another thing that keeps me up at night trying to figure it out...
a plane stalls when the airflow across the top of the wing is
if that is correct, then why is it difficult to regain control when the
plane is falling as when
it falls the airflow across the wing is increased again.
wouldn't it be the same as just being in a dive?
thx all - Craig
If forward motion can be restored to facilitate airflow over the wing
the aircraft will dive to increase speed and the wing incur lift. If
an aircraft drops with no forward motion, at an attitude (pitch) which
prevents air flow over the wings to induce lift, the aircraft will drop
'flat' towards the earth like a home sick brick. This situation is
recoverable if ample altitude is available. The old saying...always fly
the airplane. If you fail to fly the plane and altitude to low, the
results tend to be fatal.
Not necessarily. As the aircraft stalls, it can fall out of the sky with the
wing at great angle to the direction of movement. What little airflow there
is over the wing will be turbulent and no lift will be generated. As there
is no airflow over the control surfaces, there will also be no control
authority. Hopefully the aircraft design will be such that it will pitch
down if all the controls are centralised, which is the traditional way of
recovering from a stall. Once that happens the aircraft *does* go into a
dive and once the airspeed builds up, control authority is restored. The
problem is that you have to have enough altitude for this to happen...
On 17-Nov-2006, firstname.lastname@example.org wrote:
That isn't at all correct. A wing stalls when it exceeds its critical angle
of attack. That's approximately 18 degrees from the relative wind give or
take a few degrees depending on the wing design. This can occur at any speed
or any attitude relative to the ground, even inverted or in a dive. The
"Cobra" maneuver performed by some high-perfomance fighters is nothing more
than a high-speed stall, accomplished by pulling back on the stick so
quickly that the wing exceeds the critical angle of attack before the
aircraft starts to climb. A stall is caused by flow separation from the top
of the wing. What makes most people think a stall is related to airspeed is
that as speed decreases, the angle of attack must be increased to keep the
same lift, to keep the aircraft from descending. Lift increases until the
critical angle of attack is reached, at which point the wing stalls and lift
drops off precipitously. There is usually still enough airflow over the
control surfaces to control the aircraft. Reducing the angle of attack will
break the stall. Aircraft with positive stability will tend to do this on
their own if you relase the controls, but neutral or negative stability
aircraft like many modern fighters need flight control inputs to break the
stall. If you want a pretty in-depth look at stalls and other aspects of
flying, check out this website:
The "coffin corner" of the flight envelope. As you go higher the air
gets thinner so stall speed increases. As you go higher the air
temperature reduces so the speed of sound decreases. The U-2 is
decidedly subsonic and operates at altitudes where the Mach limit and
stall speed approach one another.
The SR-71 escapes this by being decidedly supersonic at operational
On Fri, 17 Nov 2006 22:07:14 +0000, Enzo Matrix wrote:
The Boeing 707 had that same problem. This is one reason why turns at
speed and altitude must be made gently if they are to be made at all. You
could potentially overspeed the outside wing while stalling the inside
wing at the same time. Pilots are allergic to doing that.
A real problem with the 104 was upon landing. In order to reduce
landing speeds....bleed air from the engine is used for ' boundary
layer ' control. Basically ' blown ' air is forced over the rear flap
on the rear of the wing. ( This is also why the F-4 made strange
sounds on takeoff and landing ) If the boundary layer air is not
working properly ( such as an improper working valve )....landing
speeds for the 104 can be excessive....we are talking above 200 knots !
Also....the pilot has to be careful not to reduce the throttle upon
landing....or on approach because lower engine RPM's also mean less '
blown ' air over the flaps. So if a pilot suddenly ' chops ' the
throttle while landing in a F-104 he is probably going to smack the
runway pretty hard.
The F-104 was not a forgiving airplane. But in the hands of a
skilled pilot it was a wonder.
lol I can remember when I was stationed over at Haun AB in Ger when we had
war games the German 104s would fly simulated attacks on our airfield geeze
tree top level you wouldn'y hear them till it was to late
FWIW In their hurry to get the "new" Luftwaffe up to speed they were
putting kids straight from T-33s onto the 104. That was a formula for
disasters. The first Belgian pilot to fly the 104 was their chief flying
instructor. He went home and wrote the regs for 104 training selection.
First requirement was that a pilot had to have at least one previous
tour on some other jet fighter (F-84, Hunter, etc.) and the result was a
stellar safety record. The Belgian pilots were sorry to see the 104s
Like they say at Nellis: "Spam, no matter what kind of can you put it
in, is still Spam"!
According to the Albatros F-104 decal sheet: "Spain was unique in operating
its small number of Starfighters without a single accident during their
seven years of service and 17,500 flying hours."
I assume that means Cat5 accidents. I can't imagine them operating for seven
years without a Cat3 accident, but it is nevertheless an excellent safety
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