On Jul 27, 11:48*pm, wrote:
On Jul 26, 8:29*am, wrote:



As I understand it, when jet aircraft were flown from aircraft
carriers, procedures and equipment used with piston aircraft proved
inadequate, and the United States adopted a set of devices developed
by the British, including the angled deck, the optical glide path, and
the angle of attack indicator. By the time the Douglas Skyhawk was
built, the angle of attack (AOA) indicator was used with a head up
display.

Was the head up display used from the beginning, or were there earlier
types of AOA indicators with some type of panel display?

Were AOA indicators retrofitted to earlier types of aircraft designed
without AOA equipment?

When did AOA indicators begin to be installed on Air Force planes?

Thank you,
Peter Wezeman
anti-social Darwinist

There are two types of sensor, a simple stall warning switch placed at
the stagnation point at whcih stall would occur on the leading edge of
the wing and the more sophisticated type that actually gives precise
angle of attack.

In passenger jet aircraft you will notice usually 4 of these 'vanes'
mounted to either side of the cockpit. *An A320 has two either side an
A380 no less than 4 either side. *(Pre FBW these were seperate for
pilot an co pilot)

In single engine piston aircraft you will see the mounted on the wing
tips.

In Jets you will usually see similar vertical vanes mounted on the
nose to measure side slip.

A modern stall warning system uses not only Angle of Attack but side
slip to calculate stall warnings since the prescence of side slip
effects stall angle, presumably due to the greatee distance the air
must flow over the wing during side slip.

Thank you very much for your reply. Military fighter and attack planes
have angle of attack displays visible to the pilot. Do you see any
advantage to having something like this for pilots of airliners,
possibly for use as part of normal flying routine, possibly as a back-
up and cross check for airspeed information?

Some aircraft have an Air Data Probe mounted in the nose which
combines AOA, side slip and pitot static (properly called a prandl
tube). *Usually used for testing due to its precision.

Military aircraft have a sort of conical or tube shaped devise with
two pressure ports offsest slightly, these have pressure sensors in
them that drive a servo motor till they are in balance. *This is a
'pressure nulling sensor'

I believe the Grumman Cougar gave zero stall warning however an AOA
sensor, stick shaker and stick pusher fixed that and gave plenty of
warning.



In FBW aircraft the AOA, side slip and prandl sensor data are fed to
the ADIRU (air data inertial reference unit) a sort of box of
gyroscopes and accelerometers that keeps track of up and smoothes' the
jittery aerodynamic data.

That Airfrance Flight 547 that crashed in the Atlantic eroute from
Brazil to France probably losts its pitot static tube.

Normally A330 airbuses have a Honeywell ADIRU with BF Goodrich pitot
static tubes but Air France took the optional Thales Units whose pitot
tube have a tendancy to not drain water properly and ice up.
Apparently the A320 doesn't suffer from this and A330s are getting the
A320 sensors

Once iced up the FBW system would have detected the inconsistencies
and switched the control laws from full to secondary, a sort of semi
automatic mode where stall protection and flight envelop protection is
reduced. *The pilot now has to fly manually.

I once read that the control sticks on Airbus planes do not have force
feedback. If this is still the case, what is the procedure for
manually flying the plane without overstressing it?

It would have lmited the rudder to stop the pilot from over stressing
it accidently.

Flying an aircraft whether it be FBW or Normal cabled aircraft without
pitot static data at night and the middle of a storm is not easy.

Thank you again,
Peter Wezeman
anti-social Darwinist