Disc Golf Winter Ribbon Mount/Clip

Q: Why would you attach a ribbon to the underside of your disc golf disc?
A: In the winter, specifically in deep snow, it is easy to lose your disc after a throw. The ribbon provides a visible indicator of where your disc went in and ideally is not hugely impactful to the inertia and aerodynamics of your disc. (See the “Pedantic and Unnecessary Nerd Details” section for details on this).
It's also handy for yanking your disc back out of a hole and avoiding snow on your gloves (or hands), but you need a secure mounting solution for that.

This design is made nominally to work with standard 48mm wide duct-tape, and the 5mm shiny gift wrapping ribbon from the dollar store (since it is very visible and light). Any thin ribbon should work fine.

This provides an easy, low-drag centre mounting point for the ribbon, and doubles as a ‘clip’ you can tuck the ribbon underneath for organization in your bag (OR to get it out of your way when throwing; if you just tuck the end under, it should pull free easily during the throw).

Installation Steps:
0. (optional) Mark the X and Y centre lines on the underside of your disc for easy alignment
1. Bend the centre tab out slightly (towards the side marked ‘OUT’) so it is easier to tuck your ribbon under this later for storage.
2. Cut a length of ribbon and tie it to the centre post of the print within the provided groove.
Ensure your knot is on the opposite side of the ‘OUT’ indicator.
3. Thread the ribbon through the centre hole towards the OUT side.
4. Cut a 128mm (5 freedom inches) piece of duct-tape, and mark the centre.
5. Insert the duct-tape into the ribbon mount, align the centre to the middle of the ribbon hole.
6. Install the part-tape assembly centred on the bottom of your DRY disc, press the tape firmly with a spare card, e.g. an expired driver's license or credit card.

Storage steps:
1. Wrap the ribbon around the disc so it matches the direction of the duct-tape, and tuck the end under the centre tab, pull to apply enough tension/friction to prevent the ribbon from slipping off.


Pedantic and Unnecessary Nerd Details:
Since I am a pedantic person, I have tried to keep the inertia of this part exactly balanced, including the mass of the duct-tape used to adhere it.

This part is approximately balanced in both the X and Y axes about the centre ribbon hole.
For the standard 0.32 layer height 6mm hole variant, the total mass in PLA+ is around 2 grams, with a dense ‘square’ dimension of around 57mm x 36mm.

The inertia about a given axis ‘X’ for a flat plate is:
Ixx = 1/12 * mass * side_length^2

Then our inertias about the Y and X axes respectively for the printed part are:
[9.5 × 10^-12 m^3*kg, 6.0 × 10^-12 m^3*kg]

For a 41.15m roll of 48mm-wide duct-tape, with a total weight of 181.44 grams:
We can subtract around 10 grams for packaging and cardboard, and end up at a ‘weight per meter’ of around
4.1664 g/m

We know we have a deltaI = 3.5 x 10^-12 m^3*kg discrepancy between the 2 axes, so we need to solve for the length of tape required to produce this offset in the opposite axis to compensate.
We have 2 variables, and a single unknown here, since the mass of the tape is a function of the length. Where tape_mass_g = 0.0041664 g/mm * tape_length_mm

define C = 0.0041664 kg/m

Then by rearranging equations for the tape piece Ix and Iy we get:
tape_length_mm^3 = 12 * deltaI * 1/C - 48mm^2

tape_length_mm = 128mm

Which is just about perfect for what we can fit on a disc!

Total mass is around 2g print + 0.533g tape = 2.533g
With an inertia of about 1.16 × 10-11 m^3*kg for both the Ixx and Iyy axes.