Thread: Discussion Parkzone UM Spitfire with AS3X
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Old Feb 05, 2012, 11:00 AM
JRuggiero is offline
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Blacksburg, VA 24060 USA
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Being too lazy to research propeller efficiency relative to number of blades, and the UMX Spit's 4-blade prop, I offer this. The first of the full-size Spits (and Hawker Hurricane) were equipped with two-blade fixed-pitch props. The next generation had three-blade props. The Mark XI Spit had four-bladers; some Griffon-engined Spits had five-blade props, as did the Hawker Sea Fury.

Prototypes of the B-29 had three-blade props, but production versions had four-bladers. Likewise the early C-130 had three-bladers, while later versions had four-bladers. Newer C-130s have six-blade props. The Grumman C-2 has eight-blade propellers.

It would seem to me that, as power is increased, it is more practical to add more blades to the propeller to convert that power it into thrust, rather than increase the diameter. A smaller propeller disk allows shorter landing gear and closer placement of two engines per wing on a four-engine airplane.

How that translates to model airplanes, particularly very small ones, I don't know. Has anybody done tests?

Jim R.
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