The flipper broken down during testing, subject to material failure.

I shall use low gear ratio and less wing span for my next trial test.

It seems to me that it can work under water.

The name of this book in English is "DIY Model Airplane Making". 

I shall make a flipper airplane during the coming Chinese Lunar New Year.  Hoping that it can work under water.

Overall dimension.

The original flyer in this book.