As a non-real life pilot here, can you explain please?
hey @Scoop , with your first hand exp in Long-EZ I think you can explain some of the magic of the canard concept
What would you like to know?
short version or long?
particularly would like to know more about the stall characteristics of canard design and how is the landing profile different from classic configuration. tia
EDIT: Post deleted. For correct explanation of canard vs stalls and landings, refer to @Scoop post right below.
Speaking based on only three canards, the Goldwing (non Rutan) and the Varieze and Longeze (flown three different examples of the latter and also own one).
A canard stalls just like any other aircraft. However, the angle of attack of the canard is set greater than the mainplane causing the canard to stall well before the mainplane. The nose therefore pitchs down while the mainplane continues to generate ample lift, even enough to climb! It is possible to take off, fly a circuit and land with the stick held fully back throughout! All that happens is the nose ‘bobs’ up and down. When the canard stalls it pitchs down a little, unstalls and regains lift/elevator authority immeadiately. So no, a stall close to the ground DOES NOT cause a rapid sink and a crash.
Such a technique with the stick fully back is not recommended but it realy does work… however:
On take off do not raise the nose above the horizon below about 300 feet. Should the engine fail while in a high nose attitude, then the sink rate may be such that contact with the ground may occur before the canard has unstalled. The first point of contact would possibly be the nosewheel, perhaps causing a collapse of the nose leg and a certain amount of damage. NB the eze family may land without a nosewheel, again not recommended but I have done it during an aborted take off - nose wheel detached, landed on mains and nose leg less wheel. I should have retracted the nose leg completely but didnt think it through fast enough - the wheel had bounced into the prop so I had to shut down the engine and flare, all below 50’. The wheel came off after contacting a RHAG on take off. NB BURT RUTAN SAYS ALWAYS LAND NOSEWHEEL DOWN.
Can it be made to stall properly. No, or at least not by me. I have tried hard. I have pitched up at speed and held c90 degrees to the horizon with the stick progressively being brought fully aft to maintain the pitch as the canard stalls the nose pitchs down towards the horizon and then the canard unstalls. At no point in this was the mainplane stalled. Full aileron and rudder authority was maintained throughout. Even applying these controls did not induce a classic stall, and of course it was impossible for me to enter a spin despite full pro spin control and power.
Landing. I confess to causing @Victork2 some concern when I flew him. On landing I increased the flare into a high nose up attitude having kept extra speed to facilitate this. I maintained this high nose attitude down the runway until canard stall. It looks cool, just like some fast jets land. Not the recommended landing technique which is quite ordinary.
Prior to engine start lower the airbrake. Do not raise it until starting the take off roll - unless you have an extra 50m available. If the latter the airbrake will close itself as airspeed builds. The air brake stops FOD damaging the propeller after being thrown up by the nose wheel.
Always land with air brake and keep it out until after you shut down, again to stop FOD.
Wear you watch on your right arm, or reverse it to the inside of your left wrist. When the airbrake closes due to increasing speed the brake handle slams down onto your watch! This may occur during the approach. I put the brake out in the overhead when I lower the noseheel. Ezes want to fly fast and they will accelerate, hence I broke a watch downwind.
Lift your toes off the rudder pedals on rotation at take off. A bit of brake pedal in a crosswind means rudder is deployed at rotate - it has a bigger roll input than the aileron. The wing could dig in. As stick is pulled back, just lift your toes of the rudders briefly.
Rudders. You have two. They can both be used at once when braking on the ground or in flight as an extra air brake. The rudder pedals are independent of each other. They also work as rudders and ailerons. In the cruise i put my feet behind the pedals for leg comfort and dont use them until rejoining.
Canards are fun, and are actualy easy to fly.
NB the Goldwing had a hatch like a bomb bay beneath the pilots knees. Push down with your feet opens it and enable you to use your feet v power. The goldwing has no brakes. Also as the nosewheel only steers about 15/20 degrees. For large turns on the ground push down with your feet and lift the nose off the ground. Shuffle sideways with your feet to turn on the spot!
NB No one has made a sim of an eze that flies like one
Sorry. Not correct. I refer you to my comments on subject.
Thanks for making that clear. Something new I learnt today
I had such landing mishap in MSFS twice so thought it was usually the case with canards. But no. It probably has something to do with this:
I also edited my post above (deleted it).
FYI this is extremely disconcerting at first but becomes quite natural and even quite reassuring after a few moments
Its still weird though. I’d love a long eze if i had anywhere local to keep it
I have the MSFS Long Eze and it bears no relationship aerodynamicly to a Long Eze. The module stalls like a non canard. I often get asked about approach and landing speeds. I deliberately stall to find canard stall for the actual weight by downwind, if I do not already know it. Not many aircraft pilots do this! I approach at 1.3 canard stall. I land at about 1.15 but never look at an ASI at that point. I do it by just holding the nose off and then placing all wheels on the deck, mains then nose. Then brake as required unless showing off to @Victork2 . Sorry Ace
Nb the landing weight varies far more than in the average spam can. Fuel, cargo, passenger. Lots of fuel…
Thanks for the post! That’s quite an unusual way for flying an airplane. Some of that stuff sounds as reverse as the EZ looks like. It all makes sense but I’d never have guessed it.
Thanks for explaining that in a way I could understand
I just tried with the Velocity V-Twin in XP11 (because that is most likely the aircraft that I will use this year) and they appear to have modelled the canard characteristics quite well?
Throttles back to idle, let some airspeed bleed off and held full back on the stick - nose came up about 20 degrees and ‘stalled’ then dropped to about 20 degrees below the horizon until I picked up some airspeed again and it then continued to oscillate up and down in decreasing amounts as more and more airspeed bled off until it settled to bobbing up and down about 5 degrees with a steady rate of descent. At no stage did I lose aileron or rudder authority.
And I couldn’t get it to spin, the best I could achieve was more like a steep descending spiral turn and it rolled level and the nose came up as soon as I centered the controls.
I did not make clear that the two rudders work opposit to each other. Port rudder only does yaw to port and vv. Using both pedals makes the rudders oppose each other, hence extra airbrakes. Imagine a cessna rudder splitting and each half moving in different directions
My girl. The canopy is not secure - it can be a greenhouse on the ground the crack allows a nice cooling breeze. I often taxi with the canopy fully open. I check at the hold and when lined up that the lid is secure. I also check for audio alarms which I will have canceled prior to the powerchecks. Damn noisy with the wheels up or the lid insecure.
Brakes are on,I think you can make out the rudders have moved in opposit directions. Under my seat, you can see the airbrake is deployed as a FOD deflector.
NB take off trim is set, yet the elevator is deflected down. Took a minute to get used to the elevator operating in the opposite way to normal. Full free and correct control checks are interesting.
I always wondered… is the nose gear as flimsy as it looks?
Its a single piece of carbon fibre with metal fittings at each end. It is less robust than the main gear.
That is some cool information. Don’t want to lose it in the other thread.
Excellent post, @Scoop! Rutans designs have always intrigued me, ever since I was a little kid. Of course, he did design the Vari Viggen…!
I’d just like to add to what Scoop writes in the quote above, that this is part of what makes the aircraft statically stable in pitch. Consider the opposite, that the canard stalled at a higher AoA than the main wing… What would happen in a stall? Yes, the aircraft would pitch up and that’s not what you want in such a situation.
Unless you put those canards on a rotating axis, controlled by powerful servos and a fly-by-wire computer which would make it possible to utilize this instability to increase the maneuverability of the aircraft.
Rutan canards are wonderfully fun to fly, and real performers. They’re easy, but require different technique than conventional designs. I have time in them and my experience all mirrors @Scoop, so I won’t repeat anything he’s already said more eloquently than I could.
One thing you do want to avoid is a full-stall landing like some learn to do in a Cessna. If the nose drops in the flare and the nose gear hits hard while the mains are still airborne it will break off the nose gear at the lower mount/castor and trunion.
In my experience this is more apt to happen to pilots with lots of light aircraft experience but no jet hours, such as when my mom did so, resulting in some significant martial distress and a young WarPig spending his whole summer assisting with repairs.
In the case of the accident I witnessed/helped repair, the nose gear leg was undamaged beyond scuffs from detaching and sliding down the runway. The aluminum at both ends was what sheared.
The ones I flew the stall was immediately self-recovering once the nose dropped and AOA simultaneously decreased. The exception would be if back pressure was kept on, in which case the nose would fall, then rise a bit as elevator authority returned, then fall again sorta like a falling leaf.
The initial climb was because I still had too much speed when I pulled back on the stick. I just had another try - chopped the throttles, kept straight & level and waited for the ‘stall’. It behaved almost exactly as you describe