For space & weight concerns, we are considering a one or two belt shooter.
The main concern we have is for how to maintain consistent & adequate belt contact pressure/friction against the disk edge, for a decent amount of travel distance, while still ensuring that the disk stays centered on the belts, without developing up/down “shear” forces shifting alignment of disks with the the belts’ centerline(s), and raising friction against upper/lower guide-glide surfaces.
We prefer to have dual belts, in order to allow using lower belt speeds and to hopefully give less resulting belt slippage, from the velocity boost that having a 2nd MOVING opposing belt surface allows. We also plan to have the two belts running at a suitable differential velocity to impart adequate disk spin.
We will initially try this by using the very thin layered (<.001) and low stretch (kevlar-polyester?) urethane surfaced style of belts, and with a generous belt width of ~1.5"
We are thinking that pivot arms with an adjustable pressure spring loaded belt tensioning mechanisms, and idler rollers with slightly convex dished roller ODs, located at at least at the shooter’s outlet end, would work best to help belts maintain consistent grip. The dished rollers could also help shape the belt slightly to better contact & contain the disks on center.
A pair of these idler arms for each belt may likely be needed so that as the frisbee flexes the inlet pair of idler arms outward. the outlet pair of arms would close inward the corresponding amount to take up the resulting belt slack.
Having similar opposing idler arms for each belt at both ends should also help keep the belts in better and more consistent contact with the moving disks over a longer belt arc segment worth of contact, as disks pass through this idler arm “pinch zone”.
These pivot points mounting of these belt tesnion rollers should likely be placed on a rocker plate to better handle the dynamics of belt flexing motions as the disks squeeze their way through the roller pinch zone.
There would still also be a fixed idlers and a powered pulley located at each end of the belt oval, just beyond the swing arm tension idlers, but spaced wide enough so they would barely pinch the disk on entry & exit.
The opposing idler arms at the entry end would separate as the disk wedged into the V caused by the bends in the two belt paths. Then, as the belts separated at the entry end, being spread wider by the disk, at the shooters exit end, that pair of opposing rollers would be closing tighter until the disk reached the midpoint.
With the disk at midpoint, the entry idler arm rollers would begin closing back together, while the exit pair of idler arm rollers would start spreading to allow the disk to pass between them.
It would be kinf of like an intestine with fast moving walls to squeeze, flex and accelerate the disk through the shooter.