AoA keep it going!

Ian wrote:
On 20 Dec, 14:42, "kirk.stant" wrote:

Ian, we appear to be comparing apples and oranges - you are talking
about not stalling on final, while I am talking about being able to
accurately thermal, and incidentally have a better instrument for
flying accurate approaches.

I wonder how much "flying at Clmax" matters in good thermalling
compared with "being in the right bit of the thermal"?

Minor correction: you should be thermaling at min.sink, which is the
point at which Cl^3/Cd^2 is maximized.

This is not in general the same as Cl max. Min.sink is usually at a
slightly lower AOA than CL max because Cd is rising steeply with
increasing AOA in the Cl max region. As a result, by the time you've
slowed to Cl max you've passed min.sink and your sinking speed has
started to increase.

Since the polar is usually flatter on the faster side of min.sink I
think you're better off thermaling somewhere between the min.sink and
best glide speeds, preferably nearer the former. Best glide is the speed
where Cl/Cd is a maximum.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

On 21 Dec, 16:11, "Bert Willing"
wrote:

"Ian" wrote in message

...

On 21 Dec, 10:35, Cats wrote:

I also find the radio useful to listen for downwind calls, along with
the communication from launchpoint to winch. That's all we hear on
our ground frequency so it's not a lot and it's useful (to me). I
also like to have the vario on as whilst sink & lift can be obvious
(10 down certainly is!), it points it out very clearly and helps me
adjust the circuit to suit. A lot of my worst circuits have been
flown without the audio vario.

As I wrote, " ... final approach ..."

I had a buddy who was killed in his sailplane when he was hit by a powered
plane while on final (the 3 people in the plane died even faster).

That's very sad.

However, like all individual cases, it doesn't really add much
evidence. Some might say that it shows how important it is to have a
radio on. Some might say it shows how important it is not to be
distracted by a vario ... or radio.

Ian

Ian wrote:


Would you prefer to know about the free stream AoA or the local one...?


I have never received a bit of help from the free-stream. Like anything
free, it has little value. I prefer ground speed.

As to local AoA--how local is your airfoil? You needn't ask which
airfoil. I leave the aerodynamics questions to S-H, DG, et al. If they
insist on building wings using multiple airfoil sections, then it is up
to them to determine whether, and where, to place AoA sensors.


Jack

Ian wrote:
On 21 Dec, 10:35, Cats wrote:

I also find the radio useful to listen for downwind calls, along with
the communication from launchpoint to winch. That's all we hear on
our ground frequency so it's not a lot and it's useful (to me). I
also like to have the vario on as whilst sink & lift can be obvious
(10 down certainly is!), it points it out very clearly and helps me
adjust the circuit to suit. A lot of my worst circuits have been
flown without the audio vario.

As I wrote, " ... final approach ..."

But final approach is the easy part, Ian. You have so few alternatives
left, after all.

Don't most die in the final turn?



Jack

Ian wrote:


I find the radio useful for expanding awareness of those things which
are not readily visible.

It also has a tendancy to concentrate attention on the gliders you can
here. Accidents have happened - to powered aircraft as well - when
pilots assumed that what they could hear was what they could see,


I very nearly included a reference to that in a recent response to you.
I'm glad you mentioned the fallacy of believing that those you hear are
those you see, or that there is no one whom you do not hear. Yours is
not an argument for discontinuing radio monitoring, however.

Your position seems to be that removing as many inputs as possible will
insure a focus on flying the final approach safely. Again, I believe
that expanding your awareness and prioritizing your responses in real
time is far safer than pre-determining what you wish to know and what
you can afford at any cost to ignore.

Admittedly, as I get older I also wish to reduce the cacophony of
stimuli, but I also believe there is a limit beyond which we must not
cocoon ourselves. Better to keep pushing our limits outward, even as we
might wish to do otherwise.

Fortunately, or otherwise, I have some small experience in very complex
piloting situations, including urgent life-or-death dialogs on three
different radios--each on a different frequency band--in a rather
challenging combat environment. I don't expect others to have a similar
need ever to operate near their true limits. But it does color my views
of the topic of awareness, processing, and prioritizing cockpit information.

Enjoy the new season, and always be safe.



Jack

Ian wrote:


...like all individual cases, it doesn't really add much
evidence. Some might say that it shows how important it is to have a
radio on. Some might say it shows how important it is not to be
distracted by a vario ... or radio.


Is that an argument for ignoring statistical aggregations of individual
events, or the experience of generations of pilots distilled into
training manuals and, hopefully, regulations?


Jack

On 21 Dec, 21:21, J a c k wrote:
Ian wrote:

...like all individual cases, it doesn't really add much

evidence. Some might say that it shows how important it is to have a
radio on. Some might say it shows how important it is not to be
distracted by a vario ... or radio.

Is that an argument for ignoring statistical aggregations of individual
events, or the experience of generations of pilots distilled into
training manuals and, hopefully, regulations?

It's an argument for not reading too much into an individual case,
that's all.

Incidentally, it's worth remembering that every significant change to
a training manual or regulation indicates a willingness to admit that
the distilled experience of generations of pilots has, in some
respect, been wrong.

Or would you care for me to make an argument that since generations of
glider pilots have seen no need for AoA indicators, they must be
useless ... ?

Ian

On 21 Dec, 20:52, J a c k wrote:
Ian wrote:
On 21 Dec, 10:35, Cats wrote:

I also find the radio useful to listen for downwind calls, along with
the communication from launchpoint to winch. That's all we hear on
our ground frequency so it's not a lot and it's useful (to me). I
also like to have the vario on as whilst sink & lift can be obvious
(10 down certainly is!), it points it out very clearly and helps me
adjust the circuit to suit. A lot of my worst circuits have been
flown without the audio vario.

As I wrote, " ... final approach ..."

But final approach is the easy part, Ian. You have so few alternatives
left, after all.

Yes. That's why I don't see any great problem in having audio
distractions off and concentrating on landing.

Normally I soar with the radio off, turn it on when I decide to
return, use it as appropriate in the circuit and kill it when it's not
going to be of any more use.

Don't most die in the final turn?

The overwhelming majority survive the final turn!

Ian

On 21 Dec, 21:17, J a c k wrote:

Your position seems to be that removing as many inputs as possible will
insure a focus on flying the final approach safely.

Extraneous inputs.

Ian

On 21 Dec, 09:58, J a c k wrote:
Ian wrote:

Seeing other aircraft is often aided by hearing radio transmissions.
Have you literally heard an aircraft you didn't first see?

Are you remembering that in the UK we have a very limited range of
frequencies, and that it is quite possible to be able to hear calls
from gliders at several different airfields at once? I have on
occasion wasted time trying to see the glider which has just called
downwind at an airfield ten miles from the one I am about to land at.

Ian