Mysteries of prop pitch

[BHChieftain]

I've heard that you can't always determine the best prop by just the total pitch-- I've been running a Toysport Syncron for about 2 years, and figured out that props with too large of a diameter can cause chine walking-- I had been running a 1500KV motor on 4S1P with a 648 prop-- everything ran nice and cool, but the prop diameter was too much and affected the handling. I changed the motor to a 2200KV, and dropped the prop diameter to a 637, which I thought was the perfect prop--no chine walking and ran nice and stable. Well, the prop eventually got dinged up and I had to use a backup prop-- pulled out a 440 which has less total pitch than the 637, and lo and behold, the boat picked up about 5mph... go figure...

I did notice that with the 637 prop my connectors and packs were getting hot, and with the 440 it ran cooler (and faster...)-- I'm figuring that the 440 prop with less pitch let the motor reach full RPM potential.

Lesson learned...

Chief

[monojeff]

Not sure what boat or motor you have but try out a 442

Or the 1500 try out a 447 or a 445

[BHChieftain]

I've been using neu 1515 motors-- sold the 1500kv-- it ran stone cold but like I said, the only way to pick up speed was with really large diameter props which caused handling issues. Currently running a neu 1515 2200KV motor. I'll try a 442 next time and see if it still runs cool. The 440 prop makes me work hard to keep the boat upright as it is (luckily, it has a flood chamber...).

The boat is a toysport syncron (in my avatar picture).

Here's a video of my boat (on 4S1P) vs. a Ms. Geico (on 5S1P) on the 637 prop. I don't have a video of the boat on 440, but it was about 5mph faster (no gps-- eyeballing it). We are running low 50's in this video, and I eke out a victory at the end...

http://www.youtube.com/watch?v=-0HhRhUGaVQ

Cheers,
Chief