Many thanks, Kevin! I am glad you find the trick helpful.
Today I did not really feel ready for assembling and rigging, so I decided to try something else and improve the propeller.
This is the prop I have now, actually quite nice from my POV, but you can always do better, right?

IMG_1626 by
Ondřej Mokrý, on Flickr
I cut stripes of brown and yellow paper and made a sandwich:
IMG_1616 by
Ondřej Mokrý, on Flickr
IMG_1617 by
Ondřej Mokrý, on Flickr
Afterwards I soaked it with ultrathin CA:
IMG_1618 by
Ondřej Mokrý, on Flickr
And sanded it to the basic shape:
IMG_1620 by
Ondřej Mokrý, on Flickr
IMG_1622 by
Ondřej Mokrý, on Flickr
In the last step, I sanded the final shape:
IMG_1624 by
Ondřej Mokrý, on Flickr
Lessons learned from this exercise: next time I will use a lighter tone of paper for the dark lamination, as the shade gets significantly darker when soaked with CA.
Many thanks to Warren Dickinson for the heads up on this method.
Cheers
Ondra