good 12 inch prop recommendation?

So I've extended the arms on my F550 and got some Avroto motors. I started using 11x4.7 Slow Fly props and I really like them, way better then the 10x4.5's I had before. But I can't seem to find any 12x4.7 slow fly's.. Any recommendations on a good prop to use that is reasonably priced?
 

flitelab

Member
I have some wooden Gemfans coming in today in 10, 11, 12" that I plan to try on a hex build and possibly on the F550 frame. They supposedly are a nice mix between the stiffness of the full CF props but at a lower price.
 

jforkner

Member
You might consider the APC 12x6E props. I use them on my hexa with 2814-11S Avrotos.

Jack
 
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What is the main difference between 12x4.7SF, and 12x6E? Sorry I'm a complete noob when it comes to props, so far I've just ordered what I see others using, but I don't know why. What makes a prop preform good on a hexa?
 

jforkner

Member
Very simply, SF stands for "Slow Flight;" E stands for "Electric." The electric props from APC are designed for higher maximum RPM, SF props are designed with a maximum RPM of 65,000/prop diameter in inches (e.g., for a 12" SF prop, the max. RPM should not exceed 5417). A 12" E prop, on the other hand, is designed with a 12,083 RPM limit. Good info on prop design and use can be found at: http://www.apcprop.com In addition, props are usually designated in a format of "diameter" x "pitch". So a 12x4.7SF prop is a 12" diameter by 4.7" pitch Slow Flight prop.

What makes a prop perform well is due to many factors including size, which affects it's ability lift (in the case of MCs). But quality of manufacture is one of the most important.

I would recommend you invest some time learning about all aspects of multicopters before you jump in. Simply buying what someone else did may get you in trouble, especially if they made a poor choice. You need to understand why that choice was made and decide if that reason applies to you, Read the various threads on the many MC forums---there's a wealth of knowledge and information contained in many of them.


Jack
 

Thanks for the informative post! Well then that means my 11x4.7SF props are over their limit! I got the 11x4.7 ones off montorc. 770kv@14v = 10780 RPM's.. Almost twice the limit! How are so many people successfully using SF props on their hexas then? Now I want to replace my Slow Fly props as well.. I found some 11x5.5E and the 11x7E props on the APC website, allong with the 12x6's I will try. What do you think 11x7e or 11x5.5e?
 
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jforkner

Member
First, let me categorically state I'm no prop expert. My knowledge comes from experience (R/C planes & MCs) and some research.

Second, you should plug the appropriate information into eCalc (http://www.ecalc.ch/xcoptercalc_e.htm?ecalc) as a guide.

Third, your calculation is "the maximum" condition. Unlikely you'll be flying at full throttle.

Fourth, a lot of this information is "recommended" and should be used as a guide; not necessarily as hard & fast rules.

Fifth, make sure there's a corresponding "pusher" prop for the tractor prop you want to use. Many of the APC props do not have a matching (dia., pitch, & style) pusher prop.

Finally. I flew my hexa for a while on 3S batteries and APC 12x3.8SF props. It flew fine until I put more payload (i.e., heavier camera) on it, so I moved up to 12x6E props. That helped, but I needed more, so I went to 4S batteries. Now it's perfect. You may have to experiment with a fe sizes to get it right for your configuration.


Jack
 


Has anyone tried 11x7SF props? They are listed on the APC site under multirotor propellers, but I'm worried the pitch would be to much? Ecalc says it would be OK though.. I'm ordering a few different types to test.. I will definitely get the 12x6E's to test, thanks for the advice guys.

EDIT: After some research I decided the 11x7SF would not be a good idea. I ordered 11x5.5E and 12x6E props from the APC site. I'll compare them to the 11x4.7's I have now and let you guys know what I think. Thanks again for the advice!
 
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