Jim Sower wrote:

Yeah.  Also, I believe Tracy has answered all of his "questions" around tortionals and props and dynos.  Additionally, if there were problems, Tracy would have encountered one in 1500 hrs.

The guy's statement around "... sprag clutches cause the prop to freewheel in the event of engine failure putting the equivalent of a barn door (HUGE drag compared to stopped prop) behind the airplane ..." is so preposterous that it calls ALL of his other engineering into question. 

Not so fast, Jim ....

A widmilling prop DOES have hugh drag compared to a stopped one.  An unfeatherable, windmilling prop almost had me swimming in the Pacific Ocean near Wake Island many years ago.  The fact that the engine seized when a piston could no longer reciprocate inside a missing cylinder ...was what saved my bacon.  Once it stopped, even though the props' blade angle was nowhere near feathered, the drag reduction was so dramatic that we were able to level off from a forced descent and keep the ship (a C-123B) in the air long enough to make it to destination on the other engine.

When you think windmilling drag ... think prop circle area, not just the blades cross section themselves. Square yards of drag, not square ft.

His article sounds authoritative, but has all the intellectual allure of Lamar's rantings that NACA ducts and Electric Water Pumps "... cannot possibly work ...".  Stick with Tracy.  He has something flying.  This guy has nada.

I tend to like Tracy's solution also.  His hours in the air give him a lot of credibility.

Just a theory .... Jim S.

David Leonard wrote:

Dale Smith