A Miscellany of Props
There used to be the Martec and Michigan folding props; un-geared and with negligible
reverse thrust, but no one cared because the drag was low under sail. Then Max-Prop
entered with a feathering prop that, unlike the feathering props that had been
around since the thirties, was designed overall for low drag (early feathering
props had hubs like small soccer balls). Then along came the Gori, which claimed
to have superior thrust in forward and reverse (which was true, but only compared
to the non-geared, which had negligible reverse).
After that, the flood-gates opened and a plethora of props, feathering or folding,
2-blade and 3, appeared on the scene. These are a few that populate a Toronto yard
(and only one is on a C&C 27 – for comments on props on 27's, see here).
Flexofold Mk1
Flexofold Mk2
Flexofold Mk2
Gori
Gori
Gori 3-Blade
Gori 3-Blade
J-Prop
Martec
Martec Eliptec
Martec Eliptec
Martec Eliptec
Max-Prop
Michigan
Michigan
Mystery Prop
Stealth
Vari-Prop
Comparison
Un-geared folding props are:
- less expensive;
- smaller in cross-section and the blades fold close together, hence the source of less drag;
- marginally easier to install;
- unlikely to provide meaningful reverse thrust.
Geared folding props are:
- more expensive;
- larger in cross-section with gaps between the folded blades (with the exception of Vari-fold), hence the source of more drag;
- marginally more complicated to install;
- slightly more needful of maintenance;
- likely to provide significant reverse thrust.
Feathering props are:
- significantly more expensive;
- slightly larger in cross-section than geared props, hence the source of more drag;
- significantly more complicated to install;
- likely to provide better thrust in forward and reverse
- demanding of significantly more maintenance.
