An arrow that oscillates less in flight groups more tightly
1 study
The summary today
The only direct test says no, at least with a compound at thirty-five metres. A Protour 470 with X vanes, shot from a compound on a machine, was tried with the bow set to give a certain sideways oscillation about the centre of mass and then with that oscillation halved: in both cases the group was the same, within the aiming accuracy of the machine, with every arrow inside a circle one and a half centimetres across. The same work explains why with a model checked against paper tests: the point, very heavy compared with the rest of the arrow, strays less than three millimetres from a straight line while the tail swings, so even with large oscillations the arrow's sideways position in the target changes little as the distance changes. The author does set one condition: the oscillation does no harm as long as it stays the same from shot to shot, as it does on a machine. The result does not say that tuning is pointless: it says that at this distance and with this bow, half an oscillation more does not show on the target. The number of arrows shot is not reported, and nobody has tried it with a recurve, a finger release and seventy metres.
Also phrased as: "fishtailing arrow"; "clean arrow flight"; "arrow oscillation in flight"; "tuning and grouping"; "porpoising arrow"
In practice
Tuning chases an arrow that flies clean, without fishtailing, on the idea that the cleaner the flight the tighter the group.
Evidence
-
2011
Against Equipment tests Published later
Easton Protour 470 arrow with X vanes shot from a compound on a machine at 35 m, with the bow set to give the sideways oscillation seen in the paper tests and then half that amplitude: in both cases every arrow fell inside a 0.015 m circle, within the aiming precision of the machine. The author concludes that oscillations of those amplitudes do not degrade accuracy as long as they are consistent, as in the absence of technique errors. Number of arrows not reported.
Arrow behaviour in free flight · J L Park
-
2011
Context Model Published later
In the flight model, checked against paper tests up to 35 m, the point, very heavy compared with the arrow and with the aerodynamic forces dominated by the vanes, strays less than 0.003 m from a straight line while the arrow oscillates about its centre of mass with a period of about 21.8 m; for this reason, the author writes, even with large oscillations the arrow's sideways position in the target changes very little as the distance changes.
Arrow behaviour in free flight · J L Park
Status history
- 2011 Contradicted With a compound on a machine and Protour 470 arrows, halving the amplitude of the sideways oscillation does not change the group at thirty-five metres: in both cases the group is the same within the machine's aiming accuracy, with every arrow inside a circle one and a half centimetres across. The model in the same work explains why: the point, being very heavy, strays less than three millimetres from a straight line even while the tail swings. A single test, with no arrow count and a resolution of one and a half centimetres, goes against the statement: contradicted.
Related
Related articles
- Fishtailing and porpoising: what arrow flight saysDoes your arrow wag sideways or wave up and down? What causes fishtailing and porpoising, which to fix first, and how to confirm it with a bare shaft test.
- Bow tuning in archery: how to tune your bow, backed by scienceBow tuning and the research: spine, centre shot, button, nocking point, brace height and tiller. What models and machine tests show, and how precise you need to be.
- Vanes, feathers or Spin Wings: what actually changesLarge or small vanes, feathers or plastic, vane angle and orientation on the shaft: what the studies measure, and where research has not yet reached the target.
Research lines
Cite
Campagna, M. (2026). An arrow that oscillates less in flight groups more tightly (Version 1). In Evidence Registry. Retrieved 16 October 2026, from https://matteocampagna.com/en/registry/equipment/arrow-oscillation-group-size
@misc{campagna2026_frecciaondeggiamenogruppo,
author = {Campagna, Matteo},
title = {An arrow that oscillates less in flight groups more tightly},
year = {2026},
howpublished = {Evidence Registry, matteocampagna.com},
url = {https://matteocampagna.com/en/registry/equipment/arrow-oscillation-group-size},
note = {Version 1; accessed 2026-10-16}
}
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