Vertipedia currently assumes (see Glossary) that 'wash-out' (local pitch angle reduces towards the tip) is entered as a positive number. This was chosen as the vast majority of rotors have 'wash-out' (some autogiros have 'wash-in', where the local pitch increases towards the tip).
From a pure mathematical perspective, it is understandable that 'wash-out' should be quoted as -ve as the derivative '(change in pitch)/(change in radius)' would be -ve.
Also, twist is currently entered in the unit of radians rather than degrees as the database is based on the SI standard.
It is not clear if there is a VTOL industry standard, so this discussion has been raised to gain feedback from members on the preferred standards to be used in Vertipedia. Please note that whatever is chosen, there will be no change to the data within Vertipedia other than (potentially) changes to the displayed values and the definition in the Glossary.
* Last updated by: comodo15 on 7/20/2016 @ 6:58 PM *