Hi, Paul,
thank you for your kind reply and your help.
I know Benno Sabel's plans are not for meticoulous static modellers, but anywaythey are a good base: and they have the power to fly, unobtainable from static models... we must accept a trade-off.
I've found some infos about the "other" Windam monoplane
here - her propeller had a one-of-a-kind axe shape, and I'm tempted to implant the very same propeller shape on my tandem wing monoplane model.
the photos are attached and an e-mail is in your mail box
Best regards
Ermeio