wrote in news:ac796136-f9af-4608-a9ad-
:

On Feb 2, 2:21 pm, Bertie the Bunyip wrote:
So, tu summarise, if you put the "smaller wing" (sic) in the back,
it';s
a tail unless it;s lifting. If it's lifting it needs to be fairly
large
to be useful. make it large enough and you have problems with
handling,
one solutuion for this problem is to reduce the sizre of the forward
wing and move the CG aft. Voila! you have a canard!

Bertie

Seems to me that lifting tails are, and have been, illegal for
long time.


Well, i wouldn't have thought so.

The regs call for the aircraft to automatically settle into
a glide if the power should fail, to prevent stalling. A lifting tail
just won't do this. As the airplane slows it will drop, raising the
nose, and the airplane will stall, and almost certainly enter an
unrecoverable spin. If the pilot does manage to establish a glide, the
nose will drop further as glide speed increases, opposite to what we
know in our airplanes, and totally unstable. Some early airplanes were
built this way, and after they'd killed enough pilots the designers
decided to make things differently.
See FAR 23 (U.S.) or CAR 523 (Canadian) for the details.


Wel, yeah, if you just put one one on a 172 and move the CG back you're
going to have problems. , but lots of free flight airplanes use this
system with no problems. They do get very twitchy n pitch if you put a
radio elevator on them though.
this is a typicl old time FF airplane with a lifting stab.

http://www.rcgroups.com/forums/attac...mentid=1670799

These don't spin even with elevator and rudder (wel, not easily) and as
you can see are arranged very different from a modern lightplane. They
are also extremley sensitive to CG variations which would make this
arrangemetn undesirable on full size aircraft.


Bertie