Prop Difference is?

[drewpyfz6]

Being new to this hobby,
There are loads of figures, terms, power graphs banded about, and sometimes feel you should know what is meant.

Anyway, what is the difference in prop size from 10x8 to a 10x4.7
Presume the 10 is the length in inches, but the 8 and 4.7?

If someone could explain in clear words, it would be appreciated.

Cheers,
Drew

[flydiver]

A prop is a screw pulling through the air. 2nd number is picth = the movement per foot > an 8 will go 8" per revolution, a 4.7 will go 4.7"/revolution. This is ignoring slippage. A sleek plane will have less slip, a sloppy plane like the Cub has lots of drag and slip.

Do some reading on these articles:
www.stefanv.com/rcstuff/qf200203.html
www.ampaviators.com/index.php?option=com_content&task=view&id=42&Itemid=28
www.ampaviators.com/index.php?option=com_content&task=view&id=39&Itemid=28
www.ampaviators.com/index.php?option=com_content&task=view&id=38&Itemid=28

It's more complicated than that. Motors are narrow range power devices. Too small a prop and you get nowhere. Too big a prop and you burn it up since it can't handle the load. Too big/small can be a combination of either/both length and pitch. Do not just change props for the hell of it. HZ has figured out a prop that works with that combo. Those articles explains it more and provides other options.

Once you start throwing together your own power system you don't have that guidance. You have to learn how to prop new motor/plane packages. A thing called a wattmeter becomes critical. AND you generally cannot believe the motor specs the Chinese (and many others) claim.
Not terribly difficult once you get it but understanding all the variables takes some study.

Here's a great FAQ site that will answer a lot of questions:
www.ezonemag.com/pages/faq/index.shtml

Come back in 2 weeks.... ;D

fly

[drewpyfz6]

Wow, thats a lot of reading - and understanding.

Thanks for the info.

[flydiver]

Like most I thought this hobby was about buying a plane and learning to fly it. It's more about learning all kinds of stuff I had no idea about and fixing the results of learning to fly. I know more about glue and tape now than I ever imagined and went from a rotten solderer to a reasonably competent one, all through trial and error. That's pretty much the path. The groups can help with a 'map' of sorts but you still have to go the distance yourself.

fly