As Mike and
John have said, Reichmann’s method definitely works.
A common
fault in most early pilots is to turn as soon as there is any indication of
lift, usually with the result that they turn too early, an end up half in and
half our of the entrained air around a thermal, rather than the core
itself.
An
extension of Reichmann’s technique is, when you first encounter a thermal, as
long as the lift is increasing, you should carry on flying in a straight line
until the lift is constant, and then bank. This is assuming that you meet the
thermal head on of course; if one wing lifts you should make an initial turn
towards the rising wing.
Another way
of looking at the same technique is to use the lowest point in the circle;
when the vario indicates you are at the weakest (even sink) point of the
circle, look in the direction of the ‘down; wing and pick a point on the
horizon; a quarter of a turn later, when you are pointing in the same
direction as your picked point, straighten up for 2 or 3 seconds, then
recommence the bank. This has the effect of moving the circle towards the
centre of the thermal.
-----Original
Message-----
From:
[EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of Todd Sandercock
Sent: Tuesday, 19 September 2006 7:16
AM
To: Discussion of issues relating to
Soaring in Australia.
Subject: Re: [Aus-soaring]
Reichmann
Thank you
That makes more sense now. its just that
i use a technique where as you hit the strong lift you tighten up for
about 3/4 of a circle and then go back to normal and that seems to work quite
well.
Todd
John Wharington
<[EMAIL PROTECTED]> wrote:
Hi Todd,
Reichmann's technique as described in
his book does indeed work. I
think you may be misunderstanding it slightly
because of what might be a
translation error or oversimplified use of
language.
To be more formal (and correct), his technique is:
- 1)
While the climb is improving, flatten the circle
- 2) While the climb is
deteriorating, steepen the circle
The effect of 1 is to tend to head
toward the core, and the effect of 2
is to turn away from sink. Overall
this results in the center of the
spiral to gradually drift towards the
core.
So, you see the distinction is not "flatten out when at the
strongest
lift" but rather "flatten out as the lift is increasing"
etc.
In my PhD thesis I used this technique in an auto-thermalling
control
system for an unmanned aircraft and it works quite
well.
Hope this clarifies things.
Johnny
On Mon,
2006-09-18 at 22:56 +1000, Todd Sandercock wrote:
> hi all
>
> I was just reading the bible (Reichmann's "cross country soaring")
and
> came accross the thermaling technique described by reichmann.
the
> technique to me seams wrong. i'm guessing if it is, then it
has
> already been discused on this list but here it is anyway:
>
- as climb improves, flatten the circle (15-20 degrees)
> - as climb
deteriorates, steepen the circle (50 degrees)
> - if climb remains
constant, keep bank constant (25-30 degrees)
>
> in the book it
describes keeping the same bank angle for half a
> circle. so i have
attached a couple of my drawings of the situation.
> the first is of the
method above. the second picture is the opposite
> (as climb improves,
steepen the circle. as climb deteriorates, flatten
> the
circle).
>
> these drawings are my interpritations of the method
so feel free to
> tell me what im doing wrong.
>
>
Todd
>
>
>
>
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