Don't post much....but gotta ask this question. Just got back from short vacation to Outerbanks and Kitty Hawk. At the Wright Brothers Memorial I bought a great 2 hr DVD explaining their experiments. The one thing that stood out was the canard. It was explained that Wilbur wanted the elevator in the front cause it would protect him from hard landings even in the sand. He didn't want to wind up like Lilianthal(dying). But he explained he got a bonus out of it by noticing that when the nose pitched up and the glider stalled it didn't do a steep spin and dive into the ground like other gliders of the day.....it sort of pancaked down slowly and flopped gently into the sand. Why don't we all have canards(except for Burt Rutan enthusiasts) since the most common accident is stall/spin?

Once you add flaps it becomes complicated. See the sweeping Canard on the StarShip.

there is a Cassna 182 modification (Katmai) that uses a canard. It is designed for STOL and apparently works to keep the nose lower for visability as well as lift. I think the reason more has not been done with canards is the age old problem of FAA certification and the cost thereof.

There was a Katmai conversion in the avionics shop recently, while I was visiting just before having my panel updated. The owner was having a G500 installed, plus a bunch of other avionics goodies. The cowl was off, and there is no doubt, that canard set up is a complicated conversion. The airplane had been completely rehabbed, too, so for a 25 year old airplane, it looked brand new. Lotsa $$$$.

Cary

Canard first CESSNA (Original Wright Flyer was Canard !) to have Canard was the WREN in mid 1960's .Wren was designed by Robertson STOL and first sold to CIA in Laos.Todd Peterson got the Type Certificate in 70-80's after Wren had went under.Todd built I believe 10-20 Wren airplanes in 80's ,changed to Peterson 230-260 SE without wing mod (wrens teeth) retained Canard for pitch control at low air speeds.Overall really good system of contro .I've worked on several and there a bear to rig-complicated by Canard attached to engine mount and hooked to elevator control with mix master of controls.

It is all about efficiency, stability, and control.

First stability and control:
In both a canard and a traditional layout, the main lifting surface is the wing, and the canard or the horizontal tail provides the stability in the pitch axis. In a properly designed stable configuration, increasing pitch gets you to higher angle of attack and eventually the wing stalls, but the horizontal tail still provides effective pitch control. If the wing is designed properly, the ailerons will still (and are now required to by the FARs) provide roll control through the stall. The FARs don't say that exactly, but the pilot is not supposed to have to provide extraordinary effort to control the airplane through stall. The Glasair Glastar and Sportsman are designed this way. You can keep the stick back through the stall you will feel the break, keep the stick back and it will be buffeting, but you can use the ailerons to continue to provide roll control. Just relieve the back pressure a little and the buffeting goes away and off you go.

It is an interesting and cool ride.

As as stable canard configuration approaches higher angle of attack, in order for it to be stable, the canard must stall first so the airplane will pitch down to recover from a stall. Interpretation: your pitch control will be non-effective through that maneuver You do however maintain roll control through stall because the main wing doesn't stall, and that is where your roll control is.

Efficiency:
A normal airplane configuration is designed to have the wing get to 100% of its capability at stall, or rather its lifting capacity is defined by the stall. You can also put flaps, slats, etc... on the wing to really make it lift like crazy. Really you can do all that you can, as long as it is stable and you can control it.

In a stable canard configuration, the wing never gets to its maximum lifting capability because the canard must stall first and the airplane pitches down. Adding flaps provides additional issues. (Starship )

Three surface airplanes:
The Peterson machine is quite impressive, but is not technically a canard configuration. It is a three surface airplane, as is the Piaggio Avanti. There are specific reasons to use this configuration and from what is published, the Katmai is quite effective at allowing slow flight, stabilty, and control.

The real question might be, why don't we all have 3 surface airplanes

average guy wrote:Why don't we all have canards(except for Burt Rutan enthusiasts) since the most common accident is stall/spin?

Several reasons. But the short answer is that (as Burt has shown) you cannot do any better than a properly designed canard for level flight cruise efficiency on a point A to point B flight at light aircraft (<300mph) speeds. The reason is because both ends of the airplane are lifting up against gravity, as opposed to a "conventional" config. where one end of the plane is pulling down to balance it.

As mentioned, when you add flaps or other high lift devices, it becomes easier to just push down at the back a little more. Because in order to use a canard with high lift devices on the main wing, you have to put high lift devices on the canard too.

For STOL bush planes and gliders and aerobatics there is another reason. The "stall-proof" aspect of a canard airplane comes from setting the incidence angles so the canard stalls long before the main wing. So when you get to high angles of attack and/or very slow speeds, the canard is in a very high drag mode because it is getting ready to stall (to prevent the main wing from stalling). So for any airplane that needs to operate at high angles of attack, or slow speeds, the canard becomes very inefficient.

(I once had the privilege of sharing a thermal updraft in gliders with one of the greatest test pilots in the history of flight, Einar Enevoldson. He was flying Burt Rutan's brand new Solitaire" self-launching canard glider prototype a couple of miles from Mojave, and the glider simply wasn't climbing in the thermal... even though my much heavier and faster glider (a 15 meter racing ship) was climbing. The reason was that the front half of the Solitaire was just about stalled in order for it to turn tight enough to stay inside the thermal.)

This is why Burt's designs have always been unbeatable in straight line efficiency (the Vari-Eze, Long-EZ, Quickie 1 and 2, the Voyager)... and yet his bush plane (Grizzly) and glider (Solitaire) were not successful.

These problems are too complex to solve cheaply on a light homebuilt airplane. But as soon as your design can tolerate the complexity of putting flaps or computers on the canard, you can mitigate those losses and make progress. So the Piaggio Avanti, and some of Rutan's light military STOL transport designs, and especially the "three surface" type airplanes have the ability to be very efficient. But three surface airplanes like the Avanti are also EIGHT intersection airplanes at a minimum, so you have to do a bunch of computer modeling and flow analysis to keep the intersection drag from taking away whatever efficiency you gained.

Sooo.... the basic bush planes of interest to this forum are certainly not the correct place for a simple canard to shine, but to fly across the USA on 18 horsepower and 20 gallons of fuel total, in an airplane you built for $5000... you need the Quickie 1 and its canard efficiency.

Stall and spin are accidents usually related to a design problem in the flight school curriculum.

There was a katmai conversion at the Caveman fly-in. Who owns that plane?

'Greg

Thanks for the info. I was building a Vari Eze in Lancaster, Ca in the late 70's. Would take my parts out to Rutan's hangar at Mojave Airport on Saturdays...he'd look them over and give me a thumbs up or thumbs down. He was very approachable then...not famous yet. But, I talked with other builders in the area and they(aeronautical engineer types) told me it was too hot..landing speeds too high. People would try to land it like a Cessna or Piper. They told me the canard would stall and the plane would start porpoising... at 5-10 feet off the runway. And if there was a crosswind some wound up cartwheeling down the runway. They pushed for a slower approach and larger engine(Long Eze)....some were using the Lycoming 235 in a VarEze! So I stopped building it.

Thought a canard would be safe on a slower plane like the Long Eze. But got married and that was that.