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Author Topic: Using Canards vs. Tail for aircraft control in USA and other countries  (Read 74818 times)

Offline Woody

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They built them into the XB-70, the HiMAT and the X-31, Burt Ruttan likes them and all the compeditors for the ATF/F-22 and JSF/F-35 contracts initially considered them but in the end they all rejected cunards. Why? Do they really believe they can get better maneuverability/stealth/STOL out of a conventional wing and tailplane. If you're going to tell me they were too late, like forward swept wings (not that I'm a fan), they'd both been around for decades. Somebody help me out here - it's bugged me for years.
Cheers, Woody.

Offline Matej

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I think that till 70s, they didnt use the canards because without digitally supported flight control systems they were uneffective. You need a redundantly metastable plane to take some effect. After 70s, well, probably for the USA was the primary factor stealth. Europeanīs and russianīs philosophy was aimed to the high maneuvrability, so a lot of their designs have canards.

BTW, welcome on Secretprojects  ;)

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Offline Orionblamblam

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Damn you, Cunard! America hates you!!!
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Offline Kim Margosein

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Are you speaking commercially?  I think it's because people expect commercial aircraft to look like commercial aircraft.  Examples:

1.  Beechcraft Starship.  50 were built, about 10 were sold.  Beechcraft finally bought them back so they wouldn't have to deal with supporting them.

2.  Piaggio Avanti-  Virtually all were "sold" to the Italian government.  

3.  Boeing SonicCruiser-  DOA.

Kim Margosein

Offline Woody

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Thanks Matej for the quick response but I still don't get why cunards aren't steathy. A coventional tail levers downwards to effect pitch up detracting from the wing's lift, requiring it to be larger to do the same job, all else being equal. Both the F-22 and F-35 have long parallel sides between the intakes and wing that would happily accommodate cunards even before you start moving the wing aft as would be logical with extra lift up front (perhaps because that was how they were designed in the first place?). The F-23 has an excuse as the elevators serve as rudders for yaw control but not the Lockheed designs with their barn-door semi-vetical fins (how are they steathy?). Re. the flight controls, the Rockwell Sabre-bat, X-29 et al were conceived in the mid 70s and they had cunards and FSW! And did Burt Ruttan's kit planes have digital flight controls or a 'redundantly metastable' do-hicky? (only kidding-but seriously...)
Still bewildered, Woody
PS: how do you attach images. When I press the 'Instert Image' button, I just get typed. Is this an HTML thing or a Firefox thing. Any help appriciated as I'd love to attach some JSF concepts to illustrate my point.

Offline Woody

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Cheers Kim, I hadn't even concidered comercial aircraft but now you mention it why haven't Boeing and Airbus tried a serious cunard configuration without trying to re-invent some sort of half-arsed concord? You would think if they kept the speed as it is they'd save passenger-gallons per mile, as the trim drag should be better, and at the end of the day that's airlines care about. As for private aircraft I guess fashion is a factor but the Piaggio Avanti you speak of is doing quite well these days and has re-entered production if Flight Global is to be believed (but technically that's a tri-plane as it has a tail as well). But this getting off the subject as it's military jets I'm really interested in.
Woody

Offline PaulMM (Overscan)

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Offline Sundog

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I have yet to see any reliable information that says canards can't be as stealthy as conventional tailed designs. The main reason the U.S. doesn't have canards on it's fighters is that a conventional tail is better than a canard in terms of trim power over a large range of angle of attack and a conventional tail can trim an aircraft at high alpha better than a canard in general.

However, a canard arrangement usually allows you to make a smaller aircraft for the same mission. A smaller airplane is a lower cost airplane, which is the main reason the European fighters have canards. America hasn't been as constrained by costs as most other countries, so they haven't had to go with canards.

Also, in terms of three surface aircraft like the Su-35, it's been found that if you have thrust vectoring you don't need the canards. This partly explains, assuming they're accurate, why the new Russian fighter  designed by Sukhoi concepts that have been shown in artists renderings don't have canards like the Su-35.

It also has to do with mission optimization. If canards offered any advantages over a conventional tail in a highly maneuverable supercruise fighter more of the ATF submissions would have had them. I believe only the Grumman submission had them. My guess is, besides the trim capabilities, a canard is more difficult to integrate into the design for low supercruise drag than a conventional tail. Considering the F-22 supercruises at M=1.8, much higher than any other fighter out there and the fact that canards obstruct the pilots view, there are more reasons not to use them in a pure fighter, than to use them, other than cost.

Offline Woody

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Cheers Orionblamblam, I'm always happy to get spelling corrections, I'm more a pictures person, anyway 'canard' is a stupid word, doesn't it mean duck?
Also thanks Sundog: if you know any open source internet stuff that explains these sort of dynamics please let me know (see my 'Down turned wing tips' answer).
And I'm sorry but conventional tails look boring to me.
Thanks Overview for the attachment advice, hope I've got it sussed now. Why New Zealand? Did you read my blurb about it in my 'introduce myself' bit.
Here's a 2 year old design of mine, please don't steal it as hope to publish it some day and I can't afford a lawyer.
Regards, Woody

Offline dan_inbox

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...because people expect commercial aircraft to look like commercial aircraft.  Examples:
1.  Beechcraft Starship.  50 were built, about 10 were sold.
2.  Piaggio Avanti-  Virtually all were "sold" to the Italian government.  
3.  Boeing SonicCruiser-  DOA.
The Vari-eze / Long-eze being notable exceptions.

And Woody, Canard is the French for Duck. Airplanes with the main wing located way back are reminiscent of a duck in flight.

Offline PaulMM (Overscan)

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Re: Using Canards vs. Tail for aircraft control in USA and other countries
« Reply #10 on: March 11, 2007, 01:41:37 am »
Thanks Overview for the attachment advice, hope I've got it sussed now. Why New Zealand? Did you read my blurb about it in my 'introduce myself' bit.

My wife is from New Zealand, she would like to like to return there to have children.
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Offline Woody

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Re: Using Canards vs. Tail for aircraft control in USA and other countries
« Reply #11 on: March 11, 2007, 04:40:02 am »
Quote
My wife is from New Zealand, she would like to like to return there to have children.

NZ's a nice place if you like surfing or skiing and cheap steak (which I do, now being in Japan where it cost a fortune) but don't expect your kids to have a career in aerospace unless you count crop dusters. Strangely they do have a lot of pilot schools though. Good luck with it and I hope you keep up the website from there.
Cheers, Woody

Offline Firefly 2

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Re: Using Canards vs. Tail for aircraft control in USA and other countries
« Reply #12 on: March 11, 2007, 08:13:48 am »
Cheers Orionblamblam, I'm always happy to get spelling corrections, I'm more a pictures person, anyway 'canard' is a stupid word, doesn't it mean duck?
Also thanks Sundog: if you know any open source internet stuff that explains these sort of dynamics please let me know (see my 'Down turned wing tips' answer).
And I'm sorry but conventional tails look boring to me.
Thanks Overview for the attachment advice, hope I've got it sussed now. Why New Zealand? Did you read my blurb about it in my 'introduce myself' bit.
Here's a 2 year old design of mine, please don't steal it as hope to publish it some day and I can't afford a lawyer.
Regards, Woody

That is some nice design. :o
Is there a specific reason wgy you opted for the inverted double delta?

Offline Woody

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Re: Using Canards vs. Tail for aircraft control in USA and other countries
« Reply #13 on: March 11, 2007, 05:20:37 pm »
Is there a specific reason wgy you opted for the inverted double delta?

Ah, don't get me started. I wanted to make a compact shape as I envisioned it as a carrier based fighter/attacker. The forward swept outer main wing has a lot of area without using up too much edge 'real estate' needed for the canard placement - which is also forward swept; to minimise the number of radar return 'lobes' and since I wanted to put it behind the intake so as not to obstruct it or the pilots vision, I thought it would be good to reach as far forward as possible for control purposes. Obviously FSWs have got all the other airflow boundary layer separation benefits as well which probably wouldn't hurt. I wanted to make the outer wings all-moving for a bunch of more secret reasons but how that would work with a carrier folding wing I don't know. Otherwise the plane's optimised for stealth from below with a flattened underside, for low observability from ground defenders or for the look down - shoot down roll. The intakes are supposed to open from below at high angles of attack but the 2D shape necessary for this presents some nasty 90 degree angles from the side above. Like I said it's about 2 years old and needs some area-ruling but I still think it's got a few features that would benefit current planes.
Thanks for the interest, Woody
Any other comment gratefully received (as long as they're nice).

Offline Woody

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Re: Using Canards vs. Tail for aircraft control in USA and other countries
« Reply #14 on: March 11, 2007, 06:56:32 pm »
These would have been much cooler JSFs. I did have a BAe canard concept but it's gone. I know a lot of people don't think the X-36 was a JSF but MD would say that after they'd lost. Anyone got any more?
Cheers, Woody