### Overview

Restorative lift refers to the aerodynamic forces that help stabilize and
re-align an arrow's flight path following a disturbance or initial
misalignment (e.g. an out-of-tune bow or torqued shot). While direct
measurement of aerodynamic lift in free flight is extremely challenging,
this study used controlled horizontal misalignment to quantify the arrow's
ability to recover (or not recover) from an imposed angular deviation. The
result is a practical, real-world proxy for restorative lift based on
observed group position at distance.

### Test Environment and Setup

- All testing was performed indoors at the Easton Salt Lake Archery Center
  (Easton Foundation), Salt Lake City, UT, under the same controlled
  conditions used for drag and velocity measurement.
- An Easton Archery custom shooting machine was used to ensure precise,
  repeatable shots and to eliminate human error.
- For this protocol, the Hoyt AX-2 29 bow was intentionally set out of tune
  and consistently torqued horizontally to produce a nock-left tear of
  approximately 1.5 inches at 15 feet. This setup induces a consistent
  horizontal launch angle error across all test arrows.

### Arrow and Broadhead Types

- Two field points
- Two Sevr 2.0 mechanical broadheads
- Two Iron Will Wide fixed blade broadheads

Each arrow was shot at a 70-yard target using the same shooting machine and
out-of-tune bow setup.

### Impact Measurement and Image Analysis

- Each group of arrows was photographed at the target using a Lumix S5IIX
  camera, positioned consistently for all shots.
- A 36″ piece of tape was included in every photo for scale calibration.
- Photos were converted to PDF and analyzed with Blue Beam software. A
  digital marker was placed on each arrow impact, and the X-coordinate
  (horizontal displacement) was recorded.
- To correct for slight camera alignment variations, a fixed reference
  point was marked on the left side of the target and its X-coordinate was
  also recorded.
- Only horizontal displacement (X) was considered; vertical displacement
  (Y) was not analyzed for this study as there was variation in drop due to
  aerodynamic drag.
- A scale factor was applied using the tape reference, and the horizontal
  distance from the fixed point to each arrow impact was computed in
  inches.

Data are presented as horizontal deviation from the reference point for
each arrow and broadhead type.

95% confidence intervals were computed based on the t-distribution, with
degrees of freedom equal to the sample size minus one, to appropriately
reflect the increased uncertainty associated with small sample sizes.

### Interpretation as Restorative Lift Proxy

Less deviation from the fixed reference point indicates greater aerodynamic
correction (restorative lift) of the initial misalignment, resulting in
more controlled arrow flight. Conversely, greater deviation suggests less
restorative effect and less ability for the arrow to recover from the
induced horizontal angular velocity.

While restorative lift was not measured directly, this protocol captures
its effects through repeatable, measurable outcomes at 70 yards. Results
are compared across vanes to assess differences in aerodynamic stability
and recovery.