Prop issues

[5150SR71]

Ok guys, need some help from some pro's here. Putting together my second scale plane and am having some issues. I really want to use a 4 blade prop. I know they aren't as efficient and all that crap. I still want to use one for looks and such.

My problem is determining which pitch and size to use?!?!?! Is there a formula or some voodoo magic you can use to get the correct size prop?

The plane is a Top-Flite 65" wing span Mustang(not the Giant) and the engine is a Saito 1.80 4 stroke.

Any help would be appreciated as I'm totally freakin clueless on this one. I'm not that expert of a pilot to just throw on a prop and trust taking my plane off without some sort of research first.

Thanks,
5150

[Dave Robelen]

Hi,
I would determine the best prop size in a 2-blade version from the engine and kit literature, Then drop down one notch in dia. (keep the pitch). This is a decent starting point. Whether it is a 2-blade or 4-blade, you will have some experimenting to do to get the best match for your model, and your engine at your location, running on your fuel. Let us know how you make out.
Regards, Dave

[5150SR71]

Thanks for the help Dave. I'll give that a shot. I think I'll just grab a couple of 4 blades at the LHS next time I'm there so I can see which works best. That gives me a good start as to which size and such though. Thanks for the info! I'll let you know what happens with it!

Mike