Does anyone makes an bladed air-coil?

[Mike Sulzer]

Exactly. That's why I said my sidewinders are also technically air coils. Neos are the same way... they have the permeability of air.

Sometimes you need some steel in there though.

A sidewinder core needs a material with significant permeability. The magnetic flux from the vibrating string comes down from the strings and needs to be bent 90 degrees to pass through the coil(s). This requires a material that guides the flux lines, that is, has a high permeability. So if your sidewinder uses ceramic cores in the coils, this must be a type of ceramic with a significant permeability. Ceramic materials in general have a wide range of permeability.

[David Schwab]

A sidewinder core needs a material with significant permeability. The magnetic flux from the vibrating string comes down from the strings and needs to be bent 90 degrees to pass through the coil(s). This requires a material that guides the flux lines, that is, has a high permeability. So if your sidewinder uses ceramic cores in the coils, this must be a type of ceramic with a significant permeability. Ceramic materials in general have a wide range of permeability.

Those are good points. It's a regular C8 magnet.

They are fairly inefficient pickups without steel cores.