Great stuff on the prop discs H ! Remember though, the 'blur' of the individual blades is not normally seen, and is a feature often mistakenly included in artist's paintings, even from the top artists. The only time you will normally see a 'motionless' blur of a blade is in a photograph, as the shutter speed of the camera has partly 'frozen' the action. If any form of 'movement' is needed, it's better to make the disc from either a tinted clear plastic, or, as already mentioned, give the clear disc a thin wash to give the impression of a moving disc.
I have to say though, that the results shown are very good, if accepted as that millisecond in time.