Could someone please tell me the different between a 4 cycle prop and a 2 cycle prop. I have seen a Rev-up prop that said it was for 4 cycle. Thanks for any information.

There is no difference that I have ever come accross

Tower has some props they advertise as "four stroke" but they don't say what they really mean by that or the difference. I've never seen anyone use such a prop.

Hi!
There is no difference!!! All propellers could be used on any engine. Simple as that.
Some manufacturers/advertisers just try to sell things. Don't belive every thing you read...

Regards!
Jan K
Sweden

The label

The difference is that some props are designed to revolve twice per power cycle while others expect a power cycle every revolution. OK, that is complete BS. There really isn’t any such thing as a 4C vs 2C prop… it is just marketing. However, there may be prop designs that lend themselves more toward one engine type. 4C engine tend to produce their power at lower RPMs compared to 2C. This RPM/power curve difference does lean toward slightly different ideal designs for 4C vs 2C props. But even so, any prop with the proper loading will work on any engine, which is why in general you will never see a prop marked as for 4C or 2C as they work fine on either. Cheers.

Thanks for the fast reply. I did't think there was a different Thanks again.

LOL!!! That is great.

The correct word is: "DIFFERENCE".

Hey Bruce, were you an English professor? Are you still? Or just a purrrr...fectionist?

Just a person trying to help someone out.

Interesting post. I bought a Master 12X4 to use on my OS 50SX and I noticed that it was VERY noisy in flight. I mentioned it to the guy at the LHS and he told me it was designed for a 4 stroke and although it would be noisy on a 2 stroke that it wouldn't hurt anything. He claimed that prop is designed for much lower RPMs. Hmmmm, what gives?

DUH! All props are quieter when turned slower.

That prop is probably turning high rpms on that engine. The suggested props for the 50SX are 10-8 to 11-7. To go to a 12" prop a 12-6 would be a match or you might be able to go to a 12-5. [8D]

Noisy props are caused by several things. Too much RPM, blade shape, tip shape and a small host of others though the 3 I mentioned are most common.

Master Airscrew props are amongts the loudest around followed by Zinger. Both flex allot so are also somewhat inefficent. For glow engines 18 inch and below I'd stick with APC. Tons quieter and much more efficent

Hope you meant "Flex".

It says flew...I do not know where you got that quote from ....I know it says I edited it but it wasn't me

Nah, I fixed it.

I think Bruce got a girlfriend that teaches english. He's been running around correcting spelling mistakes for everyone.

Nah, my mother just wouldn't tolerate that type of thing when I grew up. Must be why I was runner-up in high school spelling bee. The winner was a girl, of course, but I barely knew her.

I try not to be too picky but sometimes it changes the entire message, so I critique for clarity.

No problem Bruse. I was just bustin' on ya

In that case, I'm sure you meant "a lot"

Sorry, couldn't resist

I was being nice as I figured everyone would understand that error.

My foot is tasting pretty bad right now [:'(]

We did take it easy on you yesterday and it WAS your day.

Actually, there is a difference between the props. A propeller designed for 4 cycle engines may have broader blades and a different design to make use of the greater torque available. Electric props are a more obvious example. Sure, they can be put on a 2 cycle, but it's not as efficient. Just like a 2c prop isn't as efficient on a 4c engine. Just because the load is the same, it doesn't mean it's delivering the same thrust. Heck, you can get different amounts of thrust from brand to brand with the same loading.

The main reason you don't use electric props on glow engines is because they are not designed for the rpm and torque that a glow engine can put out, you risk injury from prop failure. Using glow engine props on a electric is safe but the overdesigned prop adds ounces of needless weight to the plane. The ultra high powered electric systems that rival glow power and rpm should use glow engine props for the same reason glow engines need them.
Today, 4-stroke engines are spinning 10,000+ rpm and higher in some cases. The power gap has really closed up so I don't think they need special props. Those 4-stroke Rev Ups may be relics of the days when 4-stroke engines had open rocker arms and only revved 8,000 rpm.