Dedicated to my lifelong friend, teacher of PhD Level Aerodynamics, collaborator, Dr. Andy Bauer    Book TOC    Bio    Insight    Privacy    Contact    . 
Betz makes it the perfect propeller equivalent of Prandtl's perfect, elliptical Spitfire wing. GoldsteinTheodorsen 3D math makes it exact. 


Why Tapered Tips? A Rotating Wing Tries Violently to be a Tip Thrust Loss, Tip Vortex Loss Disaster.  
Any Wing wants max loading Inboard, Zero at the Tip, Zero tip Lift, or Thrust, to Minimize Tip Vortex Loss. Basic! A Rotating Wing: Tip Dynamic Pressure, q, proportional to V2, is a Disaster of Lost Thrust into a Violent Tip Vortex Loss! Simply, Tapered Tips Counteract the Disaster, Minimize Energy Loss, have Least Torque Demand, get Max Thrust! Easy! Simply, The Prop with the Least Loss, Least Torque Demand, Creates the Most Thrust – Tapered Tips Win! Norris's 8th law. 
It's rare genius: Classic Betz exact logic; essentially exact GoldsteinTheodorsen math that teaches us how; Jack Norris's insight.  
A group of RV Pilots just placed an order for 74 Whirlwind 200 RV props, the first exact prop. They get it. The First Exactly Correct, All 6 Way Optimized Perfect Prop, in the History of Flight! 

At Reno, in the Formula 1 Gold Race, 14 September 2008, a Cassutt with an extra high pitch race prop left everyone in the dust in the takeoff race to the first pylon. It won second, beating better planes, losing only to the far superior airplane "Endeavor". Race pilots bought a lot of these books at Reno that day. 
Rare Genius Work by Historic Technical Giants, it took a 10 year World Class Program to get all the brilliance in their 83 year program really correctly understood, and simplified. We discovered Classic, Perfect Betz
prop logic, Goldstein
 Theodorsen
essentially exact math. But, with no
math, the book teaches it all in
understandable, incisive insight. We learn the exact logic; the
bottom line of 142 years' historic work. We see, through easily
understood physical logic, the horse
sense of what happens physically:

Simply
Flying the IAS, Indicated
Airspeed
that Maximizes
IAS vs. Drag ,
gets you 31.6%
more Speed
for only
15% more Drag
than the Absolute Minimum. But then, Climbing to the Max Possible
Altitude holding that IAS, Finally Wide Open, Lean, (never
Lean, Low),
your
Plane and Engine are Perfectly, Optimally Matched,
Power
Exactly Equal, Matched!
If your plane Tops Out at 12,500 feet, TAS/IAS is 1.21. Now, 1.316 x 1.21 = 1.59. You’re flying 59% faster for only 15% more Drag than the Min. Drag Possible, The Thinking Man’s Way to Fly, The Engine at Low Power, Optimally Leaned, Low Fuel Burn, Optimum TAS, MPG! All
Learned on the Cover, The First Few Pages, Optimum Flight, the Flight
Book
becomes the Simple,
Insightful Pilot’s Aero 101 Course that you could normally never
find !
Basic Aero, Engines, all the insight you could never find, everything
in One
Double Book! It’s
the Pro’s Lifetime of Insight, the logic, all
purposely “easy
enough”,
the insightful, understandable, horse sense of what’s happening
physically, the kind
of insight we can all see through, and understand! 