replace a standard rudder/elevator in the rear, can a canard-type aircraft with the main wing in the rear function without a vertical stabilizer if the nose-mounted canard is V-shaped instead of horizontal, and if each front control surface worked independently and was tied in with the respective main-wing control surface in the rear? In other words, the front and rear control surfaces would be run off a pair of servos with mixing, so that when a front control surface is down, its respective rear control surface would be up, and vice versa. So left, right, up and down movements are coordinated through all four control surfaces. Is this possible, or am I way off.

[Sparky Paul]

There's a reason arrows have the feathers at the back. :D
If you have a rate gyro on the yaw axis, possibly a vee-canard might work..
With the vertical surface ahead of the c.g., the plane will want to swap ends.

[Dave Hederich]

Ironically, I was thinking about the comparison with an arrow and thinking the rudder function would probably not work up front. OK, throw that out and add a vertical stabilizer at the rear. Would there be any merit to the rest of the concept, i.e. a standard horizontal canard, but split so that each side works independently, with each side of the canard sharing a single servo with the control surfaces on the main wing at the rear? This is not really an original idea, but just trying to apply the concept used by Todd Long's V-tail Tiny of using just two servos to control both the front and rear control surfaces.

http://www.rcmicroflight.com/dec99/tiny03.asp

[Sparky Paul]

As long as you have more side area behind the c.g. than in front, anything can be done.
I use a all-flying vee-tail on my latest large e-plane. Works quite well both as both rudder and elevator.

[Dave Hederich]

>> As long as you have more side area behind the c.g. than in front, anything can be done.

From the shapes of some of the things that people are sticking motors on and flying these days, I was beginning to think exactly that.

[Thomas B]

Burt Rutan used front elevons only on the first version of the Vari-eze. The trailing edge surfaces of the front canard were mixed to be both elevator and aileron.

Poor roll performance lean him to convert to typical canard controls, but it worked ok and something similar would be ok for a model.

i think as long as you had enough vertical tail in the back to keep it pointed in the right direction, you could use a properly mixed forward V canard to steer the model, even with no controls in the rear.

[Ollie]

A major factor in roll control effectiveness is the distance of the control surfaces from the centerline. The fore plane needs to be high aspect ratio (small induced angle of attack) to help it stall before the aft wing. If the span of the fore plane is nearly as great as the span of the aft wing, then the roll control effectiveness will be almost as good as with the controls on the main wing. A configuration close to a tandem wing setup will be best for roll control on the fore plane. Such a configuration has the advantage of the aft wing not having to operate at different downwash angles along its span.