AoA keep it going!

Marc Ramsey wrote:

An indicator for an AoA meter could consist of something as simple as
three LEDs, say a bright red one for approaching stall, green for
minimum sink, blue for best L/D and above, with the red LED blinking
faster as AoA gets closer to stall. The LEDs could be mounted on a
short stick above the instrument glare shield, or even attached to
sunglasses

Or even better, install a fist which knocks your head every time you get
slow... I still can't see the advantage of three LEDs over one pointer.
Obviously I'm getting old...

On 19 Dec, 14:38, "kirk.stant" wrote:

Ian, do you look at your airspeed indicator while landing (well,
during the approach, of course - no one looks at their airspeed while
actually landing, do they?)? If you do, then a properly designed AoA
indicator could make your approaches easier and safer. Remember,
airspeed is just an inaccurate way to show angle of attack - the AoA
gauge shows it directly.

This is going to lead on to my second favourite question for
instructors: "We all fly the approach a bit faster if there is likely
to be significant wind shear. As we fly through the wind shear, should
we (a) attempt to keep the higher speed or (b) allow speed to decrease
(which is why we added a bit to start)?

Now, if all gliders had AoA gauges, you could jump from one glider to
another and not worry about what the right approach speed is for the
glider you happen to be in.

Wouldn't I have to worry about what the right approach AoA was
instead?

Ian

On 19 Dec, 20:43, John Smith wrote:

I don't see what an AoA instrument could add to this. If you are
distracted enough to get slow with an ASI, then I see no reason why you
wouldn't be distracted enough to get slow with an AoAI.

That, I think, is a very, very good point.

Ian

John Smith wrote:
Marc Ramsey wrote:

An indicator for an AoA meter could consist of something as simple as
three LEDs, say a bright red one for approaching stall, green for
minimum sink, blue for best L/D and above, with the red LED blinking
faster as AoA gets closer to stall. The LEDs could be mounted on a
short stick above the instrument glare shield, or even attached to
sunglasses

Or even better, install a fist which knocks your head every time you get
slow... I still can't see the advantage of three LEDs over one pointer.
Obviously I'm getting old...

Yes, I'm sure someone could provide you with the option of a knock in
the head or even an electric shock (non-lethal, I'd assume), if you
prefer. The problem with pointers is that they don't do much good if
you're currently looking at something else.

Marc

On 19 Dec, 21:26, Marc Ramsey wrote:

An indicator for an AoA meter could consist of something as simple as
three LEDs, say a bright red one for approaching stall, green for
minimum sink, blue for best L/D and above, with the red LED blinking
faster as AoA gets closer to stall.

My glider does all sorts of things as it approaches stall. It gets
awful quiet. The stick starts shaking. The vario plummets. If I manage
to miss all these clear signs, why would a small flashing red light
grab my attention?

And can you imagine what would happen with a stall warning sounder?
Pilots used to flying with gear-down warnings would anxiously check he
undercarriage lever ... subconsciously pulling back to give themselves
a bit more time ...

Ian

But can you instantly recall the exact speeds for all of them, under
pressure, without fail?

Yes. But if I really couldn't and were in the situation you describe, I
just would write them into a little booklet which I could take with me
and consult before getting into the glider. Just as I do with many other
things. (Besides: If you can't remember the exact speeds to fly, why
should you be able to remember the exact AoA to fly?)

Ok, you probably have never flown an aircraft with an actual AOA
system installed. The point is, there is only one AOA you care about,
and that is what a simple AOA gauge shows. Thats it - if you are
below that angle, you are fast. Above that angle, you are slow. No
matter what your gross weight, bank angle, etc.

I've done the booklet route, and it's fine, up to a point.

My personal experience was in giving commercial rides (sightseeing and
aerobatic) in 2-33s, 2-32s, G-103s, and ASK-21s. With a wide variety
of passenger size, in no particular order, often moving to a different
glider immediately after landing.

I shudder at the thought that a pilot would give commercial rides to
passengers without being absolutely sure of the exact speeds to fly!

Have you ever been there? When you fly a lot of different gliders,
every one has a different "exact" speed to fly. This is where
experience comes in - you learn real fast the speed ranges for the
gliders involved, and how they feel. And how to carry some extra
airspeed in the pattern until you can safely get rid of it.

But it would still be nice to have ACCURATE instrumentation. While
airspeed works, it is by design only an approximation of the correct
speed.

It may not be ACCURATE, but it certainly is accurate enough. For me, anyway.

Yes, and for me too. But that doesn't mean we can't have something
better. Otherwise, with that logic, we would be all still flying with
uncompensated pellet varios. Sure they work, but we can do better!

Now, get slow on your turn to final in a
2-32 and you may wish you had an AoA indicator!

The solution is simple: Just don't get slow on your turn to final. This
has been hammered into my head since my very first flight, and it works
for me. I don't see what an AoA instrument could add to this. If you are
distracted enough to get slow with an ASI, then I see no reason why you
wouldn't be distracted enough to get slow with an AoAI.

ARGGG you just do not understand the concept. Oh well, fun discussion
anyway.

Cheers, and Merry Chrismas!

Kirk

Ian wrote:
On 19 Dec, 21:26, Marc Ramsey wrote:

An indicator for an AoA meter could consist of something as simple as
three LEDs, say a bright red one for approaching stall, green for
minimum sink, blue for best L/D and above, with the red LED blinking
faster as AoA gets closer to stall.

My glider does all sorts of things as it approaches stall. It gets
awful quiet. The stick starts shaking. The vario plummets. If I manage
to miss all these clear signs, why would a small flashing red light
grab my attention?

Because, unless you're offering an open invitation for me to fly your
glider, I've flown a number that don't give such clear signs,
particularly in landing flap.

And can you imagine what would happen with a stall warning sounder?
Pilots used to flying with gear-down warnings would anxiously check he
undercarriage lever ... subconsciously pulling back to give themselves
a bit more time ...

Did I say anything about a sounder?

Marc

On Dec 19, 4:26 pm, Marc Ramsey wrote:
toad wrote:
On Dec 19, 3:43 pm, John Smith wrote:
...snip...
for me. I don't see what an AoA instrument could add to this. If you are
distracted enough to get slow with an ASI, then I see no reason why you
wouldn't be distracted enough to get slow with an AoAI.

This seems to be the real reason people stall. It's not that they
don't know what the speed is, it's that they can't maintain the speed
that they do know !

An indicator for an AoA meter could consist of something as simple as
three LEDs, say a bright red one for approaching stall, green for
minimum sink, blue for best L/D and above, with the red LED blinking
faster as AoA gets closer to stall. The LEDs could be mounted on a
short stick above the instrument glare shield, or even attached to
sunglasses such that it would always be at the edge of the field of
view. All the interpretation required is that the bright flashing red
light means get the nose down, right now.

No one has said anything about taking away anyones ASI...

Marc

I didn't think that were advocating taking away the ASI.

Let me re-phrase my point, since everybody has a different take.

Glider pilots stall because 1) they are distracted from the airspeed
or 2) they attempt to fly too slow to "maximize" performance.
Changing the reference from ASI to AOA doesn't seem to address either
of these issues. Maybe it's because I fly a glider than warns me
about impending stall in the traditional ways. (stick back, low
noise, mushy controls, etc ...).

I agree that holding a max performance target might be improved by an
AOA indicator, but don't see it worth that much money.

Todd Smith
3S

Cats wrote:



Why might an AoA guage be any more accurate than an ASI?





Because an AoA gauge responds directly with "relative wind"
Airspeed indicators respond to ram air pressure measured against static
pressure. Have you ever noticed that your airspeed indicator seems to
read higher in the winter due to denser air (assuming you live in a
climate with vastly different temps between summer and winter). Also,
have you ever noticed your airspeed indicator reads lower at higher
altitudes (due to less dense air)? AoA is accurate regardless of the
above mentioned differences.

--
Scott
http://corbenflyer.tripod.com/
Gotta Fly or Gonna Die
Building RV-4 (Super Slow Build Version)

Scott wrote:

Have you ever noticed that your airspeed indicator seems to
read higher in the winter due to denser air
....

Which is a very good thing, considering that the aerodynamic behaviour
of an airfoil changes with the air density. Back to field 1.