homebuilt safety

On 19 May 2004 12:49:13 -0700, (Paul Lee)
wrote:

:Richard Riley wrote in message . ..
:
:.................................... When I say exactly, I mean
: exactly - to the fraction of an inch in planform, with the same
: templates, with the same modified Eppler airfoil on the mains, and the
: same Roncz 1145 MS on the canard.............
:
:Rich,
:
:There is a curiosity that I found about the SQ2000. When Stan
:demonstrated stall, the plane did not dip and dive (bobing) like
:typical canards, but simply descended at a steady rate - or climbed at
:a steady rate in a power stall. The canard just shakes slightly
:almost like conventional aircraft before a stall - i.e. it failed
:gradually and not suddenly. The feature shure wis handy if you
:inadvertendly land too slow - it would descend at steady rate and not
:dive into the ground.
:
:I haven't seen this behaviour mentioned for other canards and Stan would
:not tell me how he got that. Are there other canard designs that do
:that? Do you know how it works?

What you saw is basically how the EZ canard pushers behave. The
canard bob is never large. A lot of things affect it - density
altitude, humidity, how many bugs are on the leading edge, CG, the
shape of the canard and exact placement of the elevators in
relationship to the rest of the canard. If the entire surface is
stalling at exactly the same time, the bob is more noticeable. If
parts of it hold on slightly longer than other parts, the oscillation
will be smaller.

When Rick was doing the Berkut airshow, one of his moves was a low
speed level pass, showing the canard bob at minimum airspeed. But the
real canard bob couldn't be seen from the ground - it could barely be
seen from inside the plane. So he worked the elevator up and down to
bob the nose.

I've never seen a canard let go and "dive into the ground" - the nose
always stays well above the horizon. But if you're power off, your
decent rate at canard bob is much higher than it would be at best
glide.