MI 25 - The Arch (Intermediate)
Compulsory figure from the series Multi-line individual figures.
Reference diagram
Official document: ISK Compulsories Book v3.0, p. 87
Official description
Judges will particularly consider
- Speed control
- Arch
- Landing
Explanation
- IN is at <30 of the wind window on the ground.
- Movement is continuous and at a constant speed throughout the figure.
- The kite flies up vertically transitioning smoothly into an arc at ˄50
- On completing a semi-circle the kite transitions smoothly into vertical downward flight
- Finally the kite makes a controlled landing at >30 of the wind window on the ground. Pilot calls OUT.
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.
- douteWe added a brief stop (0.25 s) before and after each rotation on the spot, and at each corner where the wing goes from one translation to another with a different leading-edge orientation. It does not appear in the list of steps, and the rules do not ask for it: they only mention the stops marked on the diagram or cited in the text.
Keep going
In the series Multi-line individual figures
- MI 22 - The Felix (Experienced)
- MI 23 - Slide and Square (Intermediate)
- MI 24 - Basic Elevator (Novice)
- MI 25 - The Arch (Intermediate) — you are here
- MI 26 - The Arch with Stops (Experienced)
- MI 27 - Up, Down, Up (Intermediate)
- MI 28 - Square (Intermediate)
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