Why is it that Americans have not come forward in implementing this tech into their fighter aircrafts (keeping in mind the EF and Rafale both have canards)?
I really cant think of any American fighter/bomber (except the Rockwell Lancer :diablo: ) which comes with canards.
Important Hyper Note: I am NOT an Aeronautical Engineer NOR an Aerospace Expert, etc, etc nor do I claim to be one.
A few early Grumman VFX proposals had canards and fixed wings. The final F-14 had "glove vanes," hardly canards, though.
Lockheed's ASTOVL/CALF proposal had canards. The same basic configuration was preserved for the wining X-35 JSF proposal - but the canards were deleted.
A quote from a Northrop designer I believe it was "where's the best place to locate a canard? On the other guy's aircraft." There was a study done in the late eighties I believe it was that determined that canards aren't all that. For the conditions that fighters fly under a conventional tailed design is the best compromise. That's why while they may look cool (the reason they were all over US artist's concepts of the ATF) they never appeared on a single ATF or JSF proposal. Aircraft the US has flown with canards? The X-36, F-15, X-31, HiMat, X-29, and XB-70. The B-1's don't really count because they are for the ride control system. If you count those the the remaining XB-70 flew with TWO sets of canards when it was with NASA because that's where they began developing the system.Originally Posted by aced_inc
Actually the ony thing that remained the same is the location of the intakes, the number of engines, and the color of the paint.Originally Posted by TinWing
"where's the best place to locate a canard? On the other guy's aircraft."
If that was true , you wouldn't have aviation giants like Dassault, Saab (who was actually the first to do it with Viggen), EF implementing this tech in their 4.5-5th gen.projects. Sukhoi too BTW.
Look when they were all designed. Late 80's. Damn near every artist concept on the face of the planet had a canard back then
Sukhoi and the F15 Active are very different. They are tri planes, not bi planes in the form of a canard and main wing and in the some cases they are quad planes with the vectored thrust. The X31 is also different in that it is basically a triplane with the vector thrust as the third "plane". The question here is whether a canard is better than a tail plane. In terms of aerodynamics, the answer is clear, a tail plane is theoretically better than a canard. This has been proven some 70 years ago theoretically. The attributes of a canard is that if designed right it yields some built in controls advantages not aerodyanmic. But, with today's FBW and CCV fighters as standard equipment, this is no longer an advantage over a tail plane in this regard. Keep in mind all that simple books describing how a canard is better than a tailplane is only when no computer control is involved and without an unstable platform...which means it actually makes sense for a simple 2/4 seat plane to use a canard. There are attributes of the canard that is used in the F22 and the F35. Canards is used to generate a force vector and a pair of strong vortices. The latter is kept in the F22 and F35 by using a very angled fuselage (besides for stealth) and short strakes to generate those vortices. Since the required vortex strength should be higher at higher angles of attackes, the shaping should be designed to contribute to this at higher angles attack. This means that at higher and higher alphas, more part of the strake and fuselage begin to contribute to this forward vortices to counter balance the ones generated by the main wing. This is what a close coupled canard is supposed to do, but in this case the F22/F35 used neither moving parts nor any significant added wetted surfaces.Originally Posted by aced_inc
Country::US of A
If you are trying to make a stealthy fighter that supercruises, canards don't help at all. They have more drag and they are another complex surface to reflect radar. Thats why they are not on the F-22 and F-35.
Originally Posted by Vortex
Thats the first I've heard of that!
In subsonic flight it is well known a canard will reduce the loading on the main wing in comparison to a conventional tailplane layout and thus reduce the induced drag of the aeroplane as a whole. However, it does affect the spanwise lift distribution on the main wing by dint of its wake downwash, which may need some twisting and camberline changes to the main wing to compensate.
about US canarded aircraft, dont forget the F-16CCV, XB-70, SR-71 (well, was planned to be fitted with) and the F-21 (US Kfir). for the rest i should also mention the aircraft noted above
The F-14A also has retractable canards, but i dont think they count
Is thurstvectoring not a much better way to improve the maneuverability of a fighter? The F/A-22 was designed to have TV, if my old mind is right.
that's correct, iirc Prandtl did a study on the theory of multiple wings and found that, unsurprisingly, the single main wing that's producing the lift is the most efficient. One can then argue that a tailplane is a "lift" surface much like the canard, but for reasons you've just described, the result is whether you want a less efficient main wing or canard/tail? The choice is rather obvious there. Now, the next question is for control purposes. Yes, for a stable aircraft, you can optimize the canard to give you better cruise and stall characteristics, however, keep in mind that the fighter planes we are taking about are not statically stable anymore. For that very simple fact the idea of a canard in the aerodynamic and control sense becomes less efficient. As to stealth, it has often been cited as the reason for not having canards, but that's somewhat suspecious for a fixed canard while for a moving one it's also suspecious since the F22 does have that leading edge flap, which has more and larger moving edges than a canard. It obviously would increase the RCS since any edge moving or not does, but to the level of simply not having if the aerodynamic advantages are so great? As i've mentioned before, one component of the rationale for a canard has been kept without using the physical canard that we're so accustomed to.Originally Posted by kilcoo316
they are certaintly cool though...i'll give you that.
Last edited by Vortex; 29th October 2005 at 20:57.
Country::US of A
The Mig-8 flew during WWII and showed that a swept wing plus canards had various advantages... including being stall proof and very nice to fly. (It was a pusher prop driven aircraft)If that was true , you wouldn't have aviation giants like Dassault, Saab (who was actually the first to do it with Viggen),
If you spoke of eurocanards, it's more like early 80.Originally Posted by sferrin
Because they don't need it. Canards are a mean to improve tailess delta designs.Originally Posted by aced_inc
Maybe the simple reason is that no one ever build a canard in the US. The F-16 and F-18 design was prior to any Canard-thniking and actually already incorporated relaxed statical stability. So the drawbacks of a conventional design are less. So if there are no serious gains in building something different why should you do it?
The French had the Mirage with tailles delta and also used canards for the Mirage 2000 and later versions of the Mirage V. The Eurofighter nations had actually nothing to start from (except low-level fighter-bombers Tornado and Jaguar). The swedish hat a tailles design (Draaken), than a canard (Viggen, but I think a stabe one) and finally the Gripen.
So it maybe a little bit due to evolution of designs. Modern CCV-technology actually makes some things easier, but nevertheless a well designed airplane is much easier to control.
No American canard was ever intended for service and I can thin of no design that actually is comparable to Gripen, Eurofighter, Rafale or J-10 in terms of general configuration.
I wouldn't say that there are major advantages/disadvantages of designs. For American designs the influence of the F-18 is clearly visible for the F-22 and finally for the F-35.
The SR-71 did not have Canards. It did have chines that faired the round fuselage in to the wings and they were carried forward to the nose of the aircraft, adding lift. Canards are used for pitch control, the SR-71 had elevons on the trailing edge of the wings, used for both pitch and roll control.
Kelly Johnson the designer of the SR-71 once said: Canards belong on someone else's airplanes not mine.
A YF-12 had for test reasons small wings or canards where there IRST sensors were.
I presume, those wings were more for stabilation than for flight control.
I looked through my books to find a pic to prove my statement.
Source: Page 19 from "SR-71 Blackbird in action", Aircraft No. 55, Squadrun/signal publications, ISBN 0-89747-139-9
Last edited by fightingirish; 24th February 2007 at 12:32.
Avatar: Ho-Yeol Ryu, Flughafen (Airport), Hannover [HAJ / EDDV] 2005
At one point in the design process the Blackbird had a canard. It was removed before they settled on the final configuration.Originally Posted by glhcarl
The SR-71 design was an offshoot of the A-12, I seem to remember in designs A-1 thru A-11 there my have been a design with canards. But none of these early designs got past the model stage.Originally Posted by sferrin
Kelly Johnson had his hand on every Lockheed design from the P-38 through the F-117 and I didn't see canards on any ot them. He also had a thing about wing fences (stall fences) he said any design that needed a wing fence, really needed a new wing design. You don't find them on Lockheed aircraft.
You hardly find any fences on western aircraft, especially not at American designs. The Russian used fences much much more, some early bomber designs had 4 fences on each wing (and actually proved Kelly's statement)!Originally Posted by glhcarl
The one with the canard was towards the end of development. It pretty much looked like a Blackbird with a canard. Actually. . . here ya go:Originally Posted by glhcarl
Yeah. The Lavi, Gripen, EAP/Typhoon, Rafale, Piranah. . .they all had canards as did most of the ATF artist's impressions. The Mig 1.42 started development in 1986 too and then the ATF prototypes were revealed and whoops, neither of them had a canard. Too funny.Originally Posted by glitter
So you think they just missed the bus? You make a design choice, based on your requirements and the available technology. In case of the Eurofighter they chose canards, in case of the ATF the chose not.Originally Posted by sferrin
The point is they are not on any production Blackbird model (A-12, F-12, SR-71) because they were not required. I've seen the pictures have read all the books, and unlike about 99.99% of the people talking about them, I actually worked on the SR-71. USAF 9th FMS Beale AFB 1966-1969.Originally Posted by sferrin
Can't think of any US JET fighters......but the Curtis XP-55 Ascender was a "pusher" piston powered fighter with canards.......
North American XF-108 which only made it to mock-up, had canards.Originally Posted by hawkdriver05
By the B-1 this small "canards" are installed for another reason.They are called Low Altitude Ride Control (LARC).Even small turbulences cause g-forces of +4g/-2g and this LARC system decrease this forces during low flight.The "canards" can move with 200°/s.
There are currently 1 users browsing this thread. (0 members and 1 guests)