Does anyone have a source for 4 bladed props for 1/2a sized engines.  (I was torn as to where to post this but its for a scale project so I figured the scale fourm would be best.)  I need at least 4 but would prefer to have some spares as well.  you guys will never guess what plane Im going to build.

i cannot say i've seen any 4 blade props for 1/2 A but if you know how to mold a prop i can tell you how to make a perfect blank to mold from.

if you are still looking for 4 bladed 1/2A props .i have 7/2 carbon 4 bladed props for go or show.

Hi Jeffrey,
I have made four bladed flying props for 1/2 A's by half lapping two two bladed props. Notch the hubs out so they slide together. Then epoxy them together. I would use a bolt in the center of a flat plate jig and draw some lines that will accurately index the blades so the are 90 degrees apart. They need to be about 5 inch diameter and 3 inch pitch or less to be able to let the usual 1/2 A turn them at a useful rpm.
Chris...

Chris,

I have not made 4-blade props for the 1/2A's  --  BUT  --  I have tried it for larger engines.  I took 10" diameter props and notched them so they would fit together.  The fit was good.  I used good epoxy to put them together.  The first time I ran one on a test stand, it shed a plade.  The failure was along a grain line that was at the notch.  Unless you anchor each blade with bolts through each blade to a metal back plate, your are courting disaster, even with the smaller props.

The solution to this is make up a display prop with however many blades are needed for scale, then fly with the two blade prop that is appropriate for the engine.  There is no penalty in scale points of flight points to do this.

Keith