- 6 weeks ago
For educational purposes
When the small tail surface wings which enable an airplane to go up or down are moved to the front, they are called canards.
It is a technology as old as crewed flight, the Wrights used canards on their early airplanes. Canards were rarely used after the first World War until computer technology provided the control needed to make the technology feasible.
Featured Aircraft:
- Piaggio Avanti EVO
- Curtiss-Wright XP-55 Ascender
- North American Aviation XB-70 Valkyrie
- Scaled Composites ARES
When the small tail surface wings which enable an airplane to go up or down are moved to the front, they are called canards.
It is a technology as old as crewed flight, the Wrights used canards on their early airplanes. Canards were rarely used after the first World War until computer technology provided the control needed to make the technology feasible.
Featured Aircraft:
- Piaggio Avanti EVO
- Curtiss-Wright XP-55 Ascender
- North American Aviation XB-70 Valkyrie
- Scaled Composites ARES
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📚
LearningTranscript
00:01Hi, I'm Neil Armstrong. Join me for an adventure through time.
00:58This machine would be a
00:59appropriate for a science fiction movie, but it's a business turboprop, the Piaggio Avanti.
01:07Part of its unique look is due to this forward surface called a canard. In fact, the technology
01:15is as old as flying itself. The Wright brothers used canards on all their early flyers. Canards
01:23were out of favor for half a century, but they're making a bold reappearance on the modern aviation
01:29scene.
01:38Canards appeared early in the history of flight. The Wright brothers used front horizontal surfaces
01:44on their gliders as well as the early flyers. In fact, the canard was used a decade before
01:51the Wright brothers' first flight on the unsuccessful aircraft of British inventor Hiram Maxim.
02:04The name itself, canard, comes from the first airplane to fly in Europe, the 14BIS, built
02:10by the Brazilian aviation pioneer Alberto Santos Dumont. Dumont called his airplane Bird of Prey,
02:19but the French word for duck, canard, seemed to fit better.
02:37Most aircraft have their elevator and horizontal stabilizer surfaces attached to the back of
02:42the fuselage. If these surfaces are moved to the front, as with the canard, the elevator's authority
02:48becomes more pronounced. As a result, canard aircraft are more maneuverable. The Wright brothers
02:55used this to their advantage. The Wright flyer sat very low to the ground and had skids instead of wheels
03:01for takeoff. A canard allowed the airplane to pitch up sharply for takeoff. A tail would have dragged in the
03:07sand.
03:20Canards have been called stall-proof because the forward wing stalls, that is, loses its lift, before the main wing,
03:27causing the nose to drop slightly and the airspeed to increase, thus averting a main wing stall.
03:32But this also contributes to the main disadvantage of the canard design. It is inherently unstable in pitch.
03:41Instability was always the canard aircraft's shortcoming. Orville Wright claimed in his writings that pitch stability of a canard was
03:49a direct function of the pilot's skill.
03:51It's interesting that as soon as the Wrights adopted wheels that held their planes higher off the ground, they got
03:57rid of the canard.
04:04Another design change that made the canard unpopular occurred from about 1908 on. By then, tractor or front engines replaced
04:12pushers.
04:14Santos Dumont's Demoiselle pioneered the classic tractor configuration, and it had no canard.
04:21Still, the canard would reappear throughout aviation history, usually with a horizontal tail in front and a vertical tail in
04:28the rear.
04:28The lure of improved maneuverability has kept the military interested in the canard configuration.
04:36From the 1920s through the 1950s, only a few countries were willing to try to fly an aircraft with canards.
04:43With the horizontal tail forward, small changes in elevator control produced big changes in pitch.
04:52As the canard aircraft flew faster, elevator control became more sensitive, and the aircraft often tumbled out of control.
05:01Eventually, with the development of computers and stability augmentation systems, high-speed canard aircraft would become practical.
05:14In the 1920s and 1930s, many designers experimented with canard configurations.
05:20But serious canard research began with the Second World War, as designers searched for any gimmick that might give fighter
05:26aircraft improved performance.
05:30Two aircraft resulted, this Curtis Ascender and the Kyushu Shinden.
05:37The Japanese entry in the quest for a practical canard aircraft came late in the Second World War.
05:44Called the Shinden for a magnificent lightning, its designers envisioned it as a jet.
05:50They settled for a 2,130-horsepower engine driving a six-bladed pusher propeller.
05:57Its first flight was in August 1945, shortly before the end of the war.
06:04Earlier in World War II, the U.S. Army had awarded the Curtis Wright Corporation a contract to produce a
06:10new canard-equipped fighter.
06:12Called the XP-55 Ascender, its first flight was in July of 1943.
06:19Three XP-55s were built.
06:21The first crashed during flight tests, only a few months after its first flight.
06:27The third Ascender crashed in 1945 while doing a slow roll at a military air show.
06:35The second Ascender is housed at the National Air and Space Museum in Washington, where it awaits restoration.
06:41There, historians Hal Andrews and Bob Mickish discussed the Ascender and the Shinden.
06:47Well, you know Hal, one of the reasons the Japanese wanted to get into this design was that they needed
06:54a high-speed interceptor,
06:55one that would climb rapidly at a high rate of speed.
06:59So the Shinden was to be just an area superiority fighter as opposed to, like we know the Zero, a
07:07long-range airplane, highly maneuverable.
07:10This was a hit-and-dash type airplane.
07:13I think that the Army in this country had a similar notion when they started the airplane.
07:20In addition to wanting it to be a high-speed airplane, they primarily wanted an interceptor.
07:24It wasn't heavily gunned. It didn't carry other bombs.
07:29It was just essentially an interceptor as well.
07:32One of the problems was that instead of getting something like approaching 500 miles an hour,
07:38they came out with a speed of well less than 400 and hardly any advantage over the conventional fighters
07:46that were already in production by the time the testing was pretty well finished in 1944.
07:51One of the things that the Army had in mind was to have the airplanes more streamlined, more clean than
07:58they had been,
07:59and not have the engine up in front.
08:01And Curtis came up with the idea of putting the canard surface up in front rather than trying to put
08:09the tail on booms the way other companies had looked at it.
08:15It allowed them to put all the guns in the front of the airplane instead of in the wings,
08:20and to have a very clean fuselage design.
08:23And you didn't have a propeller with a slipstream coming back over the whole airplane.
08:28That was back in the back.
08:29There's an interesting story about what the Japanese attitude was toward new designs during World War II,
08:37and that was that a supervisor would ask the man with the idea,
08:41has anybody else done this? Have the Germans tried it?
08:44And if the answer was no, that's generally the answer that the young brain got in doing it.
08:52And the same thing held true with the Shinden.
08:54And that was the man in charge said,
08:58well, it can't be a good idea because birds and insects don't fly feet first.
09:03So that's one reason why it took so long to get their design through to the flight stage.
09:10A primary interest during flight testing was the ascender's stall characteristics.
09:14The canard surface would stall first, making the nose pitch down rather violently.
09:20The seriousness of this concern was confirmed by a crash early in the flight test program.
09:26On the third stall in a series of tests,
09:29the aircraft pitched so severely that it rotated through 180 degrees
09:33until the airplane was upside down in a stalled, zero-speed situation.
09:39The airplane fell in a flat, inverted attitude.
09:42The engine stopped because the fuel system was not designed to run upside down.
09:47The pilot tried desperately to recover.
09:50When he finally realized this was impossible,
09:52he climbed from the cockpit, which was now under the fuselage,
09:56and bailed out to safety.
10:03For any aircraft with free 1960s technology,
10:07the canard never proved feasible.
10:10Since then, however, computers and autopilots have allowed the use of canards on high-performance aircraft.
10:16Computers are used to sense any changes in pitch,
10:19and autopilots make the necessary corrections before a major problem develops.
10:25Some recent canard aircraft include the Italian SS-4,
10:28the US XP-70, and the Swedish Saab Viggen jet fighter,
10:32whose canard gives it short takeoff and landing capabilities.
10:36The Viggen, or Thunderbolt, was the first production aircraft with a canard since before World War I.
10:43It continues to fly in the Swedish Air Force, operating off-roads and short airstrips.
10:50The XB-70 Valkyrie was the most advanced aircraft of its day.
10:55Two were built, and the first flew in September of 1964.
10:59The XB-70 was designed for the Air Force as a strategic bomber that could fly at Mach 3 and
11:04higher than 70,000 feet.
11:07Its canard four wings were an integral part of why the XB-70 was so successful.
11:14Neil spoke with XB-70 test pilot Fitzhugh Fulton about the XB-70's design and what it was like to
11:21fly it.
11:29The V-70 was one of the early airplanes to have a horizontal surface on the forward end of the
11:36fuselage of modern aircraft.
11:39What was the purpose of that?
11:41Well, the canard surface, or the forward surface as you call it, it ties into the longitudinal control.
11:48In other words, the pitch up and down on the airplane.
11:51You can either put a surface up front or you can put it in the back.
11:55In the case of the B-70, we had the surface up front and in the back.
12:00The surface up front, the canard, was very, very effective doing high-speed flight.
12:06At low-speed flight, the surface in the rear was more effective.
12:09So you had a little bit of the best of both worlds, you might say.
12:14And from the cockpit, what awareness did you have of this surface being there?
12:23Well, I think that shows that it was ideally designed because you had no difference of feel.
12:29You didn't know that the surface was forward or rear.
12:32The airplane responded just like it would if it didn't have a front surface.
12:36And it flew extremely well.
12:39And so from a pilot standpoint, you didn't know the difference.
12:42Did the crew have the obligation to lock that forward surface and switch control from back to front?
12:49Or was that part of the automatic system?
12:51Well, you had, as I mentioned, you had a flap on the trailing edge of this canard.
12:55And so when you selected the flap down, the canard automatically went to a locked position and stayed there.
13:00When the flaps came up, it entered right into the flight control system.
13:05It was one degree of movement up front to six degrees in the rear.
13:09So it had a six to one ratio.
13:11But even though it only had one sixth of the motion at high speeds, it had a lot more control
13:16power.
13:17It had more effectiveness, yes.
13:18The canard equipped aircraft have made a comeback.
13:23What was for decades a rejected form of flight control has become relatively common.
13:32Modern canard equipped aircraft demonstrate excellent control and maneuverability characteristics.
13:40Bert Rutan has been instrumental in reintroducing the canard from his home-built designs to the
13:48beach starship. Bert Rutan is a unique designer and builder of composite aircraft. His initial
13:58kit-built Vara Viggen was based on the Swedish Viggen fighter. Many of Rutan's subsequent designs
14:04are also canard aircraft. Neil spoke with Bert about his use of canard technology. Bert you've
14:11been using canards in a number of designs for some period of years but some airplanes don't have them.
14:19Why do you choose canards for some configurations and not for others? Well each airplane has a
14:25different set of requirements so the main reason that I've used canards on most of my canard
14:31airplanes has been really one issue and that is to provide this natural stall limiting. On an
14:38airplane where its stall characteristics and its stall safety are not as important why I wouldn't
14:44be as inclined to do so and sometimes they'll all fly about the same or all cost about the same
14:52and
14:52the customer will say I want that one because it looks better. Bertan's influence extends beyond
14:59kit-built to the design of beach aircrafts model 2000 starship one corporate turboprop. The
15:06conventional tail is replaced by large distinctive tip sails that provide directional stability and
15:12reduce wingtip vortices. The starship canard is notably different from others. It features a variable
15:20sweep from four degrees forward to thirty degrees aft. This sweep is linked to flap movements to offset
15:27resultant pitch and trim changes. A competitor of the beach starship in the field of commercial aviation
15:34is the Piaggio Avanti. The Avanti's fixed forward surface is fitted with slotted flaps that are coupled to the
15:41main wings flaps. They deflect together to offset changes and trim. The canard has also appeared on research and military
15:54craft.
15:56The Grumman X-29 was built as a research craft to test forward swept wing technologies including
16:02the interaction of a canard with the wings. The canard balances the aircraft at supersonic speeds by sharing the
16:10aerodynamic load with the wing. Unlike a horizontal stabilizer which carries a download during supersonic flight
16:17flight that must be overcome by the wing. So for supersonic flight the canard is a plus. But when the
16:23airplane slows down the center of lift moves forward and the airplane becomes unstable continually trying to pitch
16:30nose up or down. To provide stability a computerized flight control system monitors what the airplane is doing,
16:38compares it with what the pilot wants it to do, and adjusts the canards accordingly 40 times a second.
16:52The Rockwell B-1B bomber is the long awaited replacement for the B-52. It features two small winglets under
17:00its nose to enhance maneuverability and pitch control.
17:09Several new fighters use canard technology including the Israeli Air Force's Kefir, the Swedish Saab Gripen, and the Ares Lightweight
17:18close air support fighter.
17:24Neil spoke with Scaled Composites test pilot Mike Melville about how the use of the canard affects the Ares performance.
17:31This airplane is a shoulder canard. Is there any particular characteristics of that obvious to the pilot?
17:41It's really you don't see it. It's very much in your absolute limits of your peripheral vision because it's behind
17:47your shoulders.
17:48And so you have excellent visibility much like a standard fighter or even a helicopter.
17:54The reason for putting the canard on this kind of an airplane is the natural angle of attack stall limiting
18:01that you get with the canard.
18:02In other words, the canard stalls before the wing does. So you're able to pull this airplane in very tight
18:07trying to support someone on the ground
18:09and not have an accidental departure, a stall, a spin, and an accident.
18:13This airplane can be just pulled at will in any direction you want to go 100 feet above the ground
18:19and you're not going to lose control of the airplane.
18:21That was the basic reason to do a canard airplane.
18:36The canard takes care of pitch control and longitudinal stability.
18:40But you've still got the problem of directional stability and, as you know, you need vertical surface installed somewhere on
18:46the airplane behind the CG.
18:47The further back, the more stable it's going to be. And in order that we didn't have to have a
18:52very, very long airplane,
18:54we went to twice or two tails, which doubled the area, the vertical surface area.
18:59And then we were able to keep it a short, small airplane so that you could park it in a
19:04smaller hangar.
19:17The.
19:31The..
19:33The..
19:33The..
19:37The..
19:59The airplane flies more like a light plane than it does like a fighter in some respects.
20:05It has extreme agility. You can turn this thing on a dime. It turns in half the radius of anything
20:11that you've flown probably. We can outturn an A-10 so badly it would be amazing. So it is very
20:19agile and in the pattern. You can make very tight patterns. It has good sync rate. You can generate a
20:24lot of sync with it. It has good speed brakes on it. Trailing edge speed brakes that you can pop
20:27out instantly and put them back in instantly.
20:29Very nice handling airplane in the traffic pattern. Easy to land. The first time you ever fly it you make
20:36a perfect landing. It's actually a very easy airplane to fly.
21:04Join me next time for First Flights.
21:07First Flights.
21:09Now we see if you have a crash with youræ°´.
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