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jkr
12-01-2011, 08:09 AM
Hello.
How much power i need to spin a x646?

Fluid
12-01-2011, 08:25 AM
There is no way to answer your question without more information. What size and exact type of hull? What type of running - oval racing, SAW, sport? What speeds are you looking for? This prop can be used on 4S, 6S, 8S and 10S applications.



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jkr
12-01-2011, 08:30 AM
Ok.
40'' mono 12s sport running.

Make-a-Wake
12-01-2011, 08:35 AM
12s for "sport running"..........?........wow, if that's correct you need a kv of 800 or less for sure.........

kendt
12-01-2011, 08:35 AM
Wow 12s sport ...lol thats heafty. I have a 32 in mono on 6s. I have used a 646 with both turnigy 4074 and leopard 4082. Both were able to handle it quite well. Mine was modded a bit so it makes some difference. I thin the blades out on my props as much as possible.

jkr
12-01-2011, 08:46 AM
I am considering for the:
http://www.hobbyking.com/hobbyking/store/__19111__Turnigy_SK3_Fandrive_3994_850kv_120mm_EDF _.html

siberianhusky
12-01-2011, 08:46 AM
Is that the prop I borrowed for a couple runs Ken? If so it was being run on a LSH with a Geico motor and Swordfish 120, temps were fine on everything. Water was almost ice cold though, really!
LOL same prop run in a variety of different setups.

kendt
12-01-2011, 08:49 AM
That motor should have tones of power. You could likely get two water jackets on that sucker...lol. I was looking at the other version of that one for my 6s rigger.

Make-a-Wake
12-01-2011, 08:54 AM
I have caught myself eyeing that motor several times...................it's the size of a Neu 1524 and should pack a pretty good punch. I bet a Neu 1527 jacket would fit it......................should turn that 646 with no problem.

jkr
12-01-2011, 09:06 AM
I have a leo 4068 water jacket.
I will run with frsky telemetry for temps and gps so ineed a litle space for the sensor.

Fluid
12-01-2011, 02:00 PM
An x648 is 'way too small for any 40" mono. It will not efficiently transfer the motor's power to the water. You will need a minimum 55mm diameter prop for that hull with 12S power.

An 40mm 850 Kv motor on 12S is not a good idea. Amp draw will be high even with that tiny prop, and power delivery will be low. For 12S a Leo 5692 or Castle 2028 are far more appropriate.


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Make-a-Wake
12-01-2011, 02:24 PM
The 39" mono in my signature hit 55 with only an x447 and 59 with an x450.

jkr
12-01-2011, 03:00 PM
So it would be better to choose a leo 4082 1600kv 6s 2p?

kendt
12-01-2011, 03:41 PM
I have that in my mono and it is very fast. It depends on how fast you want to be. 40 is a good size boat. If you want to really rock it I could sell you my 1717. It would be perfect for that boat on 6s.The problem with 12s is you need a very expensive esc to handle the voltage where as lots of good ones around for 6s that arent as scary price wise.

jkr
12-01-2011, 04:32 PM
I have a cc240hv for 12s a t180 for 6s and a cc1717.
I don't want to use the cc1717.
I want to keep the weight to the bottom of the hull for self righting.

6BOOST
12-01-2011, 05:52 PM
An 40mm 850 Kv motor on 12S is not a good idea. Amp draw will be high even with that tiny prop, and power delivery will be low. For 12S a Leo 5692 or Castle 2028 are far more appropriate.


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I'm sure you know your stuff far more than I do Fluid, but care to explain the factors that go into supporting your above statement? People run 1527 1y's on 10s which is a 40mm motor and 1250kv, and the 1.5y is 850kv, I own both but haven't tested yet. I also have this 3994 edf motor in my genesis and will be running it tomorrow for the first time, I'm just trying to understand how the diameter of the motor effects it's power usage and heat production for a given power output compared to a larger diameter similar kv motor?

6BOOST

6BOOST
12-01-2011, 05:57 PM
And considering a 4082 will run a x645 no probs, I would say that 3994 with 1kw more rated power is gonna drive a much more substantial prop. For speed maybe a detounged x452 or x455, and for acceleration an x447/3, 450/3 or 452/3 might work nicely, you'll just have to do some testing. I'll be running mine on an x447 tomorrow as a starting point and have a 645, and everything right up to 60mm to try, but I'm only doing 2 pass saw runs.

6BOOST

jkr
12-01-2011, 07:04 PM
Ok.At this point i can say that i'm burning some of my brain cells!
Kyle i would like to know your results from the 3994.

6BOOST
12-01-2011, 07:42 PM
I bet a Neu 1527 jacket would fit it......................should turn that 646 with no problem.

I tried the 1527 jacket on there and it's just a little too loose, you may very well get it with some thicker O rings but I didn't have any on hand so I just thru a 1515 jacket on it, while its a little short, the 1515 is 39mm so fits perfect and will do for saw runs.

6BOOST

nata2run
01-15-2012, 08:55 PM
Any results from the 3994? in the Genesis? That should really RIP! I ordered the 3994 for my osprey Should land today (had 4080 Leo 1600kv on 6s2p 5000mah) doing just over 53mph or 86 km/h 444 prop

I would like to spin a 447 or 450 on 8 to 12s and maybe get in the high 90's maybe even 100km/h

this is just a "for fun' project while waiting for parts for my MHZ Mystic

6BOOST
01-15-2012, 09:30 PM
It drove the 447 like it was a 37mm prop, the motor after 2 minutes of running was only 90deg! I tried a 450/3 with no probs as well. We ended up with 68mph, but my lake is tiny, it was only full throttle for 1-2sec tops. Torque is insane, Took some throttle control to keep it on the water. I will have more results this weekend from the same motor and 450/3 in my DF33 copy, I just finished building it sunday.

6BOOST

nata2run
01-15-2012, 11:41 PM
LOVE IT 68mph is quick enough.....

Chrisg81983
02-12-2012, 08:10 PM
6 boost any more news with the 3994Thanks chris g