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Old Dec 30, 2010, 12:11 PM
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Lots of parts have been added to the new Duck this week. I will share the dress rehearsal with you.
Charles
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Old Dec 30, 2010, 11:07 PM
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I purchased a Graupner Canary last year while working in Germany, I have the Speed 440 (build in ESC, support for LiPo), prop and adpater. I was hoping to start the build but finding time seems to be hard.

I was wondering about changing some of the build.

Is it possible to have the canards perform both elevator and aileron?
Or is this a bad idea with canard type planes.

Thanks in advance
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Old Dec 30, 2010, 11:11 PM
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It's a span thing. If the span and area of the canard are similar to that of the wing, elevons on the canard might work OK. However, if the span and or area are much less, odds are that ailerons on the canard will probably not be very effective.

The prototype VariEze had elevons on the canard, but Rutan switched to ailerons on the wing for all VariEzes after that first one.
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Old Dec 31, 2010, 07:07 PM
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We had a warm 64 degrees F here this afternoon. Nickchud and I went to the local field and had a great time.
Charles
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Old Dec 31, 2010, 09:44 PM
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Originally Posted by Don Stackhouse View Post
It's a span thing. If the span and area of the canard are similar to that of the wing, elevons on the canard might work OK. However, if the span and or area are much less, odds are that ailerons on the canard will probably not be very effective.

The prototype VariEze had elevons on the canard, but Rutan switched to ailerons on the wing for all VariEzes after that first one.
So I am thinking I need to engineer ailerons on the wing. It was only a thought. The kit call for the canard and rudder on the tips. I was thinking adding ailerons would give me more fun while flying.

http://www.rcgroups.com/forums/showp...07&postcount=1

the above is what is on RC Groups, not much to help but it does show the kit and pictures.

thanks for your reply
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Old Dec 31, 2010, 10:08 PM
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The Canary looks like it should fly well. I would skip the rudder controls and just use ailerons and elevator. Have fun with it and please keep us informed.

Charles
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Old Dec 31, 2010, 10:20 PM
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The Canary looks like it should fly well. I would skip the rudder controls and just use ailerons and elevator. Have fun with it and please keep us informed.

Charles
Will do......simple kit, I have seen videos. That is why I picke it up, it looked like it would be fun, plus its hard to find here in the US.
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Old Dec 31, 2010, 10:43 PM
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So I am thinking I need to engineer ailerons on the wing. It was only a thought. The kit call for the canard and rudder on the tips. I was thinking adding ailerons would give me more fun while flying.

http://www.rcgroups.com/forums/showp...07&postcount=1

the above is what is on RC Groups, not much to help but it does show the kit and pictures.
Not clear from the photo, but it appears there is some dihedral, but not very much. This may or may not be a problem for no-ailerons operations.

There is a common "rule of thumb" that says each three degrees of sweep is about equal to one degree of dihedral. At high angles of attack this is reasonably close to the truth. Unfortunately, the dihedral effect is related to the lift coefficient. At zero lift, the dihedral effect of sweep goes away, and at high speeds and low lift coefficients it's very weak. Your roll authority from rudder alone on that plane at high speeds is likely to be a bit lacking. Adding ailerons to that short, skinny canard is not likely to improve that situation much at all. If you want maneuverability, and you plan to fly fast, you will probably want some ailerons. If all you plan to do is putter around at low speeds, the rudders alone will probably be sufficient.
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Old Jan 01, 2011, 05:27 AM
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Is it possible to have the canards perform both elevator and aileron?
Or is this a bad idea with canard type planes.

Thanks in advance
My Phase3 F-16 and 50" scratch F-100 fly well with "tailerons" only. But they are the full-flying bits, moving the complete stab. In answer to your question, I think it's worth a try. Tex.
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Old Jan 01, 2011, 08:23 AM
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Quote:
I was thinking adding ailerons would give me more fun while flying.
No doubt about it! Rudders are more expendable than ailerons, I think. With both rudders and ailerons you can try a few more moves, such as slow, flat turns.

Good luck with it!

Nick
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Old Jan 01, 2011, 08:29 AM
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Not clear from the photo, but it appears there is some dihedral, but not very much. This may or may not be a problem for no-ailerons operations.
It does have dihedral and the airfoil on the leading edge is simple.

Maybe its better to build as designed. I know it flys just fine, not a rocket but from reading a viewing the few videos it does seem to be fun. I may add ailerons just becuase its the way I fly, I like to control the flight with my right stick and use the rudder for flying straight. I may add ailerons, just enough to smooth out the turns, but not looking for high speed rolls.

Still I think I will have fun either way.

I do love my functioning canards on my Euro Fighter, what a magical way to fly.
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Old Jan 01, 2011, 09:05 AM
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It does have dihedral and the airfoil on the leading edge is simple.
Airfoil will have little or nothing to do with it.

The problem here is that at high speeds you will see a decrease in roll authority because of the loss of the dihedral effect from the sweep. If there is enough actual dihedral to still maintain adequate roll control, then this is not a problem. From the 3-view you posted, it does appear that there is enough dihedral to maintain some reasonable amount of roll control without help from the sweep.

If it isn't, monkeying with the amount of dihedral can open the door to other problems. There is a balance between dihedral and static yaw stability. Too much fin can cause spiral instability, where the plane tries to overbank into a "graveyard spiral" Not enough fin, or too much dihedral can cause dutch roll. Given that canards tend to have marginal yaw stability, the setting for the appropriate dihedral to match it can be a bit tricky. Add the fact that the dihedral effect from sweep varies with angle of attack and lift coefficient, and you could easily end up with a plane that has spiral instability at high speeds and dutch roll at low speeds.

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Maybe its better to build as designed. I know it flys just fine, not a rocket but from reading a viewing the few videos it does seem to be fun.
In science, we always strive to do "controlled experiments" wherever possible. I do find it very disturbing when someone decides to make significant mods to an airplane, without trying the stock design first, has problems related to the mod, and blames the original design for them. That is terribly unfair to the original designer.

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I may add ailerons just becuase its the way I fly, I like to control the flight with my right stick and use the rudder for flying straight.
Human factors studies have shown that we get the best control quality when the primary steering function (roll control in the case of an aircraft) and the primary pitch control (elevator) on the same stick, typically the right stick. Sorry all you "Mode 1" fans, that's what the data says.

In a plane with rudder+dihedral in place of ailerons, the RUDDER is the primary roll control, and therefore the rudder should be plugged into the aileron channel on the receiver.

Of course with a modern computer transmitter there is another option. Mix the aileron channel 100% into the rudder channel, and then you can steer the airplane equally well with the right or the left stick.

Quote:
I may add ailerons, just enough to smooth out the turns, but not looking for high speed rolls.

Still I think I will have fun either way...
That's what matters.
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Old Jan 01, 2011, 10:51 AM
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50 mph, Is that ducted fan power at the rear? The model looks slow and graceful to me. Without speed or air to the prop coming over the wings, rudder control may be best for the Canary. As Don said in effect, the designer deserves credit. The model has appeared on this thread before.
Charles
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Old Jan 01, 2011, 11:03 AM
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Graupner Canary

Rudder control here.
Charles

http://www.rcgroups.com/forums/showthread.php?t=688404
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Old Jan 01, 2011, 11:38 AM
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That Canary is a beauty. I agree with Don about giving the designer credit. IMHO this one was designed for cruising around gently.

However, I'm not one of those people who can let well alone. I like to fly with ailerons+rudder. I built an Aquastar kit a few years ago and I had great success with removing the dihedral and adding ailerons, with just a little differential, ie a couple of mm up on each aileron in the neutral position. As I remember it, the aileron panels were about 80% of the span and 10% of the chord.

If the Canary were mine, I'd do the same.

What could possibly go wrong?

Nick
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