Predator Rigger 2S setup?

[j.m.]

Hey guys,

Looking to get a new brushless setup for my pred outrigger now that I have some lipos from my cars. (2s packs)

So, should I go with a 540 7S, 6S, or 6L? I'm looking for a good reliable sport setup, with speeds near 40.

On a 120A esc? I hope I won't be drawing that much current, my batteries are 25c 4Ah.

I'd be running 1/8" props...

Jon

[Fluid]

Our club runs an N-2 sport hydro class, all the boats run the same setup - 2S1P, a Feigao 7L and an x440 prop. Speeds are mid/upper 40s. 70-amp ESCs are borderline, a 100-120 would be safer.




.

[Ub Hauled]

I am with Jay,
I run my sport setup with a 120 ESC, 8L Feigao, 2s1p with a 440... great fun setup...
I used that motor on 4s on a DH Shovel a few times but just for a couple of fast passes... fun as well.

[j.m.]

I'll take it from your experience that these setups will work, but I did try a 7L on 6 GP3300's with a graupner 40mm prop, and the speeds were less than exciting; around 25mph. Though those cells weren't very well kept and my CG was too far back.

I was told that the 3500Kv motor wasn't much of a 6cell setup, and I should go higher in the Kv department.

I do think the boat will get up out of the water much better with the lipos though. I already moved the strut back 1.5" so the prop should have more leverage to lift the rear up.

Im looking more for an efficient setup that won't tax my batteries much and give me a little bit of runtime. High 30's to 40mph might be more reasonable. FECalc was giving me ridiculous numbers for a 440 and a 7L, something around 90 amps ?? That's why I was thinking to go with the higher RPM, less prop setup.

Jon

[Rex R]

fix the cg issue first or you'll continue to have problems associated with running the prop too deep(high amp draw for example).

[j.m.]

Another reason I thought a smaller can might be better...

Or I could just make a new hull. I didn't construct the pred too great, and the design is lacking in a few places...

[Rex R]

one of my friends has a similar size rigger (from climate) and was getting good results with an 8s (on 6 NiMH's) for sport running, he would change out the motor to a 7s for racing.

[Ub Hauled]

Im looking more for an efficient setup that won't tax my batteries much and give me a little bit of runtime. High 30's to 40mph might be more reasonable. FECalc was giving me ridiculous numbers for a 440 and a 7L, something around 90 amps ?? That's why I was thinking to go with the higher RPM, less prop setup.

Jon

if you want a little less amp draw use a 438 prop... I have used a 440 and a 442 with the 8L, the 442 was too much for it to handle with normal temps, 440 was about right, the 438 should unwind easy and give you more running time...
CG is vital for the boat, not only it'll keep her in the water but also leaving your prop w/o too much weight will help the unwinding.

[Fluid]

I'll take it from your experience that these setups will work, but I did try a 7L on 6 GP3300's with a graupner 40mm prop, and the speeds were less than exciting; around 25mph.....

GP3300s and a plastic prop are nowhere near equal to 2S/4000/25C packs and a metal x440. The performance difference is substantial. As Ray stated, you can't expect a poorly-built boat to run well regardless of how much power you try to stuff into it. Speed and runtime will be substandard. I would not recommed a small can motor for mosst uses, the weight penalty is small but the torque and heat handling advantages are substantial. Adding weight is not a bad thing to get the CG closer to where it needs to be, but rebuilding/reconfiguring the boat is probably the best solution.


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[Simon.O.]

You can use an S size can if you happen to have one, I have a few and still run them very hard.
If / when I need new cans I will deffo go with a L size but make sure my kv stays up there too. As a few here know I am an rpm nut !
As usual make sure you have at least 25% extra capacity in your esc and all is good.

fwiw my predator based small rigger with a 7S on 2S to a 632 runs about high 40's low 50's. On 3S to a 432 it has cleared 60

If you are buying new motors then use a L size.