canard flying boat

On Wed, 20 Jul 2005 20:05:23 +1000, "......... :-\)\)"
wrote:

The biggest issue with a canard is that the CLmax of the configuration is
low compared to a conventional configuration. This is for several reasons:

1. The smaller canard must stall first and that means that the wing will
never stall and hence never develop it maximum lift. Of course the opposite
is true for a conventional airplane. The larger wing stalls and developes
its maximum lift whilst the smaller tailplane remains unstalled.

2. Unless you do some tricky stuff you cannot really put a flap on a canard
because it is difficult to trim out the nose down pitching moments.

Low CLmax means that the configuration will not develop as much lift at a
given speed and hence the airplane will not be as suitable for short fields
as will a conventiona configuration.

For those without an engineering background, CLmax is simply a measure of
how much lift a given wing will produce per unit area at a given speed.
CLmax is the maximum lift coefficient.



"Marc J. Zeitlin" wrote in message
...
fredfighter wrote:

Hmm. ISTM that a canard does not stall when the aircraft pitches
down, it stalls when the aircraft pitches up.

Correct.

picture an aircraft flying along which has a sudden brutal increase in
the resistance of the wheels (note that is hypothetical, thankfully
the snake oil plane wasnt built)
say for instance your canard clips the main wheels on the top wire of
a fence.
in that scenario, which is similar to what I predicted with the
hovercraft skirt, the sudden rotation forward and down would be
catastrophic in that the sudden downward movement of the canard would
probably increase its angle of attack beyond the stall (due to a
change in realtive wind direction).
that is what I was referring to.
other than that I have agreed with all that has been posted.
Stealth Pilot