On Jul 28, 9:22*pm, Tom Stock wrote:


I'd also like tips for entering a pre-established gaggle. * *Keeping other
gliders in sight is not too difficult if I am in the thermal and another
glider or two enters... but I have trouble entering with another glider and
ending up in the correct position (directly across from the other glider)..
I have been practicing be entering very low as not to disrupt the gaggle,
but I find it hard to judge the entry point and bank to get into the
gaggle. *I have been watching other pilots, and it seems they come in fast,
open brakes anf get behind a thermalling glider matching bank angle, and
then continue with brakes to slow down and sort of slip backwards into
safer position... maybe this is not actually what is going on... but thats
how it looks.

any advice appreciated.

I have never used air brakes when entering a thermal and if I had to
I'd think I had really botched the entry. How to enter depends on the
situation but there is one, in my opinion, hard rule. You never join
in away that causes any other glider established in the thermal to
take evasive active or even to think they might need to take evasive
action.

When joining one glider at about the same altitude I do several things
- a) I'm looking for the other gliders in the thermal that I have not
seen yet; b) I'm looking around me for gliders joining with me that I
don't know about yet; and c) when I think I have the complete picture
I'm using pitch changes as required to change altitude, speed,
relative position, and time of the join-up so I arrive in the place I
want to be. Keep repeating a), b), c) remembering that joining safely
is far more important than gaining a second.

The dynamics of joining a larger group are much the same. Joining
wide and then working in slowly is probably good advice for the
inexperienced.

When in a thermal keep looking around for gliders joining, gliders
leaving, and the ones behind and above you that have you in their
blind spot. Use all the field of view your glider allows. I don't
fly gliders that don't allow me to look back and see the tips of the
tailplane and I scan back there in a crowded thermal. Also scan above
you so you don't climb into another gliders blind spot. If you lose
visual contact with a glider a quick radio call to ask if he sees you
may be appropriate. Of course you can't scan effectively in a thermal
if you wear a large brimmed hat or a cap with a peak. If you must
wear one of those please take it off while thermalling.

When leaving exit smoothly when your circle becomes tangential to the
desired course line. Don't be one of those guys that's circling left,
waits until 90 deg past the desired course line then cranks hard
right, totally oblivious to gliders outside and behind.

As to working the thermal it all depends who you are with. Two or
three gliders in a thermal at the same altitude can work very
effectively together to maximize climb rate if they are comfortable
with each others style. The same three gliders won't climb as well if
the 2 joining slavishly do exactly what the first was doing when they
joined unless the first has a very well defined core and has it
centered perfectly.

And please if you join a glider cranked up at 45 deg, obviously in a
good core, please don't fly an intersecting 25 deg banked circle and
knock him out of his thermal.

Andy (GY)