Darock,

Your refering to Robert S. Johnson from the Martin Caidin book "Thunderbolt". Johnson was refer to the new Paddle blade prop not a conversion from a 3 blade to 4... All 47's from the C model up that went oversea started out equipped with a Curtiss Electric 4 blade narrow cord prop. By mid 43 Hamilton and Curtis started providing the "Paddle Blade" to improve performance. Also keep in mind that Johnson wasn't running around with a Jug producing stock horsepower. It is documented that his crew chief spent a great deal of time with Pratt techs and his and many other Jugs in the 56th were probable flying around making over 2800HP in Mid 43 and early 44...

Fun stuff!

Hibrass