Jean-François Beaudin, a very fine flutist himself, devoted decades of research to the early flute. He measured the most important instruments in collections all over the world and most makers use his drawings for their own copies. Museums hired him to measure and document their holdings, since he is a true master of his craft.
If you look at the development of the flute and chose to overlook all those wonderful details and sideways of history, it might be possible to see a line that connects early makers like Haka and Bressan to IH Rottenburgh, Eichentopf and Quantz. They all used rather wide and just sligthly conical bores, obtaining a powerful sound. Quantz in a way represents the end point of this development. The next generation like A. Grenser made drastic changes in order to obtain instruments that follow a very different sound concept. Their bores get narrow, the sound gets much softer and they do favor the high end of the range. The late development of this we see in Mozart and Beethoven writing for the flute. In orchestral parts the instrument is used most of the time above the staff and in the 3rd octave.
If we pick it up with the Quantz flute and imagine how the flute could have continued, we can easily understand the development of the Beaudin flute. It keeps all the characteristics of a true traverso with a strong first octave and a range to a 3rd octave a''' or bb'''. The difference between simple and cross fingerings are a little less pronounced. The double key for d#/eb as on the Quantz flute assures a perfect intonation and easy high notes and trills. Besides the normal head there is a second one with a much larger embouchure and a straight edge to blow against, giving incredible dynamic possibilities and control.
The Beaudin flute is the perfect answer to problems flutists face in the 21st century, playing in very big halls, churches full of carpet and with 'historical orchestras' that are not authetic at all: sting players using set-ups with higher bridges and higher tension in order to play louder. Lute and Chitarrone players using synthetic strings that ring much longer and louder than gut. Wind players play on scaled and 'improved copies?' of mid to later 18th century models, all brought together to the Neo-Baroque pitch of 415 Hz and with Valotti tuning that has little to do with Baroque music to start with.
It's in these conditions, that the Beaudin flute proves to be a fantastic partner to get musical ideas aross, which otherwise would be lost due to outer circumstances I can't influence as a player. And it is a fun instrument to play since it doesn't have these difficult touchy areas you constantly have to worry about. So whenever 415 Hz is called for and I'm not with my own trusted colleagues, I rather relay on this wonderful instrument than play another Brandenburg V loosing the competition with the violin on 'everything you play I can play louder'.