homebuilt safety

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?

---------------------------------------------------
Paul Lee, SQ2000 canard: http://www.abri.com/sq2000

On Wed, 19 May 2004 13:49:13 -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?

--------------------------------------------------- Paul Lee, SQ2000
canard: http://www.abri.com/sq2000


I'm not Richard Riley, but I'll pipe up anyway.

I'm betting that there wasn't enough pitch authority to get the angle of
attack high enough to stall the canard. The situation might be quite
different if the CG was further aft (i.e. pilot only, or with pax in back).

--
Kevin Horton RV-8 (finishing kit)
Ottawa, Canada
http://go.phpwebhosting.com/~khorton/rv8/
e-mail: khorton02(_at_)rogers(_dot_)com

Kevin Horton wrote...

I'm not Richard Riley, but I'll pipe up anyway.

It's getting crowded in Richard and Paul's phone booth g

I'm betting that there wasn't enough pitch authority to get the angle of
attack high enough to stall the canard. The situation might be quite
different if the CG was further aft (i.e. pilot only, or with pax in
back).

You beat me to it.

Dave 'control power' Hyde

"Kevin Horton" wrote in message
I'm not Richard Riley,

God be thanked.

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.