Vers.1.0
01/02/2011
S. 17 / 33
Stall manoeuvres
Spin
If you pull one brake too much, you might induce a so called spin. The centre
of rotation is no longer far outside the wing (like during a normal turn), but it
moves inside the wing. Furthermore the rotation speed increases. The BION
will go back to normal flight, if the pilot releases both brakes. The BION’s spin
behaviour is easily manageable: It takes a lot of brake travel to induce the spin,
and then the pilot has quite some time to react and release both brakes.
Fullstall
If you pull both brakes too far, the wing will perform a so called full stall. The
wing suddenly stops its forward motion, but the pilot is still moving forward.
So from the pilots view, the glider will tilt backwards. It is very important to
not release the brakes in this moment. Otherwise the glider might surge forward
below the pilot.
The Full Stall is a complex manoeuvre and the perfect execution can not be
explained in this manual. If you want to learn a proper full stall, it makes sense
to do this under professional guidance.
The available brake travel before stalling the wing depends on the size. It is
approximately 60cm for the BION 19, 63cm for the BION 21, 66cm for the
BION 23, 70cm for the BION 25, and 73cm for the BION 27. Those numbers
are just a rough indication. (The publication of the brake travel is claimed by
the EN 926.)
It would be dangerous to use the brake travel according to those numbers,
because it is not practicable to measure the brake travel during flight, and in
turbulences the stall might occur with less brake travel. If you want to use the
whole brake travel of your glider safely, it is necessary do many intended spins
and full stalls to get a feeling for the stall behaviour.
Deep/Parachutal stall
The Deep Stall, or Parachutal Stall is kind of the pre stage to a Full Stall. The
wing has no forward motion and a high sink speed, but it is almost fully
inflated. The pilot can enter the Deep Stall by applying both brakes. It is very
difficult to keep the wing in a Deep Stall: If you pull the brakes a little too
