DAVINCI GLIDERS / HULA
9
11.5 Asymmetrical stall
11.6 B stall
It can take place when you pull one of the brakes too hard, or while spiraling at a small
speed in turbulence you increase the angle of attack. Rotation in the asymmetrical stall
is called a negative spiral. This is one of the most dangerous flying situations. In order
to get out of the asymmetrical stall, just release the brakes. There may follow side thrust
forward with the following wing collapse.
The HULA has a very clean stable B stall. To enter the B stall, the pilot has to pull the first
20cm slowly until the glider loses forward speed and starts to descend at around 6 m/s
vertically. Do not release the brake handles during B stall. If you pull too much B-line
the glider may horseshoe and move around a lot. If this happens, release the B risers.
To exit the B-stall the B-risers should be released symmetrically and in one smooth,
progressive motion. The glider will resume normal forward flight without further input.
Check you have a forward flight again before using the brakes.
11.4 Deep stall
11.3 Full stall
It is possible for gliders to enter a state of the deep stall. This can be caused by several
situations including; a very slow release from a B-line stall; flying the glider when wet; a
very old glider; or after a front/symmetric deflation.
When you meet this situation you should fully raise up both brakes and push the
A-risers forwards or use the speed bar symmetrically to regain normal flight.
The full stall can occur when you fully pull both brakes enough a long time. This means
that the wing loses its forward momentum. To recover to the normal flight you must
release both brakes. After this usually comes a front dive with a possible front deflation.
An asymmetric recovery (one control released faster than the other) from a full-stall can
cause a big dynamic collapse. The full-stall is a hazardous maneuver and as such outside
the scope of this manual. You should practice and learn this maneuver only on an SIV
course under a professional instructor.
