Tandem-wing Airplanes

On Feb 2, 4:22*pm, wrote:
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. 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.

* * * *Dan

OK, this makes sense. Since a small lifting tail would be a long way
from the CG (compared to the main wing), it would experience a much
higher angle of attack when the aircraft pitched up. It would be very
difficult to make the main wing stall before the tail.

Phil

Phil J wrote in
:

On Feb 2, 4:22*pm, wrote:
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. 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.

* * * *Dan

OK, this makes sense. Since a small lifting tail would be a long way
from the CG (compared to the main wing), it would experience a much
higher angle of attack when the aircraft pitched up. It would be very
difficult to make the main wing stall before the tail.


Actually, it wouldn't. It's easy. You're not talking about nailing a
lifting tail to a Cessna. You're talking a bespoke design and you
wouldn't have a small stab either. A lifting stab requires an aft CG and
so a completely different config anyway.

Bertie