Can't find hardly any counter-rotating 3-blades for twin... 2-blades better?

[srislash]

I have logged on my Twin Shocker(TP 4050 1850kv and 6s) where a two blade prop drew 80 amps an identical 3 blade was 120 amps. I think they were CNC props BTW. And I had no failures with them(CNC) props even at 7s on this setup.

[lt130th]

I have logged on my Twin Shocker(TP 4050 1850kv and 6s) where a two blade prop drew 80 amps an identical 3 blade was 120 amps. I think they were CNC props BTW. And I had no failures with them(CNC) props even at 7s on this setup.

I suppose 40 amps can't be negated, but 120 amps seems well within safe operating range for the SF 220A (no risk of overheating the electronics). Do you agree? What did you notice most about how the boat performed between the 2-blade and 3-blade prop's? Was there even a noticeable difference in get-up-and-go or handling?

[srislash]

I did not notice any increase in speed with 3 blades. I did notice more 'bite' on acceleration and it is a smoother sound. Should be better on bushings/bearings due to more even radial load. I do notice a shorter runtime due to that extra amp draw which BTW is certainly within Swordy limits.

[lt130th]

I did not notice any increase in speed with 3 blades. I did notice more 'bite' on acceleration and it is a smoother sound. Should be better on bushings/bearings due to more even radial load. I do notice a shorter runtime due to that extra amp draw which BTW is certainly within Swordy limits.

THANK YOU! These are the questions I've been needing answers to. I just signed up over at KBB forums. Been looking through the build threads. I think my Shocker will ship within the next couple weeks. I'll have a ton more questions once it gets here.

[785boats]

When going from a 2 blade to a three blade we usually drop down in diameter a bit. This lets the motor spin at a higher rev range & reduces the amp draw. This can give a higher speed. It certainly, in myopinion makes for a more stable boat in the turns, & the extra torque of a 3 blade overcomes the extra drag of hull & rudder in the turns keeping the speed up a bit higher.

[Meniscus]

The other thing to be careful about when running higher RPMs and switching to a 3 blade is the lift. You may be OK with the 2 blade and a little extra slip, but any extra lift in the 3 blade prop and less slippage could translate to upsetting your ride attitude. We see this more with riggers, but it is important to mention. Also remember that all props are inherently different, even those that are supposedly the same and even those that make the same impressions when profiled.

If you find one prop of the same size, pitch, manufacturer, etc. works better than another and you can't figure out why, try using a magic marker on the blades. You'll quickly realize that there are slight differences where each prop is loading.

[M3Man03]

For a ton of 3 blade (and 2 blade) L & R CNC props, I recommend this site:

http://shop.rcboatbitz.com.au/index.php?main_page=index&cPath=48_68

Ordered from them and was happy!

[Meniscus]

Just be careful that you get the correct hub size. Most use the 3/16" sizes that are available here on OSE.