More learning here, Louis! I knew about venturis & I had heard of Bernoulli's Principle & I'd even seen those venturi mechanisms on a few planes, BUT I had no idea what those mechanisms were for. I LOVE learning new things about aircraft.

As we talked about, Mr. G, I have an appreciation for the early Marks of Spits, Hurris, & MEs with the single piece, double-bladed props. Like you, Lou - I didn't used to like that look, but as I've grown, so has my appreciation for all types of aircraft, autos, armoured vehicles, motor bikes, and machinery in general.