The type of vane changes how fast the arrow spins

The summary today

The two tests that compare different vanes both say the type matters, but they disagree on which one spins the arrow faster. In JAXA's magnetic suspension wind tunnel an A/C/E competition arrow with Gas Pro vanes did not rotate at all, while with Spin Wings it rotated and the layer of air around the shaft turned from laminar to turbulent. In free flight, launched by a compressed-air device, the same arrows spun faster with Gas Pro vanes: a spin parameter of 0.039 against 0.029 for Spin Wings. The same group had already seen that the tunnel may not reproduce spin: with Spin Wings the A/C/E rotated there as it did in flight, but the model of the X10 rotated very differently. One more detail puts the figures in proportion: with the same Spin Wings, refletched whenever they were damaged, the spin parameter ranged from 0.028 to 0.033. The difference in flight between the two types is wider than the one due to fletching, but it comes from a single laboratory and from a launcher rather than a bow, and nobody has yet said whether those extra turns change anything on the target.

Also phrased as: "arrow spin"; "spin wing vanes"; "gas pro vanes"; "how fast the arrow rotates"; "vanes and arrow rotation"

Evidence

• 2011
  Context Equipment tests Published later

  In JAXA's magnetic suspension tunnel the A/C/E's spin rises in proportion to speed and the test reproduces real flight, but the model of the X10 rotates very differently in the tunnel from the way it rotates in flight, and the authors write that more work is needed to reproduce real flight. This is why a result on spin obtained in the tunnel should be read with caution.

  A10 Aerodynamic Properties of an Archery Arrow : JAXA's 60cm MSBS Experiments · Yuta Komori, Keita Mukaiyama, Takeshi Miyazaki, Hiroki Sugiura

• 2012
  Context Equipment tests Published later

  With Spin Wings on an A/C/E, spin rises in proportion to speed; the spin parameter is 0.030 in the tunnel and 0.028 and 0.033 in two series of flights. The authors put the differences down to the vanes being refletched when damaged: even the same type of vane changes spin with fletching.

  Aerodynamic properties of an archery arrow · Takeshi Miyazaki, Keita Mukaiyama, Yuta Komori, Kyouhei Okawa, Satoshi Taguchi, Hiroki Sugiura

• 2013
  For Equipment tests Published later

  Magnetic suspension wind tunnel with an Easton A/C/E competition arrow: with Gas Pro vanes the arrow does not rotate and the boundary layer stays laminar up to the highest Reynolds number explored; with Spin Wings it rotates and the boundary layer turns turbulent, with the drag coefficient jumping from 1.6 to 3.1.

  Free Flight and Wind Tunnel Measurements of the Drag Exerted on an Archery Arrow · K. Okawa, Y. Komori, T. Miyazaki, S. Taguchi, H. Sugiura

• 2015
  For Equipment tests Published later

  Free flight with a compressed-air launcher, Easton A/C/E arrows: the spin parameter (2πrf divided by speed) is 0.029 with Spin Wings and 0.039 with Gas Pro vanes. In flight the angle of attack is smaller with Spin Wings, which at a Reynolds number of 1.5 times 10⁴ stabilise the attitude significantly better.

  The relation between the boundary layer transition and the attitude of archery arrow · T. Matsumoto, R. Ando, J. Ortiz, T. Miyazaki, S. Taguchi

Status history

1. 2011 Not studied The first work from the group that will study the question does not compare different vanes. It shows that the arrow's spin rises in proportion to speed, and that in the magnetic suspension tunnel the model of the X10 rotates very differently from the way it rotates in flight. It is a warning about how to read tunnel tests, not an answer: not studied.
2. 2012 Not studied The first figures on spin arrive, but for one vane only. With Spin Wings on an A/C/E the spin parameter is 0.030 in the tunnel and 0.028 and 0.033 in two series of flights, and the difference between the series comes from the vanes being refletched when they were damaged. Fletching alone is enough to shift the spin, but there is still no comparison between vane types: not studied.
3. 2013 Reported The first comparison between two vanes. In JAXA's magnetic suspension tunnel the A/C/E arrow with Gas Pro vanes does not rotate and the layer of air stays laminar up to the highest Reynolds number explored, while with Spin Wings it rotates and the layer turns turbulent. Vane type changes spin, at least in the tunnel. It is a test on equipment, which counts as direct evidence in a claim about equipment, but there is only one: reported.
4. 2015 Reported In free flight, with a compressed-air launcher, the same A/C/E arrows spin faster with Gas Pro vanes than with Spin Wings: a spin parameter of 0.039 against 0.029. The second work confirms that vane type matters, but compared with the tunnel it reverses which one spins the arrow faster, and it comes from the same research group. The picture grows only a little stronger and the status stays reported.

Related

Related articles

• 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

• 32 studiesArrow aerodynamics: drag, boundary layer, vanes

Other claims in this domain

• CorroboratedAlong its flight the arrow loses an appreciable part of its launch speed12 studiesStatus since 2011
• CorroboratedAs it leaves the bow, the arrow flexes and snakes around the riser instead of leaving straight19 studies · 47 archers measuredStatus since 2012
• ReportedA camera-based scoring system misreads some arrows: the ones barely sticking out and the ones that shift the target face7 studies · 2 archers measuredStatus since 2017
• ReportedA chest band with fibre optic sensors measures breathing and mean heart rate with small errors, and an archer can wear it while shooting2 studiesStatus since 2019
• ReportedA compound bow stores between 70 and 100 joules and sheds about two thirds of the force at full draw4 studiesStatus since 2015

See all claims on equipment and tuning