Thanks Gaz, Rick, Ian and Richard! When I followed your advise and removed the tape, everything fell apart again ....
Well, I finished the woodwork now

Here's my Levasseur 450 in 1:32 sanded and sealed with Humbrol clear next to two original 1:1 Levasseur props:


Given the angle both originals are photographed, I think I can live with my representation. The kit's propeller has no real similarity to an actual Levasseur besides of the "cut" ends. Now it needs a proper drying overnight and some polishing and then -- I hate to say it -- I have to airbrush this prop in a dark brown solid color as French propellers were painted in a dark red-brown laquer, visible on the lower of both original props (the upper has been "restored" and it's original paintwork stripped off). I will try to airbrush this color as thin as possible to keep an idea of the wood stains visible.
Then there is still another problem: I need some "helice Levasseur" decals. I will try to print them onto clear decal paper, but isn't anybody out there to bring us high quality prop labels for French aircraft? Pleeeeeease!
Best regards
Borsos