alternative McCready theory and variometers

On Sunday, October 26, 2014 5:04:49 PM UTC+1, wrote:


As I understand it, 'Equivalent MC' reverses the STF calculation, and produces a figure from your averaged airspeed and the polar for your aircraft.

For example, assume MC theory for a glider states a STF of 150kph for a 2..0m/s estimated climb. 'Equivalent MC' reverses this equation; If you fly this glider at a constant 150kph IAS for the averaging period, the 'Equivalent MC' will be 2.0m/s.

The way I've heard it described, the idea is that you directly compare your 'Equivalent MC' figure with your MC figure and adjust your airspeed accordingly. If 'Equivalent MC' = 2.1m/s and MC = 2.0m/s, slow down. If 'Equivalent MC' = 1.9m/s and MC = 2.0m/s, speed up.

Yes.
Little clarification: for basic function you don't need to set the MC into the variometer, just keep it in mind.
Little modification: If 'Equivalent MC' shows 2.1 and you expect 2.0 in front of you don't bother slowing down. 0.1 m/s difference is negligible.

I think it's totaly intiuitive to fly fast into good weather and fly slowly into bad weather. This would be just little guidance to learn and later confirm the numbers.


Climb and sink does not directly influence 'Equivalent MC', which is one reason why 'Equivalent MC' might be a poor value to display on a vario.

No, I totally would want it to be adjusted for sink and climb.

LK8000 doesn't adjust for that, so it's probably not a good example/definition. What I meant is "flown MC". Its reversing the STF calculation and producing a figure from averaged airspeed, the polar and the rise/sink.

Also as a precaution against a common mistake of flying so slowly in sink that you're actually achieving smaller then maximal achievable L/D I would like to have immediate warning for that (spead up!).

Doesn't take long for the boffins to start once macready is mentioned.

Macready works.

What doesn't work so well is the push/pull speed to fly modes of
"smart"varios (and the way Pilots interpret them)

I like Netto in cruise so I can adjust my speed and track accordingly.

I don't require any "speed to fly" function from the electronics. (I seem
to do
OK ignoring them)

Difficult for me to find any instrument that caters for this.

Tom





01:24 27 October 2014, Tibor Arpas wrote:
On Sunday, October 26, 2014 5:04:49 PM UTC+1,
wrote:

=20
As I understand it, 'Equivalent MC' reverses the STF calculation, and
pro=
duces a figure from your averaged airspeed and the polar for your
aircraft.
=20
For example, assume MC theory for a glider states a STF of 150kph for a
2=
..0m/s estimated climb. 'Equivalent MC' reverses this equation; If you
fly
t=
his glider at a constant 150kph IAS for the averaging period, the
'Equivale=
nt MC' will be 2.0m/s.
=20
The way I've heard it described, the idea is that you directly compare
yo=
ur 'Equivalent MC' figure with your MC figure and adjust your airspeed
acco=
rdingly. If 'Equivalent MC' =3D 2.1m/s and MC =3D 2.0m/s, slow down. If
'Eq=
uivalent MC' =3D 1.9m/s and MC =3D 2.0m/s, speed up.

Yes.=20
Little clarification: for basic function you don't need to set the MC
into
=
the variometer, just keep it in mind.
Little modification: If 'Equivalent MC' shows 2.1 and you expect 2.0 in
fro=
nt of you don't bother slowing down. 0.1 m/s difference is negligible.

I think it's totaly intiuitive to fly fast into good weather and fly
slowly=
into bad weather. This would be just little guidance to learn and later
co=
nfirm the numbers.

=20
Climb and sink does not directly influence 'Equivalent MC', which is
one
=
reason why 'Equivalent MC' might be a poor value to display on a vario.

No, I totally would want it to be adjusted for sink and climb.=20

LK8000 doesn't adjust for that, so it's probably not a good
example/definit=
ion. What I meant is "flown MC". Its reversing the STF calculation and
prod=
ucing a figure from averaged airspeed, the polar and the rise/sink.

Also as a precaution against a common mistake of flying so slowly in sink
t=
hat you're actually achieving smaller then maximal achievable L/D I would
l=
ike to have immediate warning for that (spead up!).

Then it would be called MC, not equivalent MC. You would set up the real MC
you are following on the vario which is obtainable on many instruments that
send to the PNA this setting every time you change it (LX V7 for example).
And for the purpose of giving you some information you dont already know
(the MC you did set manually) it would be useless: you would never know what
you are really doing.
Despite you have set MC to 1ms, you are flying much faster because you are
in sink since some time.
Some people think that after a long sink we can expect a "long" lift, but
generally they outland if they dont do a 90 degrees turn and run away the
sink area. The loss of altitude has to be accounted as a pure loss with no
gain expected for sure.
The precaution you mention is the STF audio that since decades already does
what you say.





"Tibor Arpas" wrote in message
...

No, I totally would want it to be adjusted for sink and climb.

LK8000 doesn't adjust for that, so it's probably not a good
example/definition. What I meant is "flown MC". Its reversing the STF
calculation and producing a figure from averaged airspeed, the polar and the
rise/sink.

Also as a precaution against a common mistake of flying so slowly in sink
that you're actually achieving smaller then maximal achievable L/D I would
like to have immediate warning for that (spead up!).