Which would cause more amps?

[martin]

Even though the x642 has more pitch you will possibly see higher speeds with more efficiency from the larger diameter x445.

[TheShaughnessy]

Not sure if its relevant but in my p ltd geico I was seeing very similar amp draw from both props. 1800 kv AQ motor on 4 s so less rpm and less motor so take that for what its worth. I keep hearing amp draw is more sensitive with higher rpm set ups but I think you will be fine with the 445.

What are ambient temps like where you are right now?

[Heaving Earth]

Well it's new England so pick a day.... But mainly high 70's to low 80's with sun. I'm gonna go for it

[785boats]

Back cutting the M445 about 1/16" at the hub will give you a bit more speed & draw less amps than a stock one.

I did it between heats last weekend & went from 3rd in one heat to 1st in the next two, with a DNF in between. The boat flipped into a strong headwind & heavy chop.
The pack went from 12% remaining, after the first heat, to 18% in the next heats. The boat was visibly faster.

We were running on a longer track at a different club & I wasn't sure what prop to use without killing the packs. So I went with the prop I normally run & after the first race & only 12% left in the pack, I decided to back cut it instead of going to a smaller prop & losing speed.

I'd done a similar thing with a 447/3 at last years Nationals for the same reasons & it worked then too.

I also did it to an M447 today at the lake & picked up a bit of speed.

[Heaving Earth]

Well I got out with the m445 tonight. I forgot my gps however, but what I felt was the 445 generated a bit more heat on my stuff, the speed was comparable, and the boat was more aired out, possibly too much. I'll report back with some useful info like gps and temp readings soon.

[Mulisha]

I think I will give it a shot then...
Anyone think more diameter will give more speed?

More pitch is more speed, has alot of info in it
http://forums.offshoreelectrics.com/...chmentid=86564

[srislash]

Ok,this is just being thrown out there and most likely a completely different hull than you are using Heaving Earth but....
on my 35"DF with a 1717 and 4s2p

the X642 peaked at 83 amps,
the M445 at 93,
my accidentally modded M645 at 89 amps,
stock 646 120(also the biggest jump in speed),
and a X448 at 124 amps.

All props were sharpened and balanced and run on the same packs for pretty much one lap a piece.

[Heaving Earth]

Well Shawn it does give me a better idea. Helps me ballpark where I'm at anyways

[srislash]

It gave me a goal for the day. I'd like to do the comparison in a more real world application one day.

I might add that I just raised my stinger up 3/8" off the ride pad too. Drastically reduced my amps I see.

[gsbuickman]

Heya H.E, heya Slash' :-) . Did you figure out which prop has the best bang for the buck, on your mean machine H.E ?. My mean machine got a rebuild recently. Currently its running a 2030kv ul-1 motor, on a 60a esc. The motor is a 50a motor. I am running 2 rev-tec 6000mah 28c bullet pack lipos in series.....

[Heaving Earth]

I did run the m445, and it's was no problem for MY system as far as overheating or anything, but it was a bit much for my motor battery configuration. If I were using only 4s on 2200kv it would be perfect, but on 5s I like the 642

[gsbuickman]

Kool, thanks :-)