Pietenpol-List: Prop Info
Posted: Sat Oct 18, 2003 11:17 pm
Original Posted By: Clif Dawson
Subject: Pietenpol-List: Prop InfoIn a message dated 10/17/03 8:58:20 AM Central Daylight Time, BARNSTMR(at)aol.com writes:>Terry, et all, The name of the book is 'Propeller Making for the Amature' by Eric Clutton. He's British. You can get it from EAA library, and it only costs about8 bucks or so. It is a MUST READ TWICE if you are even thinking about building a prop. He gives building methods & tips, and all the formulas for estimating the pitch and diameter for a given horsepower / airframe, but he notesa preferred method is to use previous a successful combination of Prop / Powerplant/ Airframe. He goes into a little detail about how to build a Scimitar Prop - where the blade tips are swept back quite a bit. I've done some research on this type of prop, but for the life of me I can't figure out why everybody doesn't usethis design prop. There are six Scimitar Props hanging in Steve Wittman's hanger. It's like an automatic blade pitch, with no moving parts. At high R.P.M. for take off, using cintrifugal force and aerodynamic twisting force thewood prop blade angle is reduced for more thrust. When airborn and power is reduced, the prop 'unloads', the blade angle relax's and you have a higher bladeangle for more efficient cruise. What more could you want ??? !!! To be honest, it would require quite a bit more work to build one using the 'Cluton'method, and I suppose with all the flexing the blades are exposed to, there would be more of a chance for a blade to fail. I did read one story about a W W 1 pilot that had a Scimitar prop. It seems his opponent was on his tail slinging lead at him, so he went into a fullpower dive. Overspeed the engine, and over ran the prop when the blades beganto 'flutter' just before a blade failed and broke off. He was having a bad day. Not sure if he made it.Chuck G.________________________________________________________________________________Date: Sun, 19 Oct 2003 00:01:46 -0700
Subject: Pietenpol-List: Prop InfoIn a message dated 10/17/03 8:58:20 AM Central Daylight Time, BARNSTMR(at)aol.com writes:>Terry, et all, The name of the book is 'Propeller Making for the Amature' by Eric Clutton. He's British. You can get it from EAA library, and it only costs about8 bucks or so. It is a MUST READ TWICE if you are even thinking about building a prop. He gives building methods & tips, and all the formulas for estimating the pitch and diameter for a given horsepower / airframe, but he notesa preferred method is to use previous a successful combination of Prop / Powerplant/ Airframe. He goes into a little detail about how to build a Scimitar Prop - where the blade tips are swept back quite a bit. I've done some research on this type of prop, but for the life of me I can't figure out why everybody doesn't usethis design prop. There are six Scimitar Props hanging in Steve Wittman's hanger. It's like an automatic blade pitch, with no moving parts. At high R.P.M. for take off, using cintrifugal force and aerodynamic twisting force thewood prop blade angle is reduced for more thrust. When airborn and power is reduced, the prop 'unloads', the blade angle relax's and you have a higher bladeangle for more efficient cruise. What more could you want ??? !!! To be honest, it would require quite a bit more work to build one using the 'Cluton'method, and I suppose with all the flexing the blades are exposed to, there would be more of a chance for a blade to fail. I did read one story about a W W 1 pilot that had a Scimitar prop. It seems his opponent was on his tail slinging lead at him, so he went into a fullpower dive. Overspeed the engine, and over ran the prop when the blades beganto 'flutter' just before a blade failed and broke off. He was having a bad day. Not sure if he made it.Chuck G.________________________________________________________________________________Date: Sun, 19 Oct 2003 00:01:46 -0700