Are 4 stroke props better for electric use?

[Joel K. Scholz]

I am designing a plane that will have a phasor 45-3 geared 2:1. on 16 cells. This setup will drive a 15 x10 or 15x 8 prop at around 6000 rpm. Electric propellers of this size are fairly rare and expensive. How much difference does a normal prop really make , and am I wrong to assume a 4 stroke prop would be preferable due to the fact it is designed to provide thrust at a lower rpm than a 2 stroke prop? :confused:

[pda4you]

The APC-e are very efficient at lower RPM's. I really like them. Now to be honest I have not directly compared them, so feel free. I think you will really like the apc-e props better.

No question that it will fly with glow (4 or 2 stroke) props. I have used them before in smaller applications (a 7x3 MAS) and it worked fine, but the e props of similar size were much better IHMO.

Mike

[jrb]

Joel,

Here’s another thread that speaks to comparisons of the E to other props:
http://www.rcgroups.com/forums/showthread.php?t=260103

[AndyOne]

IC engine props and in particular 4 stroke props are designed to take higher levels of torque due to the pulsating nature of torque delivery by an engine. Props specifically designed for 4 strokes tend to be built with thick blades to withstand these forces since the torque is even peakier than with 2 strokes. IC props also have to take the rigours of engine starting. Electric props are designed with the efficiency in mind and tend to have much thinner section blades. Torque delivery from a motor is much smoother than from an IC engine and there are no starting forces to contend with.
Even though 4 stroke props may be designed to deliver more efficiency at low speed the necessities of strength completely out weigh the benefits for electric power.
Props specifically designed for electric power work much better but some have RPM limits because of the lightweight construction.

Andy.