How Low to Spin??

Mark James Boyd writes
On another subject, can someone describe the 45/V type approach that
I've heard is used in some countries?

Not sure what a "V type" is, but the circuit I've been taught to fly
here in the UK, in contrast to what I understand to be the conventional
right-angled power circuit, includes a "diagonal leg" flown between the
downwind and base...

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/ |
/ v
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|

The specific purpose, as I understand it, is to keep the intended
landing point in sight of the pilot at all times enabling the pilot to
continually asses the angle between himself and the landing area and
thus ensure he stays within reach, cutting (or at least minimising) the
risk of an undershoot.

Essentially, you fly your downwind leg as normal, and as the landing
area begins to disappear under the nearside wing, you turn 45 degrees in
and fly the diagonal leg. At the appropriate point along the diagonal
you turn onto and fly the base then make your final turn and land as
normal.

The length of the diagonal leg, the point you turn onto it, and how far
back you go before turning onto base is entirely dependent upon
conditions and circumstance. Though presumably that's true of any glider
pattern, as we don't generally have the option of hitting the throttle
to fix a balls up?


--
Bill Gribble

/---------------------------------------\
| http://www.ingenuitytest.co.uk |
| http://www.cotswoldgliding.co.uk |
| http://www.scapegoatsanon.demon.co.uk |
\---------------------------------------/

No. It's more like this:

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The base leg blends into downwind.

Graeme Cant


Mark James Boyd wrote:
Bruce Hoult wrote:

And why earth would you want to know that when you were in the circuit?
You are surely not going to go *that* far downwind that you need best
L/D into wind in order to get back.


Apparently this is a significant cause of crashes (undershot
landing from overshot downwind).

On another subject, can someone describe the
45/V type approach that I've heard is used in
some countries? Is it like this?

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/
/
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/
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The Runway | --+----| ----/
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Mark J. Boyd

Well, I've always been taught to make the transition to 45 degrees more
defined. The idea is to turn just before the landing area disappears
from view. This allows you to always see where you want to go and helps
to prevent you from going so far downwind that you won't get over the
boundary.

Keeping the landing zone in view allows you to more accurately judge if
you are too close or too far out (and make appropriate corrective
actions) and also to see if anyone is ahead of you in the circuit and/or
in your landing zone.

Robin

In message , Graeme Cant
writes
No. It's more like this:

------
--------
------
----
--
-
-
-
-
-
----------------------------

The base leg blends into downwind.

Graeme Cant


Mark James Boyd wrote:
Bruce Hoult wrote:

And why earth would you want to know that when you were in the
circuit? You are surely not going to go *that* far downwind that you
need best L/D into wind in order to get back.
Apparently this is a significant cause of crashes (undershot
landing from overshot downwind).
On another subject, can someone describe the
45/V type approach that I've heard is used in
some countries? Is it like this?
-------------------------------\
\
\
\
\
\
\
\
\
\
/
/
/
/
/
----------------- | /
| | /
| | | /
The Runway | --+----| ----/ | | |
| |
----------------- | --
------------+
Mark J. Boyd


--
Robin Birch

At 07:06 08 September 2004, Bruce Hoult wrote:
In article ,
Nyal Williams wrote:

I suspect that you may be confusing the 'best speed
to cover the most
ground in a headwind' with 'the best speed to make
a safe approach to
landing'.

Tony,

As I read his question it, he was asking for 'best
speed to cover the most ground in a headwind. Actually,
he seemed to confuse the two in the question.

And why earth would you want to know that when you
were in the circuit?
You are surely not going to go *that* far downwind
that you need best
L/D into wind in order to get back.

The extra speed with wind is to provide extra guard
against a tail gust
stalling you (though the +10 knots or *1.3 does a lot
of that), but
mostly I think so that and likely wind gradient still
leaves you with
flying speed.

--
Bruce | 41.1670S | \ spoken | -+-
Hoult | 174.8263E | /\ here. | ----------O----------

I wouldn't. He proposed the scenario and asked why
1/2 the wind speed added to the best L/D was the best
speed to cover the ground to insure getting back.
He went on to say that that seemed to be the universally
accepted figure and that no one had ever explained
it.

My suggestion to look at the polar was only about the
above formula for best speed to cover ground. I took
it as an incidental question aside from the main question
and chose to address that only. I hope my answer was
not taken as a suggestion about how to fly a pattern!