Forgive me if this sounds stupid, but if one had an extra wide frontal area, wouldn't you need a bit of lenght to get the prop into clean air? I have been toying with the idea of a three bladed,..just for looks and wondered if it were smaller in diameter, would I not lose efficiency? And at what point, as you gain in blades, would the wash from one blade interfere with another? ----- Original Message ----- From: "Colin Rainey" <brokerpilot9...@earthlink.net> To: <kr...@mylist.net> Sent: Thursday, November 17, 2005 1:25 PM Subject: KR> prop length
> According to the author on "How to Make Propellers", take the desired 2 > blade length and multiply it by the constant .933 for a 3 blade length > conversion, or .86 times the 2 blade length for a 4 blade conversion, and > you will get the "same " performance from the reduced length/more blades. > A 60 inch 2 blade, will be 55.98 inch 3 blade, or 56 inches; 4 blade will > be 51.6 or 52 inches. > > Multiple blades are quieter, and climb better with only a small increase > in drag incurred. The big engine planes use multiple blades when ground > clearance prohibits the use of a longer blade. The reasons for using a 3 > or 4 bladed prop are: 1) increased ground clearance; 2) the need for > longer blades to harness the hp, but increased blade length causes the > ends to break the speed of sound; 3) inherently balanced by the multi > blade setup/easier balanced, quieter operation. > > > Colin Rainey > brokerpilot9...@earthlink.net > EarthLink Revolves Around You. > _______________________________________ > Search the KRnet Archives at http://www.maddyhome.com/krsrch/index.jsp > to UNsubscribe from KRnet, send a message to krnet-le...@mylist.net > please see other KRnet info at http://www.krnet.org/info.html
