Another AirBus-320 question

Highflyer wrote:
"pintlar" wrote in message
...

I was lead to believe the B-52's wing took a negative angle of attack when
the engines lost power. For the crew, that is nice to know that this is
not true.



I think you will find, with ANY airplane, that the angle of attack is
solely dependant upon the airspeed and the weight. It would not be
expected to change in any way by any power setting, from zero to
max.

Notice that this is definately NOT true for a powered rotary wing
aircraft! :-)

Highflyer
Highflight Aviation Services
Pinckneyville Airport PJY



For large passenger aircraft, designers attempt to ameliorate loads
by balancing one effect against another.
An example: if you put fuel tanks in the fuselage, the wing bending
moment is greatest with full tanks. If you put fuel tanks in the wings,
the in flight bending moment is LEAST with full tanks.

In the same way, to ameliorate the wing twisting moment due to engine
thrust which increases with thrust, if the engines are set well forward
of the wing center of rotation which twists the wing down towards the
tips, the twisting moment DECREASES with increasing thrust (this is a
balancing act, of course...)

This design effort has the effect of increasing AofA with thrust, which
is a stabilizing factor.

Another design choice affecting AofA is Wing sweep.
Forward sweep has efficiency benefits, but was often considered a lethal
choice. A bump which increased wing bending moment also increases AofA
in swept forward designs, but AofA decreases in Swept back designs.
The later is a load-shedding effect. The former effect is a load
multiplying effect, just when you don't want it.

Brian W