On Oct 25, 7:12 pm, Gary Emerson wrote:
Greetings,

This may get many comments, but I'm curious as to the consensus.

On a recent training flight (wasn't me...) the student was advised to go
to about 2/3 spoiler just before the flare.

Normal approach, field was made, on target for a nice touchdown.

When I was getting instruction, I was always encouraged to progress
toward full spoiler in the pattern and to ideally get to a full spoiler
and stabilized approach once the target touchdown point was "in range".
Advice given was that full spoilers minimized the potential for
ballooning and provided maximum drag and minimized lift. i.e. get on
the ground and stay there and make a positive effect to get the glider
stopped. Additionally, I've always been of the mind set that unless
there was an unusual circumstance, that spoiler changes near the ground
were usually best avoided.

Any other thinking as to a benefit in reducing spoiler just before the
flare?

Just pondering...

Gary


One principle not commonly taught, but worth understanding, is that
spoilers
do somewhat different things in parts of the pattern.
I teach the use of approximately 1/2 spoiler from a point abeam the
touchdown.
This uses "safety altitude up at a rate proportional to distance left
to touchdown
thus providing a fairly constant rate of descent and pretty much
constant height
margin.
This assumes steady airspeed selected for conditions.
Adjust spoilers moderately for changes in angles to the touch down
point.
On final, the effect of spoilers changes.
In the early part of final , they are rate(and angle at constant
speed) of descent
control.
As we transition into the flare and touchdown phase the spoilers
become rate of
deceleration control thus determining when the glider no longer has
enough speed to fly.
Teaching this principle of leaving the spoilers alone(unless sink or
other factor dictate) allows a smooth transition into the flare
without losing the drag needed to land at the target.
This method leads to pilots who can land at low energy with minimal
extra float.
It also means that only the pitch control hand needs to do something
which is much easier
for students to master.
Some try to "improve on what we teach" thinking less spoiler near the
ground will give slower sink
and smoother landings. After bouncing around in ground affect and
landing poorly and
long, they come back to what they are taught
From the start, I teach that last part of final, if possible, is with
full spoilers to get pilots used
to steep final like is needed landing in a field . This way they will
revert to habits that work well
during their first "stressful" outlanding.
Hope this was not too "windy".
UH