proper propping

[Rumdog]

I like the x452 on my sprintcat. Temps are good without being to hot. I do not want to go any bigger in diameter. That being said, is there a 50-52mm prop with more pitch. Does octura make a x650 or x652? Steven doesn't carry them. Also, if anyone knows, in a cat are there any advantages to trying a 3 blade prop? I'm pretty sure I would need to go down in the diameter if tring one, but I'm not sure if it's worth a shot. Going from a x452 down to a x648 i lost 9mph!! I didn't expect that much! Setup is 1527 1.5d 5sp2 34" Aeromarine Sprintcat. Running the strut 1/2" above the sponsons and no angle. I do not know how to cup props, so that is out of the question for me unless someone would wanna do it for me. I don't even know how much, if any advantage it would give me.

[FE Wannabe]

Egneg (Chuck) here on the OSE forums is a prop magician. If you explain what you are looking for he should be able to modify your x452 to meet your requirements.

[MarkF]

Rum dog, motors can be funny and you have to give them what they want and not what you want. You lost mph because your motor couldn't turn a smaller prop with more pitch. It may want a 455 to go faster. You may have to change your strut height to settle the boat some but I would try that route.

Mark

[Rumdog]

No, I lost speed because the diameter of the prop wasn't large enough to ffficiently push my boat. I'm afraid the 455 will get the amp spikes pretty high!

[MarkF]

I dont agree with that statement Rumdog. But hey what do I know.

Mark

[Rumdog]

Do you think a 1527 cannot spin a 48mm prop?

[tth]

Ryan, Mark is talking about loading the motor properly to get the maximum benifit.

[Rumdog]

Ahh, gotcha. Makes sense now.

[MarkF]

My 1527 1D spins a 645 on 6s in my mono at the saws no problem. Your motor should be able to spin it easier than mine. The problem is your not giving the motor what it wants to be happy for sport running. Or your batteries are not up to the task could be the problem as well. I still recomend you try the 455.

mark

[tharmer]

This brings me back to a related question. Is there a torque curve for an electric motor? How do you know how to prop a setup if you don't know where the motor likes to run?
-t

[MarkF]

Yes there is a torque curve which has been a black magic to me in over 15 years of running boats. I have over 50 props in my propbox. The only way I know how is to try different props. The other way would be to ask people who have run that motor what they found to work well. There is no one right answer to your ?

Mark

[tharmer]

So no one's every dyno'd one of these guize. Hmmmmm.
-t

[Jeepers]

I would think that 1527 should be able to handle more than a 452, guys were turning 52mm props at Nationals on 1521 1.5d.

[Rumdog]

WOW! I'm gonna go with the 455 to start!

[m4a1usr]

This brings me back to a related question. Is there a torque curve for an electric motor? How do you know how to prop a setup if you don't know where the motor likes to run?
-t

Use of a data logger to know voltage/amperage when using certain props. Thats assuming the setup is at the least close. Like no major strut changes, rudder is close, COB is approx and you know how to drive. I see more videos on youtube of RC boaters who think partial throttle is the norm with high speed runs the excitement. I guess the benefit of that is they keep inventory stocked!


John