Talk:Canard (aeronautics)/Archive 1

Archive 1

Fake the duck

Strictly technically speaking, the Sukhoi-27 derivatives are NOT canards, because they also have tailpanes. In fact the russians themselves refer to these aircraft as having an "integrated tandem tri-plane" aerodynamics configuration instead. 82.131.210.162 16:48, 12 September 2007 (UTC)

Having tailplanes does not negate the canard aspect. Read the lead paragraph. AKRadecki^Speaketh 16:54, 12 September 2007 (UTC)

An aircraft with a canard AND a tailplane is a "three surfaces" aircraft, not a canard. Plxdesi2 (talk) 20:52, 9 April 2013 (UTC)

I wonder whether term "canard" is really an adjective, as in "canard configuration" and "canard foreplane". In ordinary English a plain "canard" means a distraction or red herring (as in "flying a canard" to distract people from the truth), while ISTR that in French it often means an ill-conceived project or white elephant. Whether the term is ever authoritatively used for a three-surface foreplane is something I don't know, but unless it can be verified I would assume it has not. — Cheers, Steelpillow (Talk) 09:37, 15 April 2013 (UTC)

Piaggio P-180 should be removed from gallery

The P-180 does not have a canard because the front wing does not have any control surfaces on it. Piaggio specifically points this out on their website:

http://www.piaggioaero.com/en/products/aircraft/p180/efficienza.php

"The Avanti II's forward wing (which is not a canard because it has no control surfaces) " —Preceding unsigned comment added by Lindec (talk • contribs) 17:38, 20 January 2008 (UTC)

I object... A new section should be created, and exceptions should be placed there. The new section could be named, for example, "Aircraft not considered canard aircraft". For each entry, a short note describing why it's not a canard aircraft should be included. --Henrickson ^{User talk | Contribs} 21:43, 20 January 2008 (UTC)

I don't think either a special section or deleting the Avanti picture is required. If you read the article: non-moving surfaces are included as canards, so the Avanti's front surface is a canard by that definition. It is fine as it is. - Ahunt (talk) 22:22, 20 January 2008 (UTC)

References

This article is a great opinion essay, but is not of very much value as an encyclopedia article, because it does not cite references, with the sole exception of one general ref at the bottom. I have tagged each para to show where in-line citations are needed. Please do not remove these tags unless they are replaced with footnotes. - Ahunt (talk) 12:11, 8 February 2008 (UTC)

canard aerodynamics

What canards do is to create additional wing tip vortices which are forced towards the main wing due to the canard induced downwash. These vortices re-attach the flow of the main wing near the wing root and offer improved high alpha (high AoA) performance. A good citation of the issue is the book of Klaus Huenecke, Modern combat aircraft design.

As far as I know the canard existence does not increase the blade root drag. The total drag however could be increased due to the existence of the canards as...external elements.

georgepehli (talk) 10:07, 16 May 2008 (UTC)

Contradictions in the pro and con sections

With regard to the canards always/sometimes stalling before the main wings, and the main wings stalling/never stalling. I don't really know, I just noticed, and "must be designed to stall before the main wing" sounds like pure BS to me. Why must it be designed that way? By U.S. law? By some international agreement? Or is just because of good taste of the designer? ;-) --80.134.46.77 (talk) 14:05, 19 May 2008 (UTC)

It is actually mentioned in a couple of books that the canards should be deigned to stall before the main wings. This as far as I know there is no US Law for that (except if we assume that the canards are some kind of terrorists ;-) ). The actual reason is that the canards create pitching moments due to their lift. Therefore if the main wing is stalling and the canards produce lift then the plane gets a highly unstable attitude. This can cause dangerous stall/spin situations e.t.c. However this is not the case in combat aircrafts, since these planes are already designed to be unstable (or...artificially stable) in order to be more manuverable. Therefore I do not think that the comment about the stalling point applies in general. Maybe a special note is needed. georgepehli (talk) 21:40, 19 May 2008 (UTC)

Having the canard stall at an angle-of-attack lesser than that at which the wings stall may or may not be mandatory -- so long as the aircraft’s center-of-gravity is located forward of the center-of-lift. If there is not an authoritative justification for that assertion, my elementary explanation is available here http://www.niquette.com/puzzles/canards.htm#safety. Paul Niquette (talk) 12:15, 30 July 2016 (UTC)

Overuse of fact tags.

"This template is intended for specific passages which need citation. For articles or sections which have significant material lacking sources (rather than just specific short passages), there are other, more appropriate templates, such as {{unreferenced}}." Tagging every paragraph in the article adds nothing but clutter. Gigs (talk) 04:33, 5 August 2008 (UTC)

Fine, works for me. :P Gigs (talk) 04:42, 5 August 2008 (UTC)

Characteristics

I have restored a much-modified discussion of the characteristics of canard aircraft, and have added another reference. Hopefully none of the addition is contentious, so it should not need any inline cites. If any of it does not come up to scratch, it should be possible just to remove those bits rather than the entire discussion, which IMHO is sorely needed. -- Cheers, Steelpillow (Talk) 22:08, 5 September 2008 (UTC)Fixed-pitch canards

I would say at least some of that is quite contentious. For instance:

"In order to provide stability in pitch, a canard foreplane is trimmed to a higher angle of incidence than the main wing. This contrasts with the need to trim a conventional tailplane to a lower angle."

"Due to this high angle of incidence, a canard foreplane produces more lift per unit area than a conventional tail plane (i.e. it is more highly loaded). This allows both the canard and the main wing to be smaller, reducing overall drag and weight, and increasing performance."

Actually most canard aircraft use a completely different airfoil for the canard than the main wing (see The Incomplete Guide to Airfoil Usage - Canards) and these airfoils are selected specifically because the forward one doesn't have to operate at higher drag increased angles of attack in cruise just to stall first. Instead the airfoil selected for the canard will naturally stall at a lower angle of attack than the main wing airfoil and this may mean that the canard is actually set at a lower angle of incidence than the main wing in some cases.

I think the text needs some revisions and definitely needs inline citations to support it. - Ahunt (talk) 23:05, 5 September 2008 (UTC)

I endorse Ahunt's view that Steelpillow's additions need inline citations. Much of what Steelpillow has added looks like little more than popular but scientifically-incorrect views. For example, consider the leading sentence In order to provide stability in pitch, a canard foreplane is trimmed to a higher angle of incidence than the main wing. A canard foreplane may well be rigged at a higher angle of incidence than the main wing, and the converse for a conventional stabiliser, but this has NOTHING to do with Longitudinal static stability! There are various strategies available to aeronautical engineers to increase or decrease the static margin, but fiddling with the rigging incidence of the horizontal stabiliser or canard foreplane isn't one of them. (The rigging incidence is determined more by attempting to have the fixed stabiliser and moveable elevator colinear in cruise at a representative CG position.) If Steelpillow methodically looks for references for each of his additions with a view to finding a citation for each one, he (or she) will find many of his statements cannot be supported and so must be deleted. Dolphin51 (talk) 08:23, 6 September 2008 (UTC)

Fair enough, I should perhaps have qualified the statement about angle of incidence in some way or discussed angle of attack instead, but I was trying to keep the introduction simple and clear: the theory of canard design gets quite complicated quite quickly. I disagree with Dolphin51's idea that the relative angle of incidence has nothing to do with stability. I recall a prototype (forgotten its name) from the 1970's which for simplicity employed three identical wing pieces for left and right main and whole fore planes. To provide longitudinal static stability, the foreplane was rigged to a higher incidence than the main wing. Of course the center of gravity needs adjusting accordingly, but that is not the point being made here. And yes, many designs modify the canard aerofoil section for this reason among others - I also mention this later on, but perhaps it should be given more prominence. I suppose one's approach depends on whether one is considering how to fiddle the airfoil to stabilise a given planform, CG and incidence, or how to fiddle the planform, CG and incidence to accommodate a given aerofoil. Perhaps this is why there seem to be two competing strands of popular "folkore" - one that canards are inherently stable and safe, and the other that they are inherently vicious little brutes. The truth is far more complex. I have tried to touch on this issue in a non-contentious way, evidently without success. Perhaps some inline cites might be necessary if things get too heated, but I think it better to avoid contentious areas of opinion as far as possible and stick to well established principles to be found in the referenced literature (maybe I may not have done as well there as I thought either). Anyway, I thought the important thing was to get something up there for people to improve on - nobody is going to write a perfect and accessible overview of canard theory first time round! Go to it. -- Cheers, Steelpillow (Talk) 13:35, 6 September 2008 (UTC)

Hi Steelpillow. Thanks for the prompt reply. The Wikipedia approach is to begin with that information for which you have citations, and hope that other editors fill in the gaps with verifiable information of their own. The approach whereby one editor writes down what he believes to be true in the hope that other editors will find suitable citations is discouraged. WP:VERIFIABILITY contains the advice that The threshhold for inclusion in Wikipedia is verifiability, not truth. You have given as one of your references Mechanics of Flight by A.C. Kermode; but without quoting an edition number or chapter or verse. I have the eighth edition open in front of me. Admittedly this is now an elderly edition, but the Index does not mention the word canard. In Chapter 5, Level Flight there is a very brief mention of tail-less and tail-first aeroplanes, including a photograph of the experimental retractable fore-planes on the Dassault Mirage Milan, but little more. If you are planning to use Kermode as a source for your information it will be important to quote edition number, chapter etc. I suggest you delete all your information for which you can't provide an in-line citation, and then proceed to add information with citations. Regards. Dolphin51 (talk) 06:58, 7 September 2008 (UTC)

Verifiability is necessary, as you say. But that is not to say that sometning must be verified before it it written up. WP:POLICY states:

Editing policy

Improve pages wherever you can, and don't worry about leaving them imperfect. It is advisable to explain major changes.

and Wikipedia:Editing policy expands on this.Fixed-pitch canards

Your criticisms make it clear that some of my "facts" are questionable and that my attempts at netural POV were not very successful. My hope is merely that others will take the section from here and improve it, rather than delete it all wholesale.

As for citations and references, I'll delete Kermode. My memory must have let me down: I know I read most of that stuff somewhere, but my (very old) reference books are all in storage, and it may not be in any of them anyway. So unfortunately I cannot add sensible references at this point. (Instead, I have tried to include example aircraft which illustrate the point). Nevertheless, I think there should be enough non-contentious material to allow some sort of discussion to remain, and sooner or later someone with access to better references will come along.

Meanwhile, if you see a way to make improvements, please feel free to attack the section with vigor - you will not offend me. I'll see if I can think of some way to accommodate your technical POV, too. -- Cheers, Steelpillow (Talk) 10:22, 7 September 2008 (UTC)

Thanks Steelpillow. The history of Canard (aeronautics) shows that by 13 July 2008 the article had comprehensive information about the characteristics, advantages and disadvantages of tail-first configurations, but all of that information was unsourced. Every paragraph carried a "citation needed" tag. On 5 August 2008 there was a mini edit-war and all the unsourced information was finally deleted, leaving the article in the state you found it a week ago. Clearly, there are lots of views and ideas out there about canards, but none of us has been particularly successful in finding authoritative sources to support that information. I will do what I can to find authoritative sources and begin re-building the article over the coming week. Dolphin51 (talk) 01:23, 8 September 2008 (UTC)

Well, I am disappointed that you felt the whole thing had to go. But I'm not going to start another edit war. At least, I hope the structure I gave it was a better starting point than the previous one. Especially, the close coupled canard delta is an important canard configuration, given its prevalence among modern combat aircraft, so that discussion needs to come back eventually. -- Cheers, Steelpillow (Talk) 19:57, 8 September 2008 (UTC)

The concept of the so-called close coupled canard can be retained. I have Aircraft Design: A Conceptual Approach by Daniel P. Raymer (AIAA Education Series, New York, NY) and he distinguishes between the lift-canard and the control-canard. In WP, citations are everything. The control-canard mostly operates at zero lift coefficient and its role is to generate beneficial vortices and downwash onto the mainplane for the purpose of boundary layer control at high alpha. The control-canard is seen in high performance combat aircraft. The lift-canard mostly operates at a significant lift coefficient and is seen in low performance aircraft such as the Rutan Vari-Eze. Dolphin51 (talk) 23:12, 8 September 2008 (UTC)

Fluid dynamics as well?

This article is linked from the Sea_Shadow article. Could someone please explain how it applies to water vessels as well? Aar☢n Bruce^Talk/_Contribs 21:20, 24 February 2009 (UTC)

I checked that - just a linking error I suspect, it isn't really the right place to send readers for more info, is it? - Ahunt (talk) 21:39, 24 February 2009 (UTC)

I think they meant to link to Hydrofoil. --McSly (talk) 22:53, 24 February 2009 (UTC)

Hydrofoil would make sense. Dolphin51 (talk) 01:44, 25 February 2009 (UTC)

Lifting-canard

On 4 April 2009, user 208.103.75.112 added three paragraphs under the sub-heading Lifting-canard. None of the additional information was supported by a reference or an in-line citation.

I believe most of this additional information reflects a popular understanding of lifting-canards, but unfortunately it contains a fair amount of hangar talk and it is not sufficiently accurate for Wikipedia. I will shortly give my reasons for believing it is not accurate.

I will delete the information added by 208.103.75.112. I have no obection to someone restoring some or all of that information, provided it is accurate and supported by a suitable in-line citation.

Here is my analysis of the additional information:

An added advantage of a lifting-canard is the prevention of stalls.
COMMENT: The canard configuration is not intrinsically immune to high-alpha stalls. It can be designed to be spin-resistant, but so too can the conventional aft-tail configuration. A poorly designed or operated canard aircraft can be just as vulnerable to the high-alpha stall as a conventional aircraft. In some respects, the canard configuration requires greater attention to detail to protect against poor low-speed handling characteristics. For example, the upwash from the vortices which trail behind the canard cause the angle-of-attack on the outboard regions of the main wing to be higher than it is on the inboard regions. This promotes wing-drop at high angle-of-attack and so necessitates special steps to guard against wing-tip stall.

The article’s opening seems to emphasize military purposes for the canard (“…to reduce the main wing loading, to better control the main wing airflow, or to increase the aircraft’s maneuverability, especially at high angles of attack or during a stall”). Inasmuch as a civilian aircraft devotes almost its entire lifetime aloft in level flight, the lifting canard’s support for increased useful load should not be ignored. There must be plenty of authoritative references that make that point. If not, have a look at http://www.niquette.com/puzzles/canards.htm#safety. Paul Niquette (talk) 12:18, 30 July 2016 (UTC)

In a conventional aft-tail design, it is possible for the pilot to place the aircraft in an attitude in which the main wing is no longer producing lift (most commonly by attempting to fly at too steep of an angle). This is a safety issue -- to recover, the pilot must "push forward" to dive and thus increase airspeed, which is both a counter-intuitive action and one which requires enough altitude from which to descend to recover enough airspeed for the main wing to begin flying again.
COMMENT: The editor’s objective here is unclear. In a canard aircraft the pilot must also push forward to increase airspeed. If pushing forward to avoid low-speed handling problems is counter-intuitive in an aft-tail aircraft, it is also counter-intuitive in a canard aircraft.

Many lifting-canard aircraft are designed such that the canard is set at a higher angle of attack than the main wing.
COMMENT: To achieve longitudinal static stability, I would say that all lifting-canard aircraft must operate with the canard at a higher angle-of-attack than the main wing. However, this is achieved by appropriately specifying the aft center-of-gravity position. CG position and fore-plane/tail-plane angle are tied together by the need for the aircraft to be balanced in pitch during flight. When the designer specifies one, the other follows automatically. It is a simple matter to specify CG position and then determine what fore-plane/tail-plane angle is needed to support that position. It would be much less practical to specify fore-plane/tail-plane angle and then determine what CG position is needed, because the result would most likely be an impractical loading case.

It will thus stall before the main wing, and the nose will drop back to a safe attitude.
COMMENT: In Aircraft Design: A Conceptual Approach, Daniel Raymer says: … a canard can be made to stall before the wing by making it a very high-spect-ratio surface. This prevents the pilot from stalling the wing, and is seen in several canarded homebuilt designs. (Page 56, fourth edition.) In this book, Raymer is identifying the way choice of aspect ratio is important in designing a canard aircraft with good low-speed handling characteristics. Raymer is fully aware that the canard configuration is not intrinsically spin-resistant, and must be designed carefully if it is to have good handling qualities.

If the pilot attempts to hold the nose up, a periodic (but generally safe) "nose bob" effect may occur.
COMMENT: Yes, in a well-designed and correctly operated canard, if airspeed is reduced slowly ( eg one knot per second) the aircraft will display a minimum steady-flight speed rather than a stall. Most aft-tail aircraft at forward CG position also display a minimum steady-flight speed rather than a stall when airspeed is reduced slowly. However, when the approach to the stall is accelerated (eg three to five knots per second) the result may be different, regardless of whether the aircraft has a fore-plane or a tail-plane!

In some aircraft, such as the Cozy MK IV, testing for this effect is part of the standard flight testing procedures.
COMMENT: What standard flight testing procedures does the editor have in mind?

However, this effect also requires a specific aircraft center-of-gravity (CofG) range, specified by the manufacturer/designer. Pilots must take care to ensure the aircraft is always within the specified range. Otherwise, under certain conditions, a main wing stall is possible.
COMMENT: All this is universally true. It is just as true for aft-tail aircraft as for canards, except that main-wing stall is usually not a problem for aft-tail aircraft.

In a lifting-canard, this often leads to a "deep stall" from which recovery is difficult or impossible to Fixed-pitch canardsachieve.
COMMENT: If it happens often there would not be many lifting-canard aircraft remaining! I think the expression deep stall used here is very different to the deep stall that troubles designers of T-tail jet aircraft.

Dolphin51 (talk) 02:45, 5 April 2009 (UTC)

D51: Good analysis. I agree that most of it is WP:OR or just plan apocryphal. I tagged it for refs and had it on my list to cut it all unless refs were cited within a few days. You saved me the work! - Ahunt (talk) 12:47, 5 April 2009 (UTC)

Alternatives

Fixed-pitch canards Chines and leading edge extensions are often used as alternatives, but the current article doesn't say much about this. Can somebody drag up some refs for the tradeoffs please? Hcobb (talk) 21:33, 1 August 2009 (UTC)

The GAO should have a report somewhere that states that canards would have more cost effective on the F-22 than LERXes, and how much using LERXes cost the US taxpayers. P: - BilCat (talk) 22:12, 1 August 2009 (UTC)

Restructuring

I'd like to do some significant restructuring:

• Discuss lifting canards before control canards, since that was the historical development.
• Add a third class for ride control, as in the B-1 Lancer.Fixed-pitch canards
• Sub-divide the list of examples into the three classes.

Any objections or other comments? -- Cheers, Steelpillow (Talk) 12:33, 14 August 2009 (UTC)

Historically the key problem with this article has been uncited and speculatory text, so I would say as long as you have refs then by all means do so! - Ahunt (talk) 19:07, 14 August 2009 (UTC)

Is linking to an existing article good enough, if that article already has a decent bibliography? I do not intend to add any information that is not already present on Wikipedia. In fact, all but the phrase "Active vibration damping" is already in this article. -- Cheers, Steelpillow (Talk) 20:14, 16 August 2009 (UTC)

Each article really needs its own footnoting. It doesn't help readers if the refs are elsewhere, as they can't assess the accuracy of the article and also the refs may be removed from the other article or even the article deleted! You can cheat a bit and copy refs over, however. - Ahunt (talk) 22:18, 16 August 2009 (UTC)

OK I had a go - durned login session timed out and logged it as an IP edit. The B-1 Lancer article does not cite a specific reference for active vibration damping, but it is a well-enough known feature that it is surely covered in the docs given as general references - none of which I have, so I can't copy one across as a specific ref here. Hope it's acceptable to just link the Lancer article as my "reference". -- Cheers, Steelpillow (Talk) 21:12, 19 August 2009 (UTC)

Fixed-pitch canards

How should we classify fixed-pitch canards, as on the Atlas Cheetah, IAI Kfir and so on? Their direct contributions to stability and overall lift are negligible, so they are not true lifting-canards. Nor do they have any movable surface for conventional pitch control, so they are not control-canards as described here. And they are certainly not active vibration dampers. Their function is more akin to leading-edge slats, to direct air downwards over the wing when flying at high angle-of-attack, reducing turbulence and hence leading to improved lift and drag. For the time being I have classified them as control-canards, on the basis that many movable control-canards also act in this way, while lifting canards generally do not. Or, do fixed-pitch canards really represent a fourth class of canard? -- Cheers, Steelpillow (Talk) 11:44, 23 August 2009 (UTC)

I suggest fixed-pitch canards deserve their own paragraph, and their own explanation modelled on Steelpillow's summary above. Dolphin51 (talk) 12:28, 23 August 2009 (UTC)

I agree - they are more like remotely installed leading edge devices! - Ahunt (talk) 12:29, 23 August 2009 (UTC)

How much can we say without formal references? In the absence of such for an appropriate descriptor or technical appraisal, can we call them "fixed-pitch canards"? I'm thinking to tile the subsection as such, and be careful to avoid a formal descriptor in the text, along the lines of "Canard planes of fixed pitch are used by some aircraft. The canards surfaces deflect air ...". It seems unreasonable to avoid describing a visible design feature because we don't yet have any references (see WP:IAR and related policies), but will the citation police agree? -- Cheers, Steelpillow (Talk) 13:13, 23 August 2009 (UTC)

Let's invent less and use the actual industry terms like "close-coupled canards". Canards do exactly three things.

• Some shift center of pressure by acting as tiny wings.
• Some are close-coupled with the main wings to massage the airflow.

and

• Some use some or all of their surfaces as driven control surfaces for moving some or all of the aircraft.

Hcobb (talk) 14:54, 23 August 2009 (UTC)

Now there's a perfect example of the citation police problem. Last September I added a section on close-coupled canards, only to have it reverted by ardent citationists because I didn't have a reference to hand. Do you have one? That would be wonderful. -- Cheers, Steelpillow (Talk) 15:45, 23 August 2009 (UTC)

"Many current aircraft designs for future air-superiority fighters incorporate close-coupled canards. This relatively new configuration has been developed, principally, through wind tunnel testing that indicates a favorable aerodynamic interaction between the canard and wing at high incidence. The favorable interaction creates a high total lift capability and reduced trimmed drag, leading to important gains in combat effectiveness." http://www.sageaction.com/aircraft_testing1.htm#JetAircraft

Of course The Force gave up on canards when they went all stealth, but the Europeans never venture out where hostile radars might illuminate them, so they don't care. Hcobb (talk) 13:45, 25 August 2009 (UTC)

OK I've done my best. The division of the examples into control and close-coupled types may need attention, especially as some types such as the Dassault Rafale are described as "active close-coupled", meaning that they act as control-canards during normal flight and as close-coupled typed at high a-o-a, so really need to go in both lists. For some types, I have no idea whether they fit in either or both categories, but have made educated guesses. -- Cheers, Steelpillow (Talk) 19:15, 25 August 2009 (UTC)

Concorde

Concorde has small strakes on the forward fuselage, whose purpose (IIRC) is to reduce buffet at high a-o-a by stabilising the small vortices shed by the fuselage. I'm not sure if they also act as close-coupled canards; Concorde relies on larger wing-generated vortices to direct the airflow at high a-o-a, however stabilising the fuselage vortices does help stabilise the wing vortices too. Do they really count as canards anyway, or are they just too small? -- Cheers, Steelpillow (Talk) 19:26, 25 August 2009 (UTC)

I suggest Concorde's strakes are vortex generators rather than canards. They are in the same class as the strake on some engine nacelles such as on Boeing 737 with CFM56 engine, visible here. Dolphin51 (talk) 22:44, 25 August 2009 (UTC)

User:Dolphin51: I think you may well be right about that. In which case perhaps they should be mentioned in this article for sake of completeness with a link to Vortex generator. - Ahunt (talk) 22:46, 25 August 2009 (UTC)

http://books.google.com/books?id=bs9EbQ6pdRQC&pg=PA25&lpg=PA25 "are there to reduce side slip" Hcobb (talk) 23:12, 25 August 2009 (UTC)

Canards and stability

Hi,

This topic is being discussed here. I'd be grateful if you could help us reach a consensus. — Cheers, Steelpillow (Talk) 18:53, 19 May 2012 (UTC)

I have read the debate and left my comment. (My diff.) Dolphin (t) 12:57, 20 May 2012 (UTC)

Moved and getting urgent

Hi again,

The discussion has now moved to Talk:Stabilizer (aircraft) and is rapidly turning into an edit war. Please help reach consensus! — Cheers, Steelpillow (Talk) 14:28, 3 June 2012 (UTC)

Unlike a conventional tailplane

"in order to achieve longitudinal stability a canard surface is trimmed to increase lift as speed increases. This equates to a negative coefficient for trim drag." - GraemeLeggett These two sentences don't make any sense. They may have made sense in some context, but that context is not represented here. "Unlike a conventional tailplane" is an oxymoron. A canard is a conventional fore plane, not an unconventional tailplane. "Tail" planes go on tails.

"in order to achieve longitudinal stability a canard surface is trimmed to increase lift as speed increases", again this statement makes no sense in itself. If you can explain what it means, knock yourself out, but don't put it in this article just because you found the words written down somewhere.--Stodieck (talk) 07:16, 28 May 2012 (UTC)

No, "Unlike a conventional tailplane" is not an oxymoron, it is a tautology. Clancy may be showing his age, but the sentence makes perfect sense to me as it is. By all means find a clearer and more detailed way of making the point about achieving stability and negative trim drag, or even come up with a more current reference. But for now this one meets Wikipedia's standards. And no, you should be able to tell that the words are not lifted direct from Clancy because there are no quotation marks, so I have no idea what might have given you that idea. But don't just delete what you don't understand. — Cheers, Steelpillow (Talk) 19:51, 28 May 2012 (UTC)

In following this discussion I have to add the the offending para makes perfect sense to me as well and the ref seems reliable and acceptable to Wikipedia. - Ahunt (talk) 20:01, 28 May 2012 (UTC)

Sorry, no matter how a canard is trimmed it doesn't produce longitudinal stability. Nor does the trim of tail plane.. I understand the situation quite well. The statement was removed because it is not properly cited and not verifiable. I have no way of reading the original text and the original text is not quoted. The sentences do not contribute to the article, and they are not needed. And no, a canard is not a type of tail plane anymore than a duck is a type of truck. --Stodieck (talk) 20:21, 28 May 2012 (UTC)

Doesn't this all only apply to lifting canards at best? Hcobb (talk) 21:21, 28 May 2012 (UTC)

Clarify

The General Characteristics are both negative and makes me wonder why this design was used for the Eurofighter Typhoon. There must be something good about it. The Eurofighter Typhoon article seems quite impressed with the design even the handling. QuentinUK (talk) 14:35, 4 December 2012 (UTC)

Added a pair of advantages to that section, but it really does depend on the type of canard. Hcobb (talk) 16:46, 4 December 2012 (UTC)

Historically it has been hard to find adequate references for this article, so it has become biased towards whatever points could be referenced. IMHO that has not made for a well-balanced article, but I live in hope (grin). — Cheers, Steelpillow (Talk) 21:12, 4 December 2012 (UTC)

Putting canards on the outside of aircraft is exactly like filling the aircraft with lifting gases. It's a solution that's been in search of the right problem since the earliest days of aviation. Every generation or so a new batch of bright young engineers pop up uneducated in the problems faced the last time this was tried and they do it for a while until they learn better. The most recent replacement for the canard is the chine. I suspect that the next time canards are replaced it will be with airframe morphing. Hcobb (talk) 00:39, 5 December 2012 (UTC)

What, you'd put them on the inside? ;) — Preceding unsigned comment added by Steelpillow (talk • contribs)

Remarks 14 april

Canard has two meanings : canard configuration and canard surface. I propose "canard aircraft" (or canard design) for the concept, and "canard" alone for the foreplane.

Better to avoid the expression "canard wing", to prevent confusion with (main) wing. So, in the text, canard alone means the foreplane, and wing means the main wing.

In "General characteristics", the second paragraph "However a canard design tends to be etc..." applies ONLY to the VariEze model 31, fitted with elevons onto the canard (Ref : Nasa TM 88354). As this concept was inefficient, it was soon discarded. So the generalized comment has to be modified or deleted. Plxdesi2 (talk) 20:18, 14 April 2013 (UTC)

Active vibration damping types

May those tiny surfaces be called "canard" surfaces ? it rather look like a special kind of vortex generators. Do you agree ?Plxdesi2 (talk) 16:18, 17 April 2013 (UTC)

Jones (U.S. Bombers, Aero, 1974) calls them canards or, to be precise, "canard" vanes (his quote marks). Googling "B1 lancer canard" gets me just under 800,000 hits. They are not vortex generators and do not serve any direct aerodynamic purpose in the usual way, but are active surfaces which apply a variable lift force to counteract mechanical forces in the forward fuselage during turbulence, providing a smoother ride and so reducing fatigue on both the crew and the airframe. They do happen to be rather small, I guess to ensure that their destabilising effect remains insignificant at all times. — Cheers, Steelpillow (Talk) 18:39, 17 April 2013 (UTC)

In WP : "Rockwell included small triangular fin control surfaces or vanes near the nose on the B-1. The B-1's Structural Mode Control System rotates the vanes automatically to counteract turbulence and smooth out the ride." WP do not call them "canards".

If these surfaces provide a smoother ride in turbulence, are they "destabilising" ? it seems they do not act as canard pitch control surfaces, just see their surfaces ! but they act on the local flow in order to modify the lift of the long-nose fuselage. So, it seems that they act as a local flow control device (like VG, fences, vortilons), a lot more sophisticated but not as canard (lift or control) surfaces, subject of this article. Plxdesi2 (talk) 15:13, 18 April 2013 (UTC)

These fin control surfaces act on the lift as well as canards : ok, they are canard surfaces. VG (on Rutan canards), or VG on wings act on the lift too (increasing the max lift) ; are the VG called "canard surfaces" or "wings" ? Plxdesi2 (talk) 15:37, 18 April 2013 (UTC)

On the Viggen, one of the canard surface's main functions is as a vortex generator. I guess that like many things, the design options vary continuously from one function to another - the point at which one says, "this has now changed function. It was a VG but is now a canard (or vice versa)" is pretty arbitrary. The Lancer is a bit different in that most small surfaces are intended to change the aerodynamic performance of the aircraft in some way but the Lancer's canard vanes are not - their purpose is to change the structural forces in the forward fuselage - so one cannot compare them directly with the way those other surfaces are named. WP may not call them canards, but Jones does. So we should accept that - unless someone finds a more authoritative reference saying that Jones is wrong to do so. For example there are many definitions of a "canard"; if the most authoritative ones conflict with Jones' usage, that would make him less authoritative. Many of these questions seem to boil down to, "So what exactly is the definition of a canard?" I am not sure we have universal agreement on that. I don't know if that helps, I'm beginning to confuse myself now. — Cheers, Steelpillow (Talk) 20:24, 18 April 2013 (UTC)

The Viggen canard is a true lifting surface, because of his area and position relative to the wing. His secondary trim role (elevators) and vortex effect on the wing lift are also a lift function. So it's first a lift-canard surface.

"but (the small fins) are active surfaces which apply a variable lift force to counteract mechanical forces in the forward fuselage during turbulence"

I think, according to their areas, that these small fins do not apply any significant lift forces but modify the flow (the "2 alpha flow") around the Lancer long nose, in order to smooth the variations of the own fuselage (destabilising) lift in turbulent conditions. Imo, they act as VG do, in modifying a local flow condition. Being controlled, are they control pitch surfaces ? If we consider that the fuselage is a lifting surface, yes, they have a role in fuse lift. Accordingly, we have to consider the B1-B as a three-surface aircraft. If we do not agree with that, we consider the fuse lift is not significant, so the small fins are neither lift nor control (canard) surfaces. Generally (except wing bodies), fuses are not considered as lifting surfaces (although higly destabilising). Anyway I agree that the final answer is not easy ; I would like to consider these devices not as canards but as minor features "looking like small canard" acting on fuselage lift. Plxdesi2 (talk) 08:32, 19 April 2013 (UTC)

I do not know if you are right about the vanes modifying the airflow. But the key point is that their intended action is confined to the forward fuselage and not like a VG which is intended to affect the gross aerodynamic behaviour of the aircraft (e.g. by delaying the stall). So I see it as definitely not a 3-surface design or a VG. Their control function is similarly local, so they are not flight control surfaces in the usual sense either. Are they canard surfaces? That depends on what we mean by a "canard". If we mean "tail-first" then these vanes are not canards, if we mean "forward horizontal(-ish) plane significantly smaller than the main lifting surface" then they are, or if we mean something in between then we must turn to authoritative references to decide for us. That's where Jones is so far the only voice mentioning canards in the present context (though like so many authors, he does not define "canard"). — Cheers, Steelpillow (Talk) 09:38, 19 April 2013 (UTC)

Postscript: I seem to recall reading that the vanes were originally supposed to be larger, but had to be shrunk in order to stop them interfering with (destabilising) the overall aerodynamics. But never trust my memory. — Cheers, Steelpillow (Talk) 09:42, 19 April 2013 (UTC)

Are these small fins "forward horizontal (-ish) planes " ? forward, sure ; but "horizontal-ish", being 35° down angled surfaces, possibly yes/no. Amazingly too, Jones called the Curtiss XP-55, with 0.10 S canard area, lifting about 0.15 weight, "not a true canard", and these tiny 0.003 S (or 0.015 Stail) "canards vanes" (with S the wing area). Ok for "vanes", that is their function (deflecting/modifying only the local fuselage flow, as your postscript adds). "Forward vanes" would be more neutral than "canard vanes" that would be interpreted in this article as wing surfaces.

"As placed in front of the plane and acting on the lift, these surfaces are often described as "canard surfaces"." Is "often" meaning Jones only or others too ? Plxdesi2 (talk) 13:26, 19 April 2013 (UTC)

The talk about "Concorde" is consistent with VG / strake fonction, controlled or not. Concorde "petites ailettes" (small wings) serve as VG at high AoA, to increase the directional stability (there was a lack of yaw stability beyond 18° AoA). In Les avions de Transport modernes et futurs, André Peyrat-Armandy, Teknea. Plxdesi2 (talk) 13:47, 19 April 2013 (UTC)

Flight "B-1 Roll-out" in 1974 refers to them as "canard fins for ride control". GraemeLeggett (talk) 14:53, 19 April 2013 (UTC)

Canard foreplane stability

(talk moved from Stabilizer)

"This can be achieved with a combination of factors, including:

• 1 by making the lift slope of the foreplane less than the lift slope of the main wing[16];
• 2 by giving the foreplane a smaller lever arm about the center of gravity than the main wing;
• 3 by making the lift coefficient slope of the foreplane less than that of the main wing etc..."

Please notice :
1 et 3 are the same, 2 is wrong : this is a parameter upon balancing considerations, not a stabilisation one. Plxdesi2 (talk) 14:22, 17 April 2013 (UTC)

No.

• 1 and 3 are the same only if the wing and canard are of the same surface. Increasing the CL of a small canard and large wing by (say) 0.5 will yield a different change in the vertical force values.
• 2 is about CG position. Increasing the canard lift by 2 Newtons and the wing lift by 4 Newtons will not have the same effect depending on their position relative to the center of gravity. This is usually represented by the notion of tail volume coefficient (Vt in our article, Vh in Phillips).

Balancing (trim) and static stability are both affected together by lever arm distances.

Have a look at equation 4.3.30 in Phillips 2010 (2nd ed) and you will see that there are many more terms than the two lift coefficient slopes that can make for a negative pitch moment coefficient slope... I am not saying we should list them all but only concentrating on the lift slopes only is a step in the wrong direction. Ariadacapo (talk) 16:22, 17 April 2013 (UTC)

about 1 and 3 : as "lift slope" means "lift coefficient slope" (dCl/da), what is the difference ?

about 2 : the lever arm of the canard is one of many parameters affecting the trim. If you decrease this distance without modifying anything else, you increase the wing loading of the canard, and his Lift coef too : as a result the lift slope of the canard is (or may be, it depends of the airfoil) lower : that is the same that 1 and 3. Just a remark, if the canard lever arm is lower than the wing one, the aircraft is no longer a canard, but a tandem.

Another possibility, different from (1-2-3) is to decrease the aspect ratio of the canard (see Hoerner/Lift, page 11-30, aspect ratio), with more lift induced drag and possibly a higher angle stall than the wing.

A stabilisation parameter is the power effect. In case of canard pusher propeller : "the power-induced flow clean up of the wing trailing edge" (Nasa TP 2382, VariEze) increases the wing lift slope. Conversely, a propeller located ahead of the canard (increasing the lift slope of the canard) has a strong destabilising effect (Tandem aircraft PAT-1, Nasa TM 88354).

Rutan solution is high aspect ratio canard, higher Lift coefficient (the wing loading of the canard is between 1.6 to 2 times the wing one) AND a canard airfoil the lift slope of wich is non linear (nearly flat) between 14° and 24° (Nasa TP 2382, VariEze).

The lift slope differential seems to be the main stabilisation parameter. Plxdesi2 (talk) 20:12, 17 April 2013 (UTC)

Clarification of statement?

Currently the article says: "However, the foreplane downwash effect on the wing lift distribution is unfavorable for the canard concept, so the difference in overall induced drag is actually not obvious, and depends on the details of the configuration"

Does this statement hold true for all distributions of the canard and main lift surface? I'm thinking of designs where the two are for instance set low and high respectively on the fuselage (Rutan Quickie, B.39 Libellula)? Does the sentence need clarification or qualification? GraemeLeggett (talk) 07:30, 21 April 2013 (UTC)

With a high-set main wing and a low-set canard, any downwash effect is likely to be minimal or insignificant. Conversely, where a lifting-canard is close-coupled, the downwash at high angles of attack can be the main reason for having it at all, because the downwash is primarily a vortex which re-energises the wing airflow to improve lift and delay the stall, as on the Saab 37 Viggen. So there is definitely some clarification to be done. Can I suggest modifying the sentence to, "However, in normal flight the downwash from the foreplane can affect the main wing lift distribution unfavorably, so the difference in overall induced drag depends on the details of the configuration and may not be obvious." — Cheers, Steelpillow (Talk) 11:16, 21 April 2013 (UTC)

That sounds about right. Couldn't see Rutan, or the masters of designing and building an aircraft in a few weeks getting caught out on obvious wing interference effects. GraemeLeggett (talk) 13:57, 21 April 2013 (UTC)

"With a high-set main wing and a low-set canard, any downwash effect is likely to be minimal or insignificant."

Anyway their respective vertical position, downwash effects of lifting foreplanes are significant  : one need a vertical gap equivalent to the span to avoid any deflexion effect (as for the ground effect). In Nasa TP 2382, the VariEze canard foreplane was tested in high (normal) and low position, without significant differences : "the canard in the low position had little effect on lift, pitching moment and trimmed drag.". At high AoA, the low canard deflexion effect on high wing may induce "most interference" .

About Viggen or close-coupled canards, the primary effect of canard downwash is to reduce the AoA and the lift of the main wing behind, preventing the stall of the central part of the wing, but conversely increasing the AoA of the flow outboard of the canard tip (with a local upwash peak just at the canard tip level, then an upwash decrease towards the tip). So the saw-tooth leading edge discontinuity, often present at mid span (Viggen, Gripen), inducing vortex at hig AoA to prevent the stall of the outboard section of the wing (same function as DLE - Drooped Leading Edge - on general aircraft (Lancair, Cirrus). The total lift increase comes from the upwash effect of the wing on the canard and from the canard positive pitch moment avoiding the negative wing flaps angle (and not mainly from canard vortices on main wing) : "Upwash from the main wing provides favorable (interference) flow conditions such the CL max of the canard was increased by 40 %". Nasa TM 88354.

This wash discontinuity, varying with global AoA and yaw angle is a very design problem ; lower loaded small canards (control ones with negative static stability)) are less problematic for this reason. Tandem configurations avoid the deflexion and lift distribution discontinuities, but have problems of their own, low rear wing lift, trim sensiblity to controls, strong power effect (if front propeller) on stability... Miles and Rutan tandem aircraft were not continued, the worse stability problems being with the tractor tandem configuration (Piper PAT-1, ref. Nasa TM 88354). Plxdesi2 (talk) 09:20, 22 April 2013 (UTC)

References

X-29A is a 3-surface

Discussion moved to Talk:Three_surface_aircraft

Etymology

I am very dubious about the cited etymology. For starters, there are two contradictory claims: the claim that the term was applied to the 14bis (cites Villard's Contact and a second claiming that it first used for the Fabre Hydravion (a more likely duck because it is a floatplane). The cite for this is the totally unreliable autobiography of Gabriel Voisin. I've scrabbled round contemporary sources and can find no use of the term before it is applied to the Voisin 1911 machine, again a floatplane. This suggests that Canard was a name given to this type, & later applied to othet types. I don't have Contact: I do have Villard's book on the Gordon Bennett books & although it's pretty good it's not without errors.TheLongTone (talk) 23:12, 5 April 2014 (UTC)

Agreed. Kenneth Munson's potted history of Fabre's 1910 aircraft in "Flying Boats and Seaplanes: Since 1910", Blandford (1971), refers to it throughout as "the Hydravion" (his italics). OTOH Almond's compilation of Getty images for "Aviation: The Early Years" (Ullmann 2011 Edition) Page 170, names it "Canard". Almond's text is very thin, and mostly but not always accurate. And I just had a look through the Flight archive. Throughout 1910 at least, Flight refers to the "Fabre Hydro-Aeroplane" with no associated mention of "Canard". The term does not appear in the context of aircraft until 1911, where it appears many times, from February on, reporting on the original "Voisin Canard" tail-first floatplane and (I suspect) other similar Voisin aircraft. Later, from September, Flight reports on the similarly-named "Blériot Canard" tail-first monoplane.[1] The first use in the general context of the configuration is on 11 October 1911, Page 895, where we read of two Morane all-metal monoplanes under construction, "One of them is modelled on ... torpedo-like lines and the other is a canard."(Flight's italics).[2]. Insofar as the 14-bis is mentioned in my sources, e,g, Angelucci and Matricardi's Sampson Low Guide, there is no mention of the name "Canard". All this would support a rewrite along the lines of:

The name "Canard" (Duck) was given to several early French aircraft of tail-first configuration, especially the Voisin Canard floatplane and Blériot Canard monoplane of 1911.[refs as above] By the Autumn of 1911 the term was being used to describe the tail-first configuration itself [ref as above].

I do not think that Voisin and Almond are reliable enough to support the Fabre story. The 14-bis claim is certainly not sufficiently supported. It's a shame that every source seems to have its inaccuracies, makes life difficult when information is scarce. — Cheers, Steelpillow (Talk) 12:36, 6 April 2014 (UTC)

The only use of canard in Flight during 1910 uses the word in the sense of "hoax". The OED cite is interesting: its from Horatio Barber's 1916 book on aircrat...Barber is notable for his canard Valkyrie monoplanes, but these were certainly not described at the time as canards. It's entirely possible that the description was used of the 14bis, but as a term for configuration it seems to date from 1911. It's the reliable cite combined with the removal of an existing one that is the problem.TheLongTone (talk) 12:55, 6 April 2014 (UTC)

Ah, I found Villard at Google Books, this URL might work for you:[3]. Page 37 contains the relevant material. He does claim that the 14-bis was called a canard, but then he also claims that its layout was "unconventional" and "backward". I find this last remark to be the judgement of hindsight. At the time there was no convention yet established, nor even a sustained flight in Europe, and moreover people like Voisin would follow the Wright pattern of tail-first: one could argue that tail-first was at that time the convention. He also claims it was unstable, but I seem to recall reading the opposite elsewhere - certainly, it had adequate rear vertical surface and steep dihedral which would suggest excess stability if anything. More scanning of Villard's work leaves me dissatisfied. The entire history of early British aviation prior to some international race or other ca. 1912 onward, is given a single paragraph, only two of Cody's achievements get a mention and the likes of Dunne, Blackburn and the Short Brothers get none. That chapter seems very American-centric, though I cannot access a great deal. The Table of Contents too seems American-centric, considering the widespread international activity at that time - and when I see that the book is copyright of the Smithsonian, I wonder whether there is a lesson in that. It does not look promising as an RS on European aviation, no doubt others who find what they want in it will disagree. — Cheers, Steelpillow (Talk) 15:48, 6 April 2014 (UTC)

Cheers, but the google books access runs out before I get to page 38...what you quote is hardly encouraging. I'll go and give l'Aerophile a closer read, see if there's anything about naming the voisin thing.TheLongTone (talk) 18:10, 6 April 2014 (UTC)

The canard wing was neither invented nor used for the first time by the Wright brothers

The plane built by Hiram Maxim and tested in 1894 had a clear front canard wing for pitch control (see, http://www.ctie.monash.edu.au/hargrave/images/maxim_1894_side_elev_1000.jpg ). I do not understand why the Wikipedia article about the canard wing starts with the Wright brothers. — Preceding unsigned comment added by 70.83.160.80 (talk) 23:11, 2 June 2014 (UTC)

Well spotted. I have added a paragraph. One cannot comment on the Maxim machine's flight characteristics, as it never flew freely. — Cheers, Steelpillow (Talk) 08:41, 3 June 2014 (UTC)

On second thoughts, Maxim's rig was a three-surface type, it has no place here. — Cheers, Steelpillow (Talk) 19:42, 2 September 2015 (UTC)

Put the canard wing, used by Hiram Maxim in 1894, back in the article because otherwise the Farman 1907 plane, which was also of the three surface type, can no longer be considered as having a canard wing which is evidently not true. Farman used a front elevator (canard wing), a pair of big wings in the middle and a back horizontal stabilizer. — Preceding unsigned comment added by 74.56.1.38 (talk) 06:19, 8 October 2015 (UTC)

The machine was a test rig, held down on rails because, contrary to your initial assertion, it had minimal provision for aerodynamic control. Maxim may have experimented on it with pitch control in mind, but that would need proper citation. Technically, Langley's Aerodrome was also three-surface but, because the fore and middle surfaces were of equal size with a small tail intended only for control and trim, it is invariably described as a tandem. Whatever we think of that, it illustrates how we are bound to follow usage in reliable sources (WP:RS), and the same applies to Maxim. No cites for "canard", no content. Wragg, whom I cited in my original paragraph, does not use the "c" word or discuss the nature of the experiments. Do you know any sources who do? — Cheers, Steelpillow (Talk) 07:54, 8 October 2015 (UTC)

Also, there is the issue of whether any three-surface aircraft should be discussed in this article, and to what extent. Maxim's machine belongs more to that article. — Cheers, Steelpillow (Talk) 07:56, 8 October 2015 (UTC)

Foreplane stabilizing ?

In the article : "A canard foreplane may be used as a horizontal stabiliser, whether stability is achieved statically[16][17][18] or artificially (fly-by-wire).[19]"
The three attached quotes (16-17-18) use the term "stabilizer" in lieu of foreplane or canard, without saying that the canard is a stabilizing surface, so are invalid quotes. Using foreplane to control pitch (as a horizontal stabiliser does) is a control function, not a pitch stability matter.Plxdesi2 (talk) 19:36, 7 June 2014 (UTC)

No. The article says "as a horizontal stabilizer" and the quotes use the term "stabilizer". Your comment about "stabilizing" is not relevant and the references are just fine. — Cheers, Steelpillow (Talk) 21:21, 7 June 2014 (UTC)

In the article : "Nevertheless, a canard stabilizer may be added to an otherwise unstable design to obtain overall static pitch stability.[23] = Garrison quote
This sentence means that the wing is destabilizing and the canard is added to get stability, so the canard is stabilizing. This is wrong; a canard is always a destabilizing surface (see Fundametals of Flight, Shevell, : "in case of canard, the wing IS the stabilizer.") and others (in "Stabilizer" article). Second, the quote of Garrison does not say that the canard is stabilizing; he just says that the canard is necessary to the balance ("the aircraft would tip over forard if some balancing force were not provided."). There is no matter of stability here, so the quote has no value. Plxdesi2 (talk) 19:04, 7 June 2014 (UTC)

No. A wing on its own is indeed unstable and a canard may indeed added to give stability. What a thing is called is what it is called, why it is put there is why it is put there, how it works is how it works, and Wikipedia has to respect that. — Cheers, Steelpillow (Talk) 21:21, 7 June 2014 (UTC)

Article lead

I deleted this recent addition from the article lead:

Compared to a conventional aircraft whose tailplane provides negative lift, a canard's forewing produces positive lift; accordingly, the mainwing can be smaller. Also, provided the forewing is set to stall before the mainwing, a canard aircraft should be impossible to stall, since, in the event of a forewing stall, the nose drops and flight continues; while throughout this episode the mainwing would have been flying normally.

This is over-simplified and is often wrong. Firstly, it is a myth that the conventional tailplane usually pushes down - that mostly only happens during takeoff and landing. Secondly, on modern canard fighters, the forewing is typically trimmed for little or no lift. Many other examples have historically failed the canard-stalls-first safety test (sometimes through divergent phugoid oscillation induced by repetitive stalling and recovery of the canard) - this is not an advantage but only a potential advantage. Consequently, the lead needs to reflect this complexity of behaviour and application. At present it gives a nod to this with the remark that until recently the characteristics were poorly understood. If this can be made clearer, then fine, but the lead is not the place to explain the whole complicated business, that is for the main body of the article. — Cheers, Steelpillow (Talk) 08:56, 2 September 2015 (UTC)

First, there is no question of a "war", but if I am advised: "Please discuss your proposed changes first, don't war. ", it is tempting to respond: "Please discuss your proposed reversions first, don't just revert and keep on reverting".

Moving on, the fact remains that the article's intro is substandard. It desperately need an introductory statement on the rationale(s) of the canard. Wouldn't it be better to amend my paragraph, rather than to keep deleting it? Arrivisto (talk) 18:27, 2 September 2015 (UTC)

WP:BRD is a standard approach to dispute resolution. I am sorry that it does not work for you. I answered your question in some detail when I opened this discussion, a response might be more useful than ignoring it. — Cheers, Steelpillow (Talk) 19:07, 2 September 2015 (UTC)

One might add something like this:

A foreplane typically contributes more to overall lift than a conventional tailplane, in theory allowing the main wing to be smaller and lighter. This can be difficult to achieve in practice. Canards are also used to deflect the airflow over the wing at high angles of attack, in order to enhance manoeuvrability and low-speed characteristics.

Any use? I do not think the stall characteristics are definitive enough to be mentioned in the lead (the first unstallable aeroplane was tailless!). — Cheers, Steelpillow (Talk) 19:21, 2 September 2015 (UTC)

A foreplane typically contributes more to overall lift than a conventional tailplane, in theory allowing the main wing to be smaller and lighter. This can be difficult to achieve in practice. Canards are also used to deflect the airflow over the wing at high angles of attack, in order to enhance manoeuvrability and low-speed characteristics.

"Any use?" Yes indeed, but still not ideal as an introductory statement which should give a succinct outline of the text to follow. For instance,"A foreplane typically contributes more to overall lift than a conventional tailplane ..." begs the question, are these foreplanes and tailplanes the same size? Or is there differential lift area for area? Or is it because of differing angles of attack (or is this "a myth"?). The statement "This can be difficult to achieve in practice." (which presumably refers to the possibility of a smaller main wing) may or may not be true, but needs more detail and more referencing than is appropriate in an intro. And so on! The proposed paragraph is neither better nor worse than that of mine which was twice deleted. Still, it's a start, and I would be happy to see (as I said, above} " an introductory statement on the rationale(s) of the canard". Arrivisto (talk) 23:32, 2 September 2015 (UTC)

Of course it begs the question of detail, it is an article lead, that is what it is for! The main thing is, it contains no falsehoods and avoids discussing technicalities. It introduces the key design rationales for considering a canard arrangement, i.e. it is in fact exactly what you keep asking for, an introductory statement on the rationale(s) of the canard. — Cheers, Steelpillow (Talk) 09:24, 3 September 2015 (UTC)

On the "derogatory" nature of the term "canard", Wikipedia avoids such value judgements unless they can be reliably sourced as value judgements. What is your exact sourcing here (i.e. inc. page no. and text quotation)? — Cheers, Steelpillow (Talk) 09:24, 3 September 2015 (UTC)

No sensible person, French or otherwise, would look at a canard aircraft and mistake it for a duck. The "canard" moniker arises (unfairly perhaps) because of the "ugly duckling" metaphor. As explained before, it's NOT a value judgment, but an explanation of the term's meaning. Arrivisto (talk) 09:37, 3 September 2015 (UTC)

That is clearly your personal opinion and not backed by reliable sources. Indeed it flatly contradicts the account given by Villard, who is cited for that paragraph. Your unsupported opinion has no place in a Wikipedia article. — Cheers, Steelpillow (Talk) 11:11, 3 September 2015 (UTC)

Understanding the Viggen

I don't like the recent rephrasing of the lead. Its order of explanation implies that the aerodynamics of canards were fully understood by the time they appeared on the Viggen. That is not the case. Saab understood enough for their own purposes but the fuller story - as discussed in much of the article - did not emerge until later. What is the point of trying to mislead the reader? — Cheers, Steelpillow (Talk) 19:14, 12 September 2015 (UTC)

Ah, sorry, I am not trying to mislead the reader. I feel that:

1) the statement "the canard surfaces’ complex aerodynamic characteristics were not fully understood until much later" is a very strong one -- indeed canard aerodynamics are complex, but the 60s and 70s saw canard aircraft take flight that we simply cannot dismiss as "not fully understood". Is, perhaps, what you are trying to convey, something along the lines of "but the complex flight dynamics enabled by canards (especially at high angles of attack) were not exploited until much later"?

2) I cannot find substance to back up this statement inside the article body. We do talk about pioneers not understanding canards, and we show how canards have progressively been used in more and more complex ways. But we do not describe a "full understanding" emerging in the 70s or later.

Am I missing something? Respectfully yours, Ariadacapo (talk) 19:28, 12 September 2015 (UTC)

It's not in the article at present. I followed aviation closely in those days and it was one of the things that was known. Burt Rutan got the inspiration for his canards from the Viggen, and his subsequent design ideas slowly changed over time as more became understood about their aerodynamics and he realised that he had not properly understood his earlier designs. For example the analytical distinction between lifting-canard and control-canard postdates his early designs. It is something that can be teased out of reliable sources easily enough if one knows where to look. Sadly I have long forgotten where or I would be citing them now and adding the tale to the section on the canard revival. There was some relevant comment in a long (and acrimonious) series of discussions here once, there may be some useful cites or pointers in the archives. By all means add a citation needed tag, but to reverse the order and thereby imply the opposite is equally unsourced and not in the article either. — Cheers, Steelpillow (Talk) 20:25, 12 September 2015 (UTC)

The title image probably isn't the best place to be putting a controversial statement (even if it is supportable) - especially one that is prone to misinterpretation, and FWIW, the Viggen was preceded into production by the Voisin Canard.NiD.29 02:05, 13 September 2015 (UTC)

Thank you, I take the point about the Voisin. I agree about controversial statements, but one does not always know that a statement is controversial until a couple of knowledgeale editors have talked it over. — Cheers, Steelpillow (Talk) 04:41, 13 September 2015 (UTC)

OK. Can we converge towards a consensus version of the first paragraph? After all, the lead is only to reflect the content of the article (and I think we have plenty of well-sourced key statements down there). I propose:

"Despite being used on the first powered aeroplane, the Wright Flyer of 1903, the complex flight dynamics enabled by canards, especially at high angles of attack, were not exploited until much later. Canards did not appear on a modern production machine until the Saab Viggen in 1967."

Can we re-work this to a consensus version? Steelpillow, I think a description of the "gradual understanding" you are talking about would make a very interesting addition to the article — and important enough to be summarised in the lead as soon as it's added. Ariadacapo (talk) 06:35, 13 September 2015 (UTC)

I hope we can reach consensus. The development of the theory will be difficult to tackle from home, with no college library to browse, I'll have to see what I can do. Meanwhile I do not like the idea of mentioning the development of understanding before mentioning the Viggen. This is the third time I have said it (first was in an edit comment) so here it is again, somewhat emphasised: The Viggen was designed BEFORE full understanding was developed and even though this is not yet sourced the lead should not give the opposite impression - which is equally unsourced. Also the stability and lifting vs. control aspects are important and they do not apply to high AoA. So I would prefer something like:

"Despite the use of a canard surface on the first powered aeroplane, the Wright Flyer of 1903, canard designs were not built in quantity until the appearance of the Saab Viggen jet fighter in 1967. The aerodynamics of the canard configuration are complex and require careful analysis."

Any good? — Cheers, Steelpillow (Talk) 07:53, 13 September 2015 (UTC)

this NASA paper is quite useful although it is thin on the particular point of concern. It has a couple of cites worth following up. — Cheers, Steelpillow (Talk) 08:38, 13 September 2015 (UTC)

I understand better your point now. I never meant to suggest "full understanding" was reached before the Viggen; only that it came "much later" than the Wrights. You are right, the current paragraph structure can be interpreted this way (never saw it till now), and should be changed.

I think your proposed new paragraph makes sense. Already the NASA paper you quote can be provided as a citation for the last sentence. And I look forward to new additions to the body regarding progressive understanding of canard aerodynamics. Ariadacapo (talk) 08:59, 13 September 2015 (UTC)

Well, waddya know. Saab filed a US patent for the Viggen "Delta wing canard aircraft" right back in 1963: US Patent US3188022 A. — Cheers, Steelpillow (Talk) 12:56, 13 September 2015 (UTC)

Stall tales

There is much talk of the pros or cons of the canard in regards to stalling of the aircraft, though very few reliable citations are given in the article, and most has the feel of original research. One citation (15) actually contradicted the statement it was supposed to support. Can someone knowledgeable on this subject please provide accurate references for the claims made in this article in regards to canard aircraft and their relationship to stalling? Thank you! :D Mousenight (talk) 20:15, 17 December 2015 (UTC)

The stall behaviour of canards is a highly complex subject and it is very difficult to find citable sources which give a consistent picture. Most sources assume certain design constraints, often not made explicit. So two perfectly reliable sources may appear to make quite opposite claims about stalling behaviour - all good fun for the opinionated but unenlightened Wikipedia editor. In order to untangle such a mess, one needs a third reliable source who has taken time out to lay bare the assumptions made and how they lead to different effects. This does not happen often. — Cheers, Steelpillow (Talk) 20:37, 30 July 2016 (UTC)

Ground effect on an elevator

Almost certainly there is an authoritative reference that supports the observation that I have offered here http://www.niquette.com/puzzles/canards.htm#ground-effect.Paul Niquette (talk) 12:29, 30 July 2016 (UTC)

Let us know when you find it. — Cheers, Steelpillow (Talk) 20:42, 30 July 2016 (UTC)

Canard and the environment

Not mentioned in the article is the potential reduction in greenhouse gases resulting from the canard configuration. For an aircraft of a given weight, a reduction in requisite lift and therefore drag will save fuel, as described here http://www.niquette.com/puzzles/canards.htm. — Preceding unsigned comment added by Paul Niquette (talk • contribs) 12:31, 30 July 2016 (UTC)

That reference is self-published and therefore not acceptable on Wikipedia. To add information on this subject you would need to cite a reliable source. - Ahunt (talk) 15:40, 30 July 2016 (UTC)

The potential reduction in greenhouse gases resulting from yadda yadda is not relevant to most articles about things that burn fuel, it is just too darn obvious. Just like most articles about aircraft don't explain about what colour the sky is either. Also, "For an aircraft of a given weight, a reduction in requisite lift..." is a contradiction in terms - the weight defines the requisite lift (pace vertical thrust). I hope your fuller piece is better written. — Cheers, Steelpillow (Talk) 14:54, 2 August 2016 (UTC)

As you will see in the "fuller piece," elementary illustrations show that in conventional configurations requisite lift is always greater than the aircraft's weight, which is a consequence of down-force in the empennage to overcome the mandatory location of the center of gravity forward of the center of lift.Paul Niquette (talk) 14:17, 5 August 2016 (UTC)

If you mean wing lift not net lift then you need to say so. Yours is a common fallacy. It is one of the extreme conditions, in this case experienced during rotation for takeoff, which provide critical design criteria, and as such it is all over the text books and lecture notes. But it is undesirable during cruise because it is inefficient - and that is also in any good book or lecture. The so-called "lifting tail" has always been, and still is, a common design element. However the least induced drag is experienced with zero tail lift. It is the relative downforce, i.e. less lift, on the tail compared to the wing, which satisfies the center of lift condition, not their absolute values. There is a long trail of historical literature on the subject, going from contemporary sources back to before WWI. I suggest you do some more thorough background reading. — Cheers, Steelpillow (Talk) 18:11, 5 August 2016 (UTC)

In preparing the “fuller piece,” I was unable to take up the subject in person with Orville or Wilbur; however, while doing research for A Certain Bicyclist (https://en.wikipedia.org/wiki/Utility_cycling#Bibliography), I did meet with Paul MacCready soon after his winning the second Kremer Prize (https://en.wikipedia.org/wiki/Kremer_prize) to confirm that the canard configuration in the two human-powered Gossamers was indeed chosen to minimize induced drag. Moment arm is the key. Does that not have relevance to the subject of ‘carbon footprint’ in aviation? Paul Niquette (talk) 09:00, 6 August 2016 (UTC)

How lovely, but no. Similar claims have been made for many aircraft configurations, not least the three-surface aircraft and the flying wing. By the way, "historical literature" comprises the written word, not the spoken, frankly I had thought better of you than that. Goodbye. — Cheers, Steelpillow (Talk) 10:06, 6 August 2016 (UTC)

Lifting canards

The article currently says that "With a lifting-canard type, the main wing must be located further aft of the center of gravity than a conventional wing, increasing the downward pitching moment caused by the deflection of trailing-edge flaps. Highly loaded canards do not have sufficient extra lift available to balance this moment, so lifting-canard aircraft cannot readily be designed with powerful trailing-edge flaps." That last sentence is at best badly misleading. The main wing just needs sharper sweepback, or simply fit a more sophisticated canard surface with its own high-lift devices. See for example the Miles M.39B Libellula. The passage cites Raymer (1999) which I do not have access to. Could somebody who has access, please sanity-check this citation? — Cheers, Steelpillow (Talk) 12:09, 15 May 2023 (UTC)

I inserted the offending sentence and the citation of Raymer - See my edit on 12 September 2008. I used a copy of Raymer borrowed from a friend. I recently asked the same friend if I could again borrow the book. His answer was that he had sold his copy! I will now re-double my efforts to again get access to a copy of Raymer. In the interim I will hide or delete the offending sentence. Dolphin (t) 12:35, 15 May 2023 (UTC)

Thank you. Good luck in your search. — Cheers, Steelpillow (Talk) 12:53, 15 May 2023 (UTC)

Here's a link to the book at archive.org: Raymer, Daniel P (1992). Aircraft Design: A Conceptual Approach (2nd ed.). Washington: AIAA. p. 72. ISBN 9780930403515. OCLC 0930403517.Spheroidite (talk) 13:34, 15 May 2023 (UTC)

Thank you. Raymer actually notes that "most aircraft with lifting canards cannot use sophisticated wing flaps". He immediately then notes a couple of workarounds in use. Also, other statements he makes are over-generalisations and not necessarily true. For example he claims that a canard flap is "much closer to the center of gravity" than the equivalent tail surface. But when you look at three-surface aircraft which have both (e.g. Piaggio P.180 Avanti, Scaled Composites Triumph, Sukhoi Su-33), that is quite untrue. His words also miss the fact that a flap creates lift over much of the surface in front of it, so the centre of its force delta is usually ahead of the actual hinge line. So frankly, I cannot see Raymer as a particularly reliable source. — Cheers, Steelpillow (Talk) 14:08, 15 May 2023 (UTC)

At what point does a "lifting-canard" become the forward element of a tandem wing design (something like the Miles Libellula) ?GraemeLeggett (talk) 17:33, 15 May 2023 (UTC)

Wherever the person talking wants that point to be. There is no hard and fast rule that I ever heard of. One can talk only vaguely of "significantly smaller" or "of comparable size or lifting power." One person's small fore wing is very much another's large canard surface. For example I have seen the fore wing of the Miles M.39B Libellula described as a canard, similarly that of the Dunne-Huntington triplane and the Payen PA-22. It is perhaps most correct to say that such an intermediate surface confers certain properties of both, and must be considered in that light. — Cheers, Steelpillow (Talk) 21:12, 15 May 2023 (UTC) [Updated with Payen, 09:44, 17 May 2023 (UTC)]

Stalling

The article currently says that "A danger associated with an insufficiently loaded canard—i.e. when the centre of gravity is too far aft—is that when approaching stall, the main wing may stall first," and goes on to claim that the only way to fix that is to reduce loading of the main wing. There are several things wrong with this, First, if the control surfaces remain effective then the danger is no more than for any other stall. Second, a similar danger exists with the T-tail in a deep stall, so this needs putting in perspective. Thirdly, alternative solutions include reducing the size of the foreplane and hence increasing the loading on it, and/or the the provision of powerful pitch-recovery surfaces on it. All in all, unless stronger citations of these claims can be found, they will have to go. — Cheers, Steelpillow (Talk) 10:07, 17 May 2023 (UTC)

I agree that this statement is misleading. It says “when the centre of gravity is too far aft ...” Firstly, every type-certificated aircraft has precisely defined limits on the position of the centre of gravity. The semi-infinite range of CG positions that are “too far aft” are excluded from the permitted range, and so the CG will never be too far aft, and there will never be a danger associated with it. This is just as true for conventional aircraft as it is for the canard configuration.

A sentiment that might be included here, subject to finding a reliable source, is that the foreplane must stall before the mainplane to ensure a nose-down pitching motion, and this may necessitate that the aft CG limit for the canard configuration is not as far aft as for an equivalent conventional aircraft, and therefore the CG range may not be as broad as for an equivalent conventional aircraft. Dolphin (t) 13:27, 23 May 2023 (UTC)

It's not that simple. A control canard (such as a floating canard) with sufficient authority can command a strong downforce when required. Combined with the residual lift from a stalled main wing, this can be enough to pitch the nose down and recover the craft. Moreover on the most basic stable canard design, comprising fore and aft wings of comparable section, but with the canard given increased angle of attack, the foreplane will always stall first. It is only when the designer starts trying to be clever, or the CG is moved too far aft so the foreplane AoA gets trimmed out, that the main wing is likely to stall first. There may be scope for such discussion elsewhere in the article, but in the Lift subsection of the Basic Principles, it is not really appropriate. — Cheers, Steelpillow (Talk) 14:44, 23 May 2023 (UTC)