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low wing canard?


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...just wondering...

 

What are the trade offs for high, mid, or low position of the canard relative to the wing? Looks like the Veri easy (long easy) spin-offs have the canard either in line with the wing (mid position) or slightly above the wing (high position). The Q2s/Quickies have the canard below the main wing (poor description in this particular case). What would be the aerodynamic effects of placing the canard below the main wing? It would seem to get the canard

down-wash/wake below the main wing for less interference effects.

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I can't answer these questions, but do know of some almost-canard examples...

 

Posted Image

The Aeriks 200.

 

A larger twin version of the same concept is the Piaggio P180.

 

You could design a plane in X-Plane and compare the characteristics with that of the Cozy model already available, and that might answer some real questions before you had to bring in the aeronautical engineers.

Jon Matcho :busy:
Builder & Canard Zone Admin
Now:  Rebuilding Quickie Tri-Q200 N479E
Next:  Resume building a Cozy Mark IV

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I'd say there are effects having the wing in the wash of the canard, but there may be other factors that have forced the current arrangements.

 

The wing probably can't go any lower without fouling undercarriage and requiring more dihedral for stability. It can't go any higher without blinding the back seat & requiring different fuselage structure to the upper longerons. The canard is as high as is can go without sitting on a strange looking pole, and if it were any lower it would be more vulnerable when lowering the nose for parking.

 

I've read in the info pack about the aft cg testing Nat did on the IV. One of the benefits listed of lopping 6" off the canard span was less interference with the wing.

Mark Spedding - Spodman
Darraweit Guim - Australia
Cozy IV #1331 -  Chapter 09
www.mykitlog.com/Spodman
www.sites.google.com/site/thespodplane/the-spodplane

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  • 1 year later...

I'd say there are effects having the wing in the wash of the canard, but there may be other factors that have forced the current arrangements.

 

The wing probably can't go any lower without fouling undercarriage and requiring more dihedral for stability. It can't go any higher without blinding the back seat & requiring different fuselage structure to the upper longerons. The canard is as high as is can go without sitting on a strange looking pole, and if it were any lower it would be more vulnerable when lowering the nose for parking.

 

I've read in the info pack about the aft cg testing Nat did on the IV. One of the benefits listed of lopping 6" off the canard span was less interference with the wing.

From what I understand from my own research on this topic, you're basically right. The main issue is that the airflow over the main wing must remain the same at all angles of attack to keep the aicraft stable and predictable. With the canard slightly above the main wing, the canard's wake is always above the main wing and never/rarely flows below it. If the canard were below the main wing, the canard's wake during straight and level cruise would be below the main wing which is ok but as soon as the aricraft pitched up to climb or from turbulence, the canard's wake would strike the leading edge of the main wing and interfere with the airflow over the main wing and likely cause some undesireable effects.

 

As far as the undercarriage is concerned, a low or mid main wing is desireable since the gear can be attatched to it relatively simply and retracts can retract inward into the fuselage. If the wing were high, the gear would be attached to the fuselage, have a narrower track, and be a little less stable on the ground.

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Here is one example of high wing canard versus low wing main wing,

RMT Aviation Batelelur. The canard seems to be placed back enough

to ensure that the wake turbulence goes over the main wing.

 

Posted Image

 

http://www.pilotmix.com/index.php?pgid=11&lang=en&maxInfo=158

http://www.rmtaviation.com

 

Mid wing configuration in Cozy/whatever decreases induced drag as far as I have understood.

 

The advantage of low wing back wing would be of course the advantage of Bateleur: the propeller is placed above the main wing so that the main wing protects the propeller from dirt etc. The Bateleur is approved for dirt, grass etc. fields. The another thing in Bateleur is that the canard does not block visibility to any direction as it is behind the pilot's seat.

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Now that's an unusual looking beastie! Detail is a bit lacking on the site, but one shot from the rear shows both ailerons (elevons??) deflected downward. There are elevators (more elevons???) on the canard as well, but they are rather close coupled with the wing so maybe it has both. Maybe they work in opposition like a r/c stunt aircraft??? Maybe they work together like flaps????

 

I wonder where he keeps the fuel?

Mark Spedding - Spodman
Darraweit Guim - Australia
Cozy IV #1331 -  Chapter 09
www.mykitlog.com/Spodman
www.sites.google.com/site/thespodplane/the-spodplane

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  • 2 months later...

Here is one example of high wing canard versus low wing main wing,

RMT Aviation Batelelur. The canard seems to be placed back enough

to ensure that the wake turbulence goes over the main wing.

 

Posted Image

 

http://www.pilotmix.com/index.php?pgid=11&lang=en&maxInfo=158

http://www.rmtaviation.com

 

Mid wing configuration in Cozy/whatever decreases induced drag as far as I have understood.

 

The advantage of low wing back wing would be of course the advantage of Bateleur: the propeller is placed above the main wing so that the main wing protects the propeller from dirt etc. The Bateleur is approved for dirt, grass etc. fields. The another thing in Bateleur is that the canard does not block visibility to any direction as it is behind the pilot's seat.

in a German aviation magazine (I believe it was Flieger Magazine) I read a few years ago that the Bataleur was conceptually designed as a flying wing (i.e. cg far aft, zero-moments section on the main wing) and that the canard wing was merely used for trimming purposes, supposedly to even out payload variations. Interesting concept. Also, an interesting plane, one that just cries for some external stores hardpoints and a paint job to match :)

 

bye

Hans

 

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The advantage of low wing <snip> the propeller is placed above the main wing so that the main wing protects the propeller from dirt etc.

 

----> My opinion, the low main wing doesn't protect a prop from debris any more than a mid wing or a high wing configuration. Prop protection is enhanced when the main wheels are outside the prop arc, and when the engine is mounted higher off the ground.

 

----> My opinion, I'd venture a guess to say that the wing on this plane is built as one assembly, like the glasair. I'd venture to say that the fuselage is attached to the wing(s), like the glasair. I'd venture to say the fuel tank(s) is in the wing carry-through structure under the fuselage. In the glasair (at least the older models), the human salt sacs are sitting SITTING on the fuel tank.

 

The Bateleur is approved for dirt, grass etc. fields.

 

----> I'm not sure how it works in Europe, but that's just marketing hype in the U.S.. All canards here are capable of being flown off grass fields. That doesn't mean they do it well. That may be different for this plane though. If the Cg is truly centered nearer to the wings such that the canard is just for trim, then this airplane may be better at performing off grass.

Wayne Hicks

Cozy IV Plans #678

http://www.ez.org/pages/waynehicks

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if you look at the lower picture of Bataleur on a trailer (the side view), you see that the prop hub is entirely over the main wing, so I can understand, that prop damage on grass or gravel strips is a thing of the past.

 

Also, the main wing's section looks a lot like a 23112, which is a reflexed 23012.

 

bye

Hans

 

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Help me out here. Yes, the prop hub is up high. But as I watch the pictures cycle through on their website, most of the pictures show the prop disk extending behind and below the wing trailing edge. Then there's the ONE picture that pops up showing an almost delta wing planform where prop disk is above and forward of the wing trailing edge. Are they showing different models of the same plane concept?

Wayne Hicks

Cozy IV Plans #678

http://www.ez.org/pages/waynehicks

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But as I watch the pictures cycle through on their website, most of the pictures show the prop disk extending behind and below the wing trailing edge. Then there's the ONE picture that pops up showing an almost delta wing planform where prop disk is above and forward of the wing trailing edge.

Thank goodness it's not just me ... I thought maybe I was missing something, but "one of those things is not like the other one"... I suppose it could be some sort of optical illusion, but me thinks not?

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