DI 20 - Boomerang
Compulsory figure from the series Dual-line individual figures.
Reference diagram
Official document: ISK Compulsories Book v3.0, p. 31
Official description
Judges will particularly consider
- Parallel lines
- Arc
- ½ Axels
- Placement of elements within the precision grid
Explanation
Enter at 20˄, execute a ½ axel at centre of window and continue into arc. At 70˄ execute a second ½ Axel immediately above where first ½ axel was placed and continue into level flight, parallel to original line of entry. Call out immediately above the point where IN was called.
Our reading
What follows is our reading of those documents, not an official document: the diagram and the description above are what counts.
Animation
Sequence
Doubts & discrepancies
Uncertain readings of the diagram or the official text, and disagreements between sources, to be validated. The animation follows the reading we chose, which is not an official interpretation.
No specific doubt or discrepancy about this figure.
Common to the whole family of figures
- douteOverall speed: we chose a constant speed of 15 units per second (about 4.4 m/s with 37 m lines), without any flight measurement. The ISK requires a constant speed (§II.V) without giving a value.
- douteKite size: our assumption is a wing 2.30 m wide, i.e. 8 grid units (1 unit ≈ 0.29 m with 37 m lines), with the proportions of the Hadzicki wing drawn in kite-physics; the dual-line wing has the same span. For the reference competition, we only found the scale of the grid (ISK §II.C: about 0.3 m for 38 m), not a kite size. At this size, the wings of a team overlap at times (MT 01, 02, 06 and 09). Lead: a smaller kite.
Keep going
In the series Dual-line individual figures
- DI 14 - Register
- DI 15 - LSI
- DI 16 - Two Squares and Stalls
- DI 17 - Wedge
- DI 18 - Square Cuts
- DI 19 - Launch, Circle, and Land 2P
- DI 20 - Boomerang — you are here
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