Angle of Attack Indicators

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...

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

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.

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

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...

"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

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