Angle of Attack Indicators

[[email protected]]

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

[jrw]

Ed Rasimus 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.

> I think you'll find AOA information available in some format or other
> all the way back to the early '50s in USAF aircraft.

The A-4 had no HUD, at least not until the Marines' A-4M version.
There was an Indexer on the glareshield, though.

[[email protected]]

On Jul 26, 11:11*am, "jrw" > wrote:
> Ed Rasimus 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.
> > I think you'll find AOA information available in some format or other
> > all the way back to the early '50s in USAF aircraft.
>
> The A-4 had no HUD, at least not until the Marines' A-4M version.
> There was an Indexer on the glareshield, though.

I misread the picture of the display system on the A-4. I see now that
the three color display is at the lower edge of the windscreen where
it can be seen in the pilots peripheral vision. In another source, I
found that British AOA systems circa 1960 for carrier jets had audio
output indicating whether AOA was optimal.

Peter Wezeman
anti-social Darwinist

[[email protected]]

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.

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.

I don't see the point giving an aircraft a lot of stall warning as in
say a spitfire by given a lot of washout when sensors can now do the
job. Reducing aerodynamic efficiency to give a progressive stall
development is giving away turning circle and aerodynamic efficiency.
Aircraft such as the Ta 152H had such a large degree of washout (3
degrees) they were apparently fully controllable in roll during the
stall.

Of course you still want good post stall recovery. Slats strike me as
a good way to do that.

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.

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.

[[email protected]]

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

[JR Weiss[_2_]]

wrote:

>> 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 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?

Unfortunately, the "experts" in the Transport Category Airplane world
have deemed AOA readouts as superfluous. Their argument (among others)
is that optimum AOA for any particular operation is not constant for a
large range of gross weights, so Vref or V2 as defined by the FAA and
other regulatory agencies is "better."

After 20 years of aircraft carrier operations and 11 years of airline
operations I tend to disagree, but I'm not an aerodynamicist...

FWIW, the sideslip vanes may be on Airbusses, but they're not on the
747, and I haven't noticed them on any other Boeings. Harriers had
them, and Tomcats had yaw strings (simple and effective).

[Dudley Henriques[_2_]]

On Jul 29, 10:25*pm, "JR Weiss" > wrote:
> wrote:
> >> 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 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?
>
> Unfortunately, the "experts" in the Transport Category Airplane world
> have deemed AOA readouts as superfluous. *Their argument (among others)
> is that optimum AOA for any particular operation is not constant for a
> large range of gross weights, so Vref or V2 as defined by the FAA and
> other regulatory agencies is "better."
>
> After 20 years of aircraft carrier operations and 11 years of airline
> operations I tend to disagree, but I'm not an aerodynamicist...
>
> FWIW, the sideslip vanes may be on Airbusses, but they're not on the
> 747, and I haven't noticed them on any other Boeings. *Harriers had
> them, and Tomcats had yaw strings (simple and effective).

Hi John;

I've heard the same thing from the airline industry, and I think they
might have a point. I've always wondered how you guys handle the vast
differences in gross weights you have when you arrive at the initial
approach fix.
The Navy as we both know, requires a very stable approach profile so
AOA is great for them, as it automatically compensates for the
differences in approach weight and the approach is the same AOA
regardless of weight. But this assumes a fairly (or at least
comparatively anyway) narrow gross weight for the Navy when arriving
for the approach on the boat.
You guys in the majors deal with what could loosely be described by a
Navy fighter pilot as a fair to middling gross weight range on
approach. My guess would be that using an optimum AOA on approach
might very well not be as viable as using a Vref. I would of course
bow to your better judgment on this since you have time in the big
boys and I don't.
I remember seeing a report from Boeing a while back where they were
"discussing" the addition of AOA to the approach equation both with
adjusted procedures and panel changes regarding instrumentation.
If I remember right, the bottom line on their research was that the
front offices and chief pilots of various majors couldn't reach a
consensus on the issue strong enough to warrant a major policy change
at the top level. There were specific lines who were willing to have
their panels equipped with a change from a peripheral AOA indicator to
a prominent place on the glass for an AOA tape on the approach mode,
but I never followed this through enough to discover were if anywhere
everybody went with all this.
Dudley

[JR Weiss[_2_]]

Dudley Henriques wrote:

>> Unfortunately, the "experts" in the Transport Category Airplane
>> world have deemed AOA readouts as superfluous. *Their argument
>> (among others) is that optimum AOA for any particular operation is
>> not constant for a large range of gross weights, so Vref or V2 as
>> defined by the FAA and other regulatory agencies is "better."
>>
>> After 20 years of aircraft carrier operations and 11 years of
>> airline operations I tend to disagree, but I'm not an
>> aerodynamicist...

> I've heard the same thing from the airline industry, and I think they
> might have a point. I've always wondered how you guys handle the vast
> differences in gross weights you have when you arrive at the initial
> approach fix.
> The Navy as we both know, requires a very stable approach profile so
> AOA is great for them, as it automatically compensates for the
> differences in approach weight and the approach is the same AOA
> regardless of weight. But this assumes a fairly (or at least
> comparatively anyway) narrow gross weight for the Navy when arriving
> for the approach on the boat.
> You guys in the majors deal with what could loosely be described by a
> Navy fighter pilot as a fair to middling gross weight range on
> approach. My guess would be that using an optimum AOA on approach
> might very well not be as viable as using a Vref. I would of course
> bow to your better judgment on this since you have time in the big
> boys and I don't.
> I remember seeing a report from Boeing a while back where they were
> "discussing" the addition of AOA to the approach equation both with
> adjusted procedures and panel changes regarding instrumentation.
> If I remember right, the bottom line on their research was that the
> front offices and chief pilots of various majors couldn't reach a
> consensus on the issue strong enough to warrant a major policy change
> at the top level. There were specific lines who were willing to have
> their panels equipped with a change from a peripheral AOA indicator to
> a prominent place on the glass for an AOA tape on the approach mode,
> but I never followed this through enough to discover were if anywhere
> everybody went with all this.

I still believe that AOA is a more sensitive indicator of performance
than IAS at relatively low airspeeds. That may actually be the
"problem" though -- we probably don't want transport pilots pumping the
yoke to keep an "optimum" AOA and get the passengers upset...

OTOH, the range of handling differences between a "light" (33,000 lb)
and "heavy" (36,500) A-6 on the ball and a "light" (170,000 Kg) and
"heavy" (302,000 Kg) 747 are quite different (I won't address the A-4,
because it wasn't a "heavy" in any sense of the word). The A-6
differed mainly in power response on the G/S, but the 747 differs
mainly in the flare. While AOA was critical in the A-6 to keep the
hook at the proper angle of dangle to snag the 3-wire, the 747 can be
landed comfortably anywhere in the nominal 3000' landing area (first
1/3) of a typical runway.

OTOOH, I think a "real" AOA indicator would be VERY helpful in escape
maneuvers for WindShear and Terrain warnings. The stick shaker is a
useful On/Off switch for backpressure, but a trend indicator via AOA
would be much more useful.

[Dudley Henriques[_2_]]

On Jul 30, 12:03*am, "JR Weiss" > wrote:
> Dudley Henriques wrote:
> >> Unfortunately, the "experts" in the Transport Category Airplane
> >> world have deemed AOA readouts as superfluous. *Their argument
> >> (among others) is that optimum AOA for any particular operation is
> >> not constant for a large range of gross weights, so Vref or V2 as
> >> defined by the FAA and other regulatory agencies is "better."
>
> >> After 20 years of aircraft carrier operations and 11 years of
> >> airline operations I tend to disagree, but I'm not an
> >> aerodynamicist...
> > I've heard the same thing from the airline industry, and I think they
> > might have a point. I've always wondered how you guys handle the vast
> > differences in gross weights you have when you arrive at the initial
> > approach fix.
> > The Navy as we both know, requires a very stable approach profile so
> > AOA is great for them, as it automatically compensates for the
> > differences in approach weight and the approach is the same AOA
> > regardless of weight. But this assumes a fairly (or at least
> > comparatively anyway) narrow gross weight for the Navy when arriving
> > for the approach on the boat.
> > You guys in the majors deal with what could loosely be described by a
> > Navy fighter pilot as a fair to middling gross weight range on
> > approach. My guess would be that using an optimum AOA on approach
> > might very well not be as viable as using a Vref. I would of course
> > bow to your better judgment on this since you have time in the big
> > boys and I don't.
> > I remember seeing a report from Boeing a while back where they were
> > "discussing" the addition of AOA to the approach equation both with
> > adjusted procedures and panel changes regarding instrumentation.
> > If I remember right, the bottom line on their research was that the
> > front offices and chief pilots of various majors couldn't reach a
> > consensus on the issue strong enough to warrant a major policy change
> > at the top level. There were specific lines who were willing to have
> > their panels equipped with a change from a peripheral AOA indicator to
> > a prominent place on the glass for an AOA tape on the approach mode,
> > but I never followed this through enough to discover were if anywhere
> > everybody went with all this.
>
> I still believe that AOA is a more sensitive indicator of performance
> than IAS at relatively low airspeeds. *That may actually be the
> "problem" though -- we probably don't want transport pilots pumping the
> yoke to keep an "optimum" AOA and get the passengers upset...
>
> OTOH, the range of handling differences between a "light" (33,000 lb)
> and "heavy" (36,500) A-6 on the ball and a "light" (170,000 Kg) and
> "heavy" (302,000 Kg) 747 are quite different (I won't address the A-4,
> because it wasn't a "heavy" in any sense of the word). *The A-6
> differed mainly in power response on the G/S, but the 747 differs
> mainly in the flare. *While AOA was critical in the A-6 to keep the
> hook at the proper angle of dangle to snag the 3-wire, the 747 can be
> landed comfortably anywhere in the nominal 3000' landing area (first
> 1/3) of a typical runway.
>
> OTOOH, I think a "real" AOA indicator would be VERY helpful in escape
> maneuvers for WindShear and Terrain warnings. *The stick shaker is a
> useful On/Off switch for backpressure, but a trend indicator via AOA
> would be much more useful.

It's an interesting subject and I'm sure in any end analysis, aoa
could be integrated into the heavy environment. more than it has been.
Personally I like aoa. I've always taught wing and energy management
flying from Cubs to high performance singles.
The future may very well reveal the benefits of aoa to a wider cross
section of the commercial community. Hope so anyway! :-)
DH

[Ken S. Tucker]

On Jul 29, 9:48 pm, Dudley Henriques > wrote:
> On Jul 30, 12:03 am, "JR Weiss" > wrote:
>
>
>
> > Dudley Henriques wrote:
> > >> Unfortunately, the "experts" in the Transport Category Airplane
> > >> world have deemed AOA readouts as superfluous. Their argument
> > >> (among others) is that optimum AOA for any particular operation is
> > >> not constant for a large range of gross weights, so Vref or V2 as
> > >> defined by the FAA and other regulatory agencies is "better."
>
> > >> After 20 years of aircraft carrier operations and 11 years of
> > >> airline operations I tend to disagree, but I'm not an
> > >> aerodynamicist...
> > > I've heard the same thing from the airline industry, and I think they
> > > might have a point. I've always wondered how you guys handle the vast
> > > differences in gross weights you have when you arrive at the initial
> > > approach fix.
> > > The Navy as we both know, requires a very stable approach profile so
> > > AOA is great for them, as it automatically compensates for the
> > > differences in approach weight and the approach is the same AOA
> > > regardless of weight. But this assumes a fairly (or at least
> > > comparatively anyway) narrow gross weight for the Navy when arriving
> > > for the approach on the boat.
> > > You guys in the majors deal with what could loosely be described by a
> > > Navy fighter pilot as a fair to middling gross weight range on
> > > approach. My guess would be that using an optimum AOA on approach
> > > might very well not be as viable as using a Vref. I would of course
> > > bow to your better judgment on this since you have time in the big
> > > boys and I don't.
> > > I remember seeing a report from Boeing a while back where they were
> > > "discussing" the addition of AOA to the approach equation both with
> > > adjusted procedures and panel changes regarding instrumentation.
> > > If I remember right, the bottom line on their research was that the
> > > front offices and chief pilots of various majors couldn't reach a
> > > consensus on the issue strong enough to warrant a major policy change
> > > at the top level. There were specific lines who were willing to have
> > > their panels equipped with a change from a peripheral AOA indicator to
> > > a prominent place on the glass for an AOA tape on the approach mode,
> > > but I never followed this through enough to discover were if anywhere
> > > everybody went with all this.
>
> > I still believe that AOA is a more sensitive indicator of performance
> > than IAS at relatively low airspeeds. That may actually be the
> > "problem" though -- we probably don't want transport pilots pumping the
> > yoke to keep an "optimum" AOA and get the passengers upset...
>
> > OTOH, the range of handling differences between a "light" (33,000 lb)
> > and "heavy" (36,500) A-6 on the ball and a "light" (170,000 Kg) and
> > "heavy" (302,000 Kg) 747 are quite different (I won't address the A-4,
> > because it wasn't a "heavy" in any sense of the word). The A-6
> > differed mainly in power response on the G/S, but the 747 differs
> > mainly in the flare. While AOA was critical in the A-6 to keep the
> > hook at the proper angle of dangle to snag the 3-wire, the 747 can be
> > landed comfortably anywhere in the nominal 3000' landing area (first
> > 1/3) of a typical runway.
>
> > OTOOH, I think a "real" AOA indicator would be VERY helpful in escape
> > maneuvers for WindShear and Terrain warnings. The stick shaker is a
> > useful On/Off switch for backpressure, but a trend indicator via AOA
> > would be much more useful.
>
> It's an interesting subject and I'm sure in any end analysis, aoa
> could be integrated into the heavy environment. more than it has been.
> Personally I like aoa. I've always taught wing and energy management
> flying from Cubs to high performance singles.
> The future may very well reveal the benefits of aoa to a wider cross
> section of the commercial community. Hope so anyway! :-)
> DH

Referring to sims, I found the AoA indicator of scientific interest
to measure airfoil performance, but in shooting landings I relied
on the IAS (knots/hr) and vertical airspeed indicator(feet/minute),
those together give a rough idea of angle of descent, and one
then gets a feeling of AoA from pitch.
What might be considered is an instrument that can provide all
that info in nice clear form on single gauge at a glance, let's
design it.
Ken

[JRWeiss]

Ken S. Tucker wrote:

> Referring to sims, I found the AoA indicator of scientific interest
> to measure airfoil performance, but in shooting landings I relied
> on the IAS (knots/hr) and vertical airspeed indicator(feet/minute),
> those together give a rough idea of angle of descent, and one
> then gets a feeling of AoA from pitch.

Yes, you can get a "feel" of AOA from all that, but not enough to fly
AOA with the accuracy required in modern carrier operations. A half
degree of pitch or a decel/accel trend that you don't see in time could
be the difference between a safe landing and a bolter or worse.

BTW, IAS is measured in knots, not knots/hr. A knot is a nautical
mile/hour, so "knots/hour" would be an acceleration, not a velocity.


> What might be considered is an instrument that can provide all
> that info in nice clear form on single gauge at a glance, let's
> design it.

Can't do it; there are too many different types of measurements to be
made and displayed. While a velocity vector pointer on a HUD may give
a good portion of it, speed is missing...

[Ken S. Tucker]

Hi JR.

On Aug 5, 12:22 am, "JRWeiss" > wrote:
> Ken S. Tucker wrote:
> > Referring to sims, I found the AoA indicator of scientific interest
> > to measure airfoil performance, but in shooting landings I relied
> > on the IAS (knots/hr) and vertical airspeed indicator(feet/minute),
> > those together give a rough idea of angle of descent, and one
> > then gets a feeling of AoA from pitch.
>
> Yes, you can get a "feel" of AOA from all that, but not enough to fly
> AOA with the accuracy required in modern carrier operations. A half
> degree of pitch or a decel/accel trend that you don't see in time could
> be the difference between a safe landing and a bolter or worse.
>
> BTW, IAS is measured in knots, not knots/hr. A knot is a nautical
> mile/hour, so "knots/hour" would be an acceleration, not a velocity.
>
> > What might be considered is an instrument that can provide all
> > that info in nice clear form on single gauge at a glance, let's
> > design it.
>
> Can't do it; there are too many different types of measurements to be
> made and displayed. While a velocity vector pointer on a HUD may give
> a good portion of it, speed is missing...

Indicator-instrumentation is subjective, so I'll shoot from the hip.

Let DV be rate of ascent, vertically directed, with a length.

Let IAS be Indicated AirSpeed be a vector with length and direction.
The IAS vector is a hypotenuse, let HAS be Horizotal AirSpeed then

IAS^2 = DV^2 + HAS^2

forms a right angle triangle. The IAS and DV come from standard
measurements and the HAS is readily derived, so we have
Ascent Angle embodied in the IAS vector, (pardon the math).

Next, we include Pitch, that is a measurement derived from the
artifical horizon. From those the AoA is

AoA = Ascent Angle - Pitch.

On an actual display, suppose we display the IAS as a vector,
with lengths that are colored green, yellow, red, with red-yellow
demarking a near stall, as well as the Pitch vector, then at the
origin of those displayed vectors, you can print out AoA to .1 degree
accuracy, sufficient for most pilots.

In my experience, some guys like dials (like clock hands) others
like digital, that was a hassle when Volt-Ohm meters went digital,
lots of arguments. Personally I like both. The meter provides a
sense of rate of change, but the digital provides precison at a
glance, so I think the 'AoA' indicator ought to be designed to
reflect those concerns and conditions.

One question, would you want a g-force indicator?
Ken

[JRWeiss]

Ken S. Tucker wrote:

>>> Referring to sims, I found the AoA indicator of scientific
>>> interest to measure airfoil performance, but in shooting landings
>>> I relied on the IAS (knots/hr) and vertical airspeed
>>> indicator(feet/minute), those together give a rough idea of angle
>>> of descent, and one then gets a feeling of AoA from pitch.
>>
>> Yes, you can get a "feel" of AOA from all that, but not enough to
>> fly AOA with the accuracy required in modern carrier operations. A
>> half degree of pitch or a decel/accel trend that you don't see in
>> time could be the difference between a safe landing and a bolter or
>> worse.

>>> What might be considered is an instrument that can provide all
>>> that info in nice clear form on single gauge at a glance, let's
>>> design it.

>> Can't do it; there are too many different types of measurements to
>> be made and displayed. While a velocity vector pointer on a HUD
>> may give a good portion of it, speed is missing...

> . . .

> On an actual display, suppose we display the IAS as a vector,
> with lengths that are colored green, yellow, red, with red-yellow
> demarking a near stall, as well as the Pitch vector, then at the
> origin of those displayed vectors, you can print out AoA to .1 degree
> accuracy, sufficient for most pilots.

While you may have a single display here, you actually have 3 different
"gauges": Speed vector, pitch vector, and AOA readout.

> In my experience, some guys like dials (like clock hands) others
> like digital, that was a hassle when Volt-Ohm meters went digital,
> lots of arguments. Personally I like both. The meter provides a
> sense of rate of change, but the digital provides precison at a
> glance, so I think the 'AoA' indicator ought to be designed to
> reflect those concerns and conditions.

Modern HUDs (Head-Up Displays) have many readouts on a single display
already. As you note, there are many individual preferences, so there
is no single "standard" HUD display. You may have some interesting
ideas for the display of the information, but the concept is hardly new.


> One question, would you want a g-force indicator?

In a fighter, yes. In a 747, probably not; it would be superfluous.

[Ken S. Tucker]

Hi JR.

On Aug 5, 3:28 am, "JRWeiss" > wrote:
> Ken S. Tucker wrote:
> >>> Referring to sims, I found the AoA indicator of scientific
> >>> interest to measure airfoil performance, but in shooting landings
> >>> I relied on the IAS (knots/hr) and vertical airspeed
> >>> indicator(feet/minute), those together give a rough idea of angle
> >>> of descent, and one then gets a feeling of AoA from pitch.
>
> >> Yes, you can get a "feel" of AOA from all that, but not enough to
> >> fly AOA with the accuracy required in modern carrier operations. A
> >> half degree of pitch or a decel/accel trend that you don't see in
> >> time could be the difference between a safe landing and a bolter or
> >> worse.
> >>> What might be considered is an instrument that can provide all
> >>> that info in nice clear form on single gauge at a glance, let's
> >>> design it.
> >> Can't do it; there are too many different types of measurements to
> >> be made and displayed. While a velocity vector pointer on a HUD
> >> may give a good portion of it, speed is missing...
> > . . .
> > On an actual display, suppose we display the IAS as a vector,
> > with lengths that are colored green, yellow, red, with red-yellow
> > demarking a near stall, as well as the Pitch vector, then at the
> > origin of those displayed vectors, you can print out AoA to .1 degree
> > accuracy, sufficient for most pilots.
>
> While you may have a single display here, you actually have 3 different
> "gauges": Speed vector, pitch vector, and AOA readout.
>
> > In my experience, some guys like dials (like clock hands) others
> > like digital, that was a hassle when Volt-Ohm meters went digital,
> > lots of arguments. Personally I like both. The meter provides a
> > sense of rate of change, but the digital provides precison at a
> > glance, so I think the 'AoA' indicator ought to be designed to
> > reflect those concerns and conditions.
>
> Modern HUDs (Head-Up Displays) have many readouts on a single display
> already. As you note, there are many individual preferences, so there
> is no single "standard" HUD display. You may have some interesting
> ideas for the display of the information, but the concept is hardly new.

Right! Even a nerd like me could customize your instrumentation
display to exactly what you want and where you want it. Every
pilot could have his own ROM, or punch code. Of course the standard
stuff would remain fixed, so the ROM is for accessories such as AoA
and how it's displayed, IOW's you should get what you want and how
you want it.

> > One question, would you want a g-force indicator?
>
> In a fighter, yes. In a 747, probably not; it would be superfluous.

As a pilot I've banked to 60 degs for 2g's, but in sim's I've pushed
it to
the black-out limits. I put the g-indicator on the HUD because I think
it
gives a good feed back for energy bleeding and physiology.
If I may ask how many g's have you pulled doing say a 180 turn as in
going East then to West?
Ken

[JRWeiss]

Ken S. Tucker wrote:

>>> One question, would you want a g-force indicator?
>>
>> In a fighter, yes. In a 747, probably not; it would be superfluous.
>
> As a pilot I've banked to 60 degs for 2g's, but in sim's I've pushed
it to the black-out limits. I put the g-indicator on the HUD because I
think it gives a good feed back for energy bleeding and physiology.
> If I may ask how many g's have you pulled doing say a 180 turn as in
going East then to West?

The airplanes I flew were limited to 6.5 Gs. I may have exceeded that
momentarily on occasion...

For fighter airplanes with HUDs, it makes sense to put a G meter up
there. I flew them in pre-HUD days, so I had to scan an entire
instrument panel...

[Dave in Sandy Eggo]

"Ken S. Tucker" > wrote in news:56e7269b-a30f-467b-
:

> In my experience, some guys like dials (like clock hands) others
> like digital, that was a hassle when Volt-Ohm meters went digital,
> lots of arguments. Personally I like both. The meter provides a
> sense of rate of change, but the digital provides precison at a
> glance, so I think the 'AoA' indicator ought to be designed to
> reflect those concerns and conditions.

Slightly OT.

I'm a retired cal tech. Regarding the meter thing, all that "precision"
wasn't really worth a rat's ass, since the accuracy of many digital VOMs
wasn't any better (usually in the 2% - 4% FS area) than the d'Arsonval
movement units they replaced. I still use my 25 yo Simpson 260 more than I do
my Fluke 77.

Dave in Sandy Eggo
AT1 USN Ret

[Ken S. Tucker]

On Aug 8, 2:11 am, Dave in Sandy Eggo > wrote:
> "Ken S. Tucker" > wrote in news:56e7269b-a30f-467b-
> :
>
> > In my experience, some guys like dials (like clock hands) others
> > like digital, that was a hassle when Volt-Ohm meters went digital,
> > lots of arguments. Personally I like both. The meter provides a
> > sense of rate of change, but the digital provides precison at a
> > glance, so I think the 'AoA' indicator ought to be designed to
> > reflect those concerns and conditions.
>
> Slightly OT.
>
> I'm a retired cal tech. Regarding the meter thing, all that "precision"
> wasn't really worth a rat's ass, since the accuracy of many digital VOMs
> wasn't any better (usually in the 2% - 4% FS area) than the d'Arsonval
> movement units they replaced. I still use my 25 yo Simpson 260 more than I do
> my Fluke 77.
>
> Dave in Sandy Eggo
> AT1 USN Ret

Ah, nostagia.
http://www.simpson260.com/260-1/simpson_260-1.htm

I had to use 3-4 digit accuracy for tuning scientific/precision
instruments,
setting bias etc, so the only way to go was digital. Now I measure
batteries
to 4 digits, habit I guess.
For analog volt measure I usually use Scope channel two set for DC, to
get
a sense of any ripple, meters are to slow, that way a scope is just
like a
fast vertical bar display.
Ken