So I’m in shade tree mechanic mode, sitting out here under this tree again. Waiting. I have been here before, long ago rehearsing the final steps to install the VariEze wings straight without the 10.9 inches of anhedral. Wondering whether extending the strakes forward would cause a deep stall problem like some larger canard planes were experiencing at the time. Envisioning what it would take to lower the cruise attitude slightly, more like the LongEZ. Later there was some pretty productive cooling contemplation, and some induction deduction. All routine now.
I’m literally living in your ‘slower landing’ arena, Marc. Changing to a 4000 foot runway from 6000, my approaches are a little more deliberate. I love it. So as a shade tree mechanic, besides thinking about the slower landing speeds, I get to consistently practice them. Coming in on final the other day with the nose attitude ten knots slower, the canard was fine but it sure seemed that having the wings lift a little more with the speed slower and the rear end a little higher would have been a good thing.
So I’m under the shade tree here again, mentally lingering a while with your lowering stall speed question, waiting for the solid elements to fit into place and for everything else to fall of its own weight, so to speak.
How to improve the wings for lower landing speeds.
Flaps? Slats? I have a plan, a design, several of them. I wonder if adding slats and flaps to the Eze main wing would provide a simple overall benefit, or if it would include undesired side effects. I don’t get to think about this as much as I’d like, but do wake up thinking about it every week or so. Just like the good old days.
I am waiting, expecting to be lured over the edge by someone that knows what they are doing; to settle the result of adding lift to the main wing; the result on the canard; the result on approach attitude, waiting for the physics to settle in as with the previous mods.
Basic Concepts
Marc, your initial 1 January note mentioned changing things on the wing without changing the canard. Touchy territory in Ezeland. At that time I was able to quickly work up a basic, socially acceptable position paper primarily denouncing messing with the critical canard/wing relationship. Speech #3 as my kids call those kinds of well worn monologs. Re-reading and reworking, the direction changed as two conflicting concepts met for me for the first time.
One is a position that I have nodded in agreement with for years at Eze fly-in bull sessions.
The concept was that if the weight of the engine were removed from the back, the canard would not have the authority to hold the nose up. The plane would go pure vertical nose down. Surely everyone knew this must be true.
But several years ago an actual event established the truth. You have all read about the incident right? If I remember correctly, a North Carolina VariEze was making a 200 mph-ish low pass, felt a jolt and power loss, and landed on a parallel runway.
Wondering what the heck, the pilot got out and saw dangling wires in back and fluid on the ground. He put the nose on the ground and walked back and was astonished to find that there was no lower cowl – and no engine. A crash crew pickup pulled up with the engine in the bed. I remember him attributing the engine being pulled off by a failed male inlet and lower cowl. Must have been especially interesting for the first time flyer in the back seat.
Interestingly, he stated that control response during the landing gave little or no indication that the engine had departed the aircraft. Others claiming experience in this arena seem to agree. So what about the unrecoverable nose down dive? Obviously the nose is being held up by trading off speed. There are evidently some areas of GU canard operation that haven’t been fully documented. And the area of interest here looks like one of them.
The point?
Everything in my eze ‘training’ would indicate that more complex wings would unquestionably require a more complex canard. Therefore, forget the flaps! But under the shade tree here there is at least a momentary hesitation on whether the canard might not have to be changed in conjuntion with the wing in the course of reducing landing speed. This is a very interesting moment.
Marc, your question was,
>>has anyone succeeded in lowering the stall speed of the longez?<<
As I mentioned in the Hangar Talk note, it has been done. They actually did that with the LongEZ itself. The fledgling VariEze had to be landed too fast. They modified the wing, resulting in a different wing with less sweep and about a third more area. It carried the added starter and alternator and provided the desired lower landing speed and distance.
So, an Eze wing has been modified to provide a lower ‘stall’ speed. The point here is not to make a play on words, but to try to grasp the fact that no change was made to the GU canard. It still operated almost identically with higher lift wings. Heavier follow-on aircraft had ‘normal’ handing qualities with the same GU canard.
While some may have silently nodded through this long ago, others of us have quite a ride realizing the implications here. Could another similar reduction in ‘stall’ speed be made using ‘another’ redesign of the main wing (maybe slats and flaps this time?) – while still retaining ‘normal’ canard operation? If so, this is a much simpler mod.
Now bring in the 200 lb engine weight change where the canard provided ‘fairly normal” pitch control, and you have a pretty interesting situation.
Yes, everything that is preached about the canard/wing relationship is unchanged, firmly in place, required as designed. I’m watching to see how this new element relates, and if wings optimized for landing would actually benefit the relationship.
(For two months this subject has had me wondering how many canard aircraft actually have had the stall resistance (CG) confirmed by their current owner/operator at all).
The practicality test is probably centered on what effect the added main wing flaps and/or slats actually does to approach attitude and speed and landing distance. This is what I was looking at and thinking about the other day on final with the nose fairly high. If the canard was operating with significant residual lift, couldn’t the rear be lifted a little, possibly with a move back toward the desired balance?
Much of the Eze evolution has resulted in the CG gravitating aft. Thus at full aft stick there is a higher nose attitude, with the main wing closer to stall. As mentioned in the CPs, early on, RAF’s solution for Shirl Dickey’s squirrelly landing problem was to add 12 lbs of ballast in the nose of his VariEze. Then further RAF tests showed that removing four inches off the tips decreased the canard lift capability to a just right relationship again, allowing removal of the 12 lbs.
Would adding lift to the main wing actually move the attitude more back toward an assumed (by me) middle attitude/CG sweet spot, where nose up attitude and main wing angle would still be appropriately canard limited-
Limited by a canard that has operated consistently through a significant range of applications.
Many similar mental explorations in the past have resulted in a door being gently but firmly closed against my nose. And my history of logic with these things is usually exactly 180 degrees off. We’ll see. A 24-inch long formula proving all this would certainly be impressive here.
It is interesting to imagine the variety of sugarplums dancing in Eze heads here right now. Maybe a 2000 lb LongEZ that can be landed at 40 mph!
However, in my mind over here on the other end of the spectrum there is an image of a wispy but tough 550 lb VariEze with a stock canard and articulating…even better, morphing wings, and tantalizing semi-short field capability.
I know this flap/slat stuff won’t work. Too complex. Too heavy. Too draggy. Too scary. Thank goodness. Because someone could really hurt themselves. Maybe it will just go away 
But every once in a while, about half way through waking up, I peek up and see ghostly transparent spidery looking slats and flaps hovering around the ceiling, beaconing me out to the hangar. Thanks a lot Marc.
Bill James, Fort Worth VariEze
