Blanik L13 flap use

"Jim Culp" wrote in message
...
| Does anyone have a polar curve for the Blanik L-13
| with the Fowler flaps out?
| I found several 'normal' polars on the web, but none
| for the flaps out.
| Background for this question is whether there is any
| benefit in using the Fowler flaps in weak thermals.
|
| Ton Wolfert
|

| Hi Mr. Wolfert:
|
| One may get better information from hearing experiences
| of those who have flown the L13 much, rather than by
| seeking polar info of the various Blanik L13 flap
settings.

snipped
|
| Yes, play with them and learn the effect of the flaps.
| Experiment at altitude.
|
| Learn not to dump flaps on short final approach; as
| that will bash one by dropping it hard onto ground.
|
|
| One may find that in very weak thermals one will not
| benefit from extending them. Extending the flaps
| one shall be increasing drag, shall lose more altitude,
| than by using modest bank angle, keeping zero flap,
| and staying within a weak upcurrent. This is the action
| needed for weak upwinds.
|
| In strong and narrow thermals, one may benefit by
extending
| flaps so one may turn a smaller diameter circle without
| speeding more to hold the bank angle.

I find that when thermalling in the average thermal, that
one can fly slower and more comfortably with about half
extension of the flaps.
Full extension increases drag too much, whereas half
extension gives a useful increase in low speed lift with
only moderate increase in drag.
Cheers, John G.